ObjectiveThis study employs a special conformational engineering (CE) technology to construct an α-chymotrypsin-like active center, which includes a catalytic triad, an oxyanion hole, and a substrate-binding site, on silver nanoparticles (AgNPs), thereby creating an AgNP-based artificial hydrolase with high catalytic activity. This study provides a new approach for the design of highly efficient artificial enzymes and enzyme-mimicking. MethodsAgNPs were chosen as the scaffold to build the an α-chymotrypsin-like active center. A special CE procedure enables the designed peptide, Triad5, to adopt an α‑helical conformation on AgNPs, with the key catalytic residues located on one side of the α-helix forming a catalytic active center with a catalytic triad, an oxyanion hole, and a substrate-binding site. The CE procedure consists of three steps, including conformation induction via trifluoroethanol (TFE), conformation stabilization on AgNPs via Ag-S bonds, and TFE removal via lyophilization. Circular dichroism (CD) spectra were used to confirm the formation and stabilization of the α-helix conformation. Mutations of the key residues combined with stopped-flow kinetic experiments were used to demonstrate the indispensability of each key residue and the synergistic effects among the catalytic triad, the oxyanion hole, and the substrate-binding site. ResultsCD spectra show that the designed Triad5 alone is in random coil conformation; when conjugated on AgNPs, Triad5 still remains largely unstructured; but after the CE treatment, Triad5 adopts a typical α-helical conformation on AgNPs as designed, thus produces an AgNP-based artificial hydrolase, Silverzyme. Silverzyme exhibits extremely high hydrolytic activity towards p-nitrophenyl acetate (p-NPA), with an extremely high catalytic turnover number per active site of 3.5 s^-1, which is even higher than that of α-chymotrypsin. As a comparison, the AgNP-Triad5 conjugate without CE treatment shows much lower catalytic activity than Silverzyme, highlighting the important role of the right conformation of the active center for the catalytic activity and the power of the CE treatment. When the key residues of the catalytic triad of Silverzyme were mutated to alanine, the overall catalytic efficiency of this mutant dropped by about 2 orders of magnitude, unambiguously demonstrating the key role of the designed catalytic triad. Similarly, when the residues for the oxyanion hole were deleted, the mutant with the intact catalytic triad also showed significantly decreased catalytic activity, highlighting the indispensable role of the oxyanion hole for the catalytic activity. Unexpectedly, when both the catalytic triad and the oxyanion hole were kept intact, a slight change of the binding site also resulted in significantly decreased catalytic activity, indicating that the designed binding site is at the right position to align the substrate in the right orientation in the active center for catalytic hydrolysis. These results confirm the synergy among the catalytic triad, the oxyanion hole, and the substrate-binding site, indicating successful mimicking of the active center of α-chymotrypsin. Moreover, Silverzyme shows better thermal stability than α-chymotrypsin, and can even hydrolyze the tough non-activated ester diethyl phthalate, a priority pollutant by the United States Environmental Protection Agency (USEPA). ConclusionThis study successfully mimicked the complex catalytic active center of α-chymotrypsin using a conformational engineering strategy, and produced a highly active artificial hydrolase with a well-defined structure and catalytic mechanism. The findings highlight the significant potential of conformational engineering.

Objective: To evaluate the efficacy and safety of ruxolitinib combined with low-dose hormone for patients with acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: Thirty patients with aGVHD after allo-HSCT admitted to the Department of Hematology of the General Hospital of Western Theater Command from November 2021 to November 2024 were retrospectively analyzed. All patients were treated with low-dose hormone (methylprednisolone 0.3-1 mg kg -d ) combined with ruxolitinib 5-10 mg d . The efficacy and adverse reactions were observed during the follow-up period to analyze the survival outcomes of the patients. Results: A total of 30 patients with aGVHD after allo-HSCT were included in this study, consisting of 15 (50%) males and 15 (50%) females with a median age of 34 year-old (ranging from 14 to 62). Classification by disease type: there were 18 cases of acute myeloid leukemia, 4 cases of acute lymphoblastic leukemia, 4 cases of aplastic anemia, and 4 cases of myelodysplastic syndrome. Classification by aGVHD severity: there were 27 cases (90%) of Ⅱ-Ⅳ degree aGVHD and 11 cases (36.7%) of Ⅲ-Ⅳ degree aGVHD. Ruxolitinib in combination with low-dose glucocorticoid treatment yield responses in 28 (93.3%) patients, of which 27 (90%) achieved complete remission (CR), while 1 (3.3%) showed partial remission (PR). One patient (3.3%) had no response (NR), and 1 patient (3.3%) exhibited progressed disease (PD). Overall survival (OS) at 1 year of transplantation was 73.9% (95%CI 49.5% to 87.7%), progression-free survival (PFS) was 93.3% (95%CI 75.9% to 98.3%), non-relapse mortality (NRM) was 20.6% (95%CI 7.9% to 47.4%), and median survival time was 27.6 months. Conclusion: Ruxolitinib combined with low-dose hormones is safe and effective in the treatment of aGVHD after allo-HSCT.

Purpose: Due to the preservation of the entire stomach after endoscopic resection, the occurrence of metachronous gastric cancer (MGC) remains a possibility. In this study, we investigated the incidence and risk factors for MGC in patients with early gastric cancer who underwent endoscopic submucosal dissection (ESD) and successfully eradicatedHelicobacter pylori. Materials and Methods: A retrospective analysis was conducted of 1,191 patients who underwent ESD and successfully eradicated H. pylori at the Affiliated Drum Tower Hospital of Nanjing University. Endoscopic surveillance was performed at 3, 6, and 12 months post-resection, and annually thereafter. MGC was defined as the development of a new cancer at a site other than the primary gastric cancer site, at least 1 year after the initial endoscopic resection. Results: A total of 77 patients were diagnosed with MGC during a median follow-up of 41.5 months. Kaplan-Meier analysis showed a 5-year cumulative incidence of MGC of 9.4% after successful H. pylori eradication. Multivariate analysis of the training set using Cox proportional hazards models identified male sex, severe atrophic gastritis, multiple gastric cancers before H. pylori eradication, and smoking history as independent risk factors for MGC.The nomogram exhibited favorable discrimination, with area under the curves of 0.767 and 0.822 in the training set and 0.724 and 0.745 in the testing set at 3 and 5 years, respectively. Conclusions Patients with gastric cancer who undergo endoscopic resection, even after successful H. pylori eradication, should undergo annual and continuous endoscopic surveillance for MGC.

Objective:To investigate the feasibility and effectiveness of three-dimensional visualization technology in the precise diagnosis and treatment of locally advanced differentiated thyroid cancer(DTC).Methods:A retrospective analysis was conducted on the clinical data of 196 patients with locally advanced DTC treated at the 960th Hospital of the PLA from December 2021 to August 2023. The cohort included 71 male and 125 female patients, with a mean age of 43.7 years (rangd from 18 to 77 years). All patients underwent neck-enhanced CT scans and were divided into two groups: the study group( n=102), which underwent preoperative three-dimensional visualization of CT data, and the control group( n=94), which did not. Baseline data for both groups were matched using SPSS27.0 with 1∶1 propensity score matching (PSM) and the caliper value was 0.02. A total of 49 patients were included in each group, including 35 first-time surgeries and 14 reoperation. Among the 70 first-time surgeries, 29 patients underwent robotic surgery and 41 underwent open surgery. Among the 28 reoperations, 4 underwent robotic surgery and 24 underwent open surgery. In the study group, three-dimensional visual models were used to comprehensively evaluate the tumor and metastatic lesion size, spatial location, and adjacent relationship with surrounding organs, surgical treatments were guided by these models, whereas the control group relied on two-dimensional imaging for guidance. The clinical data were statistically analyzed using SPSS27.0. Results:All operations were successfully completed. There were no statistical differences in baseline data between the two groups( P>0.05). Among first-time surgeries, the study group showed shorter operation times [175(145, 200) min vs 205(182, 249) min, P<0.001], a lower incidence of postoperative chyle leak (0 vs 8.57%, P=0.027), a higher rate of robotic surgery (48.57% vs 34.28%, P=0.225), a greater number of harvested lymph nodes [46(40, 62) vs 37(28, 56), P=0.032], a greater number of cervical lymph node metastasis[15(7, 22) vs 5(1, 14), P=0.004] and a larger diameter of metastasis lymph nodes[12(10, 16) mm vs 4(1, 10) mm, P<0.001]. There were no significant differences in intraoperative blood loss, postoperative drainage days and incidence of hypoparathyroidism( P>0.05). During the reoperation, the study group had shorter operation times[103.5(95.0, 122.5) min vs 146.50(133.25, 172.25) min, P<0.001], less intraoperative blood loss[12.50(8.75, 22.50) mL vs 30.00(17.50, 35.00) mL, P=0.021], fewer postoperative drainage days[5.00(4.00, 6.00) d vs 6.00(5.00, 7.25) d, P=0.016] and a lower incidence of hypoparathyroidism(7.14% vs 42.86%, P=0.038).The robotic surgery rate was higher in the study group (21.42% vs 7.14%, P=0.596). There were no significant differences in lymph node dissection numbers, metastatic lymph node counts, or chyle leak incidences between the two groups ( P>0.05). No acute bleeding or incision infection occurred in any patient postoperatively. Conclusion:Three-dimensional visualization technology is an effective preoperative assessment method for evaluating the resectability of tumors and metastases lesions in locally advanced DTC. It enhances the accuracy and safety of surgery for locally advanced DTC.

Objective To investigate the diagnostic value of 4 novel inflammatory markers related to routine blood tests,namely neutrophil-to-lymphocyte ratio(NLR),red blood cell distribution width(RDW),hemoglobin-to-RDW ratio(HRR)and systemic immune-inflammation index(SII),in elderly patients with chronic cardiovascular disease(CVD)complicated with frailty.Methods Retrospectively analyze 110 patients with chronic stable CVD who were hospitalized in the cadre ward of cardiovascular medicine at the Air Force Characteristic Medical Center from January 2022 to June 2023.According to the assessment results of the Fried scale,they were divided into three groups:non-frailty group(Fried score=0,n=30),the pre-frailty group(Fried score 1 or 2,n=40)and frailty group(Fried score≥3,n=40).The differences in general information,the impairment rate of daily living activities,miniature nutritional assessment-short form(MNA-SF)scores,mini-mental state examination(MMSE)scores,and the indicators such as NLR,RDW,HRR,and SII among the three groups were compared.Spearman rank correlation was used to analyze the correlation between NLR,RDW,HRR,SII and frailty scores as well as each frailty indicator.Multivariate logistic regression analysis was performed to identify the independent risk factors for frailty in elderly patients with chronic CVD,and the receiver operating characteristic(ROC)curve was used to assess the clinical diagnostic value of NLR and HRR in elderly patients with chronic CVD complicated with frailty.Results Compared with non-frailty group and pre-frailty group,patients in frailty group were older,with higher impaired rates of daily living activities,NLR,RDW,and SII,and lower MNA-SF scores,MMSE scores,and HRR,and differences were statistically significant(P<0.05).Spearman rank correlation analysis showed that the frailty score was positively correlated with NLR(rs=0.354,P<0.001),and RDW(rs=0.448,P<0.001),negatively correlated with HRR(rs=-0.232,P=0.024),and had no significant correlation with SII(rs=0.144,P=0.167).Further analysis of the correlation between the above novel inflammatory markers and the 5 components of frailty showed that NLR was positively correlated with fatigue(rs=0.228,P=0.017),slowed walking speed(rs=0.299,P<0.001),and low physical function(rs=0.319,P<0.001);RDW was positively correlated with decreased grip strength(rs=0.321,P<0.001),slowed walking speed(rs=0.422,P<0.001),and low physical function(rs=0.246,P=0.001);and HRR was negatively correlated with slowed walking speed(rs=-0.230,P=0.025),and low physical function(rs=-0.299,P=0.003).Multivariate logistic regression analysis showed that MNA-SF score(OR=0.577,95%CI 0.342-0.973)was an independent protective factor for pre-frailty in elderly patients with chronic CVD(P<0.05);NLR(OR=7.866,95%CI 1.101-56.185)was an independent risk factor for frailty,while HRR(OR=0.344,95%CI 0.120-0.983)and MNA-SF score(OR=0.292,95%CI 0.146-0.580)were independent protective factors for frailty in elderly CVD patients(P<0.05).The area under the ROC curve of NLR and HRR for diagnosing frailty in elderly patients with chronic CVD were 0.778 and 0.749,respectively.Conclusion NLR and HRR have high clinical diagnostic value for frailty in elderly patients with chronic CVD,and are expected to become effective inflammatory markers for screening elderly patients with chronic CVD complicated with frailty.

Objective To analyze the effect of Hsa-circ-0101216 on gemcitabine(GEM)chemotherapy resistance in pancreatic cancer and its mechanism.Methods Differentially expressed circRNAs between GEM-resistant pancreatic cancer cells and parent cells were screened using the GEO database.Pancreatic cancer GEM resistant cell lines(BxPC-3-GEM and Capan-1-GEM)were constructed by intermittent concentration gradient method.qRT-PCR was used to detect the expression of Hsa-circ-0101216 in cells.GEM resistant pancreatic cancer cell lines were taken and divided into sh-circ-0101216 group(knockdown of circ-0101216),sh-NC group(transfected with sh-NC),and blank control group(untreated).CCK-8 assay and EdU proliferation assay were used to detect the half inhibitory concentration(IC50)of GEM and proliferation ability of cells in each group.Western blotting was performed to detect the expression of multidrug resistance-related protein 1(MRP1),breast cancer resistance protein(BCRP),and human equilibrative nucleoside transporter-1(hENT-1).A subcutaneous xenograft tumor model of human pancreatic cancer in nude mice was constructed,and sh-NC+GEM group and sh-circ-0101216+GEM group(n=6)were set up.The volume and weight of xenograft tumor in nude mice were compared between the two groups.Western blotting and immunohistochemistry were used to detect the expression of MRP1,BCRP,and hENT-1 proteins in xenograft tumor tissues,and EDU proliferation assay was used to detect the proliferation ability of tumor cells.Results The GEO database screening showed that Hsa-circ-0101216 was up-regulated in GEM-resistant pancreatic cancer cell lines.Pancreatic cancer GEM-resistant cell lines were successfully constructed,and the expression levels of Hsa-circ-0101216 and the IC50 value in GEM-resistant pancreatic cancer cells BxPC-3-GEM and Capan-1-GEM were significantly higher than those in parental cells(P<0.05).In sh-circ-0101216 group,the IC50 values of GEM,cell viability,EdU positivity rate,and the expression levels of MRP1 and BCRP proteins in GEM-resistant pancreatic cancer cells BxPC-3-GEM and Capan-1-GEM were significantly lower than those in blank control group and sh-NC group,while the expression level of hENT-1 protein was significantly higher(P<0.05 or P<0.001).In sh-circ-0101216+GEM group,the weight and volume of subcutaneous xenograft tumors in nude mice,the expression levels and positive expression rates of MRP1 and BCRP proteins in tumor tissues,and the EdU positive rate were significantly lower than those in sh-NC+GEM group,while the expression level and positive expression rate of hENT-1 protein were significantly higher(P<0.05).Conclusions Hsa-circ-0101216 is highly expressed in GEM-resistant pancreatic cancer cell lines.Its knockdown can inhibit the proliferation of pancreatic cancer cells and enhance the chemosensitivity of pancreatic cancer cells to GEM.The mechanism may be related to the regulation of transmembrane transporter protein expression.

Objective To observe the difference of bone micro-structure in different regions of proximal femur,micro-CT scanning was performed on 30 proximal femur specimens to explain the mechanism of proximal femur fracture and to provide anatomical basis for prosthesis design.Methods Totally 30 intact proximal femur specimens were obtained from 60-80 year-old cadavers.Micro-CT scanning was used to measure the trabecular thickness(Tb.Th),trabecular number(Tb.N),trabecular space(Tb.Sp),connectivity(Conn)and bone mineral density(BMD)and other parameters in 7 regions of proximal femur,including proximal pressure trabecular(PPT),distal pressure trabecular(DPT),femoral head-neck junction(FHNJ),head and neck of femoral neck(HNFN),the base of femoral neck(BPFN),intertrochanteric line(IL)and greater trochanter(GT).Results The bone mineral density of IL and GT were higher than those of BPFN,FHNJ,DPT and PPT.The trabecular thickness of GT was the largest,followed by IL,BPFN and HNFN,and the smallest was FHNJ,DPT and PPT.The trabecular space of IL was larger than that of GT,and the data of both were larger than those of other parts,among which DPT and PPT were the smallest.The trabecular number of IL and GT were the smallest,BPFN,HNFN and FHNJ were larger,and DPT was the largest.The volume fraction of IL was the smallest,BPFN and HNFN were larger,DPT and PPT were the largest.Conclusion The bone density,trabecular thickness,bone volume,and total volume of GT and IL in the proximal femur of elderly patients are all relatively large,so the reason for the high incidence of fractures is not due to weak internal bone microstructure;The bone density,trabecular thickness,and trabecular gap at the proximal and distal ends of the vertical trabecular bone are relatively small.If it is necessary to perform core decompression for prosthesis filling at this location,the design should be conducive to the mechanical conduction of the prosthesis and the regeneration of surrounding bone tissue.

Objective To explore the effectiveness of drawing-based method in medical courses and their impact on students' learning habits,academic performance,and comprehensive competencies,in order to meet the demand for high-quality,interdisciplinary,and innovative talent,and provide theoretical support for integrating aesthetic education into medical training.Methods A questionnaire survey was conducted among medical students(n=310)at Dalian Medical University,covering the frequency of using drawing method and their effects on learning outcomes,innovation ability,and humanistic qualities.Data were analyzed using the Chi-square test and Fisher's exact test(P＜0.05).Results Totally 93.6％of students approved of using drawing method for learning medical courses,with 70.8％having developed a habit of drawing-based learning.Students with stronger drawing skills were more inclined to use drawing method and supported their application in teaching.The frequency of drawing-based learning was positively correlated with anatomy scores(P＜0.05).Students generally agreed that drawing method enhanced knowledge comprehension,learning interest,long-term memory,innovation ability,critical thinking,and humanistic qualities.However,students with weaker drawing skills perceived drawing method as potentially increasing learning burdens and being less efficient,but this perception significantly decreased with increased drawing frequency(P＜0.05).Conclusion Drawing methods are widely used in medical courses and effectively improve learning outcomes and comprehensive competencies.Drawing proficiency and frequency are key factors influencing students' acceptance and learning effectiveness.Future efforts should focus on promoting drawing method,strengthening students' drawing skills,and optimizing learning processes to deepen the integration of aesthetic education in medical training.

Objective This study aimed to provide an effective scientific basis for prevention and control of cockroaches on aircrafts by identifying cockroach-carried pathogens,and assess the insecticidal efficacy of gel bait mediated cockroach control on aircrafts,to provide technical guidance for aircraft disinsection.Methods Cassette-trapping was used to trap cockroaches,and the carried pathogens were detected using bacterial cultivation techniques.The gel bait mediated killing rate was calculated after 1,7,and 30 d by field application of gel bait.Results A total of 411 cockroaches were captured,and all were identified as Blattella germanica.26 strains of pathogenic bacteria were isolated from the trapped cockroaches.The killing rates of cockroaches were 58.8％-96.3％with 1-30 day application of gel bait.Statistically significant differences were observed in cockroach killing rates on different days(χ2=58.95,P<0.01).Conclusions B.germanica carry a large variety of pathogenic bacteria and opportunistic pathogens and are thus important infectious disease carriers.Gel bait agents have proven to be very effective against cockroaches on aircrafts.

Poly(lactic-co-glycolide)(PLGA)is a key excipient in long-acting sustained-release preparations,and its degradation properties directly affect the drug release behavior.In this study,PLGA microspheres were prepared by microfluidic techniques,and the morphology changes of the microspheres were observed by scanning electron microscopy(SEM).In alkaline environment,due to the accelerated hydrolysis of ester bonds,the surface of the microspheres was rapidly dissolved and eroded,and the degradation rate was significantly higher than that in acidic environment.High temperature accelerated the degradation of PLGA microspheres.Under neutral and alkaline conditions,the microspheres showed aggregation and adhesion.Under acidic conditions,the microspheres gradually decomposed into irregular fragments.The high ionic strength further promoted the surface corrosion of the microspheres,especially under extreme pH conditions.Simultaneously,PLGA microspheres encapsulating coumarin were prepared to simulate the microsphere formulation.The release rate of coumarin after degradation of the microspheres under different conditions was observed by measuring the absorbance with ultraviolet-visible spectrophotometry.The results were consistent with those of the blank microspheres.This study revealed that the degradation of PLGA microspheres was significantly pH-dependent,temperature sensitive and ion strength responsive.These findings not only helped to understand and optimize the long-term stability and controlled release performance of drug-carrying microspheres,but also provided a theoretical basis for further improvement of PLGA-based drug carrier design.