BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization r...BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization rates increase in elderly patients due to a decline in glomerular filtration rate(GFR).AIM To investigate the connection between GFR and comorbidity and reasons for hospitalization in elderly patients.METHODS We analyzed patients aged 75 years and over who were admitted to the internal medicine clinic of a tertiary hospital in Eskisehir.At admission,we calculated GFR values using the Modification of Diet in Renal Disease study formula and classified them into six categories:G1,G2,G3a,G3b,G4,and G5.We analyzed associations with hospitalization diagnoses and comorbidity factors.RESULTS The average age of the patients was 80.8 years(±4.5 years).GFR was 57.287±29.5 mL/kg/1.73 m2 in women and 61.3±31.5 mL/kg/1.73 m2 in men(P=0.106).Most patients were admitted to the hospital at G2 stage(32.8%).The main reasons for hospitalization were anemia(34.4%and 28.6%)and malnutrition(20.9%and 20.8%)in women and men,respectively(P=0.078).The most frequent comor-bidity leading to hospitalization was arterial hypertension(n=168,28%),fo-llowed by diabetes(n=166,27.7%)(P=0.001).CONCLUSION When evaluating geriatric patients,low GFR alone does not provide sufficient information.Patients’comorbid factors should also be taken into account.There is no association between low GFR during hospitalization and hospitalization-Hamarat H.Aging and GFR related diagnoses.Knowing the GFR value before hospitalization will be more informative in such studies.展开更多
The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwa...The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.展开更多
Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb rema...Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb remains the primary impediment to successful GFS outcomes.Perioperative utilization of antimitotics,while frontline in combating fibrosis and modulating the wound healing process,carries the risk of vision-threatening complications.Given the complexity of the wound healing cascade and the potential insufficiency of targeting a single molecule,there is an imperative to expand therapeutic modalities through combination therapies.This review offers a comprehensive elucidation of the fibrogenesis post-GFS,a synthesis unprecedented in the available literature,and aims to inform the broadening of therapeutic strategies for GFS.展开更多
Artificial intelligence techniques have been used to predict basic oxygen furnace(BOF) end-points. However,the main challenge is to effectively reduce the input nodes as too many input nodes in neural network increase...Artificial intelligence techniques have been used to predict basic oxygen furnace(BOF) end-points. However,the main challenge is to effectively reduce the input nodes as too many input nodes in neural network increase complexity,decrease accuracy and slow down the training speed of the network.Simply picking-up variables as input usually influence validity of model.It is quite necessary to develop an effective method to reduce the number of input nodes whereby to simplify the network and improve model performance.In this study,a variable-filtrating technique combining both metallurgical mechanism model and partial least-squares(PLS ) regression method has been proposed by taking the advantages of both of them,i.e.qualitive and quantative relationships between variables respectively.Accordingly,a fuzzy-reasoning neural network(FNN) prediction model for basic oxygen furnace(BOF) end-point carbon content based on this technique has been developed.The prediction results showed that this model can effectively improve the hit rate of end-point carbon content and increase network training speed.The successful hit rate of the model can reach up to 94.12%with about 0.02% error range.展开更多
A gravity-driven membrane(GDM)system is a cleaning-free ultrafiltration(UF)process for decentralized water purification.However,GDM has a poor permeate quality and low stable flux when the feed water contains high lev...A gravity-driven membrane(GDM)system is a cleaning-free ultrafiltration(UF)process for decentralized water purification.However,GDM has a poor permeate quality and low stable flux when the feed water contains high levels of particulates,organic matter,and micropollutants.To address these challenges,this study used riverbank filtration(BF)as a pretreatment for GDM.The experimental results showed that BF could effectively reduce turbidity and particulate organic matter,and preferentially remove biopolymers and protein-like fluorescent components from natural organic matter.The removal efficiencies of micropollutants(diclofenac,carbamazepine,acetamidophenol,and bisphenol A)increased by 15.2%-65.3% in the presence of BF.Moreover,BF-GDM improved the removal of assimilable organic carbon(AOC)by 42%,thereby enhancing the biological stability of the permeate.Despite a modest increase of approximately 20%in the removal of dissolved organic matter,the BF significantly improved the stable flux from 2.8 to 7.3 L·m^(-2)·h^(-1).This remarkable improvement is attributed to the effective removal of key foulants,including particulate substances,biopolymers,and protein-like fluorescent substances,which leads to a thinner bio-cake layer with a higher density of microorganisms.Additionally,because of the high microbial diversity of the soil,BF pretreatment enriched the microbial diversity of the biocake layer,thereby enriching functional microorganisms capable of degrading pollutants in BF-GDM,such as Nitrospirota and Ascomycota.Overall,BF is a highly effective pretreatment for GDM,which potentially broadens its application to polluted source water.展开更多
With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered wide...With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered widespread attention.To address the challenges of fault feature extraction,this article proposes an end-to-end diagnostic approach based on a wavelet kernel convolutional neural network (WKCNN),capable of extracting multi-scale features from current signals to significantly enhance diagnostic accuracy.This method directly uses raw three-phase current signals as input,applying wavelet kernel convolution to automatically capture frequency-domain fault features,combined with a Softmax classifier optimized by the Adam algorithm to achieve fault diagnosis for NPC threelevel inverters.Experimental results under various operating conditions demonstrate that this approach maintains robust diagnostic accuracy across multiple fault scenarios,with comparative analysis further confirming its advantages in diagnostic efficiency and performance over traditional machine learning and other deep learning methods.展开更多
As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order t...As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order to address the technical difficulties associated with the failure of filtrate loss reducers under high-temperature and high-salinity conditions.In this study,a hydrophobic zwitterionic filtrate loss reducer(PDA)was synthesized based on N,N-dimethylacrylamide(DMAA),2-acrylamido-2-methylpropane sulfonic acid(AMPS),diallyl dimethyl ammonium chloride(DMDAAC),styrene(ST)and a specialty vinyl monomer(A1).When the concentration of PDA was 3%,the FLAPI of PDA-WBDF was 9.8 mL and the FLHTHP(180℃,3.5 MPa)was 37.8 mL after aging at 240℃for 16 h.In the saturated NaCl environment,the FLAPI of PDA-SWBDF was 4.0 mL and the FLHTHP(180℃,3.5 MPa)was 32.0 mL after aging at 220℃ for 16 h.Under high-temperature and high-salinity conditions,the combined effect of anti-polyelectrolyte and hydrophobic association allowed PDA to adsorb on the bentonite surface tightly.The sulfonic acid groups of PDA increased the negative electronegativity and the hydration film thickness on bentonite surface,which enhanced the colloidal stability,maintained the flattened lamellar structure of bentonite and formed an appropriate particle size distribution,resulting in the formation of dense mud cakes and reducing the filtration loss effectively.展开更多
With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as...With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility.However,the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage(CMV)and neutral-point voltage(NPV)fluctuations,which can lead to electromagnetic interference and degrade transient performance.To address these challenges,an optimized virtual space vector pulse width modulation(OVSVPWM)strategy is proposed,aiming to suppress CMV and NPV simultaneously through coordinated multi-objective control.Specifically,a dynamic feedback mechanism is introduced to adjust the balancing factor of basic vectors in the synthesized virtual small vector in real-time,achieving autonomous balancing of the NPV.To address the excessive switching actions introduced by the OVSVPWM strategy,a phase duty ratio-based sequence reconstruction method is adopted,which reduces the total number of switching actions to half of the original.A zero-level buffering scheme is employed to reconstruct the single-phase voltage-level output sequence,achieving peak CMV suppression down to udc/6.Simulation results demonstrate that the proposed strategy significantly improves electromagnetic compatibility and operational stability while maintaining high power quality.展开更多
For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another....For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.展开更多
In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with ...In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with N≥1,m>0,p>1,such that m(p-1)>1.We give a clear classification of the self-similar solutions of the form u(x,t)=(βt)^(-α/β)((βt)^(-1/β)|x|)withα∈R andβ=α[m(p-1)-1]+p,regular or singular at the origin point.The existence and uniqueness of some solutions are established by the phase plane analysis method,and the asymptotic properties of the solutions near the origin and the infinity are also described.This paper extends the classical results of self-similar solutions for degeneratep-Laplace heat equation by Bidaut-Véron[Proc Royal Soc Edinburgh,2009,139:1-43]to the doubly nonlinear degenerate diffusion equations.展开更多
Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten ...Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten steel were investigated through steel casting tests.The results show that on the basis of surviving the thermal shock of molten steel,both filters can significantly reduce the number of non-metallic inclusions and total oxygen content of steel,thereby improving the cleanliness of the molten steel.After the thermal shock of molten steel,cracks were found in the microstructure of pure magnesia filter.Via the diffusion of non-metallic inclusions from steel into MgO grains of the filter to form solid solution,the inclusions were adsorbed to the internal and external surfaces of the pure magnesia filter.The number of inclusions was reduced by 62.5%,and the total oxygen content decreased from 0.892 to 0.265 wt.%after filtration,achieving a filtration efficiency of 70.3%.Compared with the pure magnesia filter,no cracks were found in the microstructure of the periclase-spinel filter.The mass transfer rate was accelerated due to the diffusion of inclusions from steel into MgO and MgAl2O4 grains of the filter,as well as the higher high-temperature liquid content and smaller pore structure of the filter.More non-metallic inclusions were able to enter the interior of the filter,which made the periclase-spinel filter more capable of adsorbing inclusions from steel and reducing total oxygen content.The periclase-spinel filter reduced the number of inclusions in steel by 84.4%and decreased the total oxygen content of the steel from 0.892 to 0.119 wt.%,with a filtration efficiency of 86.7%,demonstrating excellent comprehensive performance.展开更多
The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering perfor...The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.展开更多
AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mes...AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.展开更多
Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of p...Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of photocatalysts or membrane materials to improve their catalytic and filtration performance,the complex structures and interface mechanisms,as well as insufficient light utilization,are still often overlooked,limiting the overall performance improvement of photocatalytic membranes.This work provides an overview of enhancement strategies involving restricted area effects,external fields,such as mechanical,magnetic,thermal,and electrical fields,as well as coupling techniques with advanced oxidation processes(e.g.,O_(3),Fenton,and persulfate oxidation)for dual enhancement of photocatalysts and membranes.In addition,the synthesis method of photocatalytic membranes and the influence of factors,such as light source type,frequency,and relative position on photocatalytic membrane performance were also studied.Finally,economic feasibility and pollutant removal performance were further evaluated to determine the promising enhancement strategies,paving the way for more efficient and scalable applications of photocatalytic membranes.展开更多
Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filte...Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filters,yet the bulk struggle to withstand high temperatures.In this study,mullite fiber sponges were developed utilizing low-cost materials and Kármán vortex solution blow spinning,using surfac-tants to improve the spinnability of the sol.Optimized sponges demonstrate ultralight(19 mg cm^(-3)),temperature-resistant reversible compressibility(50% strain)and a water contact angle of 135°.These sponges exhibited exceptional thermal insulation(thermal conductivity:0.0256 W m^(-1) K^(-1))and per-formed well in high-temperature air filtration.At 800℃,the mullite sponge with a base weight of 35 mg cm^(-2),achieved an average filtration efficiency of 98.18%and 99.57% for PM_(2.5) and PM_(2.5-10),respectively,with a quality value of 0.98 Pa^(-1) at a wind speed of 4 cm s^(-1).This low-cost mullite fiber sponge offers a promising avenue for designing high-performance filtration materials.展开更多
This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermo...This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermodulation caused by the PWM strategy and converter topology interaction to estimate the capacitor parameters of the converter DC-link.It utilizes an observer-based structure consisting of a recursive noninteger sliding discrete Fourier transform(rnSDFT)and an RLS filter improved with a forgetting factor(oSDFT-RLS)to accurately estimate the capacitance and equivalent series resistance(ESR).Importantly,this method does not require additional sensors beyond those already installed in off-the-shelf 3L-NPC-VSI systems,ensuring its noninvasiveness.Furthermore,the oSDFTRLS estimates capacitor parameters in the time-frequency domain,enabling the tracking of capacitor degradation and predicting potential faults.Experimental results from the laboratory setup demonstrate the effectiveness of the proposed condition monitoring method.展开更多
BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the long...BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the longitudinal changes in measured glomerular filtration rate(mGFR)in patients with autosomal dominant polycystic kidney disease(ADPKD).METHODS Analysis of an ambispective data base conducted on consecutive patients diagnosed with ADPKD.The mGFR was assessed by iohexol clearance;while eGFR was calculated by three different formulas:(1)The chronic kidney disease epidemiology collaboration(CKD-EPI);(2)Modification of diet in renal disease(MDRD);and(3)The 24-hour urine creatinine clearance(CrCl).The primary end-points were the mean change in mGFR between the baseline and final visit,as well as the comparison of the mean change in mGFR with the change estimated by the different formulas.RESULTS Thirty-seven patients were included in the study.As compared to baseline,month-6 mGFR was significantly decrease by-4.4 mL/minute±10.3 mL/minute(P=0.0132).However,the CKD-EPI,MDRD,and CrCl formulas underestimated this change by 48.3%,89.0%,and 45.8%respectively,though none of these differences reached statistical significance(P=0.3647;P=0.0505;and P=0.736,respectively).The discrepancies between measured and estimated glomerular filtration rate values,as evaluated by CKD-EPI(r=0.29,P=0.086);MDRD(r=0.19,P=0.272);and CrCl(r=0.09,P=0.683),were not correlated with baseline mGFR values.CONCLUSION This study indicated that eGFR inaccurately reflects the decline in mGFR and cannot reliably track changes over time.This poses significant challenges for clinical decision-making,particularly in treatment strategies.展开更多
Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regard...Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regarding the best methods to estimate glomerular filtration rate(eGFR)in older adults.Several studies suggest the use of an age-adjusted definition to improve accuracy and avoid overdiagnosis.In contrast,some researchers argue that such changes could complicate the classification of chronic kidney disease(CKD).Several formulas,including the Modification of Diet in Renal Disease,CKD-Epidemiology Collaboration,and Cockcroft-Gault equations,are used to estimate eGFR.However,each of these formulas has significant limitations when applied to older adults,primarily due to sarcopenia and malnutrition,which greatly affect both muscle mass and creatinine levels.Alternative formulas,such as the Berlin Initiative Study and the Full Age Spectrum equations,provide more accurate estimates of values for older adults by accounting for age-related physiological changes.In frail older adults,the use of cystatin C leads to better eGFR calculations to assess renal function.Accurate eGFR measurements improve the health of older patients by enabling better medication dosing.A thorough approach that includes multiple calibrated diagnostic methods and a detailed geriatric assessment is necessary for the effective management of kidney disease and other age-related conditions in older adults.展开更多
Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on dete...Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on determination of residual protein in lincomycin hydrochloride. Methods The chromatographic conditions were SuperdexTM peptide column, 0.01 mol*L-1 phosphate buffer solution as mobile phase, and flow rate of 1 mL·min-1. Five hundred microliters of lincomycin hydrochloride solution (3 g of lincomycin hydrochloride dissolved in 10 mL of mobile phase) was injected into the chromatograph and the eluted solution was collected between 6 min and 14.5 min (protein eluted from column within this period), and the residual content of total protein in the eluted solution was assayed using Bradford assay method. Results The average recovery was more than 90% for bovine serum albumin, the calibration equation for the range of 0-12 μg·mL-1 of protein was y=-0.002 4x2+0.064 2x+0.002 9, r2=0.999 9, RSD=0.1%-0.9%, and the LOD and LOQ were 3 and 10 ng·mL-1 of protein, respectively. Conclusion The novel method for determining the residual protein in ferment antibio-tics is simple, rapid, and precise.展开更多
文摘BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization rates increase in elderly patients due to a decline in glomerular filtration rate(GFR).AIM To investigate the connection between GFR and comorbidity and reasons for hospitalization in elderly patients.METHODS We analyzed patients aged 75 years and over who were admitted to the internal medicine clinic of a tertiary hospital in Eskisehir.At admission,we calculated GFR values using the Modification of Diet in Renal Disease study formula and classified them into six categories:G1,G2,G3a,G3b,G4,and G5.We analyzed associations with hospitalization diagnoses and comorbidity factors.RESULTS The average age of the patients was 80.8 years(±4.5 years).GFR was 57.287±29.5 mL/kg/1.73 m2 in women and 61.3±31.5 mL/kg/1.73 m2 in men(P=0.106).Most patients were admitted to the hospital at G2 stage(32.8%).The main reasons for hospitalization were anemia(34.4%and 28.6%)and malnutrition(20.9%and 20.8%)in women and men,respectively(P=0.078).The most frequent comor-bidity leading to hospitalization was arterial hypertension(n=168,28%),fo-llowed by diabetes(n=166,27.7%)(P=0.001).CONCLUSION When evaluating geriatric patients,low GFR alone does not provide sufficient information.Patients’comorbid factors should also be taken into account.There is no association between low GFR during hospitalization and hospitalization-Hamarat H.Aging and GFR related diagnoses.Knowing the GFR value before hospitalization will be more informative in such studies.
基金The financial support from the National Natural Science Foundation of China(22127812,22278433,22178379)the National Key Research and Development Program of China(2021YFC2800902)are gratefully acknowledged。
文摘The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.
基金Supported by Hospital Level Project of the Eye Hospital of China Academy of Chinese Medical Sciences(No.GSP5-40)Internal Project of the Eye Hospital of China Academy of Chinese Medical Sciences(No.1011632).
文摘Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb remains the primary impediment to successful GFS outcomes.Perioperative utilization of antimitotics,while frontline in combating fibrosis and modulating the wound healing process,carries the risk of vision-threatening complications.Given the complexity of the wound healing cascade and the potential insufficiency of targeting a single molecule,there is an imperative to expand therapeutic modalities through combination therapies.This review offers a comprehensive elucidation of the fibrogenesis post-GFS,a synthesis unprecedented in the available literature,and aims to inform the broadening of therapeutic strategies for GFS.
文摘Artificial intelligence techniques have been used to predict basic oxygen furnace(BOF) end-points. However,the main challenge is to effectively reduce the input nodes as too many input nodes in neural network increase complexity,decrease accuracy and slow down the training speed of the network.Simply picking-up variables as input usually influence validity of model.It is quite necessary to develop an effective method to reduce the number of input nodes whereby to simplify the network and improve model performance.In this study,a variable-filtrating technique combining both metallurgical mechanism model and partial least-squares(PLS ) regression method has been proposed by taking the advantages of both of them,i.e.qualitive and quantative relationships between variables respectively.Accordingly,a fuzzy-reasoning neural network(FNN) prediction model for basic oxygen furnace(BOF) end-point carbon content based on this technique has been developed.The prediction results showed that this model can effectively improve the hit rate of end-point carbon content and increase network training speed.The successful hit rate of the model can reach up to 94.12%with about 0.02% error range.
基金supported by the National Natural Science Foundation of China(52270077 and 52070147)。
文摘A gravity-driven membrane(GDM)system is a cleaning-free ultrafiltration(UF)process for decentralized water purification.However,GDM has a poor permeate quality and low stable flux when the feed water contains high levels of particulates,organic matter,and micropollutants.To address these challenges,this study used riverbank filtration(BF)as a pretreatment for GDM.The experimental results showed that BF could effectively reduce turbidity and particulate organic matter,and preferentially remove biopolymers and protein-like fluorescent components from natural organic matter.The removal efficiencies of micropollutants(diclofenac,carbamazepine,acetamidophenol,and bisphenol A)increased by 15.2%-65.3% in the presence of BF.Moreover,BF-GDM improved the removal of assimilable organic carbon(AOC)by 42%,thereby enhancing the biological stability of the permeate.Despite a modest increase of approximately 20%in the removal of dissolved organic matter,the BF significantly improved the stable flux from 2.8 to 7.3 L·m^(-2)·h^(-1).This remarkable improvement is attributed to the effective removal of key foulants,including particulate substances,biopolymers,and protein-like fluorescent substances,which leads to a thinner bio-cake layer with a higher density of microorganisms.Additionally,because of the high microbial diversity of the soil,BF pretreatment enriched the microbial diversity of the biocake layer,thereby enriching functional microorganisms capable of degrading pollutants in BF-GDM,such as Nitrospirota and Ascomycota.Overall,BF is a highly effective pretreatment for GDM,which potentially broadens its application to polluted source water.
基金supported in part by Zhejiang Provincial“Pioneer”and“Leading Goose”R&D Program of China under Grant 2024C01014the National Natural Science Foundation of China under Grant52177055。
文摘With the increasing demand for high reliability and availability in power conversion equipment within power electronics systems,the fault diagnosis of neutral-point-clamped(NPC) three-level inverters has garnered widespread attention.To address the challenges of fault feature extraction,this article proposes an end-to-end diagnostic approach based on a wavelet kernel convolutional neural network (WKCNN),capable of extracting multi-scale features from current signals to significantly enhance diagnostic accuracy.This method directly uses raw three-phase current signals as input,applying wavelet kernel convolution to automatically capture frequency-domain fault features,combined with a Softmax classifier optimized by the Adam algorithm to achieve fault diagnosis for NPC threelevel inverters.Experimental results under various operating conditions demonstrate that this approach maintains robust diagnostic accuracy across multiple fault scenarios,with comparative analysis further confirming its advantages in diagnostic efficiency and performance over traditional machine learning and other deep learning methods.
基金supported by State Key Laboratory of Deep Oil and Gas(No.SKLDOG2024-ZYRC-03)supported by the Excellent Young Scientists Fund of the National Natural Science Foundation of China(No.52322401)the National Natural Science Foundation of China(52288101).
文摘As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order to address the technical difficulties associated with the failure of filtrate loss reducers under high-temperature and high-salinity conditions.In this study,a hydrophobic zwitterionic filtrate loss reducer(PDA)was synthesized based on N,N-dimethylacrylamide(DMAA),2-acrylamido-2-methylpropane sulfonic acid(AMPS),diallyl dimethyl ammonium chloride(DMDAAC),styrene(ST)and a specialty vinyl monomer(A1).When the concentration of PDA was 3%,the FLAPI of PDA-WBDF was 9.8 mL and the FLHTHP(180℃,3.5 MPa)was 37.8 mL after aging at 240℃for 16 h.In the saturated NaCl environment,the FLAPI of PDA-SWBDF was 4.0 mL and the FLHTHP(180℃,3.5 MPa)was 32.0 mL after aging at 220℃ for 16 h.Under high-temperature and high-salinity conditions,the combined effect of anti-polyelectrolyte and hydrophobic association allowed PDA to adsorb on the bentonite surface tightly.The sulfonic acid groups of PDA increased the negative electronegativity and the hydration film thickness on bentonite surface,which enhanced the colloidal stability,maintained the flattened lamellar structure of bentonite and formed an appropriate particle size distribution,resulting in the formation of dense mud cakes and reducing the filtration loss effectively.
文摘With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility.However,the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage(CMV)and neutral-point voltage(NPV)fluctuations,which can lead to electromagnetic interference and degrade transient performance.To address these challenges,an optimized virtual space vector pulse width modulation(OVSVPWM)strategy is proposed,aiming to suppress CMV and NPV simultaneously through coordinated multi-objective control.Specifically,a dynamic feedback mechanism is introduced to adjust the balancing factor of basic vectors in the synthesized virtual small vector in real-time,achieving autonomous balancing of the NPV.To address the excessive switching actions introduced by the OVSVPWM strategy,a phase duty ratio-based sequence reconstruction method is adopted,which reduces the total number of switching actions to half of the original.A zero-level buffering scheme is employed to reconstruct the single-phase voltage-level output sequence,achieving peak CMV suppression down to udc/6.Simulation results demonstrate that the proposed strategy significantly improves electromagnetic compatibility and operational stability while maintaining high power quality.
文摘For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.
基金supported by the NSFC(12271178,12171166)the Guangzhou Basic and Applied Basic Research Foundation(2024A04J2022)the TCL Young Scholar(2024-2027).
文摘In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with N≥1,m>0,p>1,such that m(p-1)>1.We give a clear classification of the self-similar solutions of the form u(x,t)=(βt)^(-α/β)((βt)^(-1/β)|x|)withα∈R andβ=α[m(p-1)-1]+p,regular or singular at the origin point.The existence and uniqueness of some solutions are established by the phase plane analysis method,and the asymptotic properties of the solutions near the origin and the infinity are also described.This paper extends the classical results of self-similar solutions for degeneratep-Laplace heat equation by Bidaut-Véron[Proc Royal Soc Edinburgh,2009,139:1-43]to the doubly nonlinear degenerate diffusion equations.
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.U21A2058 and U1860205)the Natural Science Funds of Hubei Province for Distinguished Young Scholars(Grant No.2020CFA088).
文摘Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten steel were investigated through steel casting tests.The results show that on the basis of surviving the thermal shock of molten steel,both filters can significantly reduce the number of non-metallic inclusions and total oxygen content of steel,thereby improving the cleanliness of the molten steel.After the thermal shock of molten steel,cracks were found in the microstructure of pure magnesia filter.Via the diffusion of non-metallic inclusions from steel into MgO grains of the filter to form solid solution,the inclusions were adsorbed to the internal and external surfaces of the pure magnesia filter.The number of inclusions was reduced by 62.5%,and the total oxygen content decreased from 0.892 to 0.265 wt.%after filtration,achieving a filtration efficiency of 70.3%.Compared with the pure magnesia filter,no cracks were found in the microstructure of the periclase-spinel filter.The mass transfer rate was accelerated due to the diffusion of inclusions from steel into MgO and MgAl2O4 grains of the filter,as well as the higher high-temperature liquid content and smaller pore structure of the filter.More non-metallic inclusions were able to enter the interior of the filter,which made the periclase-spinel filter more capable of adsorbing inclusions from steel and reducing total oxygen content.The periclase-spinel filter reduced the number of inclusions in steel by 84.4%and decreased the total oxygen content of the steel from 0.892 to 0.119 wt.%,with a filtration efficiency of 86.7%,demonstrating excellent comprehensive performance.
基金funded by the Universiti Teknologi Malaysia(UTM)through research Grant Number:06E05.
文摘The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.
基金Supported by the National Natural Science Foundation of China(No.82301211)Beijing Natural Science Foundation(No.J230028).
文摘AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.
基金supported by the BRICS STI Framework Programme(No.52261145703)the Higher Education Discipline Innovation Project(National 111 Project,No.B16016)the Guangxi Key Research and Development Plan Project(AB24010117).
文摘Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of photocatalysts or membrane materials to improve their catalytic and filtration performance,the complex structures and interface mechanisms,as well as insufficient light utilization,are still often overlooked,limiting the overall performance improvement of photocatalytic membranes.This work provides an overview of enhancement strategies involving restricted area effects,external fields,such as mechanical,magnetic,thermal,and electrical fields,as well as coupling techniques with advanced oxidation processes(e.g.,O_(3),Fenton,and persulfate oxidation)for dual enhancement of photocatalysts and membranes.In addition,the synthesis method of photocatalytic membranes and the influence of factors,such as light source type,frequency,and relative position on photocatalytic membrane performance were also studied.Finally,economic feasibility and pollutant removal performance were further evaluated to determine the promising enhancement strategies,paving the way for more efficient and scalable applications of photocatalytic membranes.
基金sponsored by the National Key R&D Program of China(No.2020YFC1910000)the National Natural Science Foundation of China(Grants No 51978153).
文摘Particulate matter(PM)from high-temperature emissions like chemical plants,coal stoves and vehicle exhausts poses a gravel challenge to human health.To address this issue,researchers have explored vari-ous fiber filters,yet the bulk struggle to withstand high temperatures.In this study,mullite fiber sponges were developed utilizing low-cost materials and Kármán vortex solution blow spinning,using surfac-tants to improve the spinnability of the sol.Optimized sponges demonstrate ultralight(19 mg cm^(-3)),temperature-resistant reversible compressibility(50% strain)and a water contact angle of 135°.These sponges exhibited exceptional thermal insulation(thermal conductivity:0.0256 W m^(-1) K^(-1))and per-formed well in high-temperature air filtration.At 800℃,the mullite sponge with a base weight of 35 mg cm^(-2),achieved an average filtration efficiency of 98.18%and 99.57% for PM_(2.5) and PM_(2.5-10),respectively,with a quality value of 0.98 Pa^(-1) at a wind speed of 4 cm s^(-1).This low-cost mullite fiber sponge offers a promising avenue for designing high-performance filtration materials.
基金funded by the Brazilian National Council for Scientific and Technological Development—CNPq(CNPq grant number 405997/2022-1)supported by the EMBRAPII VIRTUS Competence Center in Intelligent Hardware for Industry—VIRTUS-CC(MCTI grant number 055/2023).
文摘This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermodulation caused by the PWM strategy and converter topology interaction to estimate the capacitor parameters of the converter DC-link.It utilizes an observer-based structure consisting of a recursive noninteger sliding discrete Fourier transform(rnSDFT)and an RLS filter improved with a forgetting factor(oSDFT-RLS)to accurately estimate the capacitance and equivalent series resistance(ESR).Importantly,this method does not require additional sensors beyond those already installed in off-the-shelf 3L-NPC-VSI systems,ensuring its noninvasiveness.Furthermore,the oSDFTRLS estimates capacitor parameters in the time-frequency domain,enabling the tracking of capacitor degradation and predicting potential faults.Experimental results from the laboratory setup demonstrate the effectiveness of the proposed condition monitoring method.
文摘BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the longitudinal changes in measured glomerular filtration rate(mGFR)in patients with autosomal dominant polycystic kidney disease(ADPKD).METHODS Analysis of an ambispective data base conducted on consecutive patients diagnosed with ADPKD.The mGFR was assessed by iohexol clearance;while eGFR was calculated by three different formulas:(1)The chronic kidney disease epidemiology collaboration(CKD-EPI);(2)Modification of diet in renal disease(MDRD);and(3)The 24-hour urine creatinine clearance(CrCl).The primary end-points were the mean change in mGFR between the baseline and final visit,as well as the comparison of the mean change in mGFR with the change estimated by the different formulas.RESULTS Thirty-seven patients were included in the study.As compared to baseline,month-6 mGFR was significantly decrease by-4.4 mL/minute±10.3 mL/minute(P=0.0132).However,the CKD-EPI,MDRD,and CrCl formulas underestimated this change by 48.3%,89.0%,and 45.8%respectively,though none of these differences reached statistical significance(P=0.3647;P=0.0505;and P=0.736,respectively).The discrepancies between measured and estimated glomerular filtration rate values,as evaluated by CKD-EPI(r=0.29,P=0.086);MDRD(r=0.19,P=0.272);and CrCl(r=0.09,P=0.683),were not correlated with baseline mGFR values.CONCLUSION This study indicated that eGFR inaccurately reflects the decline in mGFR and cannot reliably track changes over time.This poses significant challenges for clinical decision-making,particularly in treatment strategies.
文摘Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regarding the best methods to estimate glomerular filtration rate(eGFR)in older adults.Several studies suggest the use of an age-adjusted definition to improve accuracy and avoid overdiagnosis.In contrast,some researchers argue that such changes could complicate the classification of chronic kidney disease(CKD).Several formulas,including the Modification of Diet in Renal Disease,CKD-Epidemiology Collaboration,and Cockcroft-Gault equations,are used to estimate eGFR.However,each of these formulas has significant limitations when applied to older adults,primarily due to sarcopenia and malnutrition,which greatly affect both muscle mass and creatinine levels.Alternative formulas,such as the Berlin Initiative Study and the Full Age Spectrum equations,provide more accurate estimates of values for older adults by accounting for age-related physiological changes.In frail older adults,the use of cystatin C leads to better eGFR calculations to assess renal function.Accurate eGFR measurements improve the health of older patients by enabling better medication dosing.A thorough approach that includes multiple calibrated diagnostic methods and a detailed geriatric assessment is necessary for the effective management of kidney disease and other age-related conditions in older adults.
文摘Aim A novel method has been developed for evaluation of the levels of total residual protein in antibiotics produced by fermentation using gel filtration chromatography (GFC) combined with Bradford assay based on determination of residual protein in lincomycin hydrochloride. Methods The chromatographic conditions were SuperdexTM peptide column, 0.01 mol*L-1 phosphate buffer solution as mobile phase, and flow rate of 1 mL·min-1. Five hundred microliters of lincomycin hydrochloride solution (3 g of lincomycin hydrochloride dissolved in 10 mL of mobile phase) was injected into the chromatograph and the eluted solution was collected between 6 min and 14.5 min (protein eluted from column within this period), and the residual content of total protein in the eluted solution was assayed using Bradford assay method. Results The average recovery was more than 90% for bovine serum albumin, the calibration equation for the range of 0-12 μg·mL-1 of protein was y=-0.002 4x2+0.064 2x+0.002 9, r2=0.999 9, RSD=0.1%-0.9%, and the LOD and LOQ were 3 and 10 ng·mL-1 of protein, respectively. Conclusion The novel method for determining the residual protein in ferment antibio-tics is simple, rapid, and precise.
