The traditional broom trade in Bushbuckridge, South Africa: Helping poor women cope with adversity

The extensive local and regional market for traditional, handcrafted twig and grass brooms in the Bushbuckridge municipality, South Africa, provides an important means of livelihood security for several hundred poor households in the face of increasing economic hardship. Participants in this trade were a vulnerable group of middle-aged to elderly women with poor levels of education and few assets. Over half headed their own house-holds, and several came from households affected by AIDS. Entry into the broom trade was mainly a coping strategy in response to crisis, becoming long-term in the absence of alternatives. Average net annual incomes for producers and traders were modest at ZAR 2,000 and ZAR 1,000 respectively (ZAR=South African Rand), although some were earning considerably more. While unlikely to provide a way out of poverty, the trade was critical in allowing diversification and in providing a safety net, assisting poor households to overcome adversity, meet several basic needs, and educate their children.     

Wood structure and function change with maturity: Age of the vascular cambium is associated with xylem changes in current‐year growth

Xylem vessel structure changes as trees grow and mature. Age‐ and development‐related changes in xylem structure are likely related to changes in hydraulic function. We examined whether hydraulic function, including hydraulic conductivity and vulnerability to water‐stress‐induced xylem embolism, changed over the course of cambial development in the stems of 17 tree species. We compared current‐year growth of young (1–4 years), intermediate (2–7 years), and older (3–10 years) stems occurring in series along branches. Diffuse and ring porous species were examined, but nearly all species produced only diffuse porous xylem in the distal branches that were examined irrespective of their mature xylem porosity type. Vessel diameter and length increased with cambial age. Xylem became both more conductive and more cavitation resistant with cambial age. Ring porous species had longer and wider vessels and xylem that had higher conductivity and was more vulnerable to cavitation; however, these differences between porosity types were not present in young stem samples. Understanding plant hydraulic function and architecture requires the sampling of multiple‐aged tissues because plants may vary considerably in their xylem structural and functional traits throughout the plant body, even over relatively short distances and closely aged tissues.     

颅内动脉粥样硬化斑块形成与血管重构的关系

目的:研究颅内动脉粥样硬化斑块的形成与血管重构的关系。方法:选择2017年3月到2017年10月在上海市第一人民医院神经内科接受治疗的47例诊断为缺血性脑血管疾病的患者,所有患者发病7天内行头颅核磁共振以及高分辨率核磁共振检查。使用vesselmass软件测量斑块处血管及正常对照处的血管壁面积、流体面积,计算斑块负荷以及血管重构比(RR)。RR1.05为正向重构,0.95≤RR≤1.05为中间重构,RR0.95为负向重构。分析大脑中动脉与基底动脉内斑块形成处血管重构情况。根据临床症状以及影像学检查,将斑块分为责任斑块与非责任斑块,比较两组斑块的负荷大小。结果:47例患者中,共有72个斑块,其中责任斑块47个(占65.28%),非责任斑块25个(占34.72%)。位于大脑中动脉的斑块有51个(占70.83%),位于基底动脉的有21个(占29.17%)。大脑中动脉出现负向重构比例较基底动脉更高(47.06%vs. 19.05%,P=0.027),基底动脉出现正向重构比例较大脑中动脉更高(57.14%vs. 25.49%,P=0.010)。相比非责任斑块,责任斑块的斑块负荷更大(0.70±0.08 vs. 0.65±0.07,P=0.017)。结论:颅内动脉在应对斑块形成后出现不同的血管重构模式,负荷更大的斑块更不稳定。     

Mechanical properties of human atherosclerotic intima tissue

Progression and rupture of atherosclerotic plaques in coronary and carotid arteries are the key processes underlying myocardial infarctions and strokes. Biomechanical stress analyses to compute mechanical stresses in a plaque can potentially be used to assess plaque vulnerability. The stress analyses strongly rely on accurate representation of the mechanical properties of the plaque components.     

Water relations of Robinia pseudoacacia L.: do vessels cavitate and refill diurnally or are R‐shaped curves invalid in Robinia?

Since 2005, an unresolved debate has questioned whether R‐shaped vulnerability curves (VCs) might be an artefact of the centrifuge method of measuring VCs. VCs with R‐shape show loss of stem conductivity from approximately zero tension, and if true, this suggests that some plants either refill embolized vessels every night or function well with a high percentage of vessels permanently embolized. The R‐shaped curves occur more in species with vessels greater than half the length of the segments spun in a centrifuge. Many have hypothesized that the embolism is seeded by agents (bubbles or particles) entering the stem end and travelling towards the axis of rotation in long vessels, causing premature cavitation. VCs were measured on Robinia pseudoacacia L. by three different techniques to yield three different VCs; R‐shaped: Cavitron P₅₀ = 0.30 MPa and S‐shaped: air injection P₅₀ = 1.48 MPa and bench top dehydration P₅₀ = 3.57 MPa. Stem conductivity measured in the Cavitron was unstable and is a function of vessel length when measured repeatedly with constant tension, and this observation is discussed in terms of stability of air bubbles drawn into cut‐open vessels during repeated Cavitron measurement of conductivity; hence, R‐shaped curves measured in a Cavitron are probably invalid.     

Ⅱ型登革病毒D01090株在人胚肺二倍体细胞KMB17上适应株选育及初步鉴定

目的:选育能在人胚肺二倍体细胞KMB17上稳定增殖的Ⅱ型登革病毒适应株,为研发以人源性细胞为基质的登革疫苗候选株奠定基础。方法:将Ⅱ型登革病毒中国株D01090提取病毒基因组,通过RT-PCR法进行登革病毒型别鉴定后,在C6/36和Vero细胞上进行毒种扩增和滴度测定;将D01090毒株以4.0MOI接种KMB17细胞并反复传代至病毒完全适应在细胞内扩增,并连续传代10代,选育出良好的KMB17细胞适应株;病毒培养液经蔗糖梯度离心和超速离心后获得高浓度病毒液,接种KMB17细胞后通过透射电镜超薄切片检测细胞的病理变化;然后经过三轮蚀斑纯化筛选出纯化病毒株,免疫荧光法检测病毒纯化株的抗原性。结果:以Ⅱ型登革病毒中国株D01090基因组为模板,能扩增出511bp的登革病毒特异基因和119bp的Ⅱ型登革病毒型特异性基因。病毒经C6/36细胞扩增后滴度达4.5CCID50/ml,感染KMB17细胞至第三代可产生明显的细胞病变(cytopathic effect,CPE),连续传10代细胞病变速度逐渐增快,至第10代达到增殖高峰,病毒滴度达5.0CCID50/ml;将病毒感染6天后病变达+++的KMB17细胞进行超薄切片后经透射电镜观察细胞的病理变化,镜下可观察到内质网中新组装成的病毒颗粒,细胞周围产生很多分裂的小碎片,伴有游离出胞的病毒;三轮蚀斑纯化后筛选出纯化克隆,免疫荧光法检测病毒的抗原性呈阳性。结论选育出了能稳定传代且病毒扩增量高的Ⅱ型登革病毒KMB17细胞适应株,经蚀斑纯化后仍保持较好的抗原性。     

Characterization and genomic analysis of a plaque purified strain of cyanophage PP

Cyanophages are ubiquitous and essential components of the aquatic environment and play an important role in the termination of algal blooms. As such, they have attracted widespread interest. PP was the first isolated cyanophage in China, which infects Plectonema boryanum and Phormidium foveolarum. In this study, this cyanophage was purified three times by a double-agar overlay plaque assay and characterized. Its genome was extracted, totally sequenced and analyzed. Electron microscopy revealed a particle with an icosahedral head connected to a short stubby tail. Bioassays showed that PP was quite virulent. The genome of PP is a 42,480 base pair (bp), linear, double-stranded DNA molecule with 222 bp terminal repeats. It has high similarity with the known Pf-WMP3 sequence. It contains 41 open reading frames (ORFs), 17 of which were annotated. Intriguingly, the genome can be divided into two completely different parts, which differ both in orientation and function.     

Airport and city-centre temperatures in the evaluation of the association between heat and mortality

A variety of ambient exposure indicators have been used to evaluate the impact of high temperature on mortality and in the identification of susceptible population sub-groups, but no study has evaluated how airport and city centre temperatures differ in their association with mortality during summer. This study considers the differences in temperatures measured at the airport and in the city centre of three Italian cities (Milan, Rome and Turin) and investigates the impact of these measures on daily mortality. The case-crossover design was applied to evaluate the association between daily mean apparent temperature (MAT) and daily total mortality. The analysis was conducted for the entire population and for subgroups defined by demographic characteristics, socioeconomic status and chronic comorbidity (based on hospitalisation during the preceding 2 years). The percentage risk of dying, with 95% confidence intervals (95% CI), on a day with MAT at the 95th percentile with respect to the 25th percentile of the June-September daily distribution was estimated. Airport and city-centre temperature distributions, which vary among cities and between stations, have a heterogeneous impact on mortality. Milan was the city with the greatest differences in mean MAT between airport and city stations, and the overall risk of dying was greater when airport MAT (+47% increase, 95%CI 38-57) was considered in comparison to city MAT (+37% increase, 95%CI 30-45). In Rome and Turin, the results were very similar for both apparent temperature measures. In all cities, the elderly, women and subjects with previous psychiatric conditions, depression, heart and circulation disorders and cerebrovascular disease were at higher risk of dying during hot days, and the degree of effect modification was similar using airport or city-centre MAT. Studies on the impact of meteorological variables on mortality, or other health indicators, need to account for the possible differences between airport and city centre meteorological variables in order to give more accurate estimates of health effects.