bluuebunny/crossref_metadata_2025_split huggingface dataset:
Altitudinal zonation of human‐disturbed vegetation on Mt. Tianmu, eastern China
Authors: Da Liang‐Jun , Kang Min‐Ming , Song Kun , Shang Kan‐Kan , Yang Yong‐Chuan , Xia Ai‐Mei , Qi Yu‐Feng 
Published: June 2009

AbstractMuch of the primary vegetation at low altitudes has been greatly altered or destroyed by a long history of human activities. This is particularly true in eastern China, where low‐altitude areas are now dominated by secondary forests or plantations. Altitudinal vegetation zonation of this region is often based on these secondary forests, resulting in seral vegetation with an obscure zonal sequence. Here, we deduced the potential climax vegetation according to the regeneration patterns of the dominant species of the secondary forests at low altitudes (below 1,000 m a.s.l.) on Mt. Tianmu (1,506 m a.s.l., 30°18′30″–30°21′37″N, 119°24′11″–119°27′11″E). Based on the potential climax vegetation combined with the floristic composition and community structure, three vegetation zones were identified, viz: (1) evergreen broad‐leaved forest zone (400–950 m a.s.l.); (2) evergreen and deciduous broad‐leaved mixed forest zone (950–1,100 m a.s.l.); (3) deciduous broad‐leaved forest zone (1,100–1,506 m a.s.l.). The altitudinal vegetation zones identified in this study correspond with the thermal conditions on Mt. Tianmu. The distribution of vegetation on Mt. Tianmu was limited by lower temperatures in winter, and the altitudinal thermal vegetation zones on this mountain were more similar to the thermal vegetation of Japan than to that of China. The vertical distributions and roles of conifers were different between the eastern and the western regions along 30°N latitude in humid East Asia. Cryptomeria fortunei formed the emergent layer, towering above the broad‐leaved canopy at middle altitudes as C. japonica on Yakushima, but disappeared at high altitudes with hydrothermal limitation on Mt. Tianmu.
Membrane Surface Nanostructures and Adhesion Property of T Lymphocytes Exploited by AFM
Authors: Wu Yangzhe , Lu Hongsong , Cai Jiye , He Xianhui , Hu Yi , Zhao HongXia , Wang Xiaoping 
Published: June 2009

Abstract
The activation of T lymphocytes plays a very important role in T-cell-mediated immune response. Though there are many related literatures, the changes of membrane surface nanostructures and adhesion property of T lymphocytes at different activation stages have not been reported yet. However, these investigations will help us further understand the biophysical and immunologic function of T lymphocytes in the context of activation. In the present study, the membrane architectures of peripheral blood T lymphocytes were obtained by AFM, and adhesion force of the cell membrane were measured by acquiring force–distance curves. The results indicated that the cell volume increased with the increases of activation time, whereas membrane surface adhesion force decreased, even though the local stiffness for resting and activated cells is similar. The results provided complementary and important data to further understand the variation of biophysical properties of T lymphocytes in the context of in vitro activation.
An Efficient Binary Solvent Mixture for Monoacylglycerol Synthesis by Enzymatic Glycerolysis
Authors: Zhong Nanjing , Li Lin , Xu Xuebing , Cheong Lingzhi , Li Bing , Hu Songqing , Zhao Xihong 
Published: June 2009

AbstractThe present study was aimed at selecting an efficient binary solvent mixture for monoacylglycerol (MAG) synthesis by enzymatic glycerolysis of soybean oil. Solvent combinations of tert‐butanol/isopropanol (v/v) at different ratios were studied. Of the investigated cases, tert‐butanol:isopropanol at ratio 80:20 was the most suitable organic medium. The optimum conditions for MAG synthesis under the selected mixture were: water 10 wt% based on glycerol, Lipozyme TL IM 15 wt% based on oil and glycerol, weight ratio of solvent to oil 4:1, and molar ratio of glycerol to oil 3.5:1. Under these conditions with a 4‐h reaction, the yield of MAG was 72.0% where the triacylglycerol (TAG) content was reduced to only 1.0% (based on acylglycerols). Fatty acid ester (FAE) formation from the solvents was very low in the final product (1.3% based on reaction mixture). The selected binary solvent mixture has good physical properties with low melting point (−26.5 °C), which can avoid the risk of crystallization in practical operations.
ON THE LENGTHS OF PAIRS OF COMPLEX MATRICES OF SIZE SIX
Authors: LAMBROU M. S. , LONGSTAFF W. E. 
Published: June 2009

AbstractThe length of every pair {A,B} of 6×6 complex matrices is shown to be at most 10, that is, the words in A,B of length at most 10, including the empty word, span the unital algebra generated by A,B. This supports the conjecture that the length of every pair of n×n complex matrices is at most 2n−2, known to be true for n<6.
EIGHT CONSECUTIVE POSITIVE ODD NUMBERS NONE OF WHICH CAN BE EXPRESSED AS A SUM OF TWO PRIME POWERS
Authors: CHEN YONG-GAO 
Published: June 2009

AbstractIn this paper we prove the following result: there exists an infinite arithmetic progression of positive odd numbers such that for any term k of the sequence and any nonnegative integer n, each of the 16 integers k−2n, k−2−2n, k−4−2n, k−6−2n, k−8−2n, k−10−2n, k−12−2n, k−14−2n, k2n−1, (k−2)2n−1, (k−4)2n−1, (k−6)2n−1, (k−8)2n−1, (k−10)2n−1, (k−12)2n−1 and (k−14)2n−1 has at least two distinct odd prime factors; in particular, for each term k, none of the eight integers k, k−2, k−4, k−6, k−8, k−10, k−12 or k−14 can be expressed as a sum of two prime powers.
History of health technology assessment in Belgium
Authors: Cleemput Irina , Van Wilder Philippe 
Published: June 2009

Objectives: This paper gives an overview of health technology assessment (HTA) in Belgium.Methods: The information included in the overview is based on legal documents and publicly available year reports of the Belgian Health Care Knowledge Centre (KCE).Results: Belgium has a relatively young history in HTA. The principle of evidence-based medicine (EBM) was introduced in the drug reimbursement procedure in 2001, with the establishment of the Drug Reimbursement Committee (DRC). The DRC assesses the efficacy, safety, convenience, applicability, and effectiveness of a drug relative to existing treatment alternatives. For some drugs, relative cost-effectiveness is also evaluated. The activities of the DRC can, therefore, be considered to be the first official HTA activities in Belgium. Later, in 2003, KCE was established. Its mission was to perform policy preparing research in the healthcare and health insurance sector and to give advice to policy makers about how they can obtain an efficient allocation of limited healthcare resources that optimizes the quality and accessibility of health care. This broad mission has been operationalized by activities in three domains of research: HTA, health services research, and good clinical practice. KCE is independent from the policy maker. Its HTAs contain policy recommendations that may inform policy decisions but are not binding.Conclusions: Although the Belgian history of HTA is relatively short, its foundations are strong and the impact of HTA increasing. Nevertheless KCE has many challenges for the future, including continued quality assurance, further development of international collaboration, and further development of methodological guidance for HTA.
Analysis ofBufo arenarumoviductal secretion during the sexual cycle
Authors: Crespo Claudia A. , Ramos Inés , Medina Marcela F. , Fernández Silvia N. 
Published: June 2009

SummaryBufo arenarumoocytes are oviposited surrounded by jelly coats, one component of the extracellular matrix required for fertilization. The secretion, released to the oviductal lumen, was analysed by SDS-PAGE. The coomassie blue staining evidenced an electrophoretic pattern with molecules ranging between 300 and 19 kDa that showed variations in their secretion profiles during the sexual cycle. In the preovulatory period the densitometric analysis showed the presence of nine peaks with marked predominance of the 74 kDa molecule. Once ovulation has occurred, the jelly coats become arranged around the oocytes during their transit throughout the oviductal pars convoluta (PC), revealing the addition of three proteins only observed during this period, which suggests a differential secretion. Some of these proteins could not diffuse under any extraction treatment, indicating for them a structural orin situfunction. Proteins of low molecular mass diffused totally while others showed a partial diffusing capacity. After ovulation a marked decrease in the relative amount of all the proteins released to the lumen, especially the 74 kDa protein, could be detected. During this period, unlike the other stages of the sexual cycle, a differential secretion pattern was observed along the PC. The histochemical analysis performed during the ovulatory period showed the presence of glycoconjugates including both acidic and neutral groups. The present results are in agreement with previous ultrastructural and histochemical studies that describe the role ofBufo arenarumjelly coats in fertilization.
Impact of insemination technique, semen quality and oocyte cryopreservation on pronuclear morphology of zygotes derived from sibling oocytes
Authors: Nicoli Alessia , Capodanno Francesco , Valli Barbara , Di Girolamo Roberta , Villani Maria Teresa , Nucera Andrea , Focarelli Riccardo , La Sala Giovanni B. 
Published: June 2009

SummaryPronuclear morphology seems to be an important predictive value of zygote development and integrity. In this study we want to evaluate the effect of insemination technique, male factor and oocyte cryopreservation on pronuclear morphology of zygotes derived from sibling oocytes in our Centre of Reproductive Medicine, Department of Obstetrics and Gynecology, Arcispedale S. Maria Nuova, Reggio Emilia, Italy. Subjects (n = 190) were submitted to IVF cycles with non-frozen and frozen sibling oocytes. Morphological evaluations were assessed using zygote pronuclear morphology (pronuclei, nucleoli and axis) in four groups: Group 1: 144 zygotes from 85 conventional IVF cycles with non-frozen oocytes; Group 2: 164 zygotes from 85 intracytoplasmic sperm injection (ICSI) cycles with Group 1 patients' sibling frozen oocytes; Group 3: 221 zygotes from 123 ICSI cycles with non-frozen oocytes; Group 4: 197 zygotes from 123 ICSI cycles with Group 3 patients' sibling frozen oocytes. No differences between Group 1 and Group 2 were seen. Group 3 was statistically different from Group 4 in relation to the nucleolar morphology. Oocyte cryopreservation procedure modified the nucleolar morphology of zygotes only in the presence of poor semen quality.
A theory for formation of large empires
Authors: Turchin Peter 
Published: June 2009

AbstractBetween 3000 BCE and 1800 CE there were more than sixty ‘mega-empires’ that, at the peak, controlled an area of at least one million square kilometres. What were the forces that kept together such huge pre-industrial states? I propose a model for one route to mega-empire, motivated by imperial dynamics in eastern Asia, the world region with the highest concentration of mega-empires. This ‘mirror-empires’ model proposes that antagonistic interactions between nomadic pastoralists and settled agriculturalists result in an autocatalytic process, which pressures both nomadic and farming polities to scale up polity size, and thus military power. The model suggests that location near a steppe frontier should correlate with the frequency of imperiogenesis. A worldwide survey supports this prediction: over 90% of mega-empires arose within or next to the Old World’s arid belt, running from the Sahara desert to the Gobi desert. Specific case studies are also plausibly explained by this model. There are, however, other possible mechanisms for generating empires, of which a few are discussed at the end of the article.
The Eurasian silver century, 1276–1359: commensurability and multiplicity
Authors: Kuroda Akinobu 
Published: June 2009

AbstractAcross the Eurasian continent, from England to Korea, silver suddenly became abundant in the late thirteenth century, only to become scarce again in the 1360s. The annual silver output from the London mint and the yearly silver rupee issued in Bengal moved virtually in tandem, arguably as a result of the Mongol empire lifting silver out of the lower tiers of the market and maintaining its flow along the highways of long-distance trade. In this first silver century, monetary usages formed multiple strata, and the circulation of silver remained in a high-level circuit in the hierarchy of monies. Units of account, denominated in terms of silver by weight, worked to give value to silver coinage in the western parts of the commercial highways and kept a link with paper monies in the eastern parts under the Mongol Yuan dynasty. Throughout the silver century, the Mongol empire lowered commercial barriers, to allow the ready flow of silver along trade routes, and consequently created a horizontal unity that, on the surface, was continent-wide. This contrasted with the second silver century, beginning in the 1570s, which ushered in a system of competition between territorial states, some of which vertically cemented the tiers of their domestic markets with credit, and created a space for compatible monies.
Congener specific organic carbon normalized soil and sediment-water partitioning coefficients for the C~1~ through C~8~ perfluoroalkyl carboxylic and sulfonic acids
Authors: Rayne Sierra , Forest Kaya 
Published: June 2009

AbstractOrganic carbon normalized soil and sediment-water partitioning coefficients (K~oc~) were estimated for all C~1~ through C~8~ perfluoroalkyl carboxylic (PFCA) and sulfonic (PFSA) acid congeners. The limited experimental K~oc~ dataset for the straight chain C~7~ through C~10~ PFCAs and C~8~ and C~10~ PFSAs was correlated to SPARC and ALOGPS computationally estimated octanol-water partitioning / distribution constants and used to predict K~oc~ values for both branched and linear C~1~ through C~8~ isomers. Branched and linear congeners in this homologue range are generally expected to have K~oc~ values >1, leading to their accumulation in organic matter on sediments and soils, retardation during ground and pore water flow, and the preferential association with dissolved organic matter in aquatic systems. Both increasing perfluoroalkyl chain length and linearity increase K~oc~ values with substantial intra- and inter-homologue variation and interhomologue mixing. Variability in K~oc~ values among the PFCA and PFSA congeners will likely lead to an enrichment of more linear and longer chain isomers in organic matter fractions, resulting in aqueous phases fractionated towards shorter chain branched congeners. The expected magnitude of fractionation will require inclusion in source apportionment models and risk assessments. A comparison of representative established quantitative structure property relationships for estimating K~oc~ values from octanol-water partitioning constants suggests that these equilibrium partitioning frameworks may be applicable towards modeling PFCA and PFSA environmental fate processes.
Blockage of receptor for advanced glycation end products prevents development of cardiac dysfunction in db/db type 2 diabetic mice
Authors: Nielsen Jan M. , Kristiansen Steen B. , Nørregaard Rikke , Andersen Claus L. , Denner Larry , Nielsen Torsten T. , Flyvbjerg Allan , Bøtker Hans E. 
Published: June 2009

AimsActivation of the receptor for advanced glycation end products (RAGE) is associated with long‐term complications in diabetes mellitus. In this study, we tested whether RAGE activation in the diabetic myocardium is implicated in the development of cardiac dysfunction.Methods and resultsUsing MRI and conductance catheter techniques, we evaluated cardiac function in a type 2 diabetic mouse model (db/db), and assessed the effect of blocking RAGE with a RAGE antibody. Gene expressions were evaluated in samples of myocardial tissue. Diabetic db/db mice demonstrated an accelerated age‐dependent deterioration in cardiac function associated with altered expression of genes related to cardiac structure and function. Blockage of RAGE signalling prevented the reduction in systolic function (preload recruitable stroke work: 109.8 ± 13.8 vs. 94.5 ± 14.9 mmHg/µL, P = 0.04) and development of increased LV diastolic chamber stiffness (0.18 ± 0.05 vs. 0.27 ± 0.07 mmHg, P = 0.01). The cardiac expression of collagen (col1a1) was reduced by approximately 45% and the expression of myosin was switched from the foetal isoform (MHCβ) to the adult isoform (MHCα).ConclusionActivation of RAGE is a significant pathogenetic mechanism for the development of cardiac dysfunction in type 2 diabetes. The underlying mechanisms involve not only the passive biophysical properties of the myocardium but also myocyte function.
Viability and Electron Microscope Studies of Phages T3 and T7 Subjected to Freeze-drying, Freeze-thawing and Aerosolization
Authors: Cox C. S. , Harris W. J. , Lee J. 
Published: June 2009

Phages T3 and T7 were freeze-dried, freeze-thawed or aerosolized. Freeze-drying and aerosolization caused dehydration and resulted in a loss of viability due mainly to one factor, loss of tails. However, the extent of loss of viability and tails was critically dependent upon the manner of rehydration, slow rehydration being best for the preservation of the head-tail complex and viability. Slow freezing (at about 1 °C/min), but fairly rapid thawing (at about 200 °C/min), resulted in marked loss of viability of T7 but only slight loss for T3, through causes other than loss of tails or lysis. Collection of aerosols of T3 and T7 by impinger resulted in much lower viabilities than were obtained by subsonic impaction (e.g. about 10 and 80 % respectively).
The results indicate that the dehydration induced by freeze-drying and aerosolization did not cause loss of viability, but that loss of viability occurred during rehydration. Dehydration of T3 and T7 did not appear to occur during slow freezing (at about 1 °C/min). Mechanisms different from those operating through shear stresses induced by freeze-drying and aerosolization caused loss of viability when T3 and T7 were slowly frozen at about 1 °C/min.
Polymorphism in a Flagellar-shape Mutant of Salmonella typhimurium
Authors: Iino T. , Oguchi Tomoko , Kuroiwa T. 
Published: June 2009

A flagellar-shape mutant, designated ‘polymorphous’, was isolated from a normal flagella strain of Salmonella typhimurium. The mutant produces normal flagella in phase 1 and polymorphous flagella in phase 2. The polymorphous flagella are either straight or possess one of the four distinct wave-forms, namely M, S, N or C, when observed with an electron microscope after negative staining with phosphotungstic acid or uranyl acetate. Conversions between the four wave-forms were found to be brought about mainly by a change in the degree of twisting of longitudinal strands around the axis of a flagella filament, without marked change in the relative lengths of the outermost and innermost strands.
The major fraction of the polymorphous mutant flagella showed the N-form under any conditions of specimen preparation. The remaining four forms appeared as minor fractions in various proportions. Specimens fixed with formalin showed less pronounced polymorphism than unfixed ones. Negative staining with uranyl acetate was more effective than with phosphotungstic acid for observing polymorphism. Even though more than one form appeared among the polymorphous flagella, each individual flagellum comprised a single form except for a rare coexistence of S and N. The same form of flagella tended to coexist in a bacterium in a heteromorphously flagellated cell population.
It was concluded that the conformation and arrangement of the flagellin molecules responsible for wave-form result from strong mutual interactions between the neighbouring molecules along the flagellar filaments and also, to a lesser extent, between the neighbouring filaments in a flagellar bundle, as well as being influenced by the physico-chemical environment.
Ultrastructural Studies on Sporulation in Wild-type and White Colony Mutants of Streptomyces coelicolor
Authors: McVITTIE ANNE 
Published: June 2009

Summary: Examination of thin sections of sporulating wild-type colonies revealed new structural details of the development of the sporulation-septum walls. Spores with very thick (about 75 nm) three-layered walls were seen in spore preparations.
Of the sporulation defective (whi) mutants examined, whiDI6 was defective in spore-wall thickening while whiF99 was defective in rounding up and produced rod-shaped, thick-walled spores. A third mutant (whi-92) showed occasional abnormality in sporulation-septum spacing and produced immature as well as mature spores. One mutant (whi-53) produced only a few spores, all structurally normal. In two whiE mutants, structural abnormalities in spores were absent or rare.
Studies on the Formation of Bacitracin by Bacillus licheniformis: Effect of Glucose
Authors: HAAVIK H. I. 
Published: June 2009

Summary: The production of bacitracin by Bacillus licheniformis closely paralleled growth in a synthetic medium without glucose. Glucose inhibited bacitracin production during the first hours of growth, whereas growth was not affected. Bacitracin was produced mainly during the later stages of growth. Formation of bacitracin was apparently not under catabolite repression control by glucose since the inhibitory effect of glucose upon the early bacitracin production was prevented by neutralizing the culture fluid with CaCO3. The inhibitory effect of glucose may be due to the low pH created by its metabolism.
Addition of 0.5% glucose markedly increased the maximum titre of bacitracin. This stimulation could also be due to the effect of glucose metabolism upon the pH of the medium. The observation that peptide antibiotics are produced mainly after growth is not always true; in appropriate media they might also be produced during the phase of rapid growth.
Metabolic Pathways Involved in Cold Acclimation Identified by Integrated Analysis of Metabolites and Transcripts Regulated by DREB1A and DREB2A
Authors: Maruyama Kyonoshin , Takeda Migiwa , Kidokoro Satoshi , Yamada Kohji , Sakuma Yoh , Urano Kaoru , Fujita Miki , Yoshiwara Kyouko , Matsukura Satoko , Morishita Yoshihiko , Sasaki Ryosuke , Suzuki Hideyuki , Saito Kazuki , Shibata Daisuke , Shinozaki Kazuo , Yamaguchi-Shinozaki Kazuko 
Published: June 2009

AbstractDREB1A/CBF3 and DREB2A are transcription factors that specifically interact with a cis-acting dehydration-responsive element (DRE), which is involved in cold- and dehydration-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Overexpression of DREB1A improves stress tolerance to both freezing and dehydration in transgenic plants. In contrast, overexpression of an active form of DREB2A results in significant stress tolerance to dehydration but only slight tolerance to freezing in transgenic plants. The downstream gene products for DREB1A and DREB2A are reported to have similar putative functions, but downstream genes encoding enzymes for carbohydrate metabolism are very different between DREB1A and DREB2A. We demonstrate that under cold and dehydration conditions, the expression of many genes encoding starch-degrading enzymes, sucrose metabolism enzymes, and sugar alcohol synthases changes dynamically; consequently, many kinds of monosaccharides, disaccharides, trisaccharides, and sugar alcohols accumulate in Arabidopsis. We also show that DREB1A overexpression can cause almost the same changes in these metabolic processes and that these changes seem to improve freezing and dehydration stress tolerance in transgenic plants. In contrast, DREB2A overexpression did not increase the level of any of these metabolites in transgenic plants. Strong freezing stress tolerance of the transgenic plants overexpressing DREB1A may depend on accumulation of these metabolites.