This paper addresses a fundamental question in rock mechanics:Are there Class II rocks?The historical development of servo-controlled rock testing machines is reviewed,followed by a brief review of some stiff testing ...This paper addresses a fundamental question in rock mechanics:Are there Class II rocks?The historical development of servo-controlled rock testing machines is reviewed,followed by a brief review of some stiff testing machines.The pioneering work of some researchers is reviewed,and the misconception of classifying rocks into Class I and Class II is discussed.The mechanism of post-peak Class II behavior is discussed based on some recent test results.When a brittle hard rock is tested using a soft testing machine under axial-strain-controlled loading,violent failure can occur when the peak strength is reached,and the post-peak stress-strain curve cannot be obtained.However,a Class II post-peak stress-strain curve can be obtained when the rock is tested under lateral-strain-controlled loading.If a stiff testing machine is used,Class I and Class II post-peak stress-strain curves will be obtained under axial-and lateral-strain-controlled loadings,respectively.It is therefore not appropriate to classify rocks into Class I or Class II rocks.The influences of other conditions,such as rock type,confinement,and specimen height-to-diameter ratio,on the type(Class I or Class II)of post-peak stress-strain curves are also discussed.Finally,some misconceptions in the rock mechanics community,stemming from the concept of“Class II rock”,are discussed.By clarifying these concepts related to Class I and Class II behaviors,this paper seeks to clarify misunderstandings and misapplications related to post-peak strength and deformation properties in the field.展开更多
Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the ...Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.展开更多
This paper addresses the performance degradation issue in a fast radio burst search pipeline based on deep learning.This issue is caused by the class imbalance of the radio frequency interference samples in the traini...This paper addresses the performance degradation issue in a fast radio burst search pipeline based on deep learning.This issue is caused by the class imbalance of the radio frequency interference samples in the training dataset,and one solution is applied to improve the distribution of the training data by augmenting minority class samples using a deep convolutional generative adversarial network.Experi.mental results demonstrate that retraining the deep learning model with the newly generated dataset leads to a new fast radio burst classifier,which effectively reduces false positives caused by periodic wide-band impulsive radio frequency interference,thereby enhancing the performance of the search pipeline.展开更多
BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic N...BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic Ni-Ti alloy wire(ISW)to address these conditions effectively.CASE SUMMARY A 17-year-old male patient presented with the chief complaint of an underbite.The patient was given a diagnosis of skeletal class III malocclusion and anterior crossbite.The orthodontic treatment plan was implemented and did not require teeth extractions or orthognathic surgery.Key interventions involved the app-lication of ISW,intermaxillary elastics,and ISW unilateral multi-bend edgewise archwire.The unique combination of these techniques enabled the correction without the need for extractions or surgery.This approach leverages the advanced biomechanical properties of ISW,including its super-elasticity and shape memory,to enhance treatment efficacy.The treatment lasted 17 months,and major improvements in overjet,overbite,and alignment were achieved.The results were favorable,and stability was discovered during follow-up.CONCLUSION The application of ISW for treating skeletal class III malocclusion with anterior crossbite in a 17-year-old male patient resulted in exceptional outcomes.The treatment led to a marked improvement in the patient’s facial profile and to proper overjet,overbite,and midline alignment.These results were maintained over a one-year follow-up,indicating that a minimally invasive orthodontic approach can effectively address complex skeletal discrepancies in adolescent patients.This case illustrates that with the careful use of advanced orthodontic techniques,major skeletal challenges can be resolved without resorting to surgical procedures.展开更多
BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully c...BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully corrected with improved super-elastic Ti-Ni alloy wire(ISW).CASE SUMMARY A 19 years old male came to our clinic with a chief complaint of anterior open bite and crossbite and not able to chew food well.Clinical examination revealed an angle class III malocclusion with anterior open bite,crossbite and spaced arch.Ra-diographic and clinical examination showed a skeletal class III pattern.We used ISW to level the upper and lower arch and to correct the anterior open bite and crossbite.Intermaxillary elastics were also used to achieve a better interdigitation.Finally,adequate overbite,overjet and a desirable occlusion were achieved.The active treatment time took 2 years and 2 months.CONCLUSION In a case of class III angular malocclusion with open bite and crossbite in the ante-rior teeth,ideal results were achieved using the ISW technique and the patient was satisfied with the outcome.展开更多
BACKGROUND This case report presents an innovative approach to managing a complex class II division 1 malocclusion with ectopic maxillary canines using a modified twin block(TB)appliance.The modification facilitated s...BACKGROUND This case report presents an innovative approach to managing a complex class II division 1 malocclusion with ectopic maxillary canines using a modified twin block(TB)appliance.The modification facilitated simultaneous skeletal correction and canine eruption,reducing treatment time and improving patient satisfaction.CASE SUMMARY A 14-year-old male presented with concerns about a retruded chin and spacing between teeth.Clinical and radiographic evaluation revealed a class II division 1 malocclusion on a moderate class II skeletal base,with palatally impacted maxillary canines.Treatment involved a modified Clark TB appliance designed with hooks to allow active traction of the canines,followed by comprehensive fixed orthodontics.Over 18 months,the patient achieved improved occlusion,corrected overjet and overbite,successful eruption of the impacted canines,and enhanced facial aesthetics.The final results showed significant dental and skeletal improvement without requiring surgical intervention.CONCLUSION A modified TB appliance can effectively manage class II malocclusion with impacted canines in growing patients.The modified approach combining functional mandibular advancement and active canine traction represents a lessdocumented clinical adaptation,offering a valuable,efficient alternative to traditional two-phase interventions.展开更多
[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-Whi...[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.展开更多
Objectives: In order to investigate the role of mono-cytes and human leukocyte antigen (HLA) class II an-tigen in herpes simplex virus-2 (HSV-2) infection, westudied the effect of HSV-2 infection in vitro on theexpres...Objectives: In order to investigate the role of mono-cytes and human leukocyte antigen (HLA) class II an-tigen in herpes simplex virus-2 (HSV-2) infection, westudied the effect of HSV-2 infection in vitro on theexpression of HLA class II antigen on monocytes.Methods: Monocytes were infected with HSV-2(Strain 333). Culture cells were collected 1, 3, 5 and 7days after infection. The levels of expression of HLAclass II antigen were measured by using alkaline phos-phatase antialkaline phosphatase method (APAAP).Results: The levels of the expression of HLA class IIantigen on monocytes significantly decreased on thefirst day of post-infection, and then gradually returnedto levels found in the controls by the 7th day post-infection.Conclusion: HLA class II antigen expression onmonocytes was inhibited with HSV-2 infection, whichmight be one means of virus escape at an early phase.The expression of HLA class II antigen may play animportant role in herpes simplex viurs-2 pathogenic-ity and immunity.展开更多
Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes over...Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes overtime, leading to class imbalance and concept drift issues. Both these issuescause model performance degradation. Most of the current work has beenfocused on developing an ensemble strategy by training a new classifier on thelatest data to resolve the issue. These techniques suffer while training the newclassifier if the data is imbalanced. Also, the class imbalance ratio may changegreatly from one input stream to another, making the problem more complex.The existing solutions proposed for addressing the combined issue of classimbalance and concept drift are lacking in understating of correlation of oneproblem with the other. This work studies the association between conceptdrift and class imbalance ratio and then demonstrates how changes in classimbalance ratio along with concept drift affect the classifier’s performance.We analyzed the effect of both the issues on minority and majority classesindividually. To do this, we conducted experiments on benchmark datasetsusing state-of-the-art classifiers especially designed for data stream classification.Precision, recall, F1 score, and geometric mean were used to measure theperformance. Our findings show that when both class imbalance and conceptdrift problems occur together the performance can decrease up to 15%. Ourresults also show that the increase in the imbalance ratio can cause a 10% to15% decrease in the precision scores of both minority and majority classes.The study findings may help in designing intelligent and adaptive solutionsthat can cope with the challenges of non-stationary data streams like conceptdrift and class imbalance.展开更多
将1.4kb Class I patatin基因的5′侧翼区与GUS基因融合,构建了双元表达载体pPATIs(含patatin部分信号顺序)和pPATI(不含patatin部分信号顺序)。pPATI通过基因枪介导在块茎切片中获得了瞬间表达。以上建构物通过农杆菌介导转入了马铃薯...将1.4kb Class I patatin基因的5′侧翼区与GUS基因融合,构建了双元表达载体pPATIs(含patatin部分信号顺序)和pPATI(不含patatin部分信号顺序)。pPATI通过基因枪介导在块茎切片中获得了瞬间表达。以上建构物通过农杆菌介导转入了马铃薯品种Desiree。X-Gluc染色(PATIs不能染色)及PCR结果证实已获得转基因植株。利用离体块茎诱导系统,GUS的表达进一步用荧光进行定量检测,结果显示,PATI-GUS的转基因植株中GUS比活性均以块茎明显高于茎段,达10-20倍。蔗糖浓度的升高,PATI-GUS植株中的GUS比活性无明显变化,与前人报道有不同。此外,光照促进PATI-GUS的表达。展开更多
Several phosphoinositide 3-kinase(PI3 K) inhibitors are currently approved to treat hematolymphatic malignant diseases worldwide, and many drugs that have the same target are in the clinical research stage. In March 2...Several phosphoinositide 3-kinase(PI3 K) inhibitors are currently approved to treat hematolymphatic malignant diseases worldwide, and many drugs that have the same target are in the clinical research stage. In March 2022,duvelisib became the first PI3 K inhibitor approved in China indicated for the treatment of hematolymphatic malignant diseases. Meanwhile, linperlisib and copanlisib have almost completed the technical review of the clinical specialty. The Center for Drug Evaluation(CDE) of the China National Medical Products Administration(NMPA) found that class I PI3 K inhibitors can cause various degrees of immune-related adverse events, which are associated with action mechanisms, affecting the benefit-risk assessment of the drugs. On April 21, 2021, the United States Food and Drug Administration(FDA) convened the Oncologic Drugs Advisory Committee(ODAC)meeting to discuss the safety of PI3 K inhibitors indicated for hematolymphatic malignancies and their related risk of death. The hematological tumor group of CDE of the China NMPA summarized and combined the data on PI3 K inhibitors listed or under technical review for marketing authorization applications and found that such products may have unique efficacy and safety characteristics in Chinese patients with malignant lymphoma.展开更多
BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during or...BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.展开更多
BACKGROUND Severe skeletal class II malocclusion is the indication for combined orthodontic and orthognathic treatment.CASE SUMMARY A woman with a chief complaint of a protruding chin and an inability to close her lip...BACKGROUND Severe skeletal class II malocclusion is the indication for combined orthodontic and orthognathic treatment.CASE SUMMARY A woman with a chief complaint of a protruding chin and an inability to close her lips requested orthodontic camouflage.The treatment plan consisted of extracting the right upper third molar,right lower third molar,left lower second molar,and left upper third molar and moving the maxillary dentition distally using a convenient method involving microimplant nail anchors,push springs,long arm traction hooks,and elastic traction chains.After 52 months of treatment,her overbite and overjet were normal,and her facial profile was favorable.CONCLUSION This method can be used for distal movement of the maxillary dentition and to correct severe skeletal class II malocclusion in adults.展开更多
Objective： To investigate the expression change of human leukocyte antigen （HLA） class I on human peripheral blood mononuclear ceils （PBMCs） at both mRNA and protein levels, and to evaluate its roles in the devel...Objective： To investigate the expression change of human leukocyte antigen （HLA） class I on human peripheral blood mononuclear ceils （PBMCs） at both mRNA and protein levels, and to evaluate its roles in the development of colorectal cancer （CRC）. Methods： In the present study, 50 patients with CRC, 35 patients with benign colorectal lesion and 42 healthy volunteers were enrolled. Expression levels of HLA class I mRNA and protein were determined using real-time quantitative reverse transcription PCR （RT-PCR） and flow cytometry analysis, respectively. Results： The expression levels of HLA class I mRNA and proteins were not influenced by age and gender. The relative ratios of HLA class I mRNA were 0.99±0.27 in healthy controls, 0.76±0.19 in benign patients, and 0.48±0.21 in CRC patients. Mean fluorescence intensities of HLA class I were 145.58±38.14 in healthy controls, 102.05±35.98 in benign patients and 87.44±34.01 in CRC patients. HLA class I on PBMCs was significantly down-regulated at both mRNA and protein levels in patients with stage III and IV CRC. CRC patients with lymph node metastasis also showed a decreased HLA class I expression at protein level. Conclusion： HLA class I expressions on PBMCs are associated with staging of CRC and lymph node metastasis. Monitoring the expression of HLA class I on PBMCs may provide useful information for diagnosis and metastasis judgement of CRC.展开更多
The major histocompatibility complex （MHC） is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and- deat...The major histocompatibility complex （MHC） is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and- death evolution, gene conversion, and concerted evolution. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. However, the investigation of this region in nonavian reptiles is still in its infancy. We present the first characterization of MHC class I genes in a species from the family Lacertidae. We assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 4 among 37 individuals of Eremias multiocellata from a population in Lanzhou, China. We generated 67 distinct DNA sequences using cloning and sequencing methods, and identified 36 putative functional variants as well as two putative pseudogene-variants. We found the number of variants within an individual varying between two and seven, indicating that there are at least four MHC class I loci in this species. Gene duplication plays a role in increasing copy numbers of MHC genes and allelic diversity in this species. The class I exon 4 sequences are characteristic of low nucleotide diversity. No signal of recombination is detected, but purifying selection is detected in β2-microglobulin interaction sites and some other silent sites outside of the function-constraint regions. Certain identical alleles are shared by Eremias multiocellata and E. przewalskii and E. brenchleyi, suggesting trans-species polymorphism. The data are compatible with a birth-and-death model of evolution.展开更多
The study of machine learning has revealed that it can unleash new applications in a variety of disciplines.Many limitations limit their expressiveness,and researchers are working to overcome them to fully exploit the...The study of machine learning has revealed that it can unleash new applications in a variety of disciplines.Many limitations limit their expressiveness,and researchers are working to overcome them to fully exploit the power of data-driven machine learning(ML)and deep learning(DL)techniques.The data imbalance presents major hurdles for classification and prediction problems in machine learning,restricting data analytics and acquiring relevant insights in practically all real-world research domains.In visual learning,network information security,failure prediction,digital marketing,healthcare,and a variety of other domains,raw data suffers from a biased data distribution of one class over the other.This article aims to present a taxonomy of the approaches for handling imbalanced data problems and their comparative study on the classification metrics and their application areas.We have explored very recent trends of techniques employed for solutions to class imbalance problems in datasets and have also discussed their limitations.This article has also identified open challenges for further research in the direction of class data imbalance.展开更多
The eutectic high entropy alloys have attracted extensive attention and are considered one of the most promising new metal materials.The microstructures of large eutectic high entropy alloy ingot with excellent castin...The eutectic high entropy alloys have attracted extensive attention and are considered one of the most promising new metal materials.The microstructures of large eutectic high entropy alloy ingot with excellent casting performance have been rarely reported.In this study,we have prepared a ton class eutectic high entropy alloy ingot via vacuum induction melting for the first time.The evolution of microstructure and macro-segregation from the edge region to the core of the ingot were also revealed.It was found that there was no significant macro-segregation in ton class eutectic high entropy alloy ingot,and chemical elements were distributed uniformly.The coupled growth of the primary phases and eutectic colonies were homogeneously distributed in the ingot,and there is no traditional columnar grain region from the edge region of the ingot to the core.The tensile strength of the sample in the R/2 region of the ton class ingot with elongation greater than 10%is 892.3 MPa,showing an excellent comprehensive mechanical property.This study exhibits an important guidance for the industrial application of large eutectic high entropy alloy casting ingot.展开更多
With the rise of internet facilities,a greater number of people have started doing online transactions at an exponential rate in recent years as the online transaction system has eliminated the need of going to the ba...With the rise of internet facilities,a greater number of people have started doing online transactions at an exponential rate in recent years as the online transaction system has eliminated the need of going to the bank physically for every transaction.However,the fraud cases have also increased causing the loss of money to the consumers.Hence,an effective fraud detection system is the need of the hour which can detect fraudulent transactions automatically in real-time.Generally,the genuine transactions are large in number than the fraudulent transactions which leads to the class imbalance problem.In this research work,an online transaction fraud detection system using deep learning has been proposed which can handle class imbalance problem by applying algorithm-level methods which modify the learning of the model to focus more on the minority class i.e.,fraud transactions.A novel loss function named Weighted Hard-Reduced Focal Loss(WH-RFL)has been proposed which has achieved maximum fraud detection rate i.e.,True PositiveRate(TPR)at the cost of misclassification of few genuine transactions as high TPR is preferred over a high True Negative Rate(TNR)in fraud detection system and same has been demonstrated using three publicly available imbalanced transactional datasets.Also,Thresholding has been applied to optimize the decision threshold using cross-validation to detect maximum number of frauds and it has been demonstrated by the experimental results that the selection of the right thresholding method with deep learning yields better results.展开更多
基金the Natural Science and Engineering Research Council of Canada(RGPIN/4052-16,ALLRP 560390-20).
文摘This paper addresses a fundamental question in rock mechanics:Are there Class II rocks?The historical development of servo-controlled rock testing machines is reviewed,followed by a brief review of some stiff testing machines.The pioneering work of some researchers is reviewed,and the misconception of classifying rocks into Class I and Class II is discussed.The mechanism of post-peak Class II behavior is discussed based on some recent test results.When a brittle hard rock is tested using a soft testing machine under axial-strain-controlled loading,violent failure can occur when the peak strength is reached,and the post-peak stress-strain curve cannot be obtained.However,a Class II post-peak stress-strain curve can be obtained when the rock is tested under lateral-strain-controlled loading.If a stiff testing machine is used,Class I and Class II post-peak stress-strain curves will be obtained under axial-and lateral-strain-controlled loadings,respectively.It is therefore not appropriate to classify rocks into Class I or Class II rocks.The influences of other conditions,such as rock type,confinement,and specimen height-to-diameter ratio,on the type(Class I or Class II)of post-peak stress-strain curves are also discussed.Finally,some misconceptions in the rock mechanics community,stemming from the concept of“Class II rock”,are discussed.By clarifying these concepts related to Class I and Class II behaviors,this paper seeks to clarify misunderstandings and misapplications related to post-peak strength and deformation properties in the field.
基金supported by the Sinopec Technology Research and Development Project(No.30000000-22-ZC0607-0235,No.33550000-22-ZC0607-0009)the National Natural Science Foundation of China(No.52334002).
文摘Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.
基金supported by the Chinese Academy of Science"Light of West China"Program(2022-XBQNXZ-015)the National Natural Science Foundation of China(11903071)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China and administered by the Chinese Academy of Sciences。
文摘This paper addresses the performance degradation issue in a fast radio burst search pipeline based on deep learning.This issue is caused by the class imbalance of the radio frequency interference samples in the training dataset,and one solution is applied to improve the distribution of the training data by augmenting minority class samples using a deep convolutional generative adversarial network.Experi.mental results demonstrate that retraining the deep learning model with the newly generated dataset leads to a new fast radio burst classifier,which effectively reduces false positives caused by periodic wide-band impulsive radio frequency interference,thereby enhancing the performance of the search pipeline.
文摘BACKGROUND Correcting skeletal class III malocclusion with anterior crossbite in adolescents using only orthodontic treatment poses challenges.This report highlights a novel approach leveraging improved superelastic Ni-Ti alloy wire(ISW)to address these conditions effectively.CASE SUMMARY A 17-year-old male patient presented with the chief complaint of an underbite.The patient was given a diagnosis of skeletal class III malocclusion and anterior crossbite.The orthodontic treatment plan was implemented and did not require teeth extractions or orthognathic surgery.Key interventions involved the app-lication of ISW,intermaxillary elastics,and ISW unilateral multi-bend edgewise archwire.The unique combination of these techniques enabled the correction without the need for extractions or surgery.This approach leverages the advanced biomechanical properties of ISW,including its super-elasticity and shape memory,to enhance treatment efficacy.The treatment lasted 17 months,and major improvements in overjet,overbite,and alignment were achieved.The results were favorable,and stability was discovered during follow-up.CONCLUSION The application of ISW for treating skeletal class III malocclusion with anterior crossbite in a 17-year-old male patient resulted in exceptional outcomes.The treatment led to a marked improvement in the patient’s facial profile and to proper overjet,overbite,and midline alignment.These results were maintained over a one-year follow-up,indicating that a minimally invasive orthodontic approach can effectively address complex skeletal discrepancies in adolescent patients.This case illustrates that with the careful use of advanced orthodontic techniques,major skeletal challenges can be resolved without resorting to surgical procedures.
文摘BACKGROUND Orthodontic treatment for open bite and crossbite cases is always challenging.In this paper,we demonstrate a skeletal class III patient with anterior open bite and crossbite whose problem was successfully corrected with improved super-elastic Ti-Ni alloy wire(ISW).CASE SUMMARY A 19 years old male came to our clinic with a chief complaint of anterior open bite and crossbite and not able to chew food well.Clinical examination revealed an angle class III malocclusion with anterior open bite,crossbite and spaced arch.Ra-diographic and clinical examination showed a skeletal class III pattern.We used ISW to level the upper and lower arch and to correct the anterior open bite and crossbite.Intermaxillary elastics were also used to achieve a better interdigitation.Finally,adequate overbite,overjet and a desirable occlusion were achieved.The active treatment time took 2 years and 2 months.CONCLUSION In a case of class III angular malocclusion with open bite and crossbite in the ante-rior teeth,ideal results were achieved using the ISW technique and the patient was satisfied with the outcome.
文摘BACKGROUND This case report presents an innovative approach to managing a complex class II division 1 malocclusion with ectopic maxillary canines using a modified twin block(TB)appliance.The modification facilitated simultaneous skeletal correction and canine eruption,reducing treatment time and improving patient satisfaction.CASE SUMMARY A 14-year-old male presented with concerns about a retruded chin and spacing between teeth.Clinical and radiographic evaluation revealed a class II division 1 malocclusion on a moderate class II skeletal base,with palatally impacted maxillary canines.Treatment involved a modified Clark TB appliance designed with hooks to allow active traction of the canines,followed by comprehensive fixed orthodontics.Over 18 months,the patient achieved improved occlusion,corrected overjet and overbite,successful eruption of the impacted canines,and enhanced facial aesthetics.The final results showed significant dental and skeletal improvement without requiring surgical intervention.CONCLUSION A modified TB appliance can effectively manage class II malocclusion with impacted canines in growing patients.The modified approach combining functional mandibular advancement and active canine traction represents a lessdocumented clinical adaptation,offering a valuable,efficient alternative to traditional two-phase interventions.
基金Supported by National Natural Science Foundation of China(31201949,31172362)~~
文摘[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.
文摘Objectives: In order to investigate the role of mono-cytes and human leukocyte antigen (HLA) class II an-tigen in herpes simplex virus-2 (HSV-2) infection, westudied the effect of HSV-2 infection in vitro on theexpression of HLA class II antigen on monocytes.Methods: Monocytes were infected with HSV-2(Strain 333). Culture cells were collected 1, 3, 5 and 7days after infection. The levels of expression of HLAclass II antigen were measured by using alkaline phos-phatase antialkaline phosphatase method (APAAP).Results: The levels of the expression of HLA class IIantigen on monocytes significantly decreased on thefirst day of post-infection, and then gradually returnedto levels found in the controls by the 7th day post-infection.Conclusion: HLA class II antigen expression onmonocytes was inhibited with HSV-2 infection, whichmight be one means of virus escape at an early phase.The expression of HLA class II antigen may play animportant role in herpes simplex viurs-2 pathogenic-ity and immunity.
基金The authors would like to extend their gratitude to Universiti Teknologi PETRONAS (Malaysia)for funding this research through grant number (015LA0-037).
文摘Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes overtime, leading to class imbalance and concept drift issues. Both these issuescause model performance degradation. Most of the current work has beenfocused on developing an ensemble strategy by training a new classifier on thelatest data to resolve the issue. These techniques suffer while training the newclassifier if the data is imbalanced. Also, the class imbalance ratio may changegreatly from one input stream to another, making the problem more complex.The existing solutions proposed for addressing the combined issue of classimbalance and concept drift are lacking in understating of correlation of oneproblem with the other. This work studies the association between conceptdrift and class imbalance ratio and then demonstrates how changes in classimbalance ratio along with concept drift affect the classifier’s performance.We analyzed the effect of both the issues on minority and majority classesindividually. To do this, we conducted experiments on benchmark datasetsusing state-of-the-art classifiers especially designed for data stream classification.Precision, recall, F1 score, and geometric mean were used to measure theperformance. Our findings show that when both class imbalance and conceptdrift problems occur together the performance can decrease up to 15%. Ourresults also show that the increase in the imbalance ratio can cause a 10% to15% decrease in the precision scores of both minority and majority classes.The study findings may help in designing intelligent and adaptive solutionsthat can cope with the challenges of non-stationary data streams like conceptdrift and class imbalance.
文摘将1.4kb Class I patatin基因的5′侧翼区与GUS基因融合,构建了双元表达载体pPATIs(含patatin部分信号顺序)和pPATI(不含patatin部分信号顺序)。pPATI通过基因枪介导在块茎切片中获得了瞬间表达。以上建构物通过农杆菌介导转入了马铃薯品种Desiree。X-Gluc染色(PATIs不能染色)及PCR结果证实已获得转基因植株。利用离体块茎诱导系统,GUS的表达进一步用荧光进行定量检测,结果显示,PATI-GUS的转基因植株中GUS比活性均以块茎明显高于茎段,达10-20倍。蔗糖浓度的升高,PATI-GUS植株中的GUS比活性无明显变化,与前人报道有不同。此外,光照促进PATI-GUS的表达。
文摘Several phosphoinositide 3-kinase(PI3 K) inhibitors are currently approved to treat hematolymphatic malignant diseases worldwide, and many drugs that have the same target are in the clinical research stage. In March 2022,duvelisib became the first PI3 K inhibitor approved in China indicated for the treatment of hematolymphatic malignant diseases. Meanwhile, linperlisib and copanlisib have almost completed the technical review of the clinical specialty. The Center for Drug Evaluation(CDE) of the China National Medical Products Administration(NMPA) found that class I PI3 K inhibitors can cause various degrees of immune-related adverse events, which are associated with action mechanisms, affecting the benefit-risk assessment of the drugs. On April 21, 2021, the United States Food and Drug Administration(FDA) convened the Oncologic Drugs Advisory Committee(ODAC)meeting to discuss the safety of PI3 K inhibitors indicated for hematolymphatic malignancies and their related risk of death. The hematological tumor group of CDE of the China NMPA summarized and combined the data on PI3 K inhibitors listed or under technical review for marketing authorization applications and found that such products may have unique efficacy and safety characteristics in Chinese patients with malignant lymphoma.
基金Natural Science Foundation of Jiangsu Province, No. SBK2021021787the Major Project of the Health Commission ofJiangsu Province, No. ZD2022025and the Key Project of the Nanjing Health Commission, No. ZKX20048.
文摘BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.
基金Supported by Medical Science Research Project Plan by Health Commission of the Hebei Province,No.20220063.
文摘BACKGROUND Severe skeletal class II malocclusion is the indication for combined orthodontic and orthognathic treatment.CASE SUMMARY A woman with a chief complaint of a protruding chin and an inability to close her lips requested orthodontic camouflage.The treatment plan consisted of extracting the right upper third molar,right lower third molar,left lower second molar,and left upper third molar and moving the maxillary dentition distally using a convenient method involving microimplant nail anchors,push springs,long arm traction hooks,and elastic traction chains.After 52 months of treatment,her overbite and overjet were normal,and her facial profile was favorable.CONCLUSION This method can be used for distal movement of the maxillary dentition and to correct severe skeletal class II malocclusion in adults.
基金supported by Shandong Province Natural Science Foundation (No. Y2008C104)Shandong Province Science Foundation for Key Program (No. 2007GG20002027,2008GG2NS02016 and 2009GG10002043)
文摘Objective： To investigate the expression change of human leukocyte antigen （HLA） class I on human peripheral blood mononuclear ceils （PBMCs） at both mRNA and protein levels, and to evaluate its roles in the development of colorectal cancer （CRC）. Methods： In the present study, 50 patients with CRC, 35 patients with benign colorectal lesion and 42 healthy volunteers were enrolled. Expression levels of HLA class I mRNA and protein were determined using real-time quantitative reverse transcription PCR （RT-PCR） and flow cytometry analysis, respectively. Results： The expression levels of HLA class I mRNA and proteins were not influenced by age and gender. The relative ratios of HLA class I mRNA were 0.99±0.27 in healthy controls, 0.76±0.19 in benign patients, and 0.48±0.21 in CRC patients. Mean fluorescence intensities of HLA class I were 145.58±38.14 in healthy controls, 102.05±35.98 in benign patients and 87.44±34.01 in CRC patients. HLA class I on PBMCs was significantly down-regulated at both mRNA and protein levels in patients with stage III and IV CRC. CRC patients with lymph node metastasis also showed a decreased HLA class I expression at protein level. Conclusion： HLA class I expressions on PBMCs are associated with staging of CRC and lymph node metastasis. Monitoring the expression of HLA class I on PBMCs may provide useful information for diagnosis and metastasis judgement of CRC.
基金supported by the Science and Technology Project for Outstanding Youths in Life Science (KSCX2-EW-Q-6) from the Chinese Academy of SciencesNational Natural Science Foundation of China (31272281)
文摘The major histocompatibility complex （MHC） is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and- death evolution, gene conversion, and concerted evolution. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. However, the investigation of this region in nonavian reptiles is still in its infancy. We present the first characterization of MHC class I genes in a species from the family Lacertidae. We assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 4 among 37 individuals of Eremias multiocellata from a population in Lanzhou, China. We generated 67 distinct DNA sequences using cloning and sequencing methods, and identified 36 putative functional variants as well as two putative pseudogene-variants. We found the number of variants within an individual varying between two and seven, indicating that there are at least four MHC class I loci in this species. Gene duplication plays a role in increasing copy numbers of MHC genes and allelic diversity in this species. The class I exon 4 sequences are characteristic of low nucleotide diversity. No signal of recombination is detected, but purifying selection is detected in β2-microglobulin interaction sites and some other silent sites outside of the function-constraint regions. Certain identical alleles are shared by Eremias multiocellata and E. przewalskii and E. brenchleyi, suggesting trans-species polymorphism. The data are compatible with a birth-and-death model of evolution.
文摘The study of machine learning has revealed that it can unleash new applications in a variety of disciplines.Many limitations limit their expressiveness,and researchers are working to overcome them to fully exploit the power of data-driven machine learning(ML)and deep learning(DL)techniques.The data imbalance presents major hurdles for classification and prediction problems in machine learning,restricting data analytics and acquiring relevant insights in practically all real-world research domains.In visual learning,network information security,failure prediction,digital marketing,healthcare,and a variety of other domains,raw data suffers from a biased data distribution of one class over the other.This article aims to present a taxonomy of the approaches for handling imbalanced data problems and their comparative study on the classification metrics and their application areas.We have explored very recent trends of techniques employed for solutions to class imbalance problems in datasets and have also discussed their limitations.This article has also identified open challenges for further research in the direction of class data imbalance.
基金supported by the Natural Science Basic Research of Shaanxi(No.2022JC-28).
文摘The eutectic high entropy alloys have attracted extensive attention and are considered one of the most promising new metal materials.The microstructures of large eutectic high entropy alloy ingot with excellent casting performance have been rarely reported.In this study,we have prepared a ton class eutectic high entropy alloy ingot via vacuum induction melting for the first time.The evolution of microstructure and macro-segregation from the edge region to the core of the ingot were also revealed.It was found that there was no significant macro-segregation in ton class eutectic high entropy alloy ingot,and chemical elements were distributed uniformly.The coupled growth of the primary phases and eutectic colonies were homogeneously distributed in the ingot,and there is no traditional columnar grain region from the edge region of the ingot to the core.The tensile strength of the sample in the R/2 region of the ton class ingot with elongation greater than 10%is 892.3 MPa,showing an excellent comprehensive mechanical property.This study exhibits an important guidance for the industrial application of large eutectic high entropy alloy casting ingot.
基金This research was supported by Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(P0012724,The Competency Development Program for Industry Specialist)and the Soonchunhyang University Research Fund.
文摘With the rise of internet facilities,a greater number of people have started doing online transactions at an exponential rate in recent years as the online transaction system has eliminated the need of going to the bank physically for every transaction.However,the fraud cases have also increased causing the loss of money to the consumers.Hence,an effective fraud detection system is the need of the hour which can detect fraudulent transactions automatically in real-time.Generally,the genuine transactions are large in number than the fraudulent transactions which leads to the class imbalance problem.In this research work,an online transaction fraud detection system using deep learning has been proposed which can handle class imbalance problem by applying algorithm-level methods which modify the learning of the model to focus more on the minority class i.e.,fraud transactions.A novel loss function named Weighted Hard-Reduced Focal Loss(WH-RFL)has been proposed which has achieved maximum fraud detection rate i.e.,True PositiveRate(TPR)at the cost of misclassification of few genuine transactions as high TPR is preferred over a high True Negative Rate(TNR)in fraud detection system and same has been demonstrated using three publicly available imbalanced transactional datasets.Also,Thresholding has been applied to optimize the decision threshold using cross-validation to detect maximum number of frauds and it has been demonstrated by the experimental results that the selection of the right thresholding method with deep learning yields better results.
