BACKGROUND:Polylactic acid(PLA)has good biocompatibility and a controllable degradation rate and is currently widely used in biomedical engineering.However,PLA has shortcomings such as low mechanical strength and insufficient biological activity,which limits its further application in bone tissue engineering. OBJECTIVE:To construct polylactic acid/polydopamine/tantalum(PLA/PDA/Ta)bone tissue engineering scaffolds,and explore their biosafety and in vitro osteogenesis. METHODS:A PLA scaffold with a porous structure was prepared through liquid crystal display light-curing technology.PLA/PDA scaffolds and PLA/PDA/Ta scaffolds were prepared by soaking PLA scaffolds in dopamine solution and dopamine-tantalum nanoparticle solution,respectively.The microstructure and water contact angle of scaffolds were characterized.MC3T3-E1 cells were co-cultured with PLA,PLA/PDA,and PLA/PDA/Ta scaffolds,respectively,and CCK-8 assay and live/dead cell staining were performed.After osteogenic differentiation,alkaline phosphatase,alizarin red staining,and osteogenic gene detection were performed. RESULTS AND CONCLUSION:(1)The scanning electron microscope results exhibited that the three kinds of prepared scaffolds had an interconnected porous three-dimensional structure,and the average pore diameter was 200 μm.The water contact angle of PLA/PDA/Ta scaffolds was lower than that of PLA and PLA/PDA scaffolds(P<0.05).(2)CCK-8 assay showed that compared with PLA and PLA/PDA scaffolds,PLA/PDA/Ta scaffolds could promote cell proliferation(P<0.05).Live/dead cell staining showed good cell proliferation in the three groups.(3)Alkaline phosphatase and alizarin red staining showed that compared with PLA and PLA/PDA scaffolds,PLA/PDA/Ta scaffolds could promote the expression of alkaline phosphatase and the formation of mineralized nodules.RT-qPCR showed that compared with PLA and PLA/PDA scaffolds,PLA/PDA/Ta scaffolds could enhance the mRNA expression of cell bone morphogenetic protein,Runx-2,and type I collagen(P<0.05,P<0.01).(4)The results showed that the PLA/PDA/Ta scaffold had excellent osteogenic activity and the ability to promote cell proliferation.

Objective To explore clinical effect of distal tibial tubercle-high tibial osteotomy(DTT-HTO)in treating knee osteoarthritis(KO A)with medial meniscus posterior root tear(MMPRT).Methods A retrospective analysis was performed on 21 patients with varus KOA with MMPRT from May 2020 to December 2021,including 3 males and 18 females,aged from 49 to 75 years old with an average of(63.81±6.56)years old,the courses of disease ranged from 0.5 to 18.0 years with an average of(5.9±4.2)years,and 4 patients with grade Ⅱ,14 patients with grade Ⅲ,and 3 patients with grade Ⅳ according to Kellgren-Lawrence;14 patients with type 1 and 7 patients with type 2 according to MMPRT damage classification.The distance of medi-al meniscusextrusion(MME)and weight-bearing line ratio(WBLR)of lower extremity were compared before and 12 months after operation.Visual analogue scale(V AS),Western Ontarioand and McMaster Universities(WOMAC)osteoarthritis index,and Lysholm knee score were used to evaluate knee pain and functional improvement before operation,1,6 and 12 months after operation,respectively.Results Twenty-one patients were followed up for 12 to 18 months with an average of(13.52±1.72)months.MME distance was improved from(4.99±1.05)mm before operation to(1.87±0.76)mm at 12 months after operation(P＜0.05).WBLR was increased from(15.49±7.04)％before operation to(62.71±2.27)％at 12 months after operation(P＜0.05).VAS was decreased from(7.00±1.14)before operation to(2.04±0.80),(0.90±0.62)and(0.61±0.50)at 1,6 and 12 months after operation.WOMAC were decreased from preoperative(147.90±9.88)to postoperative(103.43±8.52),(74.00±9.54)and(47.62±9.53)at 1,6 and 12 months,and the difference were statistically significant(P＜0.05).Lysholm scores were increased from(46.04±7.34)before oepration to(63.19±8.93),(81.10±6.41)and(89.29±3.04)at 1,6 and 12 months after operation(P＜0.05).Conclusion For the treatment of varus KOA with MMPRT,DTT-HTO could reduce medial meniscus pro-trusion distance,improve the ratio of lower limb force line,and effectively reduce knee pain and improve knee joint function.

Objective:This study aims to explore the synergistic effects of DIP and other medical insurance supply-side policies.Method:City A that has piloted DIP reform was set as the treatment group,and City B without reform was set as the control group.A total of 1 120 public medical institution samples from 2019 to 2022 were collected.The total medical expenses during hospitalization and some structural expenses were analyzed using DID method.Result:DIP had a significant inhibitory effect on the medical expenses,and the expenses of checkups and examinations during hospitalization in city A,but had no impact on the drug and the material expenses during hospitalization.Conclusion:DIP played a significant cost control role and effectively controlled the total medical expenses during hospitalization.The synergistic effects of price adjustment of medical services policy and national centralized drug/material procurement policy on cost control were insufficient.DIP synergized with other supply-side policies to promote rational medical cost structure.It is suggested that medical insurance departments should focus on the synergistic effects of medical insurance supply-side policies to jointly improve the efficiency of medical insurance fund utilization.

Objective To develop an intelligent horizontal rotating cell culture device with high modularity,easy operation,easy disinfection,low cost and high stability.Methods The cell culture device consisted of a rotating culture module,a dirve module,a control module and control software,with the shells of all the modules being manufactured by 3D printing.The rotating culture module was composed of a tubular electrospun scaffold,a cell culture chamber,a magnetic coupling rotor and polypropylene pipeline;the drive module was made up of a N20 reduction motor and a magnetic coupling rotor;the control module included an ESP-8266 chip and a printed circuit board;the control software was developed with Blinker IoT platform and C++language.The device was used to culture human intrahepatic bile duct epithelial cells to verify its effects.Results Light microscopy and scanning electron microscopy images showed that a uniform and continuous cell layer was formed on the surface of the tubular electrospun scaffold.Conclusion The intelligent horizontal rotating cell culture device achieves uniform growth of cells on the inner surface of tubular electrospun scaffolds,and can be used as an effective platform for cell culture on tubular scaffolds.[Chinese Medical Equipment Journal,2024,45(9):41-45]

Objective To explore the prediction of hospital indoor microbial concentration in air based on real-time indoor air environment monitoring data and machine learning algorithms.Methods Four locations in a hospital were selected as monitoring sampling points from May 23 to June 5,2022.The"internet of things"sensor was used to monitor a variety of real-time air environment data.Air microbial concentration data collected at each point were matched,and the gradient boosting decision tree(GBDT)was used to predict real-time indoor microbial concentra-tion in air.Five other common machine learning models were selected for comparison,including random forest(RF),decision tree(DT),k-nearest neighbor(KNN),linear regression(LR)and artificial neural network(ANN).The validity of the model was verified by the mean absolute error(MAE),root mean square error(RMSE)and mean absolute percentage error(MAPE).Results The MAPE value of GBDT model in the outpa-tient elevator room(point A),bronchoscopy room(point B),CT waiting area(point C),and nurses'station in the supply room(point D)were 22.49％,36.28％,29.34％,and 26.43％,respectively.The mean performance of the GBDT model was higher than that of other machine learning models at three sampling points and slightly lower than that of the ANN model at only one sampling point.The mean MAPE value of GBDT model at four sampling points was 28.64％,that is,the predicted value deviated from the actual value by 28.64％,indicating that GBDT model has good prediction results and the predicted value was within the available range.Conclusion The GBDT machine learning model based on real-time indoor air environment monitoring data can improve the prediction accuracy of in-door air microbial concentration in hospitals.

Objective:To fabricate the composite scaffolds for bone regeneration with silk fibroin (SF), bacterial cellulose nanofibers (BCNR) and hydroxyapatite (HAp) and evaluate their osteogenic activity.Methods:HAp particles, BCNR and bone morphogenetic protein-2 (BMP2) were added into SF aqueous solution in turn, poured into molds of different sizes after being mixed evenly and processed at -25 ℃ for 24 hours to obtain frozen molds, and the composite scaffolds were frozen-dried by freezing-drying machine. The composite scaffolds with different mass ratios of SF and BCNR were divided into groups A (2∶1), B (4∶1) and C (6∶1), and the inactive composite scaffolds without BMP2 fell into group D. The surface morphology and pore structure of the scaffolds were detected by scanning electron microscopy. The porosity of the scaffolds was measured by mercury intrusion porosimeter. The stress-strain curve was obtained by using the universal material testing machine to compress the scaffolds, with which their compressive strength and Young′s modulus were analyzed. Immortalized mouse embryonic fibroblasts (iMEF) were inoculated on the composite scaffolds of group A, B, C and D. At 4 and 8 days after cell inoculation, the proportion of alive and dead cells in each group was detected by cell survival/death staining; the cell counting kit-8 (CCK-8) was used to detect cell proliferation activity in each group; the positive staining cells were detected in each group by alkaline phosphatase (ALP) staining; the ALP activity was observed in each group with ALP activity detection. A total of 15 female SD rats were selected to establish osteogenesis models with ectopic muscle bag. The composite scaffolds implanted with different SF/BCNR mass ratios and the inactive composite scaffolds without BMP2 fell into group A′ (2∶1), B′ (4∶1), C′ (6∶1) and D′ respectively, and a sham operation group was set at the same time, with 3 rats in each groups. In the sham operation group, the muscle bag and skin were sutured without scaffold implantation after the incision of skin, the blunt separation of the quadriceps muscle, and the formation of muscle bag in the muscle. In the other four groups, the corresponding scaffolds were implanted in the muscle bag and the muscle bag and skin were sutured. X-ray examination was performed at 2 and 4 weeks after operation to observe the osteogenesis in each group. At 4 weeks after operation, the implanted scaffolds and tissue complexes were collected by pathological tissue sectioning, HE staining and Masson staining, and for observing the osteogenesis by in each group. Immunohistochemical staining was also performed on the tissue sections to observe the expression of osteogenic markers type I collagen (COL1) and osteopontin (OPN) in each group.Results:Scanning electron microscopy showed that the lamellar and micropore structures of group B were more regular and uniform than those of groups A and C. The porosity rate analysis showed that the porosity rates of groups B and C were (89.752±1.866)% and (84.257±1.013)% respectively, higher than that of group A [(81.171±1.268)%] ( P<0.05 or 0.01), with the porosity rate of group C lower than that of group B ( P<0.01). The mechanical property test showed that the compressive strengths of groups B and C were (0.373±0.009)MPa and (0.403±0.017)MPa respectively, higher than that of group A [(0.044±0.003)MPa] ( P<0.01), and the Young′s moduli of groups B and C were (7.413±0.094)MPa and (9.515±0.615)MPa respectively, higher than that of group A [(1.881±0.036)MPa] ( P<0.01), with the compressive strength and Young′s modulus of group C higher than those of group B ( P<0.05 or 0.01). The cell survival/death staining showed that the number of dead cells of group B was significantly smaller than that of groups A, C and D at 4 days after cell inoculation, and that group B had the most living cells and the fewest dead cells at 8 days after cell inoculation. The results of CCK-8 experiment showed that at 4 days after cell inoculation, the cell proliferation activity of groups A and B was 0.474±0.009 and 0.545±0.018 respectively, higher than 0.394±0.016 of group D ( P<0.01); the cell proliferation activity of group C was 0.419±0.005, with no significant difference from that of group D ( P>0.05), while the cell proliferation activity of groups A and C were both lower than that of group B ( P<0.01). At 8 days after cell inoculation, the cell proliferation activity of group B was 1.290±0.021, higher than 1.047±0.011 of group D ( P<0.01); the cell proliferation activity of group C was 0.794±0.032, lower than that of group D ( P<0.01); the cell proliferation activity of group A was 1.086±0.020, with no significant difference from that of group D ( P>0.05); the cell proliferation activity of groups A and C was lower than that of group B ( P<0.01). At 4 and 8 days after cell inoculation, ALP staining showed that more positive cells were found in groups A, B and C when compared with group D, and more positive cells were found in group B than in groups A and C. At 4 days after cell inoculation, the ALP activity detection showed that the ALP activity of groups A, B and C was 1.399±0.071, 1.934±0.011 and 1.565±0.034 respectively, higher than 0.082±0.003 of group D ( P<0.01), while the ALP activity of groups A and C was lower than that of group B ( P<0.01). At 8 days after cell inoculation, the cell activity of groups A, B and C was 2.602±0.055, 3.216±0.092 and 2.145±0.170 respectively, higher than 0.101±0.001 of group D ( P<0.01), while the ALP activity of groups A and C was lower than that of group B ( P<0.01). X-ray examination results showed that at 2 weeks after operation, no obvious osteogenesis was observed in the sham operation group, group D′, A′ and C′, while it was observed in group B′. At 4 weeks after operation, obvious osteogenesis was observed in group A′, B′ and C′, with significantly more osteogenesis in group B′ than in the other two groups, while there was no obvious osteogenesis in the sham operation group and group D′. At 4 weeks after operation, the HE staining and Masson staining showed that a large number of uniformly distributed new bone tissue was formed in group B′, while only a small amount of new bone tissue was found locally in groups A′ and C′, and only part of new tissue was found to grow in group D′ with no obvious new bone tissue observed. The maturity of new bone tissue formed in group B′ was higher than that in group A′ and C′. Immunohistochemical staining showed more COL1 and OPN positive staining in group B′ when compared with groups A′ and C′. The expression intensity analysis of COL1 and OPN showed that in groups A′, B′ and C′, the expression intensity of COL1 was 2.822±0.384, 22.810±2.435 and 12.480±0.912 respectively and the expression intensity of OPN was 1.545±0.081, 5.374±0.121 and 2.246±0.116 respectively, with higher expression intensity of COL1 and OPN in groups B′ and C′ than that in group A′ ( P<0.01) and lower expression intensity of COL1 and OPN in group C′ than that in B′ group ( P<0.01). Conclusions:The composite scaffold for bone regeneration is successfully fabricated with SF, BCNR and HAp. The composite scaffold with a mass ratio of SF to BCNR of 4∶1 has uniform pore structure, high porosity, good mechanical properties and biocompatibility, excellent pro-osteogenic properties in vitro, as well as excellent osteo-inductivity and osteo-conductivity.

It has become an industry consensus that self-assembled nanoparticles (SAN) are formed by molecular recognition of chemical components in traditional Chinese medicine during the decoction process. The insoluble components in the decoction are mostly in the form of nanoparticles, which can improve the problem of poor water solubility. However, the transfer rate of these insoluble components in the decoction is still very low, which limits the efficacy of the drug. This study aimed to refine the traditional decoction self-assembly phenomenon. The self-assembled nanoparticles were constructed by micro-precipitation method (MP-SAN), and characterized by particle size, zeta potential, stability index and morphology. The formation of MP-SAN and alterations in related physicochemical properties were evaluated using modern spectroscopic and thermal analysis techniques. The quality value transmitting pattern of lignan components within the MP-SAN was assessed via high performance liquid chromatography (HPLC). The MP-SAN showed sphere-like structure with uniform morphology, particle size of (245.3 ± 3.2) nm, polydispersity index (PDI) of (0.13 ± 0.03), zeta potential of (-48.9 ± 5.9) mV and stability index (SI) of (86.05% ± 2.27%). Comprehensive analyses using ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and other techniques confirmed molecular recognition between the decoction and ethanol extraction, leading to electron rearrangement under the influence of non-covalent bonding. This resulted in the formation of nanoparticles possessing superior thermal stability. As determined by HPLC, the encapsulation rates of the index components in the MP-SAN were all greater than 75% (dehydrodiconiferyl alcohol: 77.00%; herpetolide A: 78.57%; herpetrione: 94.53%), and the transfer rates were all higher than 65% (dehydrodiconiferyl alcohol: 96.01%; herpetolide A: 67.86%; herpetrione: 65.55%), which were 1.34, 1.38 and 4.81 times compared with those of the traditional decoction. In summary, this study successfully constructed the MP-SAN based on micro-precipitation method to achieve high transfer rate and high encapsulation rate of insoluble components in docoction, which provides a pharmaceutics idea for the efficient utilization of pharmacodynamic substance basis of traditional Chinese medicine.

BACKGROUND:Pauwels Ⅲ femoral neck fracture is a typical unstable fracture characterized by high vertical shear force and high incidence of postoperative complications.At present,there are many fixation methods for Pauwels Ⅲ fracture,and there is no clear conclusion as to which internal fixation is the best fixation method for Pauwels Ⅲ femoral neck fracture in young adults. OBJECTIVE:To compare the clinical effect of three inverted triangle cannulated screws assisted transverse lag screws and femoral neck system in fixing Pauwels Ⅲ femoral neck fractures of young adults. METHODS:From May 2021 to December 2022,21 young and middle-aged patients with Pauwels Ⅲ femoral neck fracture were treated with three inverted triangle cannulated screws assisted by transverse lag screws and femoral neck system in Affiliated Hospital of Southwest Medical University.Of them,9 patients were treated with three inverted triangle cannulated screws and one transverse lag screws perpendicular to the fracture line as the 3+1 cannulated screw group and 12 patients were treated with femoral neck system as the femoral neck system group.The two fixation methods were compared in terms of operation time,intraoperative blood loss,total incision length,intraoperative fluoroscopy times,fracture healing time,and limb function. RESULTS AND CONCLUSION:(1)All patients were followed up.Patients in the 3+1 cannulated screw group were followed up for 10-25 months,with a mean of(17.44±4.30)months.The patients in the femoral neck system group were followed up for 8-24 months,with a mean of(15.58±4.68)months.(2)The intraoperative fluoroscopy times and Harris score at 3 months postoperatively in the femoral neck system group were better than those in the 3+1 cannulated screw group,and the difference was statistically significant(P<0.05).The intraoperative blood loss,total incision length,and femoral neck shortening distance in the 3+1 cannulated screw group were better than those in the femoral neck system group,and the differences were statistically significant(P<0.05).There was no significant difference in operation time,fracture healing time,and Harris score at the last follow-up between the two groups(P>0.05).(3)It is indicated that three inverted triangle cannulated screws assisted transverse lag screw and femoral neck system can achieve good clinical effects in the treatment of young and middle-aged Pauwels Ⅲ femoral neck fracture.The femoral neck system has fewer intraoperative fluoroscopy times and better early overall stability,while the 3+1 cannulated screw is more minimally invasive,easier to operate.Both fixation methods are worthy of clinical application and promotion,and can be selected according to the actual clinical situation.

Currently,human health due to corona virus disease 2019(COVID-19)pandemic has been seriously threatened.The coronavirus severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)spike(S)protein plays a crucial role in virus transmission and several S-based therapeutic approaches have been approved for the treatment of COVID-19.However,the efficacy is compromised by the SARS-CoV-2 evolvement and mutation.Here we report the SARS-CoV-2 S protein receptor-binding domain(RBD)inhibitor licorice-saponin A3(A3)could widely inhibit RBD of SARS-CoV-2 variants,including Beta,Delta,and Omicron BA.1,XBB and BQ1.1.Furthermore,A3 could potently inhibit SARS-CoV-2 Omicron virus in Vero E6 cells,with EC50 of 1.016 pM.The mechanism was related to binding with Y453 of RBD deter-mined by hydrogen-deuterium exchange mass spectrometry(HDX-MS)analysis combined with quan-tum mechanics/molecular mechanics(QM/MM)simulations.Interestingly,phosphoproteomics analysis and multi fluorescent immunohistochemistry(mIHC)respectively indicated that A3 also inhibits host inflammation by directly modulating the JNK and p38 mitogen-activated protein kinase(MAPK)path-ways and rebalancing the corresponding immune dysregulation.This work supports A3 as a promising broad-spectrum small molecule drug candidate for COVID-19.

Objective To assess the risk factors for carbapenem-resistant Acinetobacter baumannii(CRAB)bloodstream infection(BSI)and 28-day short-term mortality in elderly patients,and provide reference for the pre-vention and treatment of CRAB BSI.Methods Clinical data of patients aged ≥60 years and diagnosed with AB BSI in a hospital in Yulin City from January 2013 to December 2022 were retrospectively analyzed,including demogra-phic and microbiological characteristics,as well as clinical outcomes of the patients.Variables which were significant in univariate analysis were selected for multivariate analysis using binary logistic regression model and Cox propor-tional hazards model.Independent risk factors for infection were further determined,and survival analysis was per-formed using Kaplan-Meier curve.Results A total of 150 patients were included in the study,out of which 16 pa-tients(10.7％)had CRAB BSI and 134 had carbapenem-sensitive AB(CSAB)BSI.The 28-day short-term mortali-ty of AB BSI in elderly patients was 15.3％(23/150,95％CI:9.6％-21.1％),and the short-term mortality of CRAB BSI was higher than that of CSAB([56.3％,9/16]vs[10.4％,14/134]).Deep venous catheterization(OR:15.598,95％CI:1.831-132.910)and combined infections of other sites(OR:15.449,95％CI:1.497-159.489)were related to CRAB BSI in elderly patients.The independent risk factors for 28-day mortality in elderly patients with AB BSI were hemodialysis(OR:11.856,95％CI:2.924-48.076),intensive care unit admission(OR:9.387,95％CI:1.941-45.385),and pulmonary infection being suspected source of bacteremia(OR:7.019,95％CI:1.345-36.635).Conclusion The occurrence of CRAB BSI in elderly patients is related to the combined infection of other sites and deep vein catheterization.Hemodialysis,admission to ICU,and pulmonary infection being suspected source of bacteremia are independent risk factors for the prognosis of AB BSI in elderly patients.