The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-...The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture(CPF) with different joint roughness coefficients(JRCs). Based on 3D morphology scanner tests and hydraulic coupling tests, a characterization method of effective geometric parameters in fracture surfaces under various confining pressures was improved, and a relationship between effective geometric parameters and the confining pressure is established. The results indicate that the nonlinear flow behavior in a CPF primarily includes three types: non-Newtonian fluid seepage under high confining pressure and low JRC, non-Darcy seepage under low confining pressure and high JRC, and the whole process of seepage characteristics between these two conditions. Among them, nonNewtonian fluid seepage is caused by significant fracture expansion, while non-Darcy seepage can be attributed to turbulence effects. During the seepage process, the geometric parameters with different JRC fracture samples all exhibit exponential changes with the increase of confining pressure. In addition,under high confining pressure, the effective contact ratio, effective fracture aperture, and void deviation ratio with high JRC fracture samples under high confining pressure increase by 93.5%, 67.4%, and 24.9%,respectively, compared with those of low JRC fracture samples. According to the variation of geometric parameters in a CPF with external stress, a seepage model considering geometric parameters in a CPF is proposed. By introducing the root mean square error(RMSE) and coefficient of determination(R2) to evaluate the error and goodness of fit between model curves and experimental data, it is found that the theoretical curves of model in this paper have the best matching with the experimental data. The average values of RMSE and R2for model in this paper are 0.002 and 0.70, respectively, which are better than models in the existing literature.展开更多
Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions an...Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions and exospheric neutrals serve as an important diagnostic for ion-neutral interactions and upper atmospheric loss.This study presents direct observations of hydrogen ENAs(H-ENAs)on the dayside of Mars by using the Mars Ion and Neutral Particle Analyzer(MINPA)onboard China’s Tianwen-1 orbiter.By analyzing H-ENA data during a coronal mass ejection and a stream interaction region from December 29,2021,to January 1,2022,and comparing these data with MAVEN/SWIA(Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer)solar wind measurements,we examine the temporal evolution of H-ENA flux and the associated sputtered escape of atmospheric constituents.The observed H-ENA velocity is consistent with upstream solar wind ions,and the H-ENA-to-ion intensity ratio is used to infer variations in exospheric density,revealing a delayed response to enhanced solar wind activity.Penetrating H-ENA intensities reach up to 5.3×10^(6)s^(−1) cm^(−2),with energy fluxes on the order of(0.5-8.1)×10^(−3) mW/m^(2).The estimated oxygen sputtered escape rate driven by penetrating H-ENAs ranges from 5.5×10^(23)s^(−1) to 5.2×10^(24)s^(−1),comparable to or exceeding previous estimates based on penetrating ions.The findings highlight the need for low-altitude H-ENA observations to better quantify their atmospheric interactions and refine our understanding of nonthermal escape processes at Mars.展开更多
Based on in-situ observations in the East China Sea(ECS)during October 2021,we investigated a cross-shelf penetrating front(PF)in the inner shelf and explored its potential biogeochemical-ecological effects from a mul...Based on in-situ observations in the East China Sea(ECS)during October 2021,we investigated a cross-shelf penetrating front(PF)in the inner shelf and explored its potential biogeochemical-ecological effects from a multidisciplinary perspective.The results show that a pronounced tongue-shaped PF was present at the southeast of the Hangzhou Bay,with salinity of 29−32 and a seaward horizontal penetration scale of~200 km.It mainly occurred in the upper layers,and a spatial separation existed between this PF and the bottom salinity front in the northern coastal region off Zhejiang.In contrast,the salinity fronts at surface and bottom were well matched in the southern coastal area.Compared to the surface-to-bottom consistent coastal front in the southern region off Zhejiang,a stronger thermocline and halocline were sustained in the northern PF-dominated region,and suitable conditions could be achieved for phytoplankton growth and accumulation.The in-situ observed high-chlorophyll a(Chl a)zone in a seaward tongue shape was further an important indicator or signal for PF occurrence,and it was responsible for the decoupling of nutrient distributions and PF.The southern coastal front off Zhejiang might largely restrict the seaward transport of nutrients,and the dynamic environment under weak stratification in this region was disadvantageous for the growth of phytoplankton;thus the Chl a content was maintained at a relatively low level near the southern coastal region.Our results demonstrate that the PF combined with the coastal front may play an important role in shaping/regulating hydrodynamics,nutrient distributions and the Chl a regime over the inner ECS shelf.展开更多
The failures of culverts can result in water and soil loss in the surrounding subsurface,leading to collapses.In densely constructed urban areas,buried culverts are inaccessible and invisible,making Ground Penetrating...The failures of culverts can result in water and soil loss in the surrounding subsurface,leading to collapses.In densely constructed urban areas,buried culverts are inaccessible and invisible,making Ground Penetrating Radar(GPR)inspection a widely adopted nondestructive and efficient method.Previous research has employed artificial intelligence to automate GPR interpretation by identifying special radargram textures,but the irregular GPR responses of degraded subsurface soils present a challenge.Therefore,this study proposes a method for preliminary diagnosing large-scale culverts based on GPR wave attributes.The method comprises three parts:(1)evaluating soil compactness by estimating the tortuosity of GPR responses at the culvert top;(2)investigating soil moisture using the attenuation rate of GPR responses;and(3)overlaying the results of the incompact and moist soils to pinpoint potential degradations.Two long-distance culverts were inspected and diagnosed using the proposed method,and three abnormal sections were identified and confirmed by excavation evaluation.The case studies indicate that the proposed method can quickly provide reference for further in-depth investigation,thereby improving GPR survey efficiency and reducing workload by narrowing the investigation scope.Consequently,this study can facilitate large-scale GPR culvert surveys and further safeguard the water system.展开更多
Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The a...Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly,which is the so-called security constraints.In addition,the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories,which is the so-called performance constraints.To this end,an attitude control method that meets the needs of PCA has been devised,based on constraint definition,coupled constraints handling,and control law design.Firstly,mathematical descriptions of the security constraints,performance constraints,and control constraints are given.Secondly,two treatment methods,coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem.Finally,based on Nonlinear Dynamic Inverse(NDI)design,the coupled funnel controller is designed and validated by simulation for two typical mission scenarios,high-altitude penetration and low-altitude surprise defence.The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.展开更多
AIM:To assess the utility and efficiency of endoscopyassisted vitrectomy(EAV)for the treatment of corneal opacity in severe ocular trauma.METHODS:Patients who underwent fundus examination using a preoperative slit lam...AIM:To assess the utility and efficiency of endoscopyassisted vitrectomy(EAV)for the treatment of corneal opacity in severe ocular trauma.METHODS:Patients who underwent fundus examination using a preoperative slit lamp and intraoperative endoscopy,followed by EAV and additional surgery were retrospectively recruited.Silicone oil removal and penetrating keratoplasty were used in selected eyes at postoperative follow-ups.Outcome measurements included the best corrected visual acuity(BCVA),intraocular pressure(IOP),findings of endoscopic fundus examination,and postoperative complications.RESULTS:Twenty-one eyes with severe ocular trauma and corneal opacity were followed up for 24-36mo.Retinal detachment(RD)and vitreous haemorrhage(VH)were identified in 16 eyes(76.2%),RD only in four eyes(19.0%),and VH combined with intraocular foreign body in one eye(4.8%).All eyes underwent at least three surgeries.Stage-Ⅰ surgeries involved wound closure(100%),lens extraction(76.2%),and anterior vitrectomy(14.3%).Stage-Ⅱ surgeries involved scleral buckling(28.6%),membrane peeling(47.6%),retinal laser photocoagulation(100%)and silicone oil tamponade(100%)using EAV.Stage-Ⅲ surgeries were conducted using endoscopy including silicone oil removal(52.4%),retinal laser photocoagulation(52.4%)and penetrating keratoplasty(28.6%).Nearly all eyes showed improvements in BCVA and IOP.Although there were no severe complications,glaucoma was noted in one eye,chronic hypotony in another eye,and band keratopathy in three eyes.CONCLUSION:EAV is an effective adjunct for restoring ocular anatomical structures and visual function in the case of corneal opacity after severe ocular trauma.展开更多
AIM:To describe the surgical procedure of fusiform penetrating keratoplasty(FPK)using multiple trephines of different sizes for treating patients with severe infectious keratitis.METHODS:Fourteen eyes underwent FPK,an...AIM:To describe the surgical procedure of fusiform penetrating keratoplasty(FPK)using multiple trephines of different sizes for treating patients with severe infectious keratitis.METHODS:Fourteen eyes underwent FPK,and 15 eyes received conventional penetrating keratoplasty(PK)were included in the study.The best-corrected visual acuity(BCVA),refractive outcomes,endothelial cell density,and postoperative complications were recorded.RESULTS:The FPK group was followed for an average of 15.3±2.1mo,whereas the PK group was followed for 16.1±1.9mo.The corneal ulcers were elliptical-shaped in all 14 eyes in the FPK group.The mean BCVA(logMAR,0.26±0.13)showed no statistically significant differences from that in the PK group(logMAR,0.21±0.12,P>0.05)at 1y after surgery.But the mean curvature,mean astigmatism,and mean spherical equivalent in the FPK group were lower than those in the PK group(P<0.05).Peripheral anterior synechia was observed in one patient in the FPK group,whereas 6 patients in the PK group.Suture loosening and neovascularization were observed in 4 and 5 eyes in the PK group,respectively.No graft immune rejection or elevation of intraocular pressure was observed in the two groups.CONCLUSION:For patients with elliptical-shaped corneas or corneal ulcers,FPK can avoid disrupting of corneal limbus,reduce the risk of postoperative complications,and can result in satisfactory visual quality.展开更多
AIM:To investigate tomographic features of late corneal ectasia after keratoplasty for keratoconus and compare penetrating keratoplasty(PK)and deep anterior lamellar keratoplasty(DALK)in terms of incidence,time of ons...AIM:To investigate tomographic features of late corneal ectasia after keratoplasty for keratoconus and compare penetrating keratoplasty(PK)and deep anterior lamellar keratoplasty(DALK)in terms of incidence,time of onset and risk factors of corneal ectasia.METHODS:Sixty eyes with PK and 30 eyes with DALK operated between 1999 and 2021 were analyzed.Final Pentacam scans were evaluated together with vision and previous topographies.Main outcome measures were vision,K values,apparent thinning on graft-host cornea and the difference between opposing quadrants in the thinnest point measurements.Anterior segment optic coherence tomography was performed for further evaluation.RESULTS:Mean follow-up was 127.2mo(24–282mo)in PK,and 64.3mo(24–144mo)in DALK.K max was higher in DALK(60.6 vs 56.7 D,P=0.012).Inferior recipient was thinner(595.9μm)in PK than DALK(662.2μm,P=0.021),due to longer follow-up.Overall corneal ectasia rate was 20.0% within 24y.Ectasia rate was the same(6.7%)in DALK 2/30 and in PK 4/60 in 10y and 13.3%in 12y(4/30 and 8/60,respectively).It increased to 23.3%(14/60)in PK over 24y.While ectasia was not seen before 7y in PK,it could be seen in DALK starting from the 5^(th) year.The intervals between keratoplasty and ectasia were 144.5mo in PK and 99mo in DALK.Inferior recipient was significantly thinner in 18 eyes with ectasia(502.7μm)compared to 76 non-ectasia(649.1μm,P=0.000).Inferior graft was thinner(561.0 vs 620.4μm,P=0.006),K max(63.3 vs 56.5 D,P=0.000),and anterior elevation was higher in ectasia(89.1 vs 48.6μm,P=0.002).Accelerated crosslinking was performed on 5 eyes.CONCLUSION:Inferior-superior recipient and inferior graft thinning on tomography,with high K max and anterior elevation emerge as the most reliable criteria for the diagnosis of late ectasia.The incidence of corneal ectasia increases with the time.展开更多
The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurfac...The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurface structures within a depth of approximately 50 m.However,it was still difficult to identify finer layers from the cluttered reflections and scattering waves.We applied deconvolution to improve the vertical resolution of the radar profile by extending the limited bandwidth associated with the emissive radar pulse.To overcome the challenges arising from the mixed-phase wavelets and the problematic amplification of noise,we performed predictive deconvolution to remove the minimum-phase components from the Chang’E-4 dataset,followed by a comprehensive phase rotation to rectify phase anomalies in the radar image.Subsequently,we implemented irreversible migration filtering to mitigate the noise and diminutive clutter echoes amplified by deconvolution.The processed data showed evident enhancement of the vertical resolution with a widened bandwidth in the frequency domain and better signal clarity in the time domain,providing us with more undisputed details of subsurface structures near the Chang’E-4 landing site.展开更多
BACKGROUND We report a case of eye-penetrating injury in which a massive silicone oil migration into the patient’s subconjunctival space and orbit occurred after vitrectomy.CASE SUMMARY A 30-year-old male patient sou...BACKGROUND We report a case of eye-penetrating injury in which a massive silicone oil migration into the patient’s subconjunctival space and orbit occurred after vitrectomy.CASE SUMMARY A 30-year-old male patient sought medical attention at Ganzhou People’s Hospital after experiencing pain and vision loss in his left eye due to a nail wound on December 9,2023.Diagnosis of penetrating injury caused by magnetic foreign body retention in the left eye and hospitalization for treatment.On December 9,2023,pars plana vitrectomy was performed on the left eye for intraocular foreign body removal,abnormal crystal extraction,retinal photocoagulation.Owing to the discovery of retinal detachment at the posterior pole during surgery,silicone oil was injected to fill the vitreous body,following which upper conjunctival bubble-like swelling was observed.Postoperative orbital computed tomography(CT)review indicated migration of silicone oil to the subconjunctival space and orbit through a self-permeable outlet.On December 18,2023,the patient sought treatment at the First Affiliated Hospital of Nanchang University,China.The patient presented with a pronounced foreign body sensation following left eye surgery.On December 20,2023,the foreign body was removed from the left eye frame and an intraocular examination was conducted.The posterior scleral tear had closed,leading to termination of the surgical procedure following supplementary laser treatment around the tear.The patient reported a significant reduction in ocular surface symptoms just one day after surgery.Furthermore,a notable decrease in the migration of silicone oil was observed in orbital CT scans.CONCLUSION The timing of silicone oil injection for an eye-penetrating injury should be carefully evaluated to avoid the possibility of silicone oil migration.展开更多
BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetr...BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck,without signs of neurological deficit.Computed tomography(CT)demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level,causing C6 and C7 vertebral body fracture,C6 left lamina fracture,left facet joint fracture,and penetration of the cervical spinal cord.The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team.During the surgery,we found that the cervical vertebra,cervical spinal canal and cervical spinal cord were all severely injured.Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits.CONCLUSION Even with a serious cervical spinal canal penetrating trauma,the patient could resume normal work and life after appropriate treatment.展开更多
Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materia...Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materials and method: This was a descriptive and analytical study over a 48-month period at CHU la Renaissance from January 1, 2018 to December 31, 2021, concerning patients admitted for penetrating cranioencephalic trauma by pointed object. Results: Twelve cases, all male, of penetrating cranioencephalic sharp-force trauma were identified. The mean age was 34 ± 7 years, with extremes of 11 and 60 years. Farmers and herders accounted for 31% and 25% of cases respectively. The average admission time was 47 hours. Brawls were the circumstances of occurrence in 81.2% of cases. Knives (33%), arrows (25%) and iron bars (16.6%) were the objects used. Altered consciousness was present in 43.8% of cases, and focal deficit in 50%. Scannographic lesions were fracture and/or embarrhment (12 cases), intra-parenchymal haematomas (6 cases) and presence of object in place (4 cases). Surgery was performed in 11 patients. Postoperative outcome was favorable in 9 patients. After 12 months, 2 patients were declared unfit. Conclusion: Penetrating head injuries caused by sharp objects are common in Chad. Urgent surgery can prevent disabling after-effects.展开更多
Objective: Vascular injuries usually present immediately after the penetration, but the delayed onset of vascular symptoms caused by vessel dissection or aneurysm after a traumatic event is extremely rare. Vertebral a...Objective: Vascular injuries usually present immediately after the penetration, but the delayed onset of vascular symptoms caused by vessel dissection or aneurysm after a traumatic event is extremely rare. Vertebral artery injury is a low-frequency but high-mortality injury. We aim to report evidence of delayed onset of vascular symptoms following penetrating trauma in the neck. Materials and Methods: A case report. Results: A 19-year-old boy was referred to our hospital and complained of a mass in the right part of his neck (right mandibular angle). He gave a history of penetrating trauma to his neck 2 months ago. The mass was expanding during these 2 months and doesn’t respond to antibiotic therapy. In the examination, 3 × 3 cm, firm, nonmobile, and without tenderness and pain mass was palpated in the second level of his neck. Doctors ordered a Doppler sonography in the hospital where a yin-yang pattern was reported. A 36 × 43 × 40 mm heterogeneous, solid, and hypodense area close to C1-C2-C3 with vascular flow was discovered in the right submandibular area after computed tomography (CT)-angiography. The patient was referred to an interventional neurologist for angiography and due to the lack of flow at the distal of the V3 segment, he decided to sacrifice this artery by two coils. Conclusion: Penetrating neck injuries are usually asymptomatic, but these injuries are often accompanied by hemorrhage, neurological symptoms, dysphagia, odynophagia, and windpipe. Penetrating lesions of the vertebral artery are rare and very difficult to diagnose. Also, these lesions are challenging for surgeons due to complex anatomy and difficult surgical exposure. So, endovascular treatment was used to treat the patient.展开更多
The high-speed penetration of concrete targets by kinetic energy projectiles results in apparent mass loss,which blunts the nose of the projectile and decrease its penetration performance.The friction work between the...The high-speed penetration of concrete targets by kinetic energy projectiles results in apparent mass loss,which blunts the nose of the projectile and decrease its penetration performance.The friction work between the projectile and the concrete target,the plastic deformation of the projectile,and the cutting of aggregates to the projectile significantly affect the mass loss of the projectile.To address these effects,a discrete iterative model is developed for the mass loss and nose shape evolution of the projectile by coupling three mechanisms based on the effect of temperature on strength.In the model,both friction work and plastic work increase the temperature of the projectile's surface layer,thereby weakening the strength of this part and rendering it easier for mass loss to occur due to aggregate cutting.The model discretizes the projectile and penetration process with respect to the space and time dimensions,respectively.The mass loss and nose shape evolution of the projectile are obtained by iteratively calculating a point-by-point regression.The predicted depth of penetration(DOP),mass loss,and residual projectile profile are compared with experimental data to validate the model.The comparison shows satisfactory agreement between the calculated results and experimental data.Additionally,the deceleration,velocity,DOP,and mass loss during penetration are analyzed with respect to time.Finally,based on the model,the effects of projectile strength,caliber-radius-head(CRH),and concrete target strength on penetration are discussed.展开更多
PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure...PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 mm.The penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was obtained.It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure.Using the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were obtained.Then,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates.The results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment.The equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications.展开更多
The low drug bioavailability of eye drops challenges the therapy of ocular disorders with high efficacy.One of solutions is to extend the corneal retention and enhance the penetration of drug into cornea.Here we synth...The low drug bioavailability of eye drops challenges the therapy of ocular disorders with high efficacy.One of solutions is to extend the corneal retention and enhance the penetration of drug into cornea.Here we synthesize two fluorophore-conjugated peptide based analogs rich in positive charges(i.e.,NBDFFKK)and with a specific ligand(i.e.,NBD-FFRGD),respectively,to visualize their performances in vitro and in vivo.The peptides both can self-assemble into supramolecular hydrogels with the microstructure of nanofibers.The in vitro experiments exhibit that two peptides are both uniformly distributed in cytoplasm,and the intracellular amount of peptide rich in positive charges is significantly larger than that of peptide with a specific ligand.The living corneal fluorescence shows that two peptides enter the corneal stroma within 15 min,and the peptide rich in positive charges is accumulated more extensively throughout the entire cornea,revealing that the supramolecular hydrogel eye drops penetrate the cornea more efficiently via electrostatic interaction than that via ligand-receptor interaction.This work,as a comparative study of supramolecular hydrogel eye drops on penetrating efficiency,indicates a possible direction for the design of eye drops with efficient corneal penetration.展开更多
Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect pene...Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect penetration abilities of nanostructured lipid carriers（NLC）. Real--time penetration of folate--or cell penetrating peptide（CPP）-modified NLC was evaluated using a multicellular tumor spheroid（MTS） established by stacking culture method as an in vitro testing platform. The results suggested that CPP modification had a better penetration behavior both on penetration depth and intensity compared with folate-modified NLC at the early stage of penetration process.展开更多
Given its ability to knock down essentially any gene of interest, siRNA has been one of the promising candidates for gene therapy. However, like other nucleic-acid-based drugs, its poor cellular uptake poses a major c...Given its ability to knock down essentially any gene of interest, siRNA has been one of the promising candidates for gene therapy. However, like other nucleic-acid-based drugs, its poor cellular uptake poses a major challenge. Here we briefly summarize the use of cell penetrating peptides （CPPs） as a novel and promising approach for siRNA delivery. The main advantages of CPPs are their low toxicity and high efficiency.展开更多
Objective: To compare postoperative outcomes of full-bed deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in treating keratoconus. Methods: Seventy-five eyes of 64 patients who received fu...Objective: To compare postoperative outcomes of full-bed deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in treating keratoconus. Methods: Seventy-five eyes of 64 patients who received full-bed DALK and 52 eyes of 51 patients who received PK between June 2000 and August 2010 were included in this retrospective study. Full-bed DALK was performed using Yao's hooking-detaching technique. PK was performed using a standard technique. Intraoperative and postoperative complications, visual acuity, rejection, graft survival, endothelial cell density, corneal sensation recovery, and re-innervation were compared between the two groups. Results: A best correct visual acuity of 0.5 or better was achieved in 90.7% of eyes after full-bed DALK and in 92.3% of eyes after PK (P=0.75). By the fifth postoperative year, graft endothelial cell loss reached 34.6% in the PK group vs. 13.9% in the full-bed DALK group (P<0.001). There were no statistical differences in corneal sensitivity recovery or corneal re-innervation between the groups (P>0.05). Intraoperative microperforation occurred in seven out of 75 (9.3%) eyes with a temporally postoperative double anterior chamber in two eyes in the full-bed DALK group. Postoperative complications in the PK vs. the full-bed DALK groups respectively were: rejection (7.7% vs. 0%, P=0.015), high intraocular pressure (IOP) (46.2% vs. 1.3%, P<0.001), secondary glaucoma (9.6% vs. 0%, P=0.006), complicated cataract (19.2% vs. 0%, P<0.001), and wound dehiscence (9.6% vs. 0%, P=0.006). Conclusions: Both full-bed DALK and PK can offer long-term satisfactory visual outcomes for keratoconus. Graft rejection, secondary glaucoma, complicated cataracts, and constant endothelial cell loss were observed in eyes only after PK.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 52474161, and 52404093)Fundamental Research Program of Shanxi Province (Nos. 202303021222168 and 202203021221143)+1 种基金Taiyuan University of Science and Technology Scientific Research Initial Funding (No. 20242103)the Postdoctoral Research Foundation of China(No. 2023M733778)。
文摘The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture(CPF) with different joint roughness coefficients(JRCs). Based on 3D morphology scanner tests and hydraulic coupling tests, a characterization method of effective geometric parameters in fracture surfaces under various confining pressures was improved, and a relationship between effective geometric parameters and the confining pressure is established. The results indicate that the nonlinear flow behavior in a CPF primarily includes three types: non-Newtonian fluid seepage under high confining pressure and low JRC, non-Darcy seepage under low confining pressure and high JRC, and the whole process of seepage characteristics between these two conditions. Among them, nonNewtonian fluid seepage is caused by significant fracture expansion, while non-Darcy seepage can be attributed to turbulence effects. During the seepage process, the geometric parameters with different JRC fracture samples all exhibit exponential changes with the increase of confining pressure. In addition,under high confining pressure, the effective contact ratio, effective fracture aperture, and void deviation ratio with high JRC fracture samples under high confining pressure increase by 93.5%, 67.4%, and 24.9%,respectively, compared with those of low JRC fracture samples. According to the variation of geometric parameters in a CPF with external stress, a seepage model considering geometric parameters in a CPF is proposed. By introducing the root mean square error(RMSE) and coefficient of determination(R2) to evaluate the error and goodness of fit between model curves and experimental data, it is found that the theoretical curves of model in this paper have the best matching with the experimental data. The average values of RMSE and R2for model in this paper are 0.002 and 0.70, respectively, which are better than models in the existing literature.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42188101, 42274211, 41974170, 42374184, 42122032, and 41974196)the Chinese Academy of Sciences (Grant Nos. QYZDJSSW-JSC028, XDA15052500, XDA17010301, and XDB41000000)+3 种基金the CNSA (Grant No. D050103)the Specialized Research Fund for State Key Laboratories of Chinathe Specialized Research Fund for Laboratory of Geospace Environment of the University of Science and Technology of Chinasupported by the International Space Science Institute (ISSI) in Bern and Beijing through the ISSI/ISSI-BJ International Team Project titled “Understanding the Mars Space Environment Through Multi-Spacecraft Measurements” (ISSI Team Project No. 23-582 and ISSI-BJ Team Project No. 58)
文摘Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions and exospheric neutrals serve as an important diagnostic for ion-neutral interactions and upper atmospheric loss.This study presents direct observations of hydrogen ENAs(H-ENAs)on the dayside of Mars by using the Mars Ion and Neutral Particle Analyzer(MINPA)onboard China’s Tianwen-1 orbiter.By analyzing H-ENA data during a coronal mass ejection and a stream interaction region from December 29,2021,to January 1,2022,and comparing these data with MAVEN/SWIA(Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer)solar wind measurements,we examine the temporal evolution of H-ENA flux and the associated sputtered escape of atmospheric constituents.The observed H-ENA velocity is consistent with upstream solar wind ions,and the H-ENA-to-ion intensity ratio is used to infer variations in exospheric density,revealing a delayed response to enhanced solar wind activity.Penetrating H-ENA intensities reach up to 5.3×10^(6)s^(−1) cm^(−2),with energy fluxes on the order of(0.5-8.1)×10^(−3) mW/m^(2).The estimated oxygen sputtered escape rate driven by penetrating H-ENAs ranges from 5.5×10^(23)s^(−1) to 5.2×10^(24)s^(−1),comparable to or exceeding previous estimates based on penetrating ions.The findings highlight the need for low-altitude H-ENA observations to better quantify their atmospheric interactions and refine our understanding of nonthermal escape processes at Mars.
基金The National Natural Science Foundation of China under contract Nos U23A2033 and 41876085the Basic Scientific Fund of the National Public Research Institutes of China under contract No.2020S03.
文摘Based on in-situ observations in the East China Sea(ECS)during October 2021,we investigated a cross-shelf penetrating front(PF)in the inner shelf and explored its potential biogeochemical-ecological effects from a multidisciplinary perspective.The results show that a pronounced tongue-shaped PF was present at the southeast of the Hangzhou Bay,with salinity of 29−32 and a seaward horizontal penetration scale of~200 km.It mainly occurred in the upper layers,and a spatial separation existed between this PF and the bottom salinity front in the northern coastal region off Zhejiang.In contrast,the salinity fronts at surface and bottom were well matched in the southern coastal area.Compared to the surface-to-bottom consistent coastal front in the southern region off Zhejiang,a stronger thermocline and halocline were sustained in the northern PF-dominated region,and suitable conditions could be achieved for phytoplankton growth and accumulation.The in-situ observed high-chlorophyll a(Chl a)zone in a seaward tongue shape was further an important indicator or signal for PF occurrence,and it was responsible for the decoupling of nutrient distributions and PF.The southern coastal front off Zhejiang might largely restrict the seaward transport of nutrients,and the dynamic environment under weak stratification in this region was disadvantageous for the growth of phytoplankton;thus the Chl a content was maintained at a relatively low level near the southern coastal region.Our results demonstrate that the PF combined with the coastal front may play an important role in shaping/regulating hydrodynamics,nutrient distributions and the Chl a regime over the inner ECS shelf.
基金supported by National Natural Science Foundation of China[grant number 42204148]Shenzhen Science and Technology Innovation Commission[grant number 20220810173255002].
文摘The failures of culverts can result in water and soil loss in the surrounding subsurface,leading to collapses.In densely constructed urban areas,buried culverts are inaccessible and invisible,making Ground Penetrating Radar(GPR)inspection a widely adopted nondestructive and efficient method.Previous research has employed artificial intelligence to automate GPR interpretation by identifying special radargram textures,but the irregular GPR responses of degraded subsurface soils present a challenge.Therefore,this study proposes a method for preliminary diagnosing large-scale culverts based on GPR wave attributes.The method comprises three parts:(1)evaluating soil compactness by estimating the tortuosity of GPR responses at the culvert top;(2)investigating soil moisture using the attenuation rate of GPR responses;and(3)overlaying the results of the incompact and moist soils to pinpoint potential degradations.Two long-distance culverts were inspected and diagnosed using the proposed method,and three abnormal sections were identified and confirmed by excavation evaluation.The case studies indicate that the proposed method can quickly provide reference for further in-depth investigation,thereby improving GPR survey efficiency and reducing workload by narrowing the investigation scope.Consequently,this study can facilitate large-scale GPR culvert surveys and further safeguard the water system.
基金supported by the National Natural Science Foundation of China(No.62103439)the China Postdoctoral Science Foundation(No.2020M683716)+1 种基金the National Key Laboratory of Unmanned Aerial Vehicle Technology,Chinathe Youth Innovation Team of Shaanxi University,China.
文摘Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly,which is the so-called security constraints.In addition,the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories,which is the so-called performance constraints.To this end,an attitude control method that meets the needs of PCA has been devised,based on constraint definition,coupled constraints handling,and control law design.Firstly,mathematical descriptions of the security constraints,performance constraints,and control constraints are given.Secondly,two treatment methods,coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem.Finally,based on Nonlinear Dynamic Inverse(NDI)design,the coupled funnel controller is designed and validated by simulation for two typical mission scenarios,high-altitude penetration and low-altitude surprise defence.The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.
基金Supported by the Guangdong Province Natural Science Foundation(No.2019A1515011732)Guangzhou Science and Technology Foundation of Guangdong Province(No.202002030413)Science and Technology Project of General Hospital of Southern Theater Command of PLA(No.2023NZB010).
文摘AIM:To assess the utility and efficiency of endoscopyassisted vitrectomy(EAV)for the treatment of corneal opacity in severe ocular trauma.METHODS:Patients who underwent fundus examination using a preoperative slit lamp and intraoperative endoscopy,followed by EAV and additional surgery were retrospectively recruited.Silicone oil removal and penetrating keratoplasty were used in selected eyes at postoperative follow-ups.Outcome measurements included the best corrected visual acuity(BCVA),intraocular pressure(IOP),findings of endoscopic fundus examination,and postoperative complications.RESULTS:Twenty-one eyes with severe ocular trauma and corneal opacity were followed up for 24-36mo.Retinal detachment(RD)and vitreous haemorrhage(VH)were identified in 16 eyes(76.2%),RD only in four eyes(19.0%),and VH combined with intraocular foreign body in one eye(4.8%).All eyes underwent at least three surgeries.Stage-Ⅰ surgeries involved wound closure(100%),lens extraction(76.2%),and anterior vitrectomy(14.3%).Stage-Ⅱ surgeries involved scleral buckling(28.6%),membrane peeling(47.6%),retinal laser photocoagulation(100%)and silicone oil tamponade(100%)using EAV.Stage-Ⅲ surgeries were conducted using endoscopy including silicone oil removal(52.4%),retinal laser photocoagulation(52.4%)and penetrating keratoplasty(28.6%).Nearly all eyes showed improvements in BCVA and IOP.Although there were no severe complications,glaucoma was noted in one eye,chronic hypotony in another eye,and band keratopathy in three eyes.CONCLUSION:EAV is an effective adjunct for restoring ocular anatomical structures and visual function in the case of corneal opacity after severe ocular trauma.
基金Supported by the National Natural Science Foundation of China (No.81900907,No.81870639)Taishan Scholar Program (No.20231255).
文摘AIM:To describe the surgical procedure of fusiform penetrating keratoplasty(FPK)using multiple trephines of different sizes for treating patients with severe infectious keratitis.METHODS:Fourteen eyes underwent FPK,and 15 eyes received conventional penetrating keratoplasty(PK)were included in the study.The best-corrected visual acuity(BCVA),refractive outcomes,endothelial cell density,and postoperative complications were recorded.RESULTS:The FPK group was followed for an average of 15.3±2.1mo,whereas the PK group was followed for 16.1±1.9mo.The corneal ulcers were elliptical-shaped in all 14 eyes in the FPK group.The mean BCVA(logMAR,0.26±0.13)showed no statistically significant differences from that in the PK group(logMAR,0.21±0.12,P>0.05)at 1y after surgery.But the mean curvature,mean astigmatism,and mean spherical equivalent in the FPK group were lower than those in the PK group(P<0.05).Peripheral anterior synechia was observed in one patient in the FPK group,whereas 6 patients in the PK group.Suture loosening and neovascularization were observed in 4 and 5 eyes in the PK group,respectively.No graft immune rejection or elevation of intraocular pressure was observed in the two groups.CONCLUSION:For patients with elliptical-shaped corneas or corneal ulcers,FPK can avoid disrupting of corneal limbus,reduce the risk of postoperative complications,and can result in satisfactory visual quality.
文摘AIM:To investigate tomographic features of late corneal ectasia after keratoplasty for keratoconus and compare penetrating keratoplasty(PK)and deep anterior lamellar keratoplasty(DALK)in terms of incidence,time of onset and risk factors of corneal ectasia.METHODS:Sixty eyes with PK and 30 eyes with DALK operated between 1999 and 2021 were analyzed.Final Pentacam scans were evaluated together with vision and previous topographies.Main outcome measures were vision,K values,apparent thinning on graft-host cornea and the difference between opposing quadrants in the thinnest point measurements.Anterior segment optic coherence tomography was performed for further evaluation.RESULTS:Mean follow-up was 127.2mo(24–282mo)in PK,and 64.3mo(24–144mo)in DALK.K max was higher in DALK(60.6 vs 56.7 D,P=0.012).Inferior recipient was thinner(595.9μm)in PK than DALK(662.2μm,P=0.021),due to longer follow-up.Overall corneal ectasia rate was 20.0% within 24y.Ectasia rate was the same(6.7%)in DALK 2/30 and in PK 4/60 in 10y and 13.3%in 12y(4/30 and 8/60,respectively).It increased to 23.3%(14/60)in PK over 24y.While ectasia was not seen before 7y in PK,it could be seen in DALK starting from the 5^(th) year.The intervals between keratoplasty and ectasia were 144.5mo in PK and 99mo in DALK.Inferior recipient was significantly thinner in 18 eyes with ectasia(502.7μm)compared to 76 non-ectasia(649.1μm,P=0.000).Inferior graft was thinner(561.0 vs 620.4μm,P=0.006),K max(63.3 vs 56.5 D,P=0.000),and anterior elevation was higher in ectasia(89.1 vs 48.6μm,P=0.002).Accelerated crosslinking was performed on 5 eyes.CONCLUSION:Inferior-superior recipient and inferior graft thinning on tomography,with high K max and anterior elevation emerge as the most reliable criteria for the diagnosis of late ectasia.The incidence of corneal ectasia increases with the time.
基金supported by the National Natural Science Foundation of China(Grant Nos.42325406 and 42304187)the China Postdoctoral Science Foundation(Grant No.2023M733476)+3 种基金the CAS Project for Young Scientists in Basic Research(Grant No.YSBR082)the National Key R&D Program of China(Grant No.2022YFF0503203)the Key Research Program of the Institute of Geology and GeophysicsChinese Academy of Sciences(Grant Nos.IGGCAS-202101 and IGGCAS-202401).
文摘The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurface structures within a depth of approximately 50 m.However,it was still difficult to identify finer layers from the cluttered reflections and scattering waves.We applied deconvolution to improve the vertical resolution of the radar profile by extending the limited bandwidth associated with the emissive radar pulse.To overcome the challenges arising from the mixed-phase wavelets and the problematic amplification of noise,we performed predictive deconvolution to remove the minimum-phase components from the Chang’E-4 dataset,followed by a comprehensive phase rotation to rectify phase anomalies in the radar image.Subsequently,we implemented irreversible migration filtering to mitigate the noise and diminutive clutter echoes amplified by deconvolution.The processed data showed evident enhancement of the vertical resolution with a widened bandwidth in the frequency domain and better signal clarity in the time domain,providing us with more undisputed details of subsurface structures near the Chang’E-4 landing site.
基金National Natural Science Foundation of China,No.82160207Technology Plan of Jiangxi Provincial Health and Health Commission,No.202130156+1 种基金Young Scholar Project of the First Affiliated Hospital of Nanchang University,No.YFYPY202219Science and Key Projects of Jiangxi Youth Science Fund,No.20202ACBL216008.
文摘BACKGROUND We report a case of eye-penetrating injury in which a massive silicone oil migration into the patient’s subconjunctival space and orbit occurred after vitrectomy.CASE SUMMARY A 30-year-old male patient sought medical attention at Ganzhou People’s Hospital after experiencing pain and vision loss in his left eye due to a nail wound on December 9,2023.Diagnosis of penetrating injury caused by magnetic foreign body retention in the left eye and hospitalization for treatment.On December 9,2023,pars plana vitrectomy was performed on the left eye for intraocular foreign body removal,abnormal crystal extraction,retinal photocoagulation.Owing to the discovery of retinal detachment at the posterior pole during surgery,silicone oil was injected to fill the vitreous body,following which upper conjunctival bubble-like swelling was observed.Postoperative orbital computed tomography(CT)review indicated migration of silicone oil to the subconjunctival space and orbit through a self-permeable outlet.On December 18,2023,the patient sought treatment at the First Affiliated Hospital of Nanchang University,China.The patient presented with a pronounced foreign body sensation following left eye surgery.On December 20,2023,the foreign body was removed from the left eye frame and an intraocular examination was conducted.The posterior scleral tear had closed,leading to termination of the surgical procedure following supplementary laser treatment around the tear.The patient reported a significant reduction in ocular surface symptoms just one day after surgery.Furthermore,a notable decrease in the migration of silicone oil was observed in orbital CT scans.CONCLUSION The timing of silicone oil injection for an eye-penetrating injury should be carefully evaluated to avoid the possibility of silicone oil migration.
文摘BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck,without signs of neurological deficit.Computed tomography(CT)demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level,causing C6 and C7 vertebral body fracture,C6 left lamina fracture,left facet joint fracture,and penetration of the cervical spinal cord.The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team.During the surgery,we found that the cervical vertebra,cervical spinal canal and cervical spinal cord were all severely injured.Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits.CONCLUSION Even with a serious cervical spinal canal penetrating trauma,the patient could resume normal work and life after appropriate treatment.
文摘Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materials and method: This was a descriptive and analytical study over a 48-month period at CHU la Renaissance from January 1, 2018 to December 31, 2021, concerning patients admitted for penetrating cranioencephalic trauma by pointed object. Results: Twelve cases, all male, of penetrating cranioencephalic sharp-force trauma were identified. The mean age was 34 ± 7 years, with extremes of 11 and 60 years. Farmers and herders accounted for 31% and 25% of cases respectively. The average admission time was 47 hours. Brawls were the circumstances of occurrence in 81.2% of cases. Knives (33%), arrows (25%) and iron bars (16.6%) were the objects used. Altered consciousness was present in 43.8% of cases, and focal deficit in 50%. Scannographic lesions were fracture and/or embarrhment (12 cases), intra-parenchymal haematomas (6 cases) and presence of object in place (4 cases). Surgery was performed in 11 patients. Postoperative outcome was favorable in 9 patients. After 12 months, 2 patients were declared unfit. Conclusion: Penetrating head injuries caused by sharp objects are common in Chad. Urgent surgery can prevent disabling after-effects.
文摘Objective: Vascular injuries usually present immediately after the penetration, but the delayed onset of vascular symptoms caused by vessel dissection or aneurysm after a traumatic event is extremely rare. Vertebral artery injury is a low-frequency but high-mortality injury. We aim to report evidence of delayed onset of vascular symptoms following penetrating trauma in the neck. Materials and Methods: A case report. Results: A 19-year-old boy was referred to our hospital and complained of a mass in the right part of his neck (right mandibular angle). He gave a history of penetrating trauma to his neck 2 months ago. The mass was expanding during these 2 months and doesn’t respond to antibiotic therapy. In the examination, 3 × 3 cm, firm, nonmobile, and without tenderness and pain mass was palpated in the second level of his neck. Doctors ordered a Doppler sonography in the hospital where a yin-yang pattern was reported. A 36 × 43 × 40 mm heterogeneous, solid, and hypodense area close to C1-C2-C3 with vascular flow was discovered in the right submandibular area after computed tomography (CT)-angiography. The patient was referred to an interventional neurologist for angiography and due to the lack of flow at the distal of the V3 segment, he decided to sacrifice this artery by two coils. Conclusion: Penetrating neck injuries are usually asymptomatic, but these injuries are often accompanied by hemorrhage, neurological symptoms, dysphagia, odynophagia, and windpipe. Penetrating lesions of the vertebral artery are rare and very difficult to diagnose. Also, these lesions are challenging for surgeons due to complex anatomy and difficult surgical exposure. So, endovascular treatment was used to treat the patient.
基金supported by the Exploratory Research Fund of State Key Laboratory of Explosion Science and Safety Protection.
文摘The high-speed penetration of concrete targets by kinetic energy projectiles results in apparent mass loss,which blunts the nose of the projectile and decrease its penetration performance.The friction work between the projectile and the concrete target,the plastic deformation of the projectile,and the cutting of aggregates to the projectile significantly affect the mass loss of the projectile.To address these effects,a discrete iterative model is developed for the mass loss and nose shape evolution of the projectile by coupling three mechanisms based on the effect of temperature on strength.In the model,both friction work and plastic work increase the temperature of the projectile's surface layer,thereby weakening the strength of this part and rendering it easier for mass loss to occur due to aggregate cutting.The model discretizes the projectile and penetration process with respect to the space and time dimensions,respectively.The mass loss and nose shape evolution of the projectile are obtained by iteratively calculating a point-by-point regression.The predicted depth of penetration(DOP),mass loss,and residual projectile profile are compared with experimental data to validate the model.The comparison shows satisfactory agreement between the calculated results and experimental data.Additionally,the deceleration,velocity,DOP,and mass loss during penetration are analyzed with respect to time.Finally,based on the model,the effects of projectile strength,caliber-radius-head(CRH),and concrete target strength on penetration are discussed.
文摘PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 mm.The penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was obtained.It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure.Using the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were obtained.Then,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates.The results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment.The equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications.
基金supported by National Natural Science Foundation of China(Nos.82102215 and 82372129)Wenzhou Medical University Scientific Research Fund(No.KYQD20210602)。
文摘The low drug bioavailability of eye drops challenges the therapy of ocular disorders with high efficacy.One of solutions is to extend the corneal retention and enhance the penetration of drug into cornea.Here we synthesize two fluorophore-conjugated peptide based analogs rich in positive charges(i.e.,NBDFFKK)and with a specific ligand(i.e.,NBD-FFRGD),respectively,to visualize their performances in vitro and in vivo.The peptides both can self-assemble into supramolecular hydrogels with the microstructure of nanofibers.The in vitro experiments exhibit that two peptides are both uniformly distributed in cytoplasm,and the intracellular amount of peptide rich in positive charges is significantly larger than that of peptide with a specific ligand.The living corneal fluorescence shows that two peptides enter the corneal stroma within 15 min,and the peptide rich in positive charges is accumulated more extensively throughout the entire cornea,revealing that the supramolecular hydrogel eye drops penetrate the cornea more efficiently via electrostatic interaction than that via ligand-receptor interaction.This work,as a comparative study of supramolecular hydrogel eye drops on penetrating efficiency,indicates a possible direction for the design of eye drops with efficient corneal penetration.
基金National key Basic Research Program(Grant No.2013CB932501)National Natural Science Foundation of China(Grant No.81273454 and 81473156)+1 种基金Beijing National Science Foundation(Grant No.7132113)Doctoral Foundation of the Ministry of Education(Grant No.20130001110055)
文摘Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect penetration abilities of nanostructured lipid carriers（NLC）. Real--time penetration of folate--or cell penetrating peptide（CPP）-modified NLC was evaluated using a multicellular tumor spheroid（MTS） established by stacking culture method as an in vitro testing platform. The results suggested that CPP modification had a better penetration behavior both on penetration depth and intensity compared with folate-modified NLC at the early stage of penetration process.
文摘Given its ability to knock down essentially any gene of interest, siRNA has been one of the promising candidates for gene therapy. However, like other nucleic-acid-based drugs, its poor cellular uptake poses a major challenge. Here we briefly summarize the use of cell penetrating peptides （CPPs） as a novel and promising approach for siRNA delivery. The main advantages of CPPs are their low toxicity and high efficiency.
基金Project (No. 2011C13029-2) supported by the Major Program for Science and Technology Research of Zhejiang Province, China
文摘Objective: To compare postoperative outcomes of full-bed deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in treating keratoconus. Methods: Seventy-five eyes of 64 patients who received full-bed DALK and 52 eyes of 51 patients who received PK between June 2000 and August 2010 were included in this retrospective study. Full-bed DALK was performed using Yao's hooking-detaching technique. PK was performed using a standard technique. Intraoperative and postoperative complications, visual acuity, rejection, graft survival, endothelial cell density, corneal sensation recovery, and re-innervation were compared between the two groups. Results: A best correct visual acuity of 0.5 or better was achieved in 90.7% of eyes after full-bed DALK and in 92.3% of eyes after PK (P=0.75). By the fifth postoperative year, graft endothelial cell loss reached 34.6% in the PK group vs. 13.9% in the full-bed DALK group (P<0.001). There were no statistical differences in corneal sensitivity recovery or corneal re-innervation between the groups (P>0.05). Intraoperative microperforation occurred in seven out of 75 (9.3%) eyes with a temporally postoperative double anterior chamber in two eyes in the full-bed DALK group. Postoperative complications in the PK vs. the full-bed DALK groups respectively were: rejection (7.7% vs. 0%, P=0.015), high intraocular pressure (IOP) (46.2% vs. 1.3%, P<0.001), secondary glaucoma (9.6% vs. 0%, P=0.006), complicated cataract (19.2% vs. 0%, P<0.001), and wound dehiscence (9.6% vs. 0%, P=0.006). Conclusions: Both full-bed DALK and PK can offer long-term satisfactory visual outcomes for keratoconus. Graft rejection, secondary glaucoma, complicated cataracts, and constant endothelial cell loss were observed in eyes only after PK.
