Stress-driven collagen fiber remodeling in arterial walls

A stress-driven model for the relation between the collagen morphology and the loading conditions in arterial walls is proposed. We assume that the two families of collagen fibers in arterial walls are aligned along preferred directions, located between the directions of the two maximal principal stresses. For the determination of these directions an iterative finite element based procedure is developed. As an example the remodeling of a section of a human common carotid artery is simulated. We find that the predicted fiber morphology correlates well with experimental observations. Interesting outcomes of the model including local shear minimization and the possibility of axial compressions due to high blood pressure are revealed and discussed. In memory of Zinaida Hariton, 1926–2002     

黄连上清胶囊联合康复新液治疗口腔种植体周围软组织炎的临床研究

摘要 目的：观察黄连上清胶囊联合康复新液治疗口腔种植体周围软组织炎（PI）的临床治疗效果。方法：选择兰州大学第二医院2018年3月~2021年5月期间收治的口腔PI患者100例作为观察对象,所有患者根据双色球法分为对照组（50例）和观察组（50例）,对照组患者接受康复新液治疗,观察组患者接受黄连上清胶囊联合康复新液治疗,对比两组疗效、牙周功能指标、血清细胞因子和不良反应。结果：观察组的临床总有效率高于对照组（P<0.05）。两组不良反应发生率对比无差异（P>0.05）。治疗后,两组龈沟出血指数（SBI）、菌斑指数（PLI）、附着丧失（AL）、探诊深度（PD）减小,且观察组低于对照组（P<0.05）。治疗后,两组白介素-1β（IL-1β）、白介素-6（IL-6）和单核细胞趋化因子（MCP-1）水平下降,且观察组低于对照组（P<0.05）。结论：黄连上清胶囊联合康复新液治疗口腔PI,可促进牙周功能恢复,减轻种植体周围炎症,安全可靠。     

Development of a microfluidic device for determination of cell osmotic behavior and membrane transport properties

An understanding of cell osmotic behavior and membrane transport properties is indispensable for cryobiology research and development of cell-type-specific, optimal cryopreservation conditions. A microfluidic perfusion system is developed here to measure the kinetic changes of cell volume under various extracellular conditions, in order to determine cell osmotic behavior and membrane transport properties. The system is fabricated using soft lithography and is comprised of microfluidic channels and a perfusion chamber for trapping cells. During experiments, rat basophilic leukemia (RBL-1 line) cells were injected into the inlet of the device, allowed to flow downstream, and were trapped within a perfusion chamber. The fluid continues to flow to the outlet due to suction produced by a Hamilton Syringe. Two sets of experiments have been performed: the cells were perfused by (1) hypertonic solutions with different concentrations of non-permeating solutes and (2) solutions containing a permeating cryoprotective agent (CPA), dimethylsulfoxide (Me₂SO), plus non-permeating solute (sodium chloride (NaCl)), respectively. From experiment (1), cell osmotically inactive volume (V_b) and the permeability coefficient of water (L_p) for RBL cells are determined to be 41% [n = 18, correlation coefficient (r²) of 0.903] of original/isotonic volume, and 0.32 ± 0.05 μm/min/atm (n = 8, r² > 0.963), respectively, for room temperature (22 °C). From experiment (2), the permeability coefficient of water (L_p) and of Me₂SO (P_s) for RBL cells are 0.38 ± 0.09 μm/min/atm and (0.49 ± 0.13) × 10⁻³ cm/min (n = 5, r² > 0.86), respectively. We conclude that this device enables us to: (1) readily monitor the changes of extracellular conditions by perfusing single or a group of cells with prepared media; (2) confine cells (or a cell) within a monolayer chamber, which prevents imaging ambiguity, such as cells overlapping or moving out of the focus plane; (3) study individual cell osmotic response and determine cell membrane transport properties; and (4) reduce labor requirements for its disposability and ensure low manufacturing costs.     

Adaptive radiotherapy in patients receiving neoadjuvant radiation for soft tissue sarcoma

AimThe aim of this study is to evaluate tumor volume changes during preoperative radiotherapy and to assess the role of adaptive radiation.BackgroundContemporary neoadjuvant radiotherapy utilizes image guidance for precise treatment delivery. Moreover, it may depict changes in tumor size and shape.Materials and methodsBetween 2016 and 2018, 23 patients aged ≥18 years with soft tissue sarcoma were treated with neoadjuvant radiation followed by surgical resection. The tumor volumes (cc) were measured using the Pinnacle planning system prior to starting radiotherapy and during treatment, the changes in volume and absolute differences were estimated. Moreover, patient's position on the machine was evaluated to assess setup offsets. The triggers for plan adaptation were >1 cm expansion or unacceptable setup offsets.ResultsThe mean tumors volume at presentation was 810 cc (range, 55–4000). At last cone beam CT the tumor volume had changed in 14 patients (61%); it was stable in nine patients (39%). Disease regression was documented in eight patients (35%), with median shrinkage of −20.5% (range, −2 to −29%), while tumor progression was observed in six cases (26%), the median change was 12.5% (range, +10 to +25%).Adaptive radiation was required in four patients (17%). For the remaining 19 cases (83%), the dose distribution was adequate to cover target volumes.ConclusionsChange in soft tissue sarcoma volume during radiation is not uncommon. Image guidance should be used to reduce setup errors and to detect differences in tumor volume. Image guidance and adaptive radiation are paramount to ensure optimal radiation delivery.     

贵州半夏块茎腐烂病拮抗细菌的筛选与鉴定

【目的】从半夏根际土壤筛选对半夏块茎腐烂病致病菌有拮抗活性的细菌并进行鉴定。【方法】采用稀释分离法和平板对峙法分离拮抗菌,然后根据菌落形态、生理生化特性,结合分子生物学方法进行鉴定。【结果】从半夏根际土壤共分离到228株细菌,其中菌株GZDF2、GZDF3、GZDF4对病原细菌及病原真菌均有拮抗活性,抑菌圈大小达23 mm,并且抑菌谱广。经形态学观察、生理生化特性分析和分子生物学方法,将菌株GZDF2、GZDF3、GZDF4鉴定为短短芽胞杆菌(Brevibacillus brevis)。进一步采用gyr B和rpo B基因对3株短短芽胞杆菌进行聚类分析,结果显示GZDF3菌株与其他2株短短芽胞杆菌存在遗传差异。【结论】半夏根际土壤中分离到的3株短短芽胞杆菌抑菌活性强、抑菌谱广,具有开发成生防剂的潜力。     

Assessment of the biocontrol potential of a Trichoderma viride isolate: Part I: Establishment of field and fungal cellar trials

A field trial has been set up to assess the biological control potential of a Trichoderma viride isolate, T60. This isolate had been shown in previous laboratory tests to be particularly effective against certain basidiomycete decay fungi. Wood was treated with T60 spores using vacuum pressure impregnation in a pilot preservation plant. Treated stakes were planted in the field site along with CCA-treated and untreated control samples. Replicate samples were also set up in an accelerated decay facility employed to give a comparison to the field trial results. This paper describes the setting up and monitoring of the field and fungal cellar trials, and presents results of moisture monitoring and sapstain assessment which indicate that Trichoderma viride isolate T60 has a marked effect on the rate of sapstain development under certain conditions. The paper also discusses the efficacy of pressure impregnation of spore suspensions for use as biological control agents     

Use of electron microscopy for aiding our understanding of wood biodegradation

Abstract: The use of electron microscopy (EM) has proved to be an invaluable tool for studying structural aspects of lignocellulose degradation by fungi and bacteria and therefore improving our understanding of wood biodegradation. The present review details the application of conventional (SEM, TEM, STEM), analytical (EM X-ray microanalysis, (EDXA)), and immunogold cytochemical EM procedures in the field and gives specific examples of its use for each of the known important types of microbial wood decay including bacterial (tunnelling and erosion), soft rot (cavity and erosion), brown rot and white rot (simultaneous decay and preferential lignin degraders), and discusses important advances made by adopting the techniques. The more recent use of immunogold cytochemistry for studying microbe and fungal enzyme-wood cell wall interactions and its application for localization of specific wood-degrading (laccase, Mn(II) and lignin peroxidases, and cellulases) and H₂O₂ producing (pyranose oxidase) enzymes in situ during white rot decay are also reviewed, as is the application of EM for studying non-enzymatic wood decay. Methods for labelling and detecting wood components (lignin, hemi- and cellulose) in situ by EDXA and enzyme immunogold cytochemistry are also outlined. The use of EM in wood biodegradation research is rapidly expanding and is seen as an important compliment to biochemical and chemical approaches. The future should see even greater advances in our understanding of wood decay as more advanced and recently developed EM techniques are also exploited.     

Statistical Analysis of Spatial Point Processes: A Soft-Core Model and Cross-Correlations of Marks

This paper suggests correlation characteristics for marked point processes with two marks for each point and describes statistical methods for their estimation. Its use is demonstrated by means of an example, where the points are locations of pine saplings, and the marks are their heights and ages. Furthermore, a soft-core point process model is presented. It is shown that a pattern of sites of beadlet anemones on a rock has a pair-correlation function and intensity which can be very well approximated by the model.