As one of the imaging features of cerebral small vessel disease, white matter hyperintensity (WMH) of presumed vascular origin is quite common in the elderly. The burden of WMH is thought to progress slowly over time and is significantly associated with cognitive decline. However, the pathogenesis of WMH remains unclear and there is no effective treatment available. Recent studies have reported that some WMH lesions can regress during follow-up, along with progression and regression occurring alternately, suggesting that longitudinal changes in WMH are not unidirectional. This article presents a systematic review of current neuroimaging studies on WMH regression to enhance the understanding of dynamic changes in WMH and to provide new theoretical evidence for WMH intervention.

OBJECTIVES: To design and prepare silk fibroin/hyaluronic acid composite hydrogel. METHODS: The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by ¹H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope. RESULTS: The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good. CONCLUSIONS The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.
Fibroins/chemistry* ; Hydrogels/chemistry* ; Hyaluronic Acid/chemistry* ; Biocompatible Materials/chemistry* ; Click Chemistry ; Sulfhydryl Compounds ; Silk/chemistry*

Objective:To review the process, contents, theoretical basis, and evaluation methods for constructing the framework of entrustable professional activities (EPAs) in the stage of undergraduate medical education (UME) in foreign medical colleges and universities.Methods:PubMed, Web of Science, Embase, and Scopus databases were searched to obtain the articles on EPAs in the stage of UME published up to May 2022, and then a systematic review was performed.Results:A total of 17 articles were included, and the analysis showed that the framework of EPAs in the UME stage was mainly constructed by referring to the existing framework of EPAs and conducting multiple rounds of consultation and revision. The contents of EPAs include core basic EPAs, core specific professional EPAs, and individual selective EPAs. The theoretical basis for developing the EPAs framework mainly include the Miller's Pyramid of Assessment model and Dreyfus and Dreyfus's Model of Skills Acquisition. The mainstream frameworks of EPAs competency include Canadian CanMEDS, six core competencies of American ACGME and their corresponding milestones. The confidence level of EPAs evaluated at the UME stage is highlighted as 9 levels of stratification, and the evaluation methods for confidence decision mainly include observation, communication, and review of results.Conclusion:Foreign EPAs-related research in the UME stage has become more mature, but there is a lack of related studies in China. Chinese medical education researchers can learn from the experience in the development of EPAs in foreign countries and combine it with China's actual situation to construct an integrated EPAs framework for medical education covering the UME stage and the evaluation criteria for confidence level, so as to promote competency-oriented evaluation and feedback and accelerate the construction of a medical talent training system that serves the whole life cycle and the whole health process.

Objective:To construct the postgraduate teaching case database of rotation in department of cardiology, and to explore its application effect.Methods:The postgraduate teaching case base of rotation in department of cardiology was constructed during April 2020 to December 2020. A total of 32 graduate students rotating in Department of Cardiology of Affiliated Hospital of Guilin Medical University from January 2021 to April 2021 were selected and randomly divided into two groups. The routine group adopted the traditional teaching method, and the research group applied the teaching case base on this basis, both for one month. The examination results, the changes of clinical practice ability before and after the teaching, and the satisfaction with the teaching mode were compared between the two groups. SPSS 22.0 was used for t test and chi-square test. Results:The final results of the theoretical examination and practical operation examination of the two groups were higher than those of the entrance examination ( P<0.05), and the results of the theoretical examination and practical operation examination of the research group were higher than those of the routine group ( P<0.05). The scores of clinical practice ability of inquiry, case analysis, diagnosis, treatment and follow-up in the two groups after teaching were higher than those before teaching ( P<0.05), and the scores of clinical practice ability in the research group after teaching were higher than those in the routine group ( P<0.05). The satisfaction scores on improving examination results, enhancing clinical practice ability, deepening professional understanding and enhancing professional confidence of the teaching mode of the research group were higher than those of the routine group ( P<0.05). Conclusion:The construction and application of postgraduate teaching case base of cardiology rotation can improve the examination results, enhance the clinical practice ability, and achieve the satisfaction of postgraduates.

Objective To conduct the 7th investigation by Chinese Society of Radiation Oncology,Chinese Medical Association,and to further investigate the current situation of radiotherapy in mainland China,reasonably allocate personnel and equipment resources,and promote the development of radiotherapy in China.Methods From October 8,2015 to December 2015,the office for investigation of radiotherapy information was established,the list and contact information of radiotherapy units were provided by each province,and a special data submission system was used for a complete,rapid,and efficient investigation through the Internet.Results As of January 20,2016,there were 1 413 radiotherapy units in the mainland China with 52,496 employees in total,among which there were 15 839 radiotherapy physicians (4824 with senior professional titles),8 452 technical therapists (260 with senior professional titles),3 292 physicists (562 with senior professional titles),and 938 maintenance engineers (120 with senior professional titles).In the aspect of radiotherapy equipment,there were 1930 linear accelerators,96 Co-60 teletherapy units,173 X-knife units,212 γ-knife units,382 Ir-192 brachytherapy units,436 Co-60 brachytherapy units,1 051 X-ray simulators,1 353 CT simulators,642 MRI simulators,978 sets of multileaf collimators,1922 sets of treatment planning systems,and 974 sets of radiotherapy network systems.As for quality control devices,there were 1 792 dosimeters,2 143 ionization chambers,935 two-dimensional array dosimeters,540 threedimensional dosimetric verification systems,596 three-dimensional water tanks,844 anthropomorphic phantoms,and 1 168 water equivalent phantoms.In the aspect of therapeutic situation,there were 102,170 beds (including beds in departments of oncology in general hospitals),76612 episodes per day,and 919339 episodes per year.Conclusions The results of this investigation show significant increases in radiotherapy units,personnel,and equipment in recent years in mainland China.The distribution of radiotherapy units and equipment and the structure of radiotherapy personnel are becoming more reasonable,but there are still some problems.In some regions,current radiotherapy equipment cannot meet the medical needs,and there is a lack of professional technical personnel.

Objective To study the reasons of natural death of Oncomelania hupensis snails by comparing the differences of the indicator days covered with water DCW in snail marshland and non?snail marshland around the build of Three Gorges Dam in Eastern Dongting Lake areas. Methods Two marshlands were selected one was a non?snail marshland Qianliang Lake and another was a snail marshland Junshan Park . The measuring points were set through the mechanical sampling. The snails and elevation of the points were surveyed and the data of the water levels from the hydrological station were collected and then DCWs were calculated. Results From 1995 to 2013 DCWs of the marshland of natural death of snails were all more than that of the snail marshland P<0.01 . In Qianliang Lake marshland the difference between DCW before natural death and DCW from natural death until the dam was not significant P=0.23 while DCWs of the two stages both were more than that after the dam P1=0.045 P2=0.002 . Before the build of the dam DCW of the Qianliang Lake marshland of natural death of snails was more than that after the build of the dam P=0.013 and there was the same situation in Junshan Park marshland P=0.005 . The relationship between snail density and DCW was not significant in Junshan Park marshland rs=0.008 P=0.914 and the reference range of DCW of all the measuring points was 76-251 days. Conclusion In the eastern Dongting Lake district the build of Three Gorges Dam and DCW may be not the direct factors affecting the natural death of snails and the latter may change the distribution of snails.

Combined pulsed-field gradient, shaped pulses, and product operator calculations (algorithm), two-dimensional 1 H-31 P hetero-nuclear multiple quantum coherence ( HMQC) pulse sequence was established with the aid of C language. The result showed that coherent transfer path selection could be achieved by adjusting the ratio of two gradient strength ( g1 , g2 ) . The best ratio of g1 and g2 was -5:4 . The HMQC method based on the above sequence can be used for identifying the alkyl groups coupling with phosphorous nucleus. For the different alkyl groups, the sensitivity of this method decreased in the order methyl>isopropyl>ethyl>propyl. The limit of detection was about 10 mg/L. This method can be directly used for the screening and identification of phosphorus chemical warfare agents and related compounds.

Objective To study the reasons of natural death of Oncomelania hupensis snails in marshland by comparing the differences of environmental factors between snail marshland and non-snail marshland in East Dongting Lake schistosomiasis en-demic areas. Methods Two adjoining marshlands were selected,one was a snail marshland and another was a non-snail marsh-land. The measuring points were set by grid of“20m × 20m”. The soil moisture,elevation,soil pH and temperature of the points were measured,and the snails of the points were surveyed. Results The elevation,soil pH and temperature of the snail natural death marshland were all lower than those of the snail marshland(P<0.01). The soil moisture,elevation,soil pH and temperature of different snail densities in the snail marshland were different(P<0.05). The soil moisture of the non-snail group was higher than that of other four groups(P<0.01)and the soil moisture of the group with 0-11 snails per frame was lower than that of other four groups(P<0.01). The elevation of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame and the group with more than 39 snails per frame(P<0.05). The soil pH of the group without snails was higher than that of other four groups(P<0.01)and the soil temperature of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame. The differences of soil moisture and elevation of different death snail densities were not significant, while the differences of soil pH and temperature were significant. The soil pH of the non-snail died group was higher than that of the 2-died,3-died and more than 3-died groups(P<0.05). The soil temperature of the non-snail died group was higher than that of other four groups(P<0.05). Conclusion The elevation,soil pH and soil temperature within the range of the research may be the factors affecting the snail natural death and the soil moisture,elevation,soil pH and soil temperature may be the factors affect-ing the distribution of snails.

Objective To understand the distribution of univalvia molluscs in Eastern Dongting lake area where the Oncome-lania hupensis is extinct,so as to explore the causes of extinction and to provide the evidence for formulating schistosomiasis con-trol strategy. Methods The univalvia molluscs of the Qianliang Lake district,Jianxin District and Junshan Park were investigat-ed in August of 2013. All the collected snails were classified and identified. The data were analyzed by using the method of Shapiro-Wilk normality test and non-parametric test. The ecological biodiversity differences from each district were compared by the biodi-versity indexes. Results The univalvia molluscs collected were from 6 species in 3 families in Gastropoda class,namely Oncome-lania hupensis Gredler in Pomatiopsidae family,Parafossarulus striatulus,Alocinma longicornis,Parafossarulus sinensis,Bithynia fuchsisana in Bithyniidae family,and one genus provisionally named Radix in Lymaneidae family. In Junshan Park ,a total of 4 553 snails were collected,among which 1 264 were Oncomelania snails. In Jianxin District,336 univalvia molluscs were collect-ed,and no Oncomelania snails were found. In Qianliang Lake district,there were only 7 Alocinma longicornis snails,2 Parafossa-rulus sinensis snails and 1 Parafossarulus striatulus snail collected. There were significant differences among the distributions of the samples from the three districts(χ2=166.225,P<0.01).The Simpson’s diversity indexes in Qianliang Lake area,Jianxin Dis- trict and Junshan Park were 0.402 8,0.718 6 and 0.678 8,respectively,and the Shannon-Wiener indexes of the 3 areas were 0.721 5,1.431 3 and 1.199 9,respectively. Conclusions With the extinction of Oncomelania snails,the species and quanti-ties of other snails become rare in Qianliang Lake area. Whether their causes are relevant is worth further studying.

Objective To investigate the relationship between cardiac vagus nerves and changes of connexins(Cx)and intracellular gap junction(GJ)distribution pattern in superior vena cava(SVC)myosleeve in dog with atrial fibrillation(AF).Methods Twenty four hybrid dogs were divided into sham operation group(Sham group,n=8),SVC-AO fat pad removed group(RM group,n=8)and SVC-AO fat pad reserved group(RS group,n=8).In RM group and RS group,right atrial pacing was performed at a frequency of 500～650/min for 6 weeks to establish AF model.AF was induced by programmed stimulation or burst stimulation of atrial pacing.The expression and distribution of Cx40 and Cx43 in the SVC myosleeve tissue in three groups were analyzed by immunofluorescence staining.Transmission electron microscopy was used to observe the uhrastructural organization of gap junction(GJ).Results The rate of inducing sustained AF(＞ 15 min)in RS group was significantly higher than that in RM group (P ＜ 0.01).The expression of Cx40 and Cx43 in the SVC myosleeve in sham group and RS group were significantly higher than that in RM group(P ＜ 0.05).Furthermore,the expression of Cx40 and Cx43 in RS group were obviously higher than that in sham group(P ＜0.05).The ratio of end-to-end to side-to-side in RS group was lower than that in Sham group and RM group.Comparing with RM group,the channel of GJ became shorter and wider in RS group(P ＜0.05).Sarcomere was dissolved and mitochondrion showed vacuole degeneration in RS group.Conclusion The remodeling of Cx40 and Gx43 in SVC myosleeve tissue may be mediated by vagus nerves.It is conducive to the maintenance and stability of AF.However,this effect can be weakened by removing SVC-AO fat pad of canine.