依托“第二课堂”多维度开放实验室,拓展实验教学的深度和广度

实验教学是培养学生实践能力和创新能力的重要环节,如何突破课堂教学的时空限制有效实现实验资源的开放利用,是高校实验教学中心改革和建设的重要内容。本文以化学国家级实验教学示范中心(北京师范大学)为例,介绍本中心将有组织的“第二课堂活动”纳入实验教学体系,探索并创建了多层次、多维度的实验室开放模式;通过举办丰富的实验竞赛/实践活动,支持大学生开展创新创业、学科竞赛、科学研究和科普宣传等活动,为学生提供了多样化的、以自驱为主、崇尚创新的实践训练机会,从而切实发挥了实验教学中心在创新人才培养中的支撑作用和在基础教育领域的辐射和示范作用。上述举措得力、育人效果显著,值得推广借鉴。

The effect of Tai Chi exercise on motor function and sleep quality in patients with stroke:A meta-analysis

Objective:The meta-analysis is to objectively evaluate the efficacy of Tai Chi exercise for motor function and sleep quality in patients with stroke.Methods:Randomized controlled trials(RCTs)about the effects of Tai Chi versus a non-exercise or conventional rehabilitation exercise control group on motor function and sleep quality in patients with stroke were searched from multiple electronic databases(PubMed,Web of Science,the Cochrane Library,EMBASE,AMED,CBM,CNKI,Wanfang and VIP)until August 2016.Two investigators independently screened eligible studies,extracted data,and assessed the methodological quality by using the quality evaluation criteria for RCTs recommended by Cochrane Handbook.Then meta-analysis was performed by RevMan5.3 software.Results:A total of 17 RCTs with 1209 participants were included.The meta-analysis indicated that there was a significant difference on improving the balance function(P<0.001)and ability of daily activity(P=0.0003)of patients with stroke between Tai Chi group and control group.However,no significant effect was found on Tai Chi for walking function and sleep quality(P>0.05).Conclusion:Tai Chi exercise can significantly improve the balance function and ability of daily activities of patients with stroke,and there are no significant differences in walking function and sleep quality.Therefore,lots of multicenter,large-sample,higher quality randomized controlled trials are needed to verify the effects of Tai Chi exercise in improving walking function and sleep quality for patients with stroke.

First-Principles Calculations about Elastic and Li^(+) Transport Properties of Lithium Superoxides under High Pressure and High Temperature

Lithium superoxides,Li_(2)O_(3),LiO_(2),and LiO_(4),have been synthesized under high pressure.These materials have potential applications in energy storage devices.Here,we use first-principles calculations to investigate the elastic and Li^(+) transport properties of these oxides at high pressure and high temperature.The elastic constants are calculated at 20-80 GPa,and they satisfy the Born stability criteria,indicating the good mechanical stability of these oxides.Their sound velocities calculated with elastic constants are close to each other,but difference in velocity anisotropy is obvious.LiO_(2) presents significant shear sound wave anisotropy over 80%.The Li^(+) transport properties are investigated using first principles molecular dynamics(FPMD)and climbing-image nudged elastic band methods.The lowest Li^(+) migration barrier energies increase from 0.93,0.86 and 1.22 eV at 20 GPa to 1.43,1.12 and 1.77 eV at 50 GPa for Li_(2)O_(3),LiO_(2),and LiO_(4),respectively.The most favorable path for LiO_(2) and LiO_(4) is along the[001]direction.The FPMD results suggest that these oxides become unstable with increasing temperature up to 2000 K due to O-O dimer clusters in these superoxides.Consequently,a superionic transition is not observed in the simulations.

Study on Response Surface Methodology Optimization for Extraction Process of Cyclocarya paliurus Extract and Its Blood Sugar-lowering Effect

[Objectives]This study was conducted to discuss the mechanism of the blood sugar-lowering effect of Cyclocarya paliurus extract.[Methods]With C.paliurus leaves as the raw material,the ethyl acetate-butyl acetate microwave extraction process of C.paliurus was studied.With the yield of C.paliurus extract as an evaluation index,single-factor experiments were carried out on such 6 factors as the dry C.paliurus leaf powder size,solid-to-liquid ratio,extraction time,microwave frequency,microwave power,and microwave extraction time,and the extraction and purification process was further optimized by response surface analysis.The normal mice and the hyperglycemic mice modeled by alloxan were injected with C.paliurus extract to study the blood sugar-lowering effects of different groups of C.paliurus extract.[Results]The optimal process combination for the extraction of C.paliurus leaves was obtained:dry C.paliurus powder size 90-100 mesh,solid-to-liquid ratio 1∶20(g/ml),extraction time 192 min,microwave frequency 2500 MHz,microwave power 490 W,and extraction time 248 s.Under these conditions,the yield of C.paliurus extract reached the maximum,95.10%,reaching 99.83%of the predicted value.The blood sugar-lowering test on mice showed that the C.paliurus extract had a good effect on lowering blood sugar,indicating that C.paliurus extract can improve the free radical scavenging capacity to a certain extent.[Conclusions]This study provides certain reference for the in-depth study of the physiological effects of C.paliurus extract and the comprehensive development and utilization of C.paliurus extract.

二次掺杂制备聚苯胺/石墨烯/碳纳米管复合材料及其防腐性能

在高氯酸体系中通过原位聚合将苯胺(ANI)单体分别与还原氧化石墨烯(RGO)、碳纳米管(CNTs)制备了一次掺杂态产物PANI/RGO和PANI/CNTs,产物分别经氨水解掺杂后,在高氯酸体系中经二次掺杂制备得到二次掺杂态聚苯胺/石墨烯/碳纳米管(Redoped PANI/RGO/CNTs)复合材料。通过扫描电镜、透射电镜、傅里叶变换红外光谱和紫外光谱对其不同产物形貌和结构进行表征,通过电化学工作站测试了不同产物在3.5%NaCl溶液的防腐蚀性能。结果表明,在RGO与ANI质量比为1:20、CNTs与ANI质量比为1:20时,二次掺杂态产物中聚苯胺纳米纤维可分别在RGO和CNTs上均匀生长并形成网状结构,纤维长度达到850 nm,形貌均一,其防腐蚀性能最优异,缓蚀效率可达81.79%。通过二次掺杂将PANI/RGO和PANI/CNTs复合制备Redoped PANI/RGO/CNTs材料,可有效避免石墨烯和碳纳米管在制备复合材料过程中的团聚,得到结构规整、防腐性能更优异的复合材料。

Regeneration and anti-migration of sand waves associated with sand mining in the Taiwan Shoal

Sand waves in the Taiwan Shoal are characterized by two distinct spatial scales. Giant sand waves have a length of2 kilometers with height between 5 m and 25 m, whilst small sand waves is less than 100-m long with height less than 5 m between giant sand wave peaks(crests). A series of five high-resolution multi-beam echo-sounding surveys between 2012 and 2020 in the middle of Taiwan Shoal indicated that artificial dredging on the giant sand waves had caused sand wave reform and evolution. Overall, the removal of giant sand waves significantly affected the migration of small sand waves adjacent to the dredging site, with the latter on both sides of the former appear to migrate towards the dredging pit. Moreover, in the dredging area, new sand waves emerged with wavelength much smaller than the original giant sand waves, while the convergent pattern of the small sand waves tends to store and form the giant sand waves, which might spread far beyond the survey period.

Differences of polygonal faults related to upper Miocene channels:a case study from the Beijiao sag of Qiongdongnan basin,South China Sea

Deep-water coarse-grained channels are embedded within a polygonal fault tier,and the polygonal faults(PFs)present non-polygonal geometries rather than classic polygonal geometry in plan view.However,PFs present differences when they encounter deep-water(coarse-grained vs.fine-grained)channels with different lithology,which has not been further studied to date.Three-dimensional(3D)seismic data and a drilling well from Beijiao sag of Qiongdongnanbasin,South China Sea were utilized to document the plan view and cross-sectional properties of the PFs and their differences and genetic mechanism were investigated.Results show that,first,PFs can be divided morphologically into channel-segmenting PFs and channel-bounding PFs in plan view.The former virtually cuts or segments the axes of channels in highand low-amplitudes,and the latter nearly parallels the boundaries of the channels.Both are approximately perpendicular to each other.Secondly,channel-bounding PFs that related to low-amplitude channels are much longer than those of high-amplitude ones;channel-segmenting PFs related to low-amplitude channels are slightly longer than the counterparts related to high-amplitude channels.Lastly,the magnitudes(e.g.,heights)of the PFs are proportional to the scales(e.g.,widths and heights)of low-amplitude channels,whereas the magnitudes of the PFs are inversely proportional to the scales of high amplitude channels.Coarse-grained(high amplitude)channels act as a mechanical barrier to the propagation of PFs,whereas fine-grained(low-amplitude)channels are beneficial to the propagation and nucleation of PFs.Additionally,the genetic mechanism of PFs is discussed and reckoned as combined geneses of gravitational spreading and overpressure hydrofracture.The differences of the PFs can be used to reasonably differentiate coarse-grained channels from fine-grained channels.This study provides new insights into understanding the different geometries of the PFs related to coarse-grained and fine-grained channels and their genetic mechanism.

Crucial role played by CK8^(+)cells in mediating alveolar injury remodeling for patients with COVID-19

The high risk of SARS-CoV-2 infection and reinfection and the occurrence of post-acute pulmonary sequelae have highlighted the importance of understanding the mechanism underlying lung repair after injury.To address this concern,comparative and systematic analyses of SARS-CoV-2 infection in COVID-19 patients and animals were conducted.In the lungs of nine patients who died of COVID-19 and one recovered from COVID-19 but died of unrelated disease in early 2020,damage-related transient progenitor(DATP)cells expressing CK8 marker proliferated significantly.These CK8^(+)DATP cells were derived from bronchial CK5^(+)basal cells.However,they showed different cell fate toward differentiation into type I alveolar cells in the deceased and convalescent patients,respectively.By using a self-limiting hamster infection model mimicking the dynamic process of lung injury remodeling in mild COVID-19 patients,the accumulation and regression of CK8t cell marker were found to be closely associated with the disease course.Finally,we examined the autopsied lungs of two patients who died of infection by the recent Omicron variant and found that they only exhibited mild pathological injury with no CK8^(+)cell proliferation.These results indicate a clear pulmonary cell remodeling route and suggest that CK8^(+)DATP cells play a primary role in mediating alveolar remodeling,highlighting their potential applications as diagnostic markers and therapeutic targets.

Plant-inspired visible-light-driven bioenergetic hydrogels for chronic wound healing

Chronic bioenergetic imbalances and inflammation caused by hyperglycemia are obstacles that delay diabetic wound healing.However,it is difficult to directly deliver energy and metabolites to regulate intracellular energy metabolism using biomaterials.Herein,we propose a light-driven bioenergetic and oxygen-releasing hydrogel(PTKM@HG)that integrates the thylakoid membrane-encapsulated polyphenol nanoparticles(PTKM NPs)to regulate the energy metabolism and inflammatory response in diabetic wounds.Upon red light irradiation,the PTKM NPs exhibited oxygen generation and H2O2 deletion capacity through a photosynthetic effect to restore hypoxia-induced mitochondrial dysfunction.Meanwhile,the PTKM NPs could produce exogenous ATP and NADPH to enhance mitochondrial function and facilitate cellular anabolism by regulating the leucine-activated mTOR signaling pathway.Furthermore,the PTKM NPs inherited antioxidative and anti-inflammatory ability from polyphenol.Finally,the red light irradiated PTKM@HG hydrogel augmented the survival and migration of cells keratinocytes,and then accelerated angiogenesis and re-epithelialization of diabetic wounds.In short,this study provides possibilities for effectively treating diseases by delivering key metabolites and energy based on such a light-driven bioenergetic hydrogel.

Optimal geometrical configuration and oxidation state of cobalt cations in spinel oxides to promote the performance of Li-O_(2) battery

Co_(3)O_(4) is considered as one of promising cathode catalysts for lithium oxygen(Li-O_(2))batteries,which contains both tetrahedral Co^(2+)sites(Co^(2+)Td)and octahedral Co^(3+)sites(Co^(3+)Oh).It is important to reveal the effect of optimal geometric configuration and oxidation state of cobalt ion in Co_(3)O_(4) to improve the performance of Li-O_(2) batteries.Herein,through regulating the synthesis process,Co^(2+)and Co^(3+)sites in Co_(3)O_(4) were replaced with Zn and Al atoms to form materials with a unique Co site.The Li-O_(2) batteries based on ZnCo_(2)O_(4) showed longer cycle life than that of CoAl_(2)O_(4),suggesting that in Co_(3)O_(4),the Co^(3+)Oh site is a relatively better geometric configuration than Co^(2+)Td site for Li-O_(2) batteries.Theoretical calculations revealed that Co^(3+)Oh sites provide higher catalysis activity,regulating the adsorption energy of the intermediate LiO_(2) and accelerating the kinetics of the reaction in batteries,which further leads to the change of the morphology of the discharge product and ultimately improves the electrochemical performance of the batteries.

Specimen Radiography for MRI-Guided Biopsies

Background: Specimen radiography is important for the biopsy of breast microcalcifications, and MRI is limited in the detection of microcalcifications. It is unknown whether or not the presence of microcalcifications on MRI-guided biopsies is significant. Purpose: To determine whether specimen radiography of MRI-guided biopsy samples provides any added benefits in tissue assessment. Materials and Methods: This is an IRB-approved, HIPPA-compliant retrospective review of MRI-guided biopsy reports whose tissue underwent specimen radiography from 2010 to 2017. Pathology reports were queried to compare samples with and without calcium and reviewed to determine if calcifications correlated with the lesion of interest. If there was a correlation, the original MRI was reviewed. Final pathology reports were also reviewed if excision was performed. Results: A total of 889 patients ages 22 - 85 were included with 140 (15.7%, 140/889) containing calcifications. Of 140 specimens, 119 (85.0%, 119/140) cases separated the calcifications. A total of 41 (34.5%, 41/119) were malignant or high-risk lesions/atypia of which 15 (36.6%, 15/41) showed a higher-grade lesion in the specimen containing calcium. Out of these 15, 4 (26.7%, 4/15) were pathologically associated with calcium;however, pathologic diagnosis was not dependent on the presence of calcifications. All 4 were high-risk lesions and none were malignancies. MRI in these cases showed three enhancing masses and one non-mass enhancement. None were upgraded at excision. Conclusion: The presence of microcalcifications on MRI-guided biopsies does not aid in tissue assessment and does not impact pathologic diagnosis. Specimen radiography provides no added benefits in the setting of MRI-guided biopsies.

Effects of massage on newborn infants with jaundice: A meta-analysis

Objective:This meta-analysis aims to systematically evaluate the effects of massage on infants with jaundice.Methods:Multiple electronic databases,including Cochrane Library,PubMed,EMBASE,Web of Science,China Biology Medicine (CBM),Wan Fang Data,VIP Database for Chinese Technical Periodicals and China National Knowledge Infrastructure (CNKI),were used to search for studies on the effects of massage on infants with jaundice.Data were analysed by Rev Man 5.3.Results:A total of 14 randomised controlled trials with 1889 patients were included.Statistically significant difference in percutaneous bilirubin [MD =-1.21,95% CI (-1.90,-0.52),P< 0.05;MD =-2.00,95% CI (-2.68,-1.32),P<0.05;MD=-2.00,95% CI (2.56,-1.44),P<0.05;MD=-1.93,95% CI (-2.44,-1.43),P< 0.05] was found between two groups at 48,72,96 and 168 h.Studies on the serum total bilirubin level were divided into two subgroups according to sample size,and the results of subgroup analysis showed that the serum total bilirubin level in the intervention group was significantly lower than that in the control group [MD =-52.06,95% CI (-57.76,-46.36),P< 0.05 and MD =-10.65,95% CI (-14.66,-6.63),P < 0.05].Statistically significant difference in defecation frequency was observed between the two groups at 48 h after birth[SMD =0.44,95%CI (0.02,0.87),P< 0.05].Conclusion:Massage can decrease serum total bilirubin and percutaneous bilirubin levels and increasing defecation frequency.However,due to heterogeneity among studies,numerous multi-centre,largesample and high-quality randomised controlled trials are needed to verify the effects of massage.

Influence of Artificial Cofferdam and Spartina alterniflora Expansion on Evolution of Suaeda salsa Marsh in Yancheng Coastal Wetland of East China

Suaeda salsa is an important local species in the intertidal beach of the Western Pacific coast. However,under the artificial cofferdam and Spartina alterniflora expansion,Suaeda marsh has degraded seriously. Therefore,using Yancheng Nature Reserve as a case study area,taking ETM+images in 2000,2006 and 2011 as the basic data sources,we revealed the evolution characteristics of Salsa marsh which was impacted. The research results are as follows. From 2000 to 2011,Salsa marsh area in the artificial area tempestuously degraded,decreasing by 87. 158%,more than 22% than those in the natural area. The landscape was fragmentized. Landscape polymerization degree index dropped from 95. 780 to 65. 455,more than 16% than those in the natural area. The mean patch area fell down to 21. 429 ha from 389. 333 ha,more than 11% that in the natural area. Compared to the steady change in natural conditions,the area was reduced by 118. 167 ha/a from 2000 to 2006,while during 2006-2011,it was only 51. 500 ha/a in artificial area. As for spatial change of landscape,in artificial area,the Salsa marsh centroid moved forward to the southeast with 666. 350 m,but that in natural area moved forward to the north with 1 042. 710 m from 2000 to 2006. From 2006 to 2011,the centroid moved forward to east and north respectively. Artificial cofferdam transformed the area into freshwater ecosystem,and meanwhile the freshwater was beneficial to Reed marsh. During 2000 to 2006,in the artificial area,539 ha Salsa marsh controlled by cofferdam transferred into reed marsh and aquaculture ponds,of which the transformation rate was nearly 4% higher than that in natural area. From 2006 to 2011,178 ha Salsa marsh was transferred into reed marsh,the transformation rate was 20% higher than that in natural area. With rapid spreading and strong competition of Spartina species,the coastal wetland has formed the pattern of " Salsa – Spartina marshes". From 2000 to 2006,in artificial area,15. 24% of Salsa marsh was transferred into Spartina marsh,of which the transformation rate was13% higher than that in natural area. And from 2006 to 2011,30. 07% Salsa marsh was replaced by the Spartina marsh in artificial area,the rate was almost 10% higher than that in the natural area.

Characteristics and origins of middle Miocene mounds and channels in the northern South China Sea

Numerous elongated mounds and channels were found at the top of the middle Miocene strata using 2D/3D seismic data in the Liwan Sag of Zhujiang River Mouth Basin(ZRMB)and the Beijiao Sag of Qiongdongnan Basin(QDNB).They occur at intervals and are rarely revealed by drilling wells in the deepwater areas.Origins of the mounds and channels are controversial and poorly understood.Based on an integrated analysis of the seismic attribute,palaeotectonics and palaeogeography,and drilling well encountering a mound,research results show that these mounds are dominantly distributed on the depression centres and/or slopes of the Liwan and Beijiao sags and developed in a bathyal sedimentary environment.In the Liwan and Beijiao sags,the mounds between channels(sub)parallel to one another are 1.0–1.5 km and 1.5–2.0 km wide,150–300 m and 150–200 m high,and extend straightly from west to east for 5–15 km and 8–20 km,respectively.Mounds and channels in the Liwan Sag are parallel with the regional slope.Mounds and channels in the Beijiao Sag,however,are at a small angle to the regional slope.According to internal geometry,texture and external morphology of mounds,the mounds in Beijiao Sag are divided into weak amplitude parallel reflections(mound type I),blank or chaotic reflections(mound type II),and internal mounded reflections(mound typeⅢ).The mounds in Liwan Sag,however,have the sole type,i.e.,mound type I.Mound type I originates from the incision of bottom currents and/or gravity flows.Mound type II results from gravity-driven sediments such as turbidite.Mound typeⅢis a result of deposition and incision of bottom currents simultaneously.The channels with high amplitude between mounds in the Beijiao and Liwan sags are a result of gravity-flow sediments and it is suggested they are filled by sandstone.Whereas channels with low-mediate amplitudes are filled by bottom-current sediments only in the Beijiao Sag,where they are dominantly composed of mudstone.This study provides new insights into the origins of the mounds and channels worldwide.

Entropy engineering design of high-performing lithiated oxide cathodes for proton-conducting solid oxide fuel cells

A new medium entropy material LiCo_(0.25)Fe_(0.25)Mn_(0.2)5Ni_(0.2)5O_(2)(LCFMN)is proposed as a cathode for proton-conducting solid oxide fuel cells(H-SOFCs).Unlike traditional LiXO_(2)(X=Co,Fe,Mn,Ni)lithiated oxides,which have issues like phase impurity,poor chemical compatibility,or poor fuel cell performance,the new LCFMN material mitigates these problems,allowing for the successful preparation of pure phase LCFMN with good chemical and thermal compatibility to the electrolyte.Furthermore,the entropy engineering strategy is found to weaken the covalence bond between the metal and oxygen in the LCFMN lattice,favoring the creation of oxygen vacancies and increasing cathode activity.As a result,the H-SOFC with the LCFMN cathode achieves an unprecedented fuel cell output of 1803 mW·cm^(−2)at 700℃,the highest ever reported for H-SOFCs with lithiated oxide cathodes.In addition to high fuel cell performance,the LCFMN cathode permits stable fuel cell operation for more than 450 h without visible degradation,demonstrating that LCFMN is a suitable cathode choice for H-SOFCs that combining high performance and good stability.

Evaluation of growth characteristics of Aspergillus parasiticus inoculated in different culture media by shortwave infrared(SWIR) hyperspectral imaging

The growth characteristics of Aspergillus parasitic us incubated on two culture media were ex-amined using shortwave infrared(SWIR,1000-2500 nm)hyperspectral imaging(HSI)in this work.HSI images of the A.parasiticus colonies growing on rose bengal medium(RBM)and maize agar medium(MAM)were recorded daily for 6 days.The growth phases of A.parasiticus were indicated through the pixel number and average spectra of colonies.On score plot of the first principal component(PC1)and PC2,four growth zones with varying mycelium densities were identified.Eight characteristic wavelengths(1095,1145,1195,1279,1442,1655,1834 and 1929 nm)were selected from PC1 loading,average spectra of each colony as well as each growth zone.F urthermore,support vector machine(S VM)classifier based on the eight wavelengths was built,and the classification accuracies for the four zones(from outer to inner zones)on the colonies on RBM were 99.77%,9935%,99.75%and 99.60%and 99.77%,9939%,99.31%and 98.22%for colonies on MAM.In addition,a new score plot of PC2 and PC3 was used to differ-entiate the colonies incubated on RBM and MAM for 6 days.Then characteristic wavelengths of 1067,1195,1279,1369,1459,1694,1834 and 1929 nm were selected from the loading of PC2 and PCg.Based on them,a new SVM model was developed to diferentiate colonies on RBM and MAM with accuracy of 100.00%and 9999%,respectively.In conclusion,SWIR hyperspectral image is a powerful tool for evaluation of growth characteristics of A.parasiticus incubated in diferent culture media.

Anti-tumor Effect and Mechanism of Pratia Extract on H22 Tumor-bearing Mice

[Objectives]This study was conducted to investigate the inhibitory effect of pratia extract on H22 tumor-bearing mice and the effects on immune organs.[Methods]With the application of H22 liver tumor-bearing mice as an animal model,the animals were divided into such three Pratia extract groups as the high,medium and low dose groups(400,200 and 100 mg/kg)and cyclophosphamide CTX group(20 mg/kg).15 d after the administration,the animals were killed by cervical dislocation,and the tumors,thymuses and spleens were taken and weighed,followed by the calculation of the tumor inhibitory rate and the thymus and spleen index,and the serum tumor necrosis factor-α(TNF-α)and interleukin-2(IL-2)levels were determined by ELISA assay.[Results]The inhibitory rates were 54.1,32.6 and 8.2%,respectively,and there were significant differences from the model group(P<0.05);and the spleen index of the tumor-bearing mice was reduced,while the thymus index was improved.The serological results showed that the drug-administrated groups significantly improved the IL-2 levels in the tumor-bearing mice,but had no effects on TNF-α.[Conclusions]Pratia extract has an antitumor effect on H22 tumor-bearing mice,and show certain dose-effect relationship,and its mechanism may be related to enhancing the immune function in tumor-bearing mice by regulating IL-2.

Research on Channel Codec of DCR System Based on CMX7141

This article introduces a digital private network of mobile communication dedicated chipset CMX7141 that used for the 4FSK modulation and demodulation in DCR system, and introduces the application of CMX7141 inthe DCR system. Focus research on the channel codec techniques of the chip and have a simulation on the channel coding and decoding. The simulation results indicate that, through channel error correction technique in CMX7141, the BER of DCR system reduces greatly and the transmission quality of DCR system is improved.

Hybridoma-derived neutralizing monoclonal antibodies against Beta and Delta variants of SARS-CoV-2 in vivo

Neutralizing monoclonal antibodies(mAb)are a major therapeutic strategy for the treatment of severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)infection.The continuous emergence of new SARS-CoV-2 variants worldwide has increased the urgency for the development of new mAbs.In this study,we immunized mice with the receptor-binding domain(RBD)of the SARS-CoV-2 prototypic strain(WIV04)and screened 35 RBDspecific mAbs using hybridoma technology.Results of the plaque reduction neutralization test showed that 25 of the mAbs neutralized authentic WIV04 strain infection.The 25 mAbs were divided into three categories based on the competitive enzyme-linked immunosorbent assay results.A representative mAb was selected from each category(RD4,RD10,and RD14)to determine the binding kinetics and median inhibitory concentration(IC_(50))of WIV04 and two variants of concern(VOC):B.1.351(Beta)and B.1.617.2(Delta).RD4 neutralized the B.1.617.2 variant with an IC50 of 2.67 ng/mL;however,it completely lost neutralizing activity against the B.1.351 variant.RD10 neutralized both variants with an IC50 exceeding 100 ng/mL;whereas RD14 neutralized two variants with a higher IC50(>1 mg/mL).Animal experiments were performed to evaluate the protective effects of RD4 and RD10 against various VOC infections.RD4 could protect Adv-hACE2 transduced mice from B.1.617.2 infection at an antibody concentration of 25 mg/kg,while RD10 could protect mice from B.1.351 infection at an antibody concentration of 75 mg/kg.These results highlight the potential for future modifications of the mAbs for practical use.