Frost deformation and microstructure evolution of porous rock under uniform and unidirectional freeze-thaw conditions

The frost deterioration and deformation of porous rock are commonly investigated under uniform freeze-thaw(FT)conditions.However,the unidirectional FT condition,which is also prevalent in engineering practice,has received limited attention.Therefore,a comparative study on frost deformation and microstructure evolution of porous rock under both uniform and unidirectional FT conditions was performed.Firstly,frost deformation experiments of rock were conducted under cyclic uniform and unidirectional FT action,respectively.Results illustrate that frost deformation of saturated rock exhibits isotropic characteristics under uniform FT cycles,while it shows anisotropic characteristics under unidirectional FT condition with both the frost heaving strain and residual strain along FT direction much higher than those perpendicular to FT direction.Moreover,the peak value and residual value of cumulative frost strain vary as logarithmic functions with cycle number under both uniform and unidirectional FT conditions.Subsequently,the microstructure evolution of rock suffered cyclic uniform and unidirectional FT action were measured.Under uniform FT cycles,newly generated pores uniformly distribute in rock and pore structure of rock remains isotropic in micro scale,and thus the frost deformation shows isotropic characteristics in macro scale.Under unidirectional FT cycles,micro-cracks or pore belts generate with their orientation nearly perpendicular to the FT direction,and rock structure gradually becomes anisotropic in micro scale,resulting in the anisotropic characteristics of frost deformation in macro scale.

Fractal Study on the Evolution of Micro-Pores in Concrete Under Freeze-Thaw

After exposure to freeze-thaw cycles, scanning electron microscopy(SEM) and nuclear magnetic resonance(NMR) were used to test the four mixtures. The microstructure is qualitatively analyzed from the 2D SEM image and the 3D pore distribution curve before and after freezing and thawing. The fractal dimension is utilized to characterize the two-dimensional topography image and the three-dimensional pore distribution, quantitatively. The results reveal that the surface porosity and volume porosity increase as the freeze-thaw action increases. Self-similarity characteristics exist in micro-damage inside the concrete. In the fractal dimension, it is possible to characterize pore evolution quantitatively. The fractal dimension correlates with pore damage evolution. The fractal dimension effectively quantitatively characterizes micro-damage features at various scales from the local to the global level.

Freeze-thaw cycles and associated geomorphology in a post-glacial environment:current glacial,paraglacial,periglacial and proglacial scenarios at Pico de Orizaba volcano,Mexico

The glacial history of Pico de Orizaba indicates that during the Last Glacial Maximum,its icecap covered up to~3000 m asl;due to the air temperature increasing,its main glacier has retreated to 5050 m asl.The retraction of the glacier has left behind an intense climatic instability that causes a high frequency of freeze-thaw cycles of great intensity;the resulting geomorphological processes are represented by the fragmentation of the bedrock that occupies the upper parts of the mountain.There is a notable lack of studies regarding the fragmentation and erosion occurring in tropical high mountains,and the associated geomorphological risks;for this reason,as a first stage of future continuous research,this study analyzes the freezing and thawing cycles that occur above 4000 m asl,through continuous monitoring of surface ground temperature.The results allow us to identify and characterize four zones:glacial,paraglacial,periglacial and proglacial.It was found that the paraglacial zone presents an intense drop of temperature,of up to~9℃ in only sixty minutes.The rock fatigue and intense freeze-thaw cycles that occur in this area are responsible for the high rate of rock disintegration and represent the main factor of the constant slope dynamics that occur at the site.This activity decreases,both in frequency and intensity,according to the distance to the glacier,which is where the temperature presents a certain degree of stability,until reaching the proglacial zone,where cycles are almost non-existent,and therefore there is no gelifraction activity.The geomorphological processes have resulted in significant alterations to the mountain slopes,which can have severe consequences in terms of risk and water.

Effect of sodium starch octenyl succinate-based Pickering emulsion on the physicochemical properties of hairtail myofibrillar protein gel subjected to multiple freeze-thaw cycles

A Pickering emulsion based on sodium starch octenyl succinate(SSOS)was prepared and its effects on the physicochemical properties of hairtail myofibrillar protein gels(MPGs)subjected to multiple freeze-thaw(F-T)cycles were investigated.The whiteness,water-holding capacity,storage modulus(G')and texture properties of the MPGs were significantly improved by adding 1%-2%Pickering emulsion(P<0.05).Meanwhile,Raman spectral analysis demonstrated that Pickering emulsion promoted the transformation of secondary structure,enhanced hydrogen bonds and hydrophobic interactions,and promoted the transition of disulfide bond conformation from g-g-g to g-g-t and t-g-t.At an emulsion concentration of 2%,theα-helix content decreased by 10.37%,while theβ-sheet content increased by 7.94%,compared to the control.After F-T cycles,the structure of the MPGs was destroyed,with an increase in hardness and a decrease in whiteness and water-holding capacity,however,the quality degradation of MPGs was reduced with 1%-2%Pickering emulsion.These findings demonstrated that SSOS-Pickering emulsions,as potential fat substitutes,can enhance the gel properties and the F-T stability of MPGs.

Surrounding rock pressure in the tunnel portal section through moraine under freeze-thaw action

Moraines,characterized by the accumulation of rock and soil debris transported by glacial activity,present unique challenges for tunnel construction,particularly in portal sections,due to prevailing geographical and climatic conditions that facilitate freeze-thaw action.Despite these challenges,there is a dearth of studies investigating the influence of freeze-thaw action and water content on the mechanical properties of moraines,and no research on calculating surrounding rock pressure in moraine tunnels subjected to freeze-thaw conditions.In this study,direct shear tests under freeze-thaw cycles were conducted to examine the effects of freeze-thaw cycles and water content on the mechanical properties of frozen moraine.A comprehensive parameter K,integrating the number of freeze-thaws and water content,was introduced to model cohesion c.Drawing on Terzaghi Theory,we propose an improved algorithm for calculating surrounding rock pressure at the portal section of moraine tunnels.Using a tunnel as a case study,surrounding rock pressure was calculated under various conditions to validate the Improved Algorithm's efficacy.The results show that:(1)Strength loss exhibits a linear trend with the number of freeze-thaw cycles at water content levels of 4%and 8%,while at 12%water content,previous freeze-thaw cycles induce more significant damage to the soil.(2)Moraine saturation peaks between 8%and 12%water content.Following repeated freeze-thaw cycles,moraine shear strength initially increases before decreasing with varying water content.(3)The internal friction angle of moraine experiences slight reductions with prolonged freeze-thaw cycles,but both freeze-thaw cycles and water content significantly influence cohesion.(4)Vertical surrounding rock pressure increases after the initial freeze-thaw cycle,particularly with higher water content,although freeze-thaw cycles have minimal effect on it.(5)Freeze-thaw cycles lead to a substantial increase in lateral surrounding rock pressure,necessitating reinforced support structures at the arch wall,arch waist,and arch foot in engineering projects to mitigate freeze-thaw effects.This study provides a foundation for designing and selecting tunnel support structures in similar geological conditions.

Coupling Effect of Cryogenic Freeze-Thaw Cycles and Chloride Ion Erosion Effect in Pre-Cracked Reinforced Concrete

Chloride (Cl−) ion erosion effects can seriously impact the safety and service life of marine liquefied natural gas(LNG) storage tanks and other polar offshore structures. This study investigates the impact of different low-temperaturecycles (20°C, –80°C, and −160°C) and concrete specimen crack widths (0, 0.3, and 0.6 mm) on the Cl−ion diffusion performance through rapid erosion tests conducted on pre-cracked concrete. The results show thatthe minimum temperature and crack width of freeze-thaw cycles enhance the erosive effect of chloride ions. TheCl− ion concentration and growth rate increased with the increasing crack width. Based on the experimental modeland in accordance with Fick’s second law of diffusion, the Cl− ion diffusion equation was modified by introducingcorrection factors in consideration of the freeze-thaw temperature, crack width, and their coupling effect.The experimental and fitting results obtained from this model can provide excellent reference for practical engineeringapplications.

Prostate cancer with elevated free prostate-specific antigen density:A case report

BACKGROUND Prostate cancer is the second most common cancer among men worldwide,and prostate-specific antigen(PSA)is often used in clinical practice to screen for prostate cancer.Normal total PSA(tPSA)level initially excludes prostate cancer.Here,we report a case of prostate cancer with elevated free PSA density(fPSAD).CASE SUMMARY A patient diagnosed with benign prostatic hyperplasia underwent prostatectomy,and the postoperative pathological results showed acinar adenocarcinoma of the prostate.The patient is currently undergoing endocrine chemotherapy.CONCLUSION We provide a clinical reference for diagnosis and treatment of patients with normal tPSA but elevated fPSAD.

Repair of Second-Generation Recycled Fine Aggregate of Waste Concrete from Freeze-Thaw Environment by Carbonation Treatment

The reuse of waste recycled concrete from harsh environments has become a research hotspot in the field of construction.This study investigated the repair effect of carbonation treatment on second-generation recycled fine aggregate(SRFA)obtained from recycled fine aggregate concrete(RFAC)subjected to freeze-thaw(FT)cycles.Before and after carbonation,the properties of SRFA were evaluated.Carbonated second-generation recycled fine aggregate(CSRFA)at five substitution rates(0%,25%,50%,75%,100%)to replace SRFA was used to prepare carbonated second-generation recycled fine aggregate concrete(CSRFAC).The water absorption,porosity and mechanical properties of CSRFAC were tested,and its frost-resisting durability was evaluated.The results showed after carbonation treatment,the physical properties of SRFA was improved and met the requirements of II aggregate.The micro-hardness of the interfacial transition zone and attached mortar in CSRFA was 50.5%and 31.2%higher than that in SRFA,respectively.With the increase of CSRFA replacement rate,the water absorption and porosity of CSRFAC gradually decreased,and the mechanical properties and frost resistance of CSRFAC were gradually improved.Carbonation treatment effectively repairs the damage of SRFA caused by FT cycles and improves its application potential.

Spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice in multiple dimensions during 1979 to 2020

Arctic sea ice is broadly regarded as an indicator and amplifier of global climate change.The rapid changes in Arctic sea ice have been widely concerned.However,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time series.In this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation data.The results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in winter.Spatially,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian Sea.Regarding to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in summer.For SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all seasons.Furthermore,a striking freeze-thaw asymmetry of Arctic sea ice was also detected.Comparing sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical dimension.The amount of sea ice melting and freezing was disequilibrium in the Arctic during the considered period,and the rate of sea ice melting was 0.3×10^(4) km^(2)/a and 0.01 cm/a higher than that of freezing in the horizontal and vertical dimensions,respectively.Moreover,there were notable shifts in the melting and freezing of Arctic sea ice in 1997/2003 and 2000/2004,respectively,in the horizontal/vertical dimension.

Antigen epitopes of animal coronaviruses:a mini-review

Coronaviruses are widespread in nature and can infect mammals and poultry,making them a public health concern.Globally,prevention and control of emerging and re-emerging animal coronaviruses is a great challenge.The mecha-nisms of virus-mediated immune responses have important implications for research on virus prevention and control.The antigenic epitope is a chemical group capable of stimulating the production of antibodies or sensitized lympho-cytes,playing an important role in antiviral immune responses.Thus,it can shed light on the development of diagnos-tic methods and novel vaccines.Here,we have reviewed advances in animal coronavirus antigenic epitope research,aiming to provide a reference for the prevention and control of animal and human coronaviruses.

Prevalence and Factors Associated with Positivity of Antinuclear Antibodies (ANA) Patterns, Native Anti-DNA and Extractable Nuclear Antigens (ENA) Antibodies: Experience from a Laboratory in Dakar

Background: Diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) are sensitive screening tests but anti-deoxyribonucleic acid-antibody (anti-DNA), and anti-extractable nuclear antigens (anti-ENA) are specific for AIDs. We aimed to look at ANA patterns in our patients and correlated them with anti-ENA for proper interpretation and better patient management cost-effectively. Methods: A retrospective study was conducted over 1 year from January to December 2022 who were tested for ANA at biology medical laboratory of Pasteur Institute of Dakar. Anti-ENA and anti-DNA results were also analyzed for ANA-positive patients. Statistical analysis was performed using STATA 14.0, p Results: 216 patients were analyzed. Women predominated at 79.2% and mean age was 48 years [CI 95%, 46 - 50], with extremes of 10 and 89. Most represented age group was [41 - 60] with 38%. ANA was positive in 27 (12.5%) of patients, 59.2% of whom were strongly positive (titer of 1/1000, 1/3200 or 1/6400). The most common pattern was nuclear speckled, which was found in 77.8% of samples. Anti-ENA and anti-DNA positivity in ANA-positive patients was found respectively in 63% (17/27) and 1.4% (3/27) of the samples analyzed. Most commonly identified anti-ENA was anti-Sm 29.6%, anti-SSA 29.6%, anti-Ro-52 25.9%, anti-RNP 18.5% and anti-SSB 14.8% which was associated with speckled pattern. Association results indicated a significant relationship between both tests and between ANA titer in the anti-ENA- and ANA-positive patients (p 0.001). Conclusions: ANA, Anti-ENA and anti-DNA antibodies are essential for AIDS diagnosis. However, the testing repertoire should follow an algorithm comprising of clinical features, followed by ANA results with nuclear, mitotic, and cytoplasmic patterns, anti-ENA, and anti-DNA for a more meaningful, and cost-effective diagnostic approach.

Carcinoembryonic antigen in the diagnosis,treatment,and follow-up of focal liver lesions

In this editorial review,we comment on the article published in the recent issue of the World Journal of Gastrointestinal Surgery.Carcinoembryonic antigen(CEA)is a fetal glycoprotein and can be secreted in very small amounts from healthy adults after birth.CEA is widely used not only for diagnostic tumor markers but also importantly for the management of some gastrointestinal tumors.The most common clinical use is surveillance for the monitoring of colorectal carcinoma.However,CEA can become elevated in several malign or benign characterized pathologies.Serum CEA level may vary depending on the location of the lesion,whether it metastasizes or not,and its histopathological characteristics.It has been determined that cases with high preoperative CEA have a more aggressive course and the risk of metastasis to the lymph tissue and liver increases.In this editorial review,we focused on evaluating the role of CEA in clinical practice with a holistic approach,including the diagnostic and prognostic significance of CEA in patients with focal liver lesions,the role of CEA in follow-up after definitive surgery,and also hepatic resection for metastasis,and the management of all patients with raised CEA.

Combining prognostic value of serum carbohydrate antigen 19-9 and tumor size reduction ratio in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a common cancer with increasing morbidity and mortality due to changes of social environment.AIM To evaluate the significance of serum carbohydrate antigen 19-9(CA19-9)and tumor size changes pre-and post-neoadjuvant therapy(NAT).METHODS This retrospective study was conducted at the Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment,Chongqing University Cancer Hospital.This study specifically assessed CA19-9 levels and tumor size before and after NAT.RESULTS A total of 156 patients who completed NAT and subsequently underwent tumor resection were included in this study.The average age was 65.4±10.6 years and 72(46.2%)patients were female.Before survival analysis,we defined the post-NAT serum CA19-9 level/pre-NAT serum CA19-9 level as the CA19-9 ratio(CR).The patients were divided into three groups:CR<0.5,CR>0.5 and<1 and CR>1.With regard to tumor size measured by both computed tomography and magnetic resonance imaging,we defined the post-NAT tumor size/pre-NAT tumor size as the tumor size ratio(TR).The patients were then divided into three groups:TR<0.5,TR>0.5 and<1 and TR>1.Based on these groups divided according to CR and TR,we performed both overall survival(OS)and disease-free survival(DFS)analyses.Log-rank tests showed that both OS and DFS were significantly different among the groups according to CR and TR(P<0.05).CR and TR after NAT were associated with increased odds of achieving a complete or near-complete pathologic response.Moreover,CR(hazard ratio:1.721,95%CI:1.373-3.762;P=0.006),and TR(hazard ratio:1.435,95%CI:1.275-4.363;P=0.014)were identified as independent factors associated with OS.CONCLUSION This study demonstrated that post-NAT serum CA19-9 level/pre-NAT serum CA19-9 level and post-NAT tumor size/pre-NAT tumor size were independent factors associated with OS in patients with PDAC who received NAT and subsequent surgical resection.

Influencing factors and solution strategies of chimeric antigen receptor T-cell therapy(CAR–T)cell immunotherapy

Chimeric antigen receptor T-cesll therapy(CAR–T)has achieved groundbreaking advancements in clinical application,ushering in a new era for innovative cancer treatment.However,the challenges associated with implementing this novel targeted cell therapy are increasingly significant.Particularly in the clinical management of solid tumors,obstacles such as the immunosuppressive effects of the tumor microenvironment,limited local tumor infiltration capability of CAR–T cells,heterogeneity of tumor targeting antigens,uncertainties surrounding CAR–T quality,control,and clinical adverse reactions have contributed to increased drug resistance and decreased compliance in tumor therapy.These factors have significantly impeded the widespread adoption and utilization of this therapeutic approach.In this paper,we comprehensively analyze recent preclinical and clinical reports on CAR–T therapy while summarizing crucial factors influencing its efficacy.Furthermore,we aim to identify existing solution strategies and explore their current research status.Through this review article,our objective is to broaden perspectives for further exploration into CAR–T therapy strategies and their clinical applications.

Inflammatory response in gastrointestinal cancers:Overview of six transmembrane epithelial antigens of the prostate in pathophysiology and clinical implications

Chronic inflammation is known to increase the risk of gastrointestinal cancers(GICs),the common solid tumors worldwide.Precancerous lesions,such as chronic atrophic inflammation and ulcers,are related to inflammatory responses in vivo and likely to occur in hyperplasia and tumorigenesis.Unfortunately,due to the lack of effective therapeutic targets,the prognosis of patients with GICs is still unsatisfactory.Interestingly,it is found that six transmembrane epithelial antigens of the prostate(STEAPs),a group of metal reductases,are significantly associated with the progression of malignancies,playing a crucial role in systemic metabolic homeostasis and inflammatory responses.The structure and functions of STEAPs suggest that they are closely related to intracellular oxidative stress,responding to inflammatory reactions.Under the imbalance status of abnormal oxidative stress,STEAP members are involved in cell transformation and the development of GICs by inhibiting or activating inflammatory process.This review focuses on STEAPs in GICs along with exploring their potential molecular regulatory mechanisms,with an aim to provide a theoretical basis for diagnosis and treatment strategies for patients suffering from these types of cancers.

Quantitative hepatitis B core antibody and quantitative hepatitis B surface antigen:Novel viral biomarkers for chronic hepatitis B management

The management of hepatitis B virus(HBV)infection now involves regular and appropriate monitoring of viral activity,disease progression,and treatment response.Traditional HBV infection biomarkers are limited in their ability to predict clinical outcomes or therapeutic effectiveness.Quantitation of HBV core antibodies(qAnti-HBc)is a novel non-invasive biomarker that may help with a variety of diagnostic issues.It was shown to correlate strongly with infection stages,hepatic inflammation and fibrosis,chronic infection exacerbations,and the presence of occult infection.Furthermore,qAnti-HBc levels were shown to be predictive of spontaneous or treatment-induced HBeAg and HBsAg seroclearance,relapse after medication termination,re-infection following liver transplantation,and viral reactivation in the presence of immunosuppression.qAnti-HBc,on the other hand,cannot be relied on as a single diagnostic test to address all problems,and its diagnostic and prognostic potential may be greatly increased when paired with qHBsAg.Commercial qAnti-HBc diagnostic kits are currently not widely available.Because many methodologies are only semi-quantitative,comparing data from various studies and defining universal cut-off values remains difficult.This review focuses on the clinical utility of qAnti-HBc and qHBsAg in chronic hepatitis B management.

Carcinoembryonic antigen,carbohydrate antigen 199 and carbohydrate antigen 724 in gastric cancer and their relationship with clinical prognosis

BACKGROUND Gastric cancer(GC)is a common malignant tumor of the digestive system with a high degree of malignancy.It usually develops insidiously without any specific symptoms in the early stages.As one of the diseases caused by abnormal gene changes,GC has abnormal expression of various oncogenes and products during its development.Tumor markers such as carcinoembryonic antigen(CEA),carbohydrate antigen 199(CA199)and carbohydrate antigen 724(CA724)are not expressed or lowly expressed in normal people,but significantly increased after carcinogenesis.Monitoring the changes in the levels of tumor markers such as CEA,CA199 and CA724 is conducive to early diagnosis and evaluation of the occurrence of some solid tumors.AIM To investigate the expression of CEA,CA199 and CA724 in GC and their correlation with clinical features,hoping to provide more effective markers for the early preventive diagnosis of GC.METHODS Of 87 patients with GC admitted to our hospital from September 2020 to December 2021 were included in the GC group,and another 80 healthy people who came to our hospital for physical examination with normal results during the same period were selected as the control group.The serum CEA,CA199,and CA724 levels were compared between the two groups,and the serum CEA,CA199,and CA724 levels were compared in patients with GC at different TNM stages,and the differences in the positive rates of CEA,CA199,and CA724 alone and in combination in detecting TNM stages of GC and GC were compared.In addition,the relationship between the levels of tumor markers CEA,CA199 and CA724 and the clinicopathological characteristics of GC patients was also analyzed.The relationship between the serum levels of CEA,CA199 and CA724 and the survival period of GC patients was analyzed by Pearson.RESULTS The serum levels of CEA,CA199 and CA724 in GC group were significantly higher than those in control group(P<0.05).With the increase of TNM stage,the serum CEA,CA199 and CA724 expression levels in GC patients increased significantly,and the differences between groups were statistically significant(P<0.05).The positive rate of the CA724 single test was higher than that of CEA and CA199 single test(P<0.05).The positive rate of the three combined tests was 95.40%(83/87),which was higher than that of CEA,CA199 and CA724 single tests.The difference was statistically significant(P<0.05).The combined detection positive rates of CEA,CA199,and CA724 in stages I,II,III,and IV of GC were 89.66%,93.10%,98.85%,and 100.00%respectively,all of which were higher than the individual detection rates of CEA,CA199,and CA724.The differences were statistically significant(P<0.05).There was no significant difference in serum CEA,CA199 and CA724 levels between GC patients with different genders,smoking history and alcohol history(P>0.05).However,the serum CEA,CA199 and CA724 levels were significantly higher in GC patients aged≥45 years,TNM stage III-IV,with lymph node metastasis and tumor diameter≥5 cm than in GC patients aged<45 years,TNM stage I-II,without lymph node metastasis and tumor diameter<5 cm(P<0.05).CONCLUSION The expression levels of serum tumor markers CEA,CA199 and CA724 in patients with GC are high and rise with the increase of TNM stage.The levels of CEA,CA199 and CA724 are related to age,TNM stage,lymph node metastasis and tumor diameter.The combined detection of CEA,CA199 and CA724 is helpful to improve the diagnostic accuracy of GC with high clinical guidance value.

Dynamic mechanical characteristics of frozen subgrade soil subjected to freeze-thaw cycles

As a widely-applied engineering material in cold regions, the frozen subgrade soils are usually subjected to seismic loading, which are also dramatically influenced by the freeze-thaw(F-T)cycles due to the varying temperature. A series of dynamic cyclic triaxial experiments were conducted through a cryogenic triaxial apparatus for exploring the influences of F-T cycles on the dynamic mechanical properties of frozen subgrade clay.According to the experimental results of frozen clay at the temperature of-10℃, the dynamic responses and microstructure variation at different times of F-T cycles(0, 1, 5, and 20 cycles) were explored in detail.It is experimentally demonstrated that the dynamic stress-strain curves and dynamic volumetric strain curves of frozen clay are significantly sparse after 20F-T cycles. Meanwhile, the cyclic number at failure(Nf) of the frozen specimen reduces by 89% after 20freeze-thaw cycles at a low ratio of the dynamic stress amplitude. In addition, with the increasing F-T cycles,the axial accumulative strain, residual deformation,and the value of damage variable of frozen clay increase, while the dynamic resilient modulus and dynamic strength decrease. Finally, the influence of the F-T cycles on the failure mechanisms of frozen clay was discussed in terms of the microstructure variation. These studies contribute to a better understanding of the fundamental changes in the dynamic mechanical of frozen soils exposed to F-T cycles in cold and seismic regions.

Importance of human leukocyte antigen antibodies and leukocyte antigen/killer-cell immunoglobulin-like receptor genes in liver transplantation

Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance,which is described by eventual imbalances or deregulation in the balance of cytokines,mediators,effectors,and regulatory cells in the complex milieu of the liver.In this section,we will comment on the importance of donorspecific anti-human leukocyte antigen(HLA)antibodies(DSA)as well as the compatibility and pairings of HLA and killer-cell immunoglobulin-like receptor(KIR)genotypes in the evolution of liver transplantation.Thus,HLA compatibility,viral infections,and HLA-C/KIR combinations have all been linked to liver transplant rejection and survival.There have been reports of increased risk of acute and chronic rejection with ductopenia,faster graft fibrosis,biliary problems,poorer survival,and even de novo autoimmune hepatitis when DSAs are present in the recipient.Higher mean fluorescence intensity(MFI)values of the DSAs and smaller graft size were associated with poorer patient outcomes,implying that high-risk patients with preformed DSAs should be considered for selecting the graft placed and desensitization methods,according to the investigators.Similarly,in a combined kidney-liver transplant,a pretransplant with a visible expression of several DSAs revealed that these antibodies were resistant to treatment.The renal graft was lost owing to antibody-mediated rejection(AMR).The HLA antigens expressed by the transplanted liver graft influenced antibody elimination.Pathologists are increasingly diagnosing AMR in liver transplants,and desensitization therapy has even been employed in situations of AMR,particularly in patients with DSAs in kidney-hepatic transplants and high-class II MFI due to Luminex.In conclusion,after revealing the negative impacts of DSAs with high MFI,pretransplant virtual crossmatch techniques may be appropriate to improve evolution;however,they may extend cold ischemia periods by requiring the donor to be typed.

Mechanical and acoustic emission characteristics of anhydrite rock under freeze-thaw cycles

To study the damage mechanisms of anhydrite rock under freeze-thaw cycles, the physicalmechanical properties and the microcracking activities of anhydrite rock were investigated through mass variation, nuclear magnetic resonance, scanning electron microscope tests, and uniaxial compression combined with acoustic emission(AE) tests. Results show that with the increase of freeze-thaw processes,the mass, uniaxial compression strength, and elastic modulus of the anhydrite specimens decrease while the porosity and plasticity characteristics increase.For example, after 120 cycles, the uniaxial compression strength and elastic modulus decrease by 46.54% and 60.16%, and the porosity increase by 75%. Combined with the evolution trend of stressstrain curves and the detected events, three stages were labeled to investigate the AE characteristics in freeze-thaw weathered anhydrite rock. It is found that with the increase of freeze-thaw cycles, the proportions of AE counts in stage Ⅰ and stage Ⅱ show a decaying exponential trend. Contrarily, the proportion of AE counts in stage Ⅲ displays an exponential ascending trend. Meanwhile, as the freeze-thaw cycles increase, the low-frequency AE signals increase while the intermediate-frequency AE signals decrease. After 120 cycles, the proportion of low-frequency AE signals increases by 168.95%, and the proportion of intermediate-frequency AE signals reduces by 81.14%. It is concluded that the microtensile cracking events occupy a dominant position during the loading process. With the increase of freeze-thaw cycles, the b value of samples decreases.After 120 cycles, b value decreases by 27.2%, which means that the proportion of cracking events in rocks with small amplitude decreases. Finally, it is proposed that the freeze-thaw damage mechanism of anhydrite is also characterized by the water chemical softening effect.