Assessing the longitudinal structure of the early hominid foot: A two-dimensional architecture analysis

Early hominid feet are often very fragmentary preserved and their architectural approaches stayed limited and subject to controversy. This study proposes an architectural analysis of the primate foot realised on dislocated skeleton. It is based on the angular analysis of geometrical relationships between the joint areas. We investigate the longitudinal structure of the primate foot and we present the results concerning someAustralopithecus afarensis specimens from Hadar (Ethiopia) and theHomo habilis Olduvai Hominid 8 foot (Tanzania). The architectural analysis argues for the lack of a longitudinal medial arch inA. afarensis, their joints being in neutral position. On the contrary, the more recent OH8 specimen is arched both medially and laterally.     

Mapping the knowledge structure of research on patient adherence: knowledge domain visualization based co-word analysis and social network analysis

Background

Patient adherence is an important issue for health service providers and health researchers. However, the knowledge structure of diverse research on treatment adherence is unclear. This study used co-word analysis and social network analysis techniques to analyze research literature on adherence, and to show their knowledge structure and evolution over time.

Methods

Published scientific papers about treatment adherence were retrieved from Web of Science (2000 to May 2011). A total of 2308 relevant articles were included: 788 articles published in 2000–2005 and 1520 articles published in 2006–2011. The keywords of each article were extracted by using the software Biblexcel, and the synonym and isogenous words were merged manually. The frequency of keywords and their co-occurrence frequency were counted. High frequency keywords were selected to yield the co-words matrix. Finally the decomposition maps were used to comb the complex knowledge structures.

Results

Research themes were more general in the first period (2000 to 2005), and more extensive with many more new terms in the second period (2006 to 2011). Research on adherence has covered more and more diseases, populations and methods, but other diseases/conditions are not as hot as HIV/AIDS and have not become specialty themes/sub-directions. Most studies originated from the United States.

Conclusion

The dynamic of this field is mainly divergent, with increasing number of new sub-directions of research. Future research is required to investigate specific directions and converge as well to construct a general paradigm in this field.     

Recent knowledge and innovations related to hexofuranosides: structure, synthesis and applications

Hexofuranosides are widely spread in nature, and notably in numerous pathogenic microorganisms. This particular five-membered ring for hexosides leads to novel biological properties and, as usual in glycochemistry, to completely different reactivity and selectivity. Far from being exhaustive, this review will first focus on the structure of the oligosaccharidic part of hexofuranosyl conjugates found in natural sources. Original syntheses will then be presented, stressing more particularly on the development of chemical and chemo-enzymatic tools for the access to 1,2-trans or 1,2-cis linkages. Finally, innovative applications related to biological, chemical and physicochemical fields for both natural and synthetic hexofuranosyl compounds will be described.     

The consequences of spatial structure for the design and analysis of ecological field surveys

In ecological field surveys, observations are gathered at different spatial locations. The purpose may be to relate biological response variables (e.g., species abundances) to explanatory environmental variables (e.g., soil characteristics). In the absence of prior knowledge, ecologists have been taught to rely on systematic or random sampling designs. If there is prior knowledge about the spatial patterning of the explanatory variables, obtained from either previous surveys or a pilot study, can we use this information to optimize the sampling design in order to maximize our ability to detect the relationships between the response and explanatory variables?
The specific questions addressed in this paper are: a) What is the effect (type I error) of spatial autocorrelation on the statistical tests commonly used by ecologists to analyse field survey data? b) Can we eliminate, or at least minimize, the effect of spatial autocorrelation by the design of the survey? Are there designs that provide greater power for surveys, at least under certain circumstances? c) Can we eliminate or control for the effect of spatial autocorrelation during the analysis? To answer the last question, we compared regular regression analysis to a modified t‐test developed by Dutilleul for correlation coefficients in the presence of spatial autocorrelation.
Replicated surfaces (typically, 1000 of them) were simulated using different spatial parameters, and these surfaces were subjected to different sampling designs and methods of statistical analysis. The simulated surfaces may represent, for example, vegetation response to underlying environmental variation. This allowed us 1) to measure the frequency of type I error (the failure to reject the null hypothesis when in fact there is no effect of the environment on the response variable) and 2) to estimate the power of the different combinations of sampling designs and methods of statistical analysis (power is measured by the rate of rejection of the null hypothesis when an effect of the environment on the response variable has been created).
Our results indicate that: 1) Spatial autocorrelation in both the response and environmental variables affects the classical tests of significance of correlation or regression coefficients. Spatial autocorrelation in only one of the two variables does not affect the test of significance. 2) A broad‐scale spatial structure present in data has the same effect on the tests as spatial autocorrelation. When such a structure is present in one of the variables and autocorrelation is found in the other, or in both, the tests of significance have inflated rates of type I error. 3) Dutilleul's modified t‐test for the correlation coefficient, corrected for spatial autocorrelation, effectively corrects for spatial autocorrelation in the data. It also effectively corrects for the presence of deterministic structures, with or without spatial autocorrelation.
The presence of a broad‐scale deterministic structure may, in some cases, reduce the power of the modified t‐test.     

The effectiveness of the longitudinal field,coupled with depolarization in activating frog twitch muscles

EFFECTIVE EXCITATION, PRECEDING THE MECHANICAL RESPONSE IN FROG TWITCH MUSCLES, INVOLVES TWO DISTINCT EVENTS: depolarization of the excitable membrane and the flow of internal currents. To distinguish between the effects of these two potential factors in activation of the contractile machinery, experiments ought to be conducted in which one or the other is excluded. Our experiments are designed to distinguish between these effects by indirect methods. Depolarization in a longitudinal electric field can be expected to be greatest at the ends where current leaves the muscle fibers (space constant at [K] = 16 mM/liter is >1 mm.), whereas the internal longitudinal current is known to be greatest in the middle portion. Depolarization, therefore, should affect the ends more strongly and internal current the middle portion. Our experiments show that non-propagating frog twitch muscles shorten, during isotonic work, along their whole length and not only at their ends, when effectively stimulated in a longitudinal A.C. field. At a field strength about twice the new threshold value (at [K](o) = 16 mM) shortening is distinctly greater in the middle portion of the muscle than at the ends. The muscles, although temporarily non-propagating, remain intact throughout the experiment, as demonstrated by complete recovery after repolarization. These findings may be taken as an indication that internal currents are more directly linked to activation than is depolarization, but the latter is an essential priming step, which must precede or coincide with effective current flow.     

褐飞虱遇险释放挥发性物质的提取及成分分析

利用Y型嗅觉仪测定不同试验条件下褐飞虱Nilaparvata lugens(Stl)对同类昆虫遭遇草间小黑蛛Erigonidium graminicolum Sundvall捕食时挥发性物质的行为反应,并利用固相微萃取、气相色谱与质谱技术分离鉴定挥发性物质。目的明确褐飞虱遇险释放挥发性物质的最佳提取条件,并分析该挥发性物质的成分。结果表明,用乙酸乙酯、甲醇和正己烷分别提取"褐飞虱2³龄若虫+草间小黑蛛成蛛"共存体释放的挥发性物质,发现乙酸乙酯提取物能引起褐飞虱极显著的逃避行为。用不同褐飞虱虫量(100、300、600头/500 mL瓶)、不同提取时间(1、3、6 h)和不同溶剂温度(15、25、35℃)分别提取"褐飞虱23龄若虫+草间小黑蛛成蛛"共存体释放的挥发性物质,发现乙酸乙酯提取物能引起褐飞虱极显著的逃避行为。用不同褐飞虱虫量(100、300、600头/500 mL瓶)、不同提取时间(1、3、6 h)和不同溶剂温度(15、25、35℃)分别提取"褐飞虱2³龄若虫+草间小黑蛛成蛛"共存体释放的挥发性物质,发现3003龄若虫+草间小黑蛛成蛛"共存体释放的挥发性物质,发现300⁶00头、3600头、3⁶ h和25℃下的提取物能引起褐飞虱极显著的逃避行为,明确了褐飞虱遇险释放挥发性物质的最佳提取条件。利用固相微萃取法分别萃取"褐飞虱26 h和25℃下的提取物能引起褐飞虱极显著的逃避行为,明确了褐飞虱遇险释放挥发性物质的最佳提取条件。利用固相微萃取法分别萃取"褐飞虱2³龄若虫"释放的挥发性物质和"褐飞虱23龄若虫"释放的挥发性物质和"褐飞虱2³龄若虫+草间小黑蛛成蛛"共存体释放的挥发性物质。气相色谱分析表明,保留时间16 min、21.5 min时,"褐飞虱"与"褐飞虱+草间小黑蛛"共存体释放的挥发物均出现新峰;保留时间10.94 min时,仅"褐飞虱+草间小黑蛛"共存体释放的挥发物出现新峰。推测保留时间10.94 min时出现的峰为褐飞虱被草间小黑蛛捕食时释放的示警挥发物。质谱分析进一步表明,这种挥发物具有与(E)-2-己烯醛相类似的化学结构,但其实际结构还需深入研究。     

The significance of D-amino acids in soil, fate and utilization by microbes and plants: review and identification of knowledge gaps

Background

D-amino acids are far less abundant in nature than L-amino acids. Both L- and D-amino acids enter soil from different sources including plant, animal and microbial biomass, antibiotics, faeces and synthetic insecticides. Moreover, D-amino acids appear in soil due to abiotic or biotic racemization of L-amino acids. Both L- and D-amino acids occur as bound in soil organic matter and as “free“ amino acids dissolved in soil solution or exchangeably bound to soil colloids. D-amino acids are mineralized at slower rates compared to the corresponding L-enantiomers. Plants have a capacity to directly take up “free“ D-amino acids by their roots but their ability to utilize them is low and thus D-amino acids inhibit plant growth.

Scope

The aim of this work is to review current knowledge on D-amino acids in soil and their utilization by soil microorganisms and plants, and to identify critical knowledge gaps and directions for future research.

Conclusion

Assessment of “free“ D-amino acids in soils is currently complicated due to the lack of appropriate extraction procedures. This information is necessary for consequent experimental determination of their significance for crop production and growth of plants in different types of managed and unmanaged ecosystems. Hypotheses on occurrence of “free“ D-amino acids in soil are presented in this review.     

The structure of myostatin:follistatin 288: insights into receptor utilization and heparin binding

Myostatin is a member of the transforming growth factor‐β (TGF‐β) family and a strong negative regulator of muscle growth. Here, we present the crystal structure of myostatin in complex with the antagonist follistatin 288 (Fst288). We find that the prehelix region of myostatin very closely resembles that of TGF‐β class members and that this region alone can be swapped into activin A to confer signalling through the non‐canonical type I receptor Alk5. Furthermore, the N‐terminal domain of Fst288 undergoes conformational rearrangements to bind myostatin and likely acts as a site of specificity for the antagonist. In addition, a unique continuous electropositive surface is created when myostatin binds Fst288, which significantly increases the affinity for heparin. This translates into stronger interactions with the cell surface and enhanced myostatin degradation in the presence of either Fst288 or Fst315. Overall, we have identified several characteristics unique to myostatin that will be paramount to the rational design of myostatin inhibitors that could be used in the treatment of muscle‐wasting disorders.     

A controlled trial of the knowledge impact of tuberculosis information leaflets among staff supporting substance misusers: pilot study

Background

Information leaflets are widely used to increase awareness and knowledge of disease. Limited research has, to date, been undertaken to evaluate the efficacy of these information resources. This pilot study sought to determine whether information leaflets developed specifically for staff working with substance mis-users improved knowledge of tuberculosis (TB).

Method

Staffs working with individuals affected by substance mis-use were recruited between January and May 2008. All participants were subjectively allocated by their line manager either to receive the TB-specific leaflet or a control leaflet providing information on mental health. Level of knowledge of TB was assessed using questionnaires before and after the intervention and data analysed using McNemar''s exact test for matched pairs.

Results

The control group showed no evidence of a change in knowledge of TB, whereas the TB questionnaire group demonstrated a significant increase in knowledge including TB being curable (81% correct before to 100% correct after), length of treatment required (42% before to 73% after), need to support direct observation (18% to 62%) and persistent fever being a symptom (56% to 87%). Among key workers, who have a central role in implementing a care plan, 88% reported never receiving any TB awareness-raising intervention prior to this study, despite 11% of all respondents having TB diagnosed among their clients.

Conclusion

Further randomized controlled trials are required to confirm the observed increase in short-term gain in knowledge and to investigate whether knowledge gain leads to change in health status.     

The structure and distribution of the interstitial cells in the medullary substance of the kidney

Under study were peculiar features of the structure and distribution of interstitial cells of medullary substance (ICMS) in different parts of the rat renal papilla. The amount of lipid granules containing precursors of prostaglandin synthesis in ICMS was counted. The maximum lipid granulation of ICMS was found in the papilla center. The electron-microscopic study has recognized 3 types of ICMS: little differentiated (located in the papilla apex), highly differentiated (prevailing in the center) and cells of the transitional type. The degree of lipid granulation of ICMS showing the intensity of the prostaglandin synthesis and the character of distribution of ICMS seem to correlate with the functional heterogeneity of the medullary substance.     

Fine structure of the sperm head in some mammals,with particular reference to the acrosome and the subacrosomal substance

Summary An electron microscopical study was made of spermatozoa from the epididymal tail of horses, cattle, pigs, sheep, dogs, cats, rabbits, guinea-pigs, and hares. The fine structure of the sperm head, especially the acrosome and the subacrosomal substance, was analyzed.The very thin sperm heads of bulls, rams, boars, rabbits, hares, and guinea-pigs were generally slightly paddle-shaped as the anterior and anterio-lateral margins were flexed to one side and the intermediate part of the nucleus showed a plane-convex or curved cross section. The nucleus often showed a waist under the posterior part of the acrosome, in sagittal sections. The base of the head was generally asymmetrical on a horizontal plane because the implantation fossa was irregular and often displaced sideways. The cap-shaped acrosome was bounded by a typical unit membrane with about the same thickness as the plasma membrane. An acrosomal thickening along the curved edge of the nucleus was present in the thin sperm heads but was not distinct in the thicker sperm heads of dogs, stallions and cats. It was most pronounced on the convex (ventral) side of the bent nuclear margin and often contained areas with increased or decreased opacity. In an often roughly semilunar area of the posterior acrosome region, corresponding to the equatorial segment of light microscopy, the acrosome was distinctly thinner and sligthly denser. This arrangement was also found in those species-horses, cats, and very pronounced in guinea-pigs — where no equatorial segment is visible in the light microscope. The subacrosomal space was widened along the edge of the nucleus, especially apically, and generally also along the anterior border of the equatorial segment. An opaque, amorphous subacrosomal substance filled these marginal and equatorial spaces in most species. In hares large blisters in the subacrosomal space were present along the anterior border of the equatorial segment on both sides of the sperm head. A similar but less conspicuous phenomenon was often seen in rabbit spermatozoa, but not in other species. The postnuclear cap of light microscopy is probably formed by two components: the basal plate in the implantation fossa and a dense subsurface lamina in the thin layer of cytoplasm covering the remaining nuclear surface behind the acrosome.The possible relations of the subacrosomal substance to the perforatorium of rat spermatozoa and to sub- and periacrosomal structures in some evertebrate spermatozoa was discussed, as well as the role such structures may play in fertilization.Financial support for this study was received from the State Medical Research Council.