Stable Type Research Articles

Intertrochanteric fracture PFN vs DHS

Background: DHS fixation has remained a well-established gold standard in intertrochanteric fractures of femur for a long time. 1 However, it has shortcomings and pitfalls. In inter-trochanteric fractures of femur, DHS fixation has shown higher failure rates. PFN is a new fixation device proposed for fixation of unstable intertrochanteric fractures. 1 Being intramedullary, it is a biomechanically advantageous device which should allow better fixation of unstable intertrochanteric translating into lesser failure rates of fixation and also permitting early mobilization and faster rehabilitation especially in elderly patients. We present a study comparing outcomes of managing unstable intertrochanteric fractures with PFN and DHS. Materials and Methods: We evaluated 30 (PFN: 15; DHS: 15) cases of intertrochanteric fractures of femur out of which 26 were unstable and 4 stable type, from January 2017 to December 2018, with minimum 12 months follow up period. Mean age was 60 years for both PFN and DHS group. We studied the surgical complications in both groups and also compared functional and radiographic results of both groups. Results: There was significantly more clinical shortening in DHS group than in PFN group (average 1- 1.9 cm versus 0.5-0.9 cm). There were 3 cases of superficial and 2 cases of deep infection in the DHS group while there was one case of infection in PFN group. There was no case of implant failure in the DHS group compared to one case in PFN group (due to screw breakage). Harris hip score at follow up was fair to excellent in PFN as compared to DHS. This difference was statistically significant. Discussion: DHS despite remaining a gold standard for fixation of intertrochanteric fractures of femur for a long time, it may not be suitable for certain fracture patterns and in older age groups with more medical co-morbidities and osteoporosis. PFN is a biomechanically sound device for fixation of comminuted intertrochanteric fractures of femur2 which has lesser surgical morbidity and should be especially beneficial in elderly, osteoporotic and medically compromised patients. Its load sharing capability provides a more stable fixation allowing early mobilization and rehabilitation.Conclusion: PFN is unequivocally a better choice of implant for fixation of unstable intertrochanteric fractures of femur, especially in osteoporotic and medically compromised patients as compared to DHS fixation device.

Usefulness of Platelet Distribution Width and Fibrinogen in Predicting In-stent Restenosis With Stable Angina and Type 2 Patients With Diabetes Mellitus.

AimThe purpose of this study was to investigate the predicting value of platelet distribution width (PDW) and fibrinogen for in-stent restenosis (ISR) in patients with stable angina pectoris and type 2 diabetes mellitus (T2DM) after drug-eluting stent (DES) implantation.MethodsWe enrolled 161 patients who were readmitted with recurrent chest pain and successfully reviewed for coronary angiography and were divided into the ISR and non-ISR groups. We compared the levels of PDW and fibrinogen between the two groups. Logistic regression was used for analyzing independent predictors of ISR. The receiver operating characteristic (ROC) curve analysis was used to determine the optimum cutoff points of PDW and fibrinogen to predict ISR. The Kaplan–Meier survival curves for target lesion failure (TLF) by levels of PDW and fibrinogen.ResultsThe multivariate logistic regression analysis showed that PDW and fibrinogen were independent predictors of ISR [odds ratio (OR) = 1.209, 95% CI: 1.024–1.427, p = 0.025; OR = 1.006, 95% CI: 1.002–1.011, p = 0.010, respectively]. The ROC analyses showed that PDW ≥ 13.15% and fibrinogen ≥ 333.5 mg/dl were predictive of ISR in patients with stable angina pectoris and T2DM after DES implantation. However, the Kaplan–Meier estimate for TLF showed no statistical significance.ConclusionHigher levels of PDW and fibrinogen were associated with the incidence of ISR in patients with stable angina with T2DM after DES implantation, but were not independent predictors of TLF.

МОДЕЛИРОВАНИЕ ВЛИЯНИЯ РАСПОЛОЖЕНИЯ АУТРИГЕРНОЙ СИСТЕМЫ НА ДЕФОРМАТИВНЫЕ ПОВЕДЕНИЯ ЗДАНИЙ ПРИ УДАРНЫХ ВОЗДЕЙСТВИЯХ

It is known that outrigger technology enables builders, designers and other participants in the construction process to design and erect stable high-rise and other types of buildings of various shapes. Outrigger systems, in principle, can be horizontal, diagonal, two-storey or without girdling trusses or vertical connections. The design for each type of building is unique, and depending on the location in height, it can be different within the same object. Outrigger floors help to redistribute the load between the core and load-bearing elements and structures. Even if a building is exposed to a simultaneous destructive impact (for example, a blow), the consequences can be minimized. The paper considers the influence of a single-storey reinforced concrete outrigger located on the 13th floor of a 25-storey building in the Moscow region of Russia on the impact of wind load.

Neurophysiologic Reactions during Heart Rate Variability Biofeedback Session in Adolescents with Different Risk of Internet Addiction.

The aim of this study was to determine electroencephalogram (EEG) in a session of heart rate variability biofeedback (HRV BF) in adolescents with different Internet addiction (IA) risks. In total, 100 healthy adolescents aged 16–17 years with minimal risk of IA (Group I, 35%), pronounced risk of IA (Group II, 51%), and stable pattern of IA (Group III, 14%) using the Chen Internet Addiction Scale were examined. HRV and EEG parameters were determined at baseline (5 min), and then during the short-term HRV BF session (5 min), in order to increase the total power (TP, ms2) of the HRV spectrum. Against the background of an increase in the TP and a decrease in sympathetic activity, an increase in alpha EEG was revealed, especially in Groups I and II. The greatest increase in the power of beta1-activity of EEG in the frontal, central, and temporal brain regionswas found in Groups I and II. In adolescents with a pronounced risk of IA, HRV BF is accompanied by a severe activation of the brain systems, while in persons with a stable type of IA, the least brain reactivity is shown, especially in the beta1 EEG band.

Blue-Sky Albedo Reduction and Associated Influencing Factors of Stable Land Cover Types in the Middle-High Latitudes of the Northern Hemisphere during 1982–2015

Land surface albedo (LSA) directly affects the radiation balance and the surface heat budget. LSA is a key variable for local and global climate research. The complexity of LSA variations and the driving factors highlight the importance of continuous spatial and temporal monitoring. Snow, vegetation and soil are the main underlying surface factors affecting LSA dynamics. In this study, we combined Global Land Surface Satellite (GLASS) products and ERA5 reanalysis products to analyze the spatiotemporal variation and drivers of annual mean blue-sky albedo for stable land cover types in the middle-high latitudes of the Northern Hemisphere (30~90°N) from 1982 to 2015. Snow cover (SC) exhibited a decreasing trend in 99.59% of all pixels (23.73% significant), with a rate of −0.0813. Soil moisture (SM) exhibited a decreasing trend in 85.66% of all pixels (22.27% significant), with a rate of −0.0002. The leaf area index (LAI) exhibited a greening trend in 74.38% of all pixels (25.23% significant), with a rate of 0.0014. Blue-sky albedo exhibited a decreasing trend in 98.97% of all pixels (65.12% significant), with a rate of −0.0008 (OLS slope). Approximately 98.16% of all pixels (57.01% significant) exhibited a positive correlation between blue-sky albedo and SC. Approximately 47.78% and 67.38% of all pixels (17.13% and 25.3% significant, respectively) exhibited a negative correlation between blue-sky albedo and SM and LAI, respectively. Approximately 10.31%, 20.81% and 68.88% of the pixel blue-sky albedo reduction was mainly controlled by SC, SM and LAI, respectively. The decrease in blue-sky albedo north of 40°N was mainly caused by the decrease in SC. The decrease in blue-sky albedo south of 40°N was mainly caused by SM reduction and vegetation greening. The decrease in blue-sky albedo in the western Tibetan Plateau was caused by vegetation greening, SM increase and SC reduction. The results have important scientific significance for the study of surface processes and global climate change.

Tailored treatment modality in acute type A intramural hematoma

ObjectivesIntramural hematoma may be generated by a minimal intimal tear. Most surgeries for acute type A intramural hematoma are performed on the proximal aorta alone regardless of the intimal tear site. Under the assumption that major adverse aortic events (MAAEs) would be related to the location of primary intimal tear, we reviewed preoperative computed tomography scan findings. MethodsSixty patients with acute type A intramural hematoma who underwent surgery from January 2008 to December 2019 were retrospectively analyzed. The maximal diameter, maximal thickness of the intramural hematoma, and hematoma thickness ratio of the ascending and descending aortae were measured. MAAEs were defined as newly developed aortic dissection, rupture, newly developed penetrating aortic ulcer (PAU), enlargement of the PAU, and aortic death. ResultsThe number of patients with PAU in the descending aorta (dPAU) was significantly higher in the MAAE (+) group. The MAAE (+) group showed lower measurements of the ascending aorta and higher measurements of the descending aorta than the MAAE (–) group. In the univariate analysis, dPAU, hematoma thickness ratio of the ascending and descending aortae, and descending aorta hematoma thickness >8.58 mm were risk factors of MAAE. Intimal tear noted intraoperatively and ascending aorta hematoma thickness >10.25 mm were protective factors of MAAE. ConclusionsAortopathies (ie, PAU, ulcer-like projections, and the hematoma thickness ratio) are important clues to determine the location of intimal tear. Occurrence of MAAEs seems to be highly related to the pathology of the descending aorta. The modalities of treatment for stable acute type A intramural hematoma that do not meet the existing guidelines should be tailored to the location of the intimal tear.

Crystal structure determination of a new LaPO4 phase in a multicomponent glass ceramic via 3D electron diffraction

A glass ceramic from the MgO–Al 2 O 3 –SiO 2 system containing additives of ZrO 2 , TiO 2 , La 2 O 3 and P 2 O 5 was investigated. Via x-ray powder diffraction (XRPD) and Transmission electron microscopy(TEM) the crystalline phases present could be identified as MgAl 2 O 4 (Spinel), orthorhombic ZrTiO 4 and a polymorph of LaPO 4 with a previously unknown crystal structure. The crystal structure of this LaPO 4 phase was solved ab initio via 3D ED Data. The polymorph occurs in a distorted barite structure type in the same space group (P2 1 /n) as the stable monazite type polymorph, however the density is higher and the La has a higher coordination number. Furthermore the LaPO 4 is present in a spinodal relict microstructure. Potential explanations for the presence of this metastable polymorph are pressure due to residual stresses from the crystallization or surface effects due to the high surface area resulting from the spinodal relict structure.

A robust association test with multiple genetic variants and covariates.

Due to the advancement of genome sequencing techniques, a great stride has been made in exome sequencing such that the association study between disease and genetic variants has become feasible. Some powerful and well-known association tests have been proposed to test the association between a group of genes and the disease of interest. However, some challenges still remain, in particular, many factors can affect the performance of testing power, e.g., the sample size, the number of causal and non-causal variants, and direction of the effect of causal variants. Recently, a powerful test, called TREM , is derived based on a random effects model. TREM has the advantages of being less sensitive to the inclusion of non-causal rare variants or low effect common variants or the presence of missing genotypes. However, the testing power of TREM can be low when a portion of causal variants has effects in opposite directions. To improve the drawback of TREM , we propose a novel test, called TROB , which keeps the advantages of TREM and is more robust than TREM in terms of having adequate power in the case of variants with opposite directions of effect. Simulation results show that TROB has a stable type I error rate and outperforms TREM when the proportion of risk variants decreases to a certain level and its advantage over TREM increases as the proportion decreases. Furthermore, TROB outperforms several other competing tests in most scenarios. The proposed methodology is illustrated using the Shanghai Breast Cancer Study.

Correlation between circulating microRNA and lipid indicesin patients with ischemic heart disease and type 2 diabetes mellitus

The aim of the study was to investigate circulating miRNAs-27a, -221 levels and their correlations with lipid indices in patients with ischemic heart disease (IHD) and type 2 diabetes mellitus. Materials and methods. The study included 58 patients with stable IHD and type 2 diabetes mellitus, 22 IHD patients without diabetes and 19 healthy controls. MicroRNAs-27a-3р and 221-3р were determined in blood plasma by real time polymerase chain reaction. U6 small nuclear RNA was used for normalization. Results. The lowest levels of circulating miRNAs-27a and -221 were in IHD patients with diabetes. The decrease in the levels of both microRNAs in patients with diabetes was significant not only in comparison with the control group (P = 0.024, P = 0.006), but also with patients without diabetes (P = 0.011, P = 0.001). In IHD patients without diabetes, microRNAs-27a and -221 levels did not change significantly. In IHD patients with diabetes, microRNA-221 showed a significant positive correlation with high-density lipoprotein cholesterol (HDL-C) (R = 0.382, P = 0.003). MicroRNA-27a was correlated negatively with triglycerides (TG) (R = -0.284, P = 0.051) and positively – with HDL-C (R = 0.257, P = 0.078) at a borderline significance level. The lower level of microRNA-27a (the 1st tertile) was associated with significantly increased TG level in comparison with the 3rd tertile (P = 0.004), and significantly decreased HDL-C level in comparison with the 2nd (P = 0.001) and the 3rd (P = 0.023) tertiles. Patients with lower microRNA-221 level (the 1st tertile) had significantly reduced HDL-C level in comparison with the 3rd tertile(P = 0.007). Conclusions. The results have demonstrated the significant decrease in circulating microRNAs-27a and -221 levels in IHD patients with type 2 diabetes mellitus and no change in both microRNAs in patients without diabetes. In IHD patients with diabetes, the lower expression of microRNA-27a was associated with the significant elevation of TG and the significant decrease in HDL-C. The lower microRNA-221 level was associated only with the significant decrease in HDL-C.

Maturation and migration processes in intact source rock micro plugs induced by chemical and thermal treatment: A new approach combining Rock-Eval pyrolysis and organic petrography

This study proposes a new approach to investigate hydrocarbon generation and migration processes in petroleum source rocks under laboratory conditions. For the first time, programmed open-system pyrolysis using a Rock-Eval 6 instrument is applied on small, polished source rock plugs to induce changes in the type and distribution of solid bitumen, which are qualitatively investigated by means of organic petrography before and after different pyrolysis experiments. This approach allows us to directly visualize the evidence of solid bitumen (SB) formation and distribution after the following treatments: (1) thermal extraction at 300 °C for 3 min, (2) chemical extraction of the surface using dichloromethane (DCM), and subsequently (3) artificial maturation by applying the standard procedure of Rock-Eval programmed pyrolysis up to a temperature of about 400 to 500 °C (depending on the initial thermal maturity of the sample). After each step, the surface of the treated micro plugs was digitally scanned to allow a comparison of specific areas of interest before and after the respective treatments and alterations. For this study, core samples of the Eagle Ford Shale Formation are used, which are suitable for such investigation, as the Eagle Ford Shale exhibits a variety of different initial thermal maturities from immature to overmature. Furthermore, the presence of large intraparticle porosities provides suitable voids where changes in SB distribution can easily be observed. After the thermal extraction, the volume of observed SB in the early- and moderately mature samples slightly increased, while most of the thermally mobilized bitumen from inside the plug was evaporated and thus lost from the sample. The initial solid bitumen was not or hardly affected by thermal extraction at 300 °C for 3 min, i.e. it was thermally stable at this temperature. Solid bitumen reflectance was slightly higher than in the initial sample showing a minor maturation. In contrast to thermal extraction, solid bitumen in the early mature samples was almost completely dissolved after DCM treatment. These petrographic observations on micro plugs are in agreement with the pyrolysis results of powdered fractions, where the initial Rock-Eval S1 and to a much lesser extent also the S2 signal decreases after the chemical extraction in DCM. While the SB in early mature sample was almost entirely dissolved by DCM, only about half of it is was dissolved in the moderately mature sample showing more mature and more stable SB. After the artificial maturation, the volume of SB in early- as well as in moderately mature samples clearly increased within the intraparticle pores, indicating presence of new SB due to bitumen migration from the deeper part of the micro plug to the surface. In contrast, SB in initially overmature sample is mainly present as thermally-highly stable pyrobitumen, indicated by no change in the SB distribution after chemical and thermal treatments representing a stable type of SB at the very end of petroleum generation.

High-energy X-Ray diffraction study of multiwalled carbon nanotubes fabricated by arc discharge plasma process

Structural features of multiwalled carbon nanotubes (MWCNTs) have been analyzed quantitatively by high-energy X-ray diffraction (HE-XRD) with atomic pair distribution function (PDF) technique. It has been found that the nanotubes are mainly of scroll type and own an atomic arrangement defined on the nanometer length scale in terms of a unit cell and symmetry. They exhibit multipart local (sub-nanometer) and intermediate range (on nano-length-scale) structures. The structural information at different length-scales was used to probe the interlayer spacing distribution within the nanotubes. The radial dependence of interlayer spacing observed in pristine nanotubes presents tendency for alteration to uniform spacing of layer in the course of heating-cooling cycle in the range of 298–450 K. These spatial changes illustrate modification of Fermat type stroll with uneven interlayer distances in pristine nanotubes to more stable equidistant interlayer Archimedean spiral type in the heating-cooling treated ones.

Claudins and Gastric Cancer: An Overview.

Simple SummaryGastric cancer (GC) is one of the most common cancers and the third leading cause of cancer deaths worldwide, with a high frequency of recurrence and metastasis, and a poor prognosis. This review presents novel biological and clinical significance of claudin (CLDN) expression in GC, especially CLDN18, and clinical trials centered around CLDN18.2. It also presents new findings for other CLDNs.Despite recent improvements in diagnostic ability and treatment strategies, advanced gastric cancer (GC) has a high frequency of recurrence and metastasis, with poor prognosis. To improve the treatment results of GC, the search for new treatment targets from proteins related to epithelial–mesenchymal transition (EMT) and cell–cell adhesion is currently being conducted. EMT plays an important role in cancer metastasis and is initiated by the loss of cell–cell adhesion, such as tight junctions (TJs), adherens junctions, desmosomes, and gap junctions. Among these, claudins (CLDNs) are highly expressed in some cancers, including GC. Abnormal expression of CLDN1, CLDN2, CLDN3, CLDN4, CLDN6, CLDN7, CLDN10, CLDN11, CLDN14, CLDN17, CLDN18, and CLDN23 have been reported. Among these, CLDN18 is of particular interest. In The Cancer Genome Atlas, GC was classified into four new molecular subtypes, and CLDN18–ARHGAP fusion was observed in the genomically stable type. An anti-CLDN18.2 antibody drug was recently developed as a therapeutic drug for GC, and the results of clinical trials are highly predictable. Thus, CLDNs are highly expressed in GC as TJs and are expected targets for new antibody drugs. Herein, we review the literature on CLDNs, focusing on CLDN18 in GC.

Demographic and spatial structure at the stage of expansion in thepopulations of some alien land snails in Belgorod city (CentralRussian Upland)

Studying of the demographic characteristics of populations of alien species at the stage of expansion makes it possible to assess their invasive potential. Field studies of alien terrestrial gastropods Xeropicta derbentina (Gastropoda,Stylommatophora, Hygromiidae), Brephulopsis cylindrica (Gastropoda, Stylommatophora, Enidae) and Harmozica ravergiensis (Gastropoda, Stylommatophora, Hygromiidae) have been carried out in Belgorod city, the southern part of the Central Russian Upland (Russia). All studied species are native to the Black Sea region and the Caucasus; in the southern part of the Central Russian Upland, they have been registered over the past ten years. The population density, demographic structure, and spatial structure have been analyzed for three years of observations (2017, 2019, 2020). During this period, the changes in the population density have been noted for all studied species. The most pronounced changes have been observed in X. derbentina, whose population density has significantly decreased, and the spatial structure has changed from clustered type to random distribution. In addition, the age structure of X. derbentina population had a pronounced change at the beginning of the snail activity season of 2020. The expansion of the other two invaders, B. cylindrica and H. ravergiensis, is proved as more successful. At the same time, H. ravergiensis is distributed throughout the city. This species has stable population density and random type of spatial population structure on most sites. B. cylindrica has the highest population density: in 2020, it has reached 406 ind./m2 on average, with the maximum of 1215 ind./m2.Meantime, the species keeps the clustered spatial structure, which is explained by both high population density and adaptation to the arid conditions of its natural range.

杭州午潮山天然次生林木本幼苗组成及其时空分布格局

PDF HTML阅读 XML下载 导出引用 引用提醒 杭州午潮山天然次生林木本幼苗组成及其时空分布格局 DOI: 10.5846/stxb202105191310 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 浙江省省属科研院所扶持专项(2021F1065-6，2020F1065-4) Composition and the spatio-temporal distribution pattern of tree seedling in natural secondary forest of Wuchao Mountain, Hangzhou Author: Affiliation: Fund Project: Zhejiang Provincial Research Institutes Support Special Projects(2021F1065-6, 2020F1065-4)。 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:木本植物幼苗是森林生态系统的重要的组成部分,其定居、存活、生长的生态学过程对于森林植被的更新具有潜在指示和筛选作用。为探究浙江杭州午潮山亚热带常绿阔叶次生林群落更新和演替机制,基于样方法对150 m2样地内天然更新幼苗的物种组成、数量特征和基径结构进行统计,在此基础上采用最近邻分析和Ripley's K函数的点格局方法,分析其中主要优势树种的更新动态及其时空分布格局。结果表明:(1)样地内乔木幼苗树种组成丰富,共调查到幼苗811株,隶属12科20属27种,其中樟科Lauraceae、壳斗科Fagaceae、山茶科Theaceae和山矾科Symplocaceae为主要优势科。(2)红楠Machilus thunbergii、薄叶润楠M. leptophylla、毛柄连蕊茶Camellia fraterna和刨花润楠M. spauhoi在所有调查物种重要值排序前4,因而被确定为优势林下植物,绘制的基径结构小提琴图(violin plot)进一步显示它们的种群分属快速增长型、稳定增长型、缓慢增长型和稳定型。(3)红楠、薄叶润楠和刨花润楠在小径级和小尺度上多呈聚集分布,随生长发育和空间尺度的增加,聚集强度呈现先增高后降低趋势,最终向离散分布或随机分布转变,可视为群落演替的早期树种;同时,三者在聚集强度上有所差异,排序为红楠＞薄叶润楠＞刨花润楠。毛柄连蕊茶Camellia fraterna种群密度较低,在小径级和小尺度上呈随机分布,随生长发育和空间尺度的增加,聚集强度呈波动趋势,最终向离散分布转变,可视为演替的中期树种。本研究在小尺度上初步揭了午潮山木本幼苗种群的演替过程中的种群结构和分布格局,可以为亚热带森林管理与植被恢复提供理论依据。 Abstract:Woody plant seedlings are an essential part of the forest ecosystem, and their ecological processes of settlement, survival and growth are potential indicators and screening for forest vegetation regeneration. To explore the regeneration and succession mechanism of the community of the subtropical evergreen broad-leaved secondary forest in Hangzhou Wuchao Mountain, Zhejiang Province, the species composition, quantitative characteristics and stem base diameter (SBD) classes of the natural regeneration seedlings in a 150 m2 plot were counted based on the sample plot method. On this basis, the nearest neighbor analysis (NNA) and the point pattern method of Ripley's K function were adopted to analyze the regeneration dynamics of the main dominant tree species and their spatio-temporal distribution patterns. Results showed that (1) tree seedlings in the plot are rich in species composition. A total of 811 seedlings were investigated, belonging to 12 families, 20 genera and 27 species, among which Lauraceae, Fagaceae, Theaceae and Symplocaceae are the main dominant families. (2) Machilus thunbergii, M. leptophylla, Camellia fraterna and M. spauhoi were identified as dominant understory plants, ranking the top four position in importance values of all investigated species. Meanwhile, the violin plot of the SBD classes further shows that the populations of these species belong to the fast-growing type, stable-growing type, slow-growing type and stable type, respectively. (3) M. thunbergii, M. leptophylla and M. spauhoi are mostly clustered at the small SBD classes and small scales. With the increase of growth and spatial scale, the clustering intensity firstly increases and then decreases, and finally changes to a discrete distribution or a random distribution. As the growth and development and the spatial scale increase, the aggregation intensity fluctuates and eventually transforms to a discrete distribution, which can be regarded as a mid-term succession tree species. Meanwhile, the three trees are different in the intensity of aggregation, sorted as M. thunbergii > M. leptophylla > M. spauhoi. The population density of Camellia fraterna is relatively low, and it is randomly distributed on small SBD classes and small scale. With the increase of growth and spatial scale, the aggregation intensity fluctuates, and finally becomes a discrete distribution. Therefore, C. fraterna can be regarded as the middle stage of succession. This study initially revealed the population structure and distribution pattern in the succession process of Wuchao Mountain woody seedling population on a small scale, which can provide a theoretical basis for subtropical forest management and vegetation restoration. 参考文献 相似文献 引证文献

重庆喀斯特生境中桢楠种群结构与动态特征

PDF HTML阅读 XML下载 导出引用 引用提醒 重庆喀斯特生境中桢楠种群结构与动态特征 DOI: 10.5846/stxb202106171607 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市自然科学基金项目（cstc2020jcyj-msxmX0244）；中央高校基本科研业务费专项（XDJK2020B037）；国家自然科学基金项目（31500399） Population structure and dynamic characteristics of Phoebe zhennan S. Lee in karst areas of Chongqing Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:桢楠是我国珍稀渐危树种，国家二级保护植物，野生多散生于海拔1500 m以下的亚热带常绿阔叶林中。而喀斯特生境岩石裸露、土壤浅薄贫瘠、岩溶干旱频发，理论上并不适合喜湿耐荫且喜酸性土壤的桢楠生长及幼苗更新。因此重庆市大足区和永川区喀斯特生境中的天然桢楠种群可能存在一定的更新困难。为明确这两个桢楠种群的生存现状及动态特征，采用野外调查法，从径级结构、静态生命表、存活曲线、结构动态及分布格局等方面分析桢楠种群结构及其数量动态规律，以期预测种群未来发展趋势，为喀斯特地区桢楠种群的保护、群落更新及植被恢复提供理论基础。结果表明：（1）大足区桢楠种群的年龄结构趋于稳定型，而永川区桢楠种群的年龄结构为增长型。两地区幼苗充足但死亡率高。（2）静态生命表及相关曲线分析显示，两个桢楠种群存活数量总体上随径级增大而减少；两个桢楠种群的生存期望值在不同径级间存在波动，大足区桢楠种群在第Ⅱ径级而永川区则是第Ⅳ径级期望值最高。（3）两个种群的存活曲线均为Deevey-Ⅲ型，即幼树死亡率较高，并且种群的增长速度较为缓慢。（4）大足区种群为随机分布，永川区种群为集群分布；种群各生长发育阶段均为集群分布，但聚集强度随着龄级的增加而减弱。桢楠种群在喀斯特地区生长周期长，天然更新能力较强但对外部干扰敏感。建议加强对幼苗的抚育工作，提高幼苗存活率，促进桢楠种群的自然更新和恢复。 Abstract:Phoebe zhennan S. Lee is a rare and endangered tree species in China, a nationally protected secondary plant. It is mostly scattered in the wild in subtropical evergreen broad-leaved forests below 1500 m above sea level. As the primary populations are almost destroyed, the existing resources are limited and scattered. Karst habitat has exposed rocks, shallow and barren soil and frequent drought. In theory, it is not suitable for the growth and seedling regeneration of P. zhennan, which likes humidity, shade and acid soil. Therefore, it may be difficult to renew the natural P. zhennan population in karst habitats in Dazu District and Yongchuan District of Chongqing. To explore the survival status and distribution model of the two P. zhennan populations, the field survey method is used to analyze the structure and the dynamic law of the populations and their quantity, by assessing the diameter structure, static life table, survival curve, structural dynamics and distribution pattern. It is hoped that the future development trend of the population can be predicted, and the theoretical basis for the protection, community renewal and vegetation restoration of the karst area will be provided. The results showed that:(1) the age structure of P. zhennan population in Dazu District tended to be a stable type, while it was an increase type in Yongchuan District. Both areas had abundant seedlings but with high mortality rates. (2) The individual numbers of both populations of P. zhennan generally decreased with the diameter class increased. The life expectation of the two P. zhennan populations fluctuated between different diameter classes. It was the highest in the diameter class Ⅱ in the population of P. zhennan in Dazu District, while it highest in the diameter class Ⅳ in Yongchuan District.(3) Both populations had Deevey-Ⅲ type survival curves, that was, the mortality of young trees was relatively high, and a relatively low population growth rate. (4) The population in Dazu District was randomly distributed, while that of the Yongchuan District was consolidated. P. zhennan were clustered populations at the growth and development stage, but their strength weakened with the growth of the age group. The population of P. zhennan in the karst region had a long growing time, a strong capacity for natural regeneration but sensitive to external disturbances. It is suggested to enhance seedling selection and improve seedling survival to promote natural renewal and restoration of P. zhennan population. 参考文献 相似文献 引证文献

2000年以来中国潜在植被NPP的时空分布模拟

PDF HTML阅读 XML下载 导出引用 引用提醒 2000年以来中国潜在植被净初级生产力的时空分布模拟 DOI: 10.5846/stxb202111053112 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42071216）；甘肃省自然科学基金项目（21JR7RA145） Estimation of temporal and spatial distribution of potential vegetation net primary productivity in China since 2000 Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:潜在植被的净初级生产力（PNPP）是在无人类干扰情况下，立地所能发育形成最稳定成熟植被的净初级生产力，PNPP能够直接反映自然生态系统的质量状况，是分离人类活动对生态环境影响的重要指标。研究改进了CASA （Carnegie-Ames-Stanford Approach）模型，引入潜在光合有效辐射吸收比例（PFPAR）模拟了2000-2020年中国植被PNPP的时空分布格局。结果表明：中国PNPP空间分布差异较大，东南沿海和东北大、小兴安岭地区PNPP较高，新疆、西藏等西部干旱、高寒地区PNPP较低，呈现以400 mm等降水量线为界的空间分异格局。2000-2020年，中国PNPP总体上呈现递增趋势，年际波动小，PNPP减少的区域与增加的区域面积基本相等。PNPP波动较大的地区主要位于青藏高原、四川盆地和贵州高原。研究结果量化了气候变化背景下真实的生态状况和潜在生态状况的差异，可分离出人类活动对自然生态系统的直接影响，为制定针对性的生态修复对策提供了科学依据。 Abstract:Potential vegetation net primary productivity (PNPP) is the NPP of the most stable and mature vegetation type without human interference in the current climate conditions. PNPP can directly reflect the quality of natural ecosystems, which is an important index to separate the impact of human activities on ecological environment. This paper improves the CASA model and introduces the potential fraction of photosynthetically active radiation (PFPAR) to simulate the temporal and spatial distribution pattern of PNPP in China's vegetation from 2000 to 2020. The results show that the spatial distribution of China's PNPP is quite different. The PNPP is higher in the coastal areas of southeast China and the Greater and Lesser Khingan Range in northeast China, and lower in the arid and alpine regions of western China such as Xinjiang and Tibet, presenting a spatial differentiation pattern with 400 mm isoprecipitation line as the boundary. From 2000 to 2020, China's PNPP generally showed an increasing trend over time, but the interannual fluctuation was small. The area of PNPP decreased and increased was almost the same. The changes of PNPP in most regions are small, and the areas with large PNPP fluctuation are mainly located on Qinghai-Tibet Plateau, Sichuan Basin and Guizhou. The research results can separate the impact of human activities and climate change on natural ecosystem, and quantify the difference between real ecological status and potential ecological status under external pressure. It provides a scientific basis for formulating differentiated Ecological Restoration Countermeasures. 参考文献 相似文献 引证文献

The Effect of Bone Morphology on Fracture Type and Treatment Result in Patients with Intertrochanteric Femur Fracture Aged over 65 year.

We aimed to investigate the effect of bone morphology on fracture type and treatment result in patient with inter-trochanteric fracture (IFF) treated with intramedullary nailing (IMN) aged over 65 years. Primary outcome of study was to investigate the relationship between fracture type (stable or unstable) and bone density. This was a retrospective cohort study conducted at single trauma center which included patients aged >65 years, minimum 3 months' control postoperatively, patients with simple fall by evaluating the patient data from 2010 to 2021. All fractures were classified based on the AO classification system. Proximal femoral nail anti-rotation was used between 2010 and 2016, while InterTAN was used after 2016 in our clinic practice. For the evaluation of the bone morphology, we measured the canal-to-calcar ratio (CCR) and cortical thickness index (CTI) and classified with Dorr morphology on anteroposterior (AP) hip radiograph of both the fracture side and contralateral sides. Complications were also evaluated on radiological view. Failures were defined as non-union or failure of fixation. Excessive collapse and screw/blade prominence also evaluated by hip radiograph on the 3rd month control visit. One hundred and fifty females and 59 males were included in this study. The average age was 81.6±8.8 years. One hundred and forty-four patients were treated with InterTAN and 65 patients with helical blade type IMN (PFN-A®). There were 78 patients with stable IFF type A1 fracture and 131 patients with unstable IFF (109 patients with A2 and 22 patients with A3 AO type fracture). The mean CTI was 0.469±0.09 and 0.510±0.09 in the fracture and unaffected side femurs, respectively (p<0.001), the CCR was 0.636±0.15 and 0.568±12 in the fracture and unaffected side femurs, respectively (p<0.001). There were 36 patients with Dorr type A, 115 patients with Dorr type B, and 48 patients with Dorr type C in fracture side and 65 patients with Dorr type A, 123 patients with Dorr type B, and 21 patients with Dorr type C in non-affected side (p<0.001). There were 29 (13.9%) patients with screw (n=14) and blade (n=15) prominence. Excessive collapse was seen 30 patients (14.4%) and 16 patients (7.7) evaluated as a failure. We found a significant difference in the failure rate between unstable group than stable group which higher in unstable group according to the AO classification. In addition, the mean CTI, CCR, and Dorr index were significant difference in fractured side than unaffected side which indicated lower bone quality at fracture side.

Genome-wide analysis reflects novel 5-hydroxymethylcytosines implicated in diabetic nephropathy and the biomarker potential

Aim: Diabetic nephropathy (DN) has become the most common cause of end-stage renal disease in most countries for patients with type 2 diabetes (T2D). Elucidating novel epigenetic contributors to DN can not only enhance our understanding of this complex disorder but also lay the foundation for developing more effective monitoring tools and preventive interventions in the future, thus contributing to our ultimate goal of improving patient care. Methods: 5-hydroxymethylcytosines (5hmC)-Seal, a highly selective chemical labeling technique, was used to profile genome-wide 5hmC, a stable cytosine modification type marking gene activation, in circulating cell-free DNA (cfDNA) samples from a cohort of patients recruited at Zhongnan Hospital, including T2D patients with nephropathy (DN, n = 12), T2D patients with non-DN vascular complications (non-DN, n = 29), and T2D patients without any complication (controls, n = 14). Differential analysis was performed to find DN-associated 5hmC features, followed by the exploration of biomarker potential of 5hmC in cfDNA for DN using a machine learning approach. Results: Genome-wide analyses of 5hmC in cfDNA detected 427 and 336 differential 5hmC modifications associated with DN, compared with non-DN individuals and controls, and suggested relevant pathways such as NOD-like receptor signaling pathway and tyrosine metabolism. Our exploration using a machine learning approach revealed an exploratory model comprised of ten 5hmC genes showing the possibility to distinguish DN from non-DN individuals or controls. Conclusion: Genome-wide analysis suggests the possibility of exploiting novel 5hmC in patient-derived cfDNA as a non-invasive tool for monitoring DN in high-risk T2D patients in the future.

Are SER-II Ankle Fractures Actually Anatomic? Bilateral CT Demonstrates Subtle Non-Anatomic Mortise &amp; Syndesmotic Alignment in the Setting of Apparent Normal Radiographs

Category:Ankle; TraumaIntroduction/Purpose:Current treatment of ankle fractures is predicated on 1-2 mm of talar shift leading to abnormal contact pressures. Determination of anatomic alignment has conventionally been based on plain radiographs. The ability of x-ray to detect subtle mortise displacement however is unknown. The purpose of this investigation is to determine if CT scan can detect malalignment undetectable utilizing plain radiography when assessing injuries assumed to have anatomic mortise alignment. The findings have implications for utilizing higher resolution diagnostic imaging to assess malalignment and challenging the validity of previous literature in which conclusions of anatomic mortise alignment were determined based on plain radiography.Methods:24 patients with stress-negative, stable SER-II type ankle fractures were included. Contralateral ankle mortise radiographs were obtained in addition to static and gravity stress radiographs of the injured side. Bilateral CT scans were performed once patients were deemed to have achieved clinical/radiographic healing. Measurements of the medial clear space (MCS) and syndesmosis were performed by two blinded orthopedic surgeons at two different time points. Intraclass correlation coefficients (ICC) were calculated to evaluate the intra- and inter-rater reliability and consistency of measurements. Statistical analyses were performed to determine any differences between x-ray and CT scan measurements to detect discrepancies between the injured and normal ankle measurements. Statistical significance was defined as a two-sided alpha error of less than 0.05 (p < 0.05).Results:Despite plain radiographs demonstrating no statistical side-to-side differences and achieving apparent final anatomic alignment in the majority of the cohort, CT MCS on coronal, axial planes and syndesmosis measurements were significantly different when comparing the injured to the normal contralateral ankle by on average of about 0.5mm. There was also excellent intra and interobserver agreement achieved for the measurements.Conclusion:CT is superior to plain radiography in detecting subtle mortise/syndesmotic displacement and side-to-side differences undetectable by x-ray. These findings challenge conventional assumption of anatomic alignment for SER II injuries and reliance on x-rays to assess anatomic alignment. While injured ankles uniformly demonstrated non-anatomic alignment as compared to the uninjured side, the clinical implications of subtle malalignment are unknown. However, broad reaching implications of this preliminary study include challenging the validity of x-ray to detect possibly clinically-relevant mortise malalignment in patients presenting with isolated lateral malleolus fractures.

Soviet Mentality: Markers of Socio-Historical Identity

Modern historiography of Soviet society is at the stage of forming an impartial assessment of its place in the history of Russian civilization. The most famous articles on the history of the USSR are often a documented expression of the author’s research position, which does not always strive for impartiality. Such studies evoke the feeling of an ongoing “civil war” — now on the “fronts” of science and journalism. Moreover, a number of authors concentrate on studying, mainly, the negative features of the “Soviet project”, transferring these characteristics to the entire Soviet society. Following in line with the noumenal approach to the study of Soviet society, the authors call on the scientific community to move from a detailed factual description of the Soviet era to identifying its basic characteristics, while abandoning politicized assessments. The purpose of the study is to determine the main components of the Soviet mentality based on an analysis of its key manifestations in different periods of the history of the Soviet state. To achieve this goal, markers of the socio-historical identity of the Soviet person are introduced, such as “revolution”, “idea”, “atheism”, “war”, “doublethink”, etc. It was established that the set of mental characteristics was not constant, they were updated in depending on the specific historical situation. The noumenal characteristics of a Soviet person were historically formed as a result of the dialectical interaction of the ideal type of a “non-party Bolshevik” — a socially oriented collectivist with a heightened sense of duty and his antipode — the notorious “Sovok” — an irresponsible careerist and social opportunist. In conclusion, it is noted, that the Soviet mentality can be defined more as a vector of promising targeted development than as a stable socio-psychological type.