What happens when stems are embolized in a centrifuge? Testing the cavitron theory

Vulnerability curves (VCs) measure the ability of vessels to retain metastable water without embolisms that lower the hydraulic conductivity of stems. The fastest method of measuring VCs is the centrifuge technique and the Cochard cavitron is a method that allows measurement of hydraulic conductivity of stems while they are spinning. This paper describes the pattern of embolism that results after spinning the stems of hybrid aspen (Populus tremula×P. tremuloides) and two hybrid cottonwoods (P38P38 P. balsamifera×P. simonii and Northwest, which is a hybrid of P. deltoides×P. balsamifera). It is recognized that the pattern of embolism induced in a centrifuge ought to differ from the pattern during natural dehydration of plants because the profiles of tension vs distance greatly differ under the two modes of inducing stress. The pattern of embolism was visualized by a staining technique and quantified by traditional measurements of percentage loss conductivity (PLC) performed on subsample segments excised from spun stems. We found a pattern of embolism approximating that expected from theory: (1) PLC near the axis of rotation exceeded the average; (2) PLC was quite high near the ends of the stems, even though tension ought to be zero; (3) large vessels cavitated before small vessels; (4) more embolism occurred near the base than near the apex of the stems. However, we could not always scale up from subsample conductivity and PLC to whole‐stem conductivity. This pattern of embolism is interpreted in terms of vessel diameter and vessel length.     

What happens when tendons bend and twist? Proteoglycans

When tendons must bend or twist in order to fulfil their function of attaching muscle to bone they are subjected to forces that could damage the tendon. However, there are concomitant protective changes in the structure of the tendon at the location of bending. One of these changes involves increased synthesis and accumulation of the large proteoglycan aggrecan. The accumulation of aggrecan can protect the tendon by providing compressive stiffness, by allowing collagen fascicles to slide relative to one another, and by protecting vascular elements.     

What do children think happens to the food they eat?

In this study, the explanations of two classes of 10-year old children about what happens to the food that they eat were explored, particularly in the context of theories about the development of children's concepts of the human body. These ideas were investigated in a number of ways: obtaining children's own writing and drawings; semi-structured individual interviews; and examining choices made between alternative explanations. The results suggested that children applied their knowledge of everyday materials to understand the initial stages of what happens to food, but their ideas about later stages were more tentative and within the group there was a range of different kinds of explanation preferred. The limitations and achievements of the children's thinking are considered in the context of the school curriculum.     

What happens to children when they grow up? How does the human body change after the age of 18

The present study answers the question on how the human body changes in two successive decades after its final height had been reached. One hundred and three individuals (56 males and 47 females) who were followed up longitudinally by a team of scientists from birth to 18 years of age were investigated anthropometrically by 18 body measurements again when they reached the age of between 35 and 39 years. The Carter-Heath somatotype was ascertained as a part of the study. The results of the investigation at the age of 35 to 39 years were compared with the Czech Standard and with those from 18 years of age. The means of all measurements in both sexes increased with age (with the exception of stature in females). Relative measurements and indices, which were calculated only in the groups of 35-39 year-olds were all on the average greater in males than in females with the exception of relative head circumferences and pelvis width, in the pelvis width in per cent of biacromial width, in the sum of skinfolds, and in the gross percent of body fat. Males as well as females increased from the age of 18 to 35-39 as a rule in weight, muscle, bone and fat mass, which were manifested by a shift towards endomorphic and mesomorphic components of their somatotypes away from the ectomorphic one.     

What really happens in the neutrophil phagosome?

Current viewpoints concerning the bactericidal mechanisms of neutrophils are reviewed from a perspective that emphasizes challenges presented by the inability to duplicate ex vivo the intracellular milieu. Among the challenges considered are the influences of confinement upon substrate availability and reaction dynamics, direct and indirect synergistic interactions between individual toxins, and bacterial responses to stressors. Approaches to gauging relative contributions of various oxidative and nonoxidative toxins within neutrophils using bacteria and bacterial mimics as intrinsic probes are also discussed.     

How is a seita fitted to the body?

A seita is a carrier frame for backpacking used in Nishiki-cho, Yamaguchi Prefecture, Japan. In this mountainous district, people make their living by agriculture and forestry and carry everything on their backs with seita. In this study, we investigated the relationships between the sizes of a body and the dimensions of a seita. This survey was conducted on 30 subjects (mean +/- SD; 68.1 +/- 9.0 years old) at three mountain villages. We measured some anthropometric sizes and seita dimensions and found that the correlation between height and sum of shoulder-lumbar-nuki distance (back length of a seita) and shoulder strap length is significant. In additional surveys, we took photographs with some markers on iliocristale, trochanterion, and so on, when the subjects carried seita in two load conditions. The photographs indicate that the load-supporting points in 16 of 23 subjects were between the iliocristale and trochanterion (i.e., on the sacrum). It is important to note that nobody showed that point above the iliocristale (i.e., on the lumbar vertebra). These data lead to the conclusion that when people in Nishik-icho carry loads with seita, they support loads not on the lumbar vertebrae but on the sacrum, and that they adjust the perimeter consisting of the back part and shoulder strap of the seita.     

What really happens to dendritic cells during malaria?

As dendritic cells (DCs) initiate all adaptive and some innate immune responses, it is not surprising that DC function during malaria is the subject of intensive investigations. However, the results of these investigations have so far been controversial. Here, we discuss various aspects of these studies, including the influence of the species and strain of Plasmodium on DC function, the effects of Plasmodium infection on the activation of CD8(+) T cells by DCs, the effects of haemozoin and the effects of Plasmodium infections on DC Toll-like-receptor signalling.     

What happens to the sown species if a biodiversity experiment is not weeded?

Studies in experimental grasslands have extensively documented the effects of sown plant diversity on the colonization of new species, but the responses of the sown plant combinations themselves have rarely been investigated. We established experimental grasslands differing in species richness (1, 2, 4, 8, and 16) and functional group number and composition (1–4; legumes, grasses, small herbs, tall herbs), and we studied the changes in the abundance of sown species (residents) in both weeded and non-weeded subplots over a period of five years after sowing. The accumulation of new species through spontaneous colonization in the non-weeded treatment did not affect the number of resident species, but had increasingly negative effects over time on the cover of resident species and their aboveground biomass production at community level. Temporal stability of resident populations was lower and year-to-year changes in resident species composition were larger in non-weeded than in weeded subplots. Compositional dissimilarity between weeded and non-weeded treatments increased through time. These negative effects of the colonization of new species on the abundances and stability of resident populations depended on resident species identity and not on additional variation between different functional groups. The colonization of new species did not change the number of resident species emerging from seeds, but reduced seedling densities of residents. Colonization did not affect the structure of resident communities as measured by species evenness, functional trait diversity and mean trait values suggesting that colonization can destabilize the species composition of residents in terms of abundance while leaving them unchanged in terms of functional characteristics. Generally, negative impacts of colonizing species on residents which accelerated through time decreased with an increasing number of sown species. Sowing more diverse grassland mixtures increases their predictability in terms of ecosystem characteristics, which is important for ecological restoration and sustainable agriculture.     

What happens to the DNA vaccine in fish? A review of current knowledge

The primary function of DNA vaccines, a bacterial plasmid DNA containing a construct for a given protective antigen, is to establish specific and long-lasting protective immunity against diseases where conventional vaccines fail to induce protection. It is acknowledged that less effort has been made to study the fate, in terms of cellular uptake, persistence and degradation, of DNA vaccines after in vivo administration. However, during the last year some papers have given new insights into the fate of DNA vaccines in fish. By comparing the newly acquired information in fish with similar knowledge from studies in mammals, similarities with regard to transport, blood clearance, cellular uptake and degradation of DNA vaccines have been found. But the amount of DNA vaccine redistributed from the administration site after intramuscular administration seems to differ between fish and mammals. This review presents up-to-date and in-depth knowledge concerning the fate of DNA vaccines with emphasis on tissue distribution, cellular uptake and uptake mechanism(s) before finally describing the intracellular hurdles that DNA vaccines need to overcome in order to produce their gene product.     

What happens to shelter dogs? An analysis of data for 1 year from three Australian shelters

Annually, welfare shelters admit many dogs, including those whose caregivers surrender them or dogs who are strays. This article analyzes admission data from 3 metropolitan Australian shelters. The study collected data for a 1-year period and analyzed them to identify the characteristics of the typical shelter dog; patterns of relinquishment, sales, reclamation and euthanasia; and duration of stay and reasons underlying euthanasia, relinquishment, and postadoptive return. The study tracked more than 20,000 admissions during this period. To facilitate reclamation, the local Code of Practice requires a mandatory holding period for stray dogs; assessment for suitability for rehoming then occurs. Dogs failing the assessment are euthanized. Surrendered dogs can be assessed immediately. The Code of Practice also recommends that unsold dogs be euthanized 28 days postassessment. Typically, shelter dogs in Melbourne are strays, sexually entire, adult, small, and-usually-male. The majority of admissions are reclaimed or sold. Most reclamations occur within 4 days, and postadoptive return rates are low. That current desexing messages do not appear to have reached the owners of stray dogs to the same extent as they have other dog owners is a major finding, suggesting that a targeted education campaign may be required.     

What are the missing pieces needed to stop antibiotic resistance?

As recognized by several international agencies, antibiotic resistance is nowadays one of the most relevant problems for human health. While this problem was alleviated with the introduction of new antibiotics into the market in the golden age of antimicrobial discovery, nowadays few antibiotics are in the pipeline. Under these circumstances, a deep understanding on the mechanisms of emergence, evolution and transmission of antibiotic resistance, as well as on the consequences for the bacterial physiology of acquiring resistance is needed to implement novel strategies, beyond the development of new antibiotics or the restriction in the use of current ones, to more efficiently treat infections. There are still several aspects in the field of antibiotic resistance that are not fully understood. In the current article, we make a non-exhaustive critical review of some of them that we consider of special relevance, in the aim of presenting a snapshot of the studies that still need to be done to tackle antibiotic resistance.     

What are the respective host and parasite contributions to toxoplasmosis?

The toxoplasmosis pathogenesis mechanism is complex because parasite and host specificities are interrelated. Advances in fundamental research (including strain genotyping, analyzing the progeny from crosses of different strains and exploring the implication of epigenetic effects on the parasite) have contributed greatly to our current knowledge of this mechanism. At the same time new data on the clinical characteristics of the disease have come to light. For example, highly virulent strains have been isolated recently in immunocompetent patients, and some studies suggest that toxoplasmosis also might be implicated in brain disorders. These recent tools and discoveries are likely to cast new light on the pathogenicity of Toxoplasma parasites and provide the key to understanding this unique form of parasitism.