bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemoenzymatic Synthesis and Inhibitory Activities of Hyacinthacines A1 and A2 Stereoisomers
Authors: Calveras Jordi , Casas Josefina , Parella Teodor , Joglar Jesús , Clapés Pere 
Published: July 2007

AbstractA novel straightforward chemoenzymatic procedure for the synthesis of hyacinthacine stereoisomers based on the aldol addition of dihydroxyacetone phosphate (DHAP) to N‐Cbz‐prolinal under catalysis by L‐rhamnulose 1‐phosphate aldolase from E. coli is presented. The synthesis is complemented by a simple and effective purification protocol consisting of ion‐exchange chromatography on CM‐sepharose. As examples, (−)‐hyacinthacine A2 [the enantiomer of (+)‐hyacinthacine A2], 7‐deoxy‐2‐epialexine (the enantiomer of 3‐epihyacinthacine A2), ent‐7‐deoxyalexine (the enantiomer of 7‐deoxyalexine) and 2‐epihyacinthacine A2 were synthesized by these procedures and characterized for the first time. These new isomers were assayed as inhibitors of glycosidases. As a result, (−)‐hyacinthacine A2 demonstrated to be a good inhibitor of α‐D‐glucosidase from rice whereas the natural enantiomer, hyacinthacine A2, was not. Moreover, a new family of inhibitors of α‐L‐rhamnosidase was uncovered.
Growth patterns in adverse environments
Authors: Cameron Noël 
Published: July 2007

AbstractThe triple‐logistic pattern of human growth in linear dimensions is probably one of the most recognizable models within human biology. The fact that postnatal somatic growth occurs in three phases (infancy, childhood, adolescence) creates opportunities for the individual expression of this genetically directed, but environmentally modified, phenomenon. The impact of the environment works to alter the duration and intensity of critical stages within the total process resulting in individual patterns that can differ radically from the general pattern. However, the constancy of the general pattern is so fixed that its presence in children is taken as a reflection of good health. Departures from that pattern are recognized as reflecting ill health. While the cessation of growth in response to an acute attack is uniformly dramatic, the gradual response to chronic adverse stimuli is less easily predicted and interpreted. For example, in chronic scenarios the loss of centile position that precedes the eventual establishment of normal increments can be viewed as either a poor or a good growth response, as either maladaptive or adaptive, as either poor health or good health. This article reviews such growth patterns in urban South African children exploring the relationship between environment and growth outcome. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Life history trade‐offs in human growth: Adaptation or pathology?
Authors: Bogin Barry , Silva Maria Inês Varela , Rios Luis 
Published: July 2007

AbstractHuman beings growing‐up in adverse biocultural environments, including undernutrition, exposure to infection, economic oppression/poverty, heavy workloads, high altitude, war, racism, and religious/ethnic oppression, may be stunted, have asymmetric body proportions, be wasted, be overweight, and be at greater risk for disease. One group of researchers explains this as a consequence of “developmental programming” (DP). Another group uses the phrase “predictive adaptive response” (PAR). The DP group tends to view the alterations as having permanent maladaptive effects that place people at risk for disease. The PAR group considers the alterations at two levels of adaptation: (1) “short‐term adaptive responses for immediate survival” and (2) “predictive responses required to ensure postnatal survival to reproductive age.” The differences between the DP and PAR hypotheses are evaluated in this article. A life history theory analysis rephrases the DP versus PAR debate from disease or adaptation to the concept of “trade‐offs.” Even under good conditions, the stages of human life history are replete with trade‐offs for survival, productivity, and reproduction. Under adverse conditions, trade‐offs result in reduced survival, poor growth, constraints on physical activity, and poor reproductive outcomes. Models of human development may need to be refined to accommodate a greater range of the biological and cultural sources of adversity as well as their independent and interactive influences. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Is there an elephant in the room? Addressing rival approaches to the interpretation of growth perturbations and small size
Authors: Schell Lawrence M. , Magnus P.D. 
Published: July 2007

AbstractTwo interpretations of growth perturbation and small size are commonly applied in human biology: an adaptationist approach in which small size is considered to be an a relatively beneficial adjustment to environmental stressors, and a biomedical approach in which small size is considered nonadaptive, a sign of dysfunction or pathology. These two interpretations conflict, but are used without acknowledging or addressing the conflict. This article reviews the strengths and weaknesses of the two. This exercise does not prove the indisputable superiority of either approach. Considerations of epistemology show that biologists will never be faced with a decisive test of either, much as they might like such clear cut evidence. Nevertheless, it is possible that a gradual decrease in the productivity of one approach will become a sufficient reason to abandon it. Alternatively, if specific areas of application can be distinguished, each approach might continue to be productive in its own domain. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Simulation of drying process of corn kernels during microwave and convective treatment
Authors: Bihercz Gábor , Beke János , Kurják Zoltan 
Published: July 2007

AbstractDrying is a necessary technology and a very energy‐demanding process in the area of meat and vegetable processing; it is a tool for finishing semiprocessed or processed goods. Taking the given conditions into consideration, development of technology is necessary, which serves several aims that are often in disagreement with each other (in terms of improvement of availability value, avoidance of artificial additives, energy optimization, reduction of other cost factors, etc.). Until now, several scientific works have been published serving solutions for one specific problem of practice. The main idiosyncrasy of these works is the difference between their methods and availability; hence these are unsuitable to give a uniform model for products with different physical‐biological properties: because, it goes without saying, circumstances of their birth as well as their aims differ so much. Computer support nowadays allows us to build a uniform model based on previous research and auxiliary measurement results, which can simulate the drying process of some of the most important agricultural products. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Analysis of air velocity distribution in a multilayer conveyor dryer by computational fluid dynamics
Authors: Yue Xiaoyu , Zhao Jinhong , Shi Ejuan , Chen Youqing , Liu Xiangdong 
Published: July 2007

AbstractIn many drying processes of a multilayer conveyor dryer, uneven air distribution in the drying chamber often results in inefficient drying and nonuniform moisture content of the products. In order to understand this, the condition of air distribution in the drying chamber of a multilayer conveyor dryer was studied through both experimental and computational fluid dynamics (CFD) methods. The measurement of air velocity in the drying chamber of a six‐layer conveyor dryer was conducted, and a three‐dimensional CFD model for the dryer was established. The drying process using the air velocity measurement was numerically simulated, and the results were compared with those from the practical drying and measuring process. Three velocity homogenization schemes of the dryer structure were established, and their velocity distributions were obtained by the 3D CFD model and analyzed by the evaluation scheme for the optimization of velocity distribution in a multilayer conveyor dryer. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Properties of bentonite and local anesthetics composition
Authors: Zhumagalieva Sh. N. , Kudaibergenova B. M. , Beisebekov M. K. , Abilov Zh. A. 
Published: July 2007

AbstractThe interaction of the bentonite of the Manrak deposit of the East‐Kazakhstan region with the AK‐29 and richlokain local anesthetics has been studied to synthesize the new prolonged medical compounds. The methods of equilibrium swelling, sedimentation, electrophoresis, rotational viscosimetry, and IR spectroscopy have been used. The comparative analysis of interaction of bentonite clay with medical compounds has been carried out. The dependence of interaction nature on an anesthetic structure has been observed. Results of anesthetic release from polymer show a high degree of their fixation and prolongation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Determination of the polymer‐solvent contact angle by the capillary raising curve, applied to the field of supports for homogeneous catalysts
Authors: Suman M. 
Published: July 2007

AbstractA comprehension of the phenomenon that controls the diffusion of an organic solvent to the pores of a polymeric matrix is fundamental for optimizing the operating conditions to distribute a homogeneous catalyst, which has to be supported on it. The traditional sessile drop method is impossible to use when a high polymer‐solvent affinity exists. In this case, a different determination technique, similar to the Wilhelmy static mode method and based on the direct observation of the capillary raising curve of the solvent on the polymeric surface, has been set together with an experimental apparatus specifically built to perform measurements at a desired temperature and atmosphere. Such a technique has been demonstrated to be easy and promising for differentiating the behavior of different polyolefins [polypropylene (PP), high density polyethylene (HDPE), heterophasic copolymers (COPO)] at equal solvent and different temperatures. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Evaluation of swelling capacity of poly(vinyl alcohol) fibrous mats dealt with polyoxometalate containing vanadium
Authors: Yin Rong , Guan Xiao‐Hui , Gong Jian , Qu Lun‐Yu 
Published: July 2007

AbstractPoly(vinyl alcohol) (PVA) fibrous mats dealt with polyoxometalate containing vanadium were prepared by electrospinning method. The fibrous mats were characterized by infrared spectra, X‐ray powder diffraction patterns, and scanning electron microscopy photographs. The results showed that PVA could combine with polyoxometalate by intermolecular H‐bonding. The studies of the diameter distributions indicated that the average diameter of the fibrous mats was about 260–420 nm. The effects of the polyoxometalate content, electrode potential, temperature, and time on the swelling capacity of the fibrous mats in water were investigated. The existence of the polyoxometalate containing vanadium was advantaged for the crosslinking of PVA fibrous mats. The swelling degree of PVA fibrous mats containing polyoxometalate dealt with 383 K for 18 h approached zero in water. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Chemical modification of oil palm empty fruit bunch: Determination of optimum condition and characterization
Authors: Tay G. S. , Rozman H. D. 
Published: July 2007

AbstractIn this study, optimum condition for the reaction of glycidyl methacrylate (GMA), epichlorohydrin (ECH), and propylene oxide (PO) with oil palm empty fruit bunch (EFB) were determined. The treated EFB was characterized using Fourier transform infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), and differential scanning calorimeter (DSC). It is evident from FTIR analysis that all the reagents used were chemically attached to the EFB. From the results of hydroxyl (OH) group determination, it was shown that for all types of reaction, except ECH reaction, more OH groups are generated and accessible. However, no significant difference is observed as the modification level was increased. The density of treated EFB regardless of the types of reaction was relatively lower than that of the untreated EFB. From WAXD analysis, it was found that the crystallinity of EFB was disrupted when the modification level achieved about 30%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Optimization of dyeing of wool with madder and liposomes by central composite design
Authors: Montazer M. , Taghavi F. A. , Toliyat T. , Moghadam M. Bameni 
Published: July 2007

AbstractThe preparation and production of multilamellar liposomes from Soya lecithin with 75% phosphatidylcholine were carried out and the behavior of liposomes in dye‐bath at different temperature, time, and concentration were examined. It was found that liposomes with concentration of below 3% o.w.f. (on weight of fabric) in the dye‐bath increases the amount of K/S for the samples dyed at 85°C or below 85°C for 60 min. Dyeing of wool at higher temperature and longer time with higher concentration of liposomes reduces the color strength. The results showed that using 2% o.w.f. of liposomes in dye‐bath at 85°C for 60 min improves the K/S. The Central Composite Design is used for the experimental plan with three variables on the results of color strength. Statistical analysis confirms the optimum conditions obtained by the experimental results. It was also found that wash, light, wet and dry rub fastness properties of samples dyed with madder including liposomes have not changed significantly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Birefringence and orientation parameters of cold‐drawn viscose fibers
Authors: Fouda I. M. , Seisa E. A. 
Published: July 2007

AbstractThis study was carried out by two beam polarizing interference Pluta microscope to obtain changes undrawn viscose fibers. Application of the appropriate mathematical equations indicates that the refractive indices in the direction of the drawing force increase with increasing the draw ratio and decrease in the perpendicular direction. The changes in the draw ratio were evaluated to obtain the shrinkage stress, the mechanical function factors 〈P2(cos θ)〉 and 〈P4(cos θ)〉, the average work per chain W′ for a collection of chains, and the average mechanical orientation. The optical results were to obtain the three optical orientation functions, the dielectric constant and the dielectric susceptibility and the average orientation function. Also calculation of the intrinsic crystalline
$ \Delta n_c^o $
and amorphous $ \Delta n_a^o $
birefringence. Evaluation of another opto‐mechanical parameters were given, too. An empirical formula was suggested to evaluate the relationship between the draw ratio and some determined opto mechanical parameters. Illustrations using microinterferogram, graphs, and tables are given. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and characterization of biodegradable aliphatic copolyesters with poly(tetramethylene oxide) soft segments
Authors: Pepic Dragana , Nikolic Marija S. , Djonlagic Jasna 
Published: July 2007

AbstractA series of aliphatic poly(ether–ester)s based on flexible poly(tetramethylene oxide) (PTMO) and hard poly (butylene succinate) (PBS) segments were synthesized by the catalyzed two‐step transesterification reaction of dimethyl succinate, 1,4‐butanediol, and α,ω‐hydroxy‐terminated PTMO (Mn = 1000 g/mol) in the bulk. The content of soft PTMO segments in the polymer chains was varied from 10 to 50 mass %. The effect of the introduction of the soft segments on the structure, thermal, and physical properties, as well as on the biodegradation properties was investigated. The composition and structure of the aliphatic segmented copolyesters were determined by 1H NMR spectroscopy. The molecular weights of the polyesters were verified by viscometry of dilute solutions and polymer melts. The thermal properties were investigated using DSC. The degree of crystallinity was determined by means of DSC and WAXS. Biodegradation of the synthesized copolyesters, estimated in enzymatic degradation tests on polymer films in phosphate buffer solution with Candida rugosa lipase at 37°C, was compared with hydrolytic degradation in the buffer solution. Viscosity measurements confirmed that there was no change in molecular weight of the copolyesters leading to the conclusion that the degradation mechanism of poly(ester–ether)s based on PTMO segments occurs through the surface erosion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
The synthesis of poly(3‐hydroxybutyrate)‐g‐poly(methylmethacrylate) brush type graft copolymers by atom transfer radical polymerization method
Authors: Arslan Hülya , Yeşilyurt Nazlı , Hazer Baki 
Published: July 2007

AbstractBrush type of poly (3‐hydroxy butyrate), PHB, copolymer synthesis has been reported. Natural PHB was chlorinated by passing chlorine gas through PHB solution in CHCl3/CCl4 mixture (75/25 v/v) to prepare chlorinated PHB, PHB‐Cl, with the chlorine contents varying between 2.18 and 39.8 wt %. Toluene solution of PHB‐Cl was used in the atom transfer radical polymerization (ATRP) of methyl methacrylate, MMA, in the presence of cuprous bromide (CuBr)/2,2′‐bipyridine complex as catalyst, at 90°C. This “grafting from” technique led to obtain poly (3‐hydroxybutyrate)‐g‐poly(methylmethacrylate) (PHB‐g‐PMMA) brush type graft copolymers (cylindrical brush). The polymer brushes were fractionated by fractional precipitation methods and the γ values calculated from the ratio of the volume of nonsolvent to volume of solvent of brushes were ranged between 2.8 and 9.5 depending on the molecular weight, grafting density, and side chain length of the brushes, while the γ values of PHB, PHB‐Cl, and homo‐PMMA were 2.7–3.8, 0.3–2.4, and 3.0–3.9, respectively. The fractionated brushes were characterized by gel permeation chromatography, 1H‐NMR spectrometry, thermogravimetric analysis (TGA), and differential scanning calorimetry techniques. PHB‐g‐PMMA brush type graft copolymers showed narrower molecular weight distribution (mostly in range between 1.3 and 2.2) than the PHB‐Cl macroinitiator (1.6–3.5). PHB contents in the brushes were calculated from their TGA thermograms and found to be in range between 22 and 42 mol %. The morphologies of PHB‐g‐PMMA brushes were also studied by scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Objective classification of Navarro River salmon habitat: a watershed‐based critical habitat case study
Authors: Viers Joshua H. 
Published: July 2007

Abstract
Prevailing freshwater conservation approaches in the USA stem from policy‐based ecosystem management directives, science‐based gap analyses, and legal interpretations of critical habitats. In California, there has been no systematic prioritization of freshwater habitats critical to the persistence of anadromous salmonid populations.
Anadromous salmonids provide an optimal focal species for conservation prioritization of freshwater habitats in California owing to their flagship, umbrella and keystone status.
The Navarro River is a key watershed for both Endangered Species Act and Clean Water Act recovery efforts in the state of California. This watershed serves as a case study in the use of iterative discriminant analysis to objectively classify freshwater habitats critical to the persistence of two species of threatened anadromous salmonids, steelhead (Oncorhynchus mykiss) and coho (Oncorhynchus kisutch).
Riverscape parameters were used initially to define suitable habitat for focal species; subsequent refinement accounted for human disturbance within the watershed. Results from this study identify 22.1 km of riverine habitat critical to the persistence of coho salmon in the Navarro River watershed, which need active conservation or restoration; it also identified an additional 269.4 km of riverine habitat in need of protection for its aquatic habitat values.
Copyright © 2007 John Wiley & Sons, Ltd.
Genetic structure of Spanish white‐clawed crayfish (Austropotamobius pallipes) populations as determined by RAPD analysis: reasons for optimism
Authors: Beroiz B. , Callejas C. , Alonso F. , Ochando M.D. 
Published: July 2007

Abstract
Spanish populations of the white‐clawed crayfish have declined sharply over the last three decades. Although Austropotamobius pallipes was once widely distributed and very abundant in most of the limestone basins of the country, outbreaks of crayfish plague since 1978 have reduced its populations, and now only some 500–600 small populations are left.
Consequently, the species now enjoys protection under national legislation. Management decisions regarding the conservation of a threatened species require an understanding of the genetic structure of its populations.
Using random amplified polymorphic DNA (RAPD) fingerprinting the genetic variability of 11 populations of A. pallipes was assessed over the species' range in Spain, and their phylogenetic relationships determined.
Substantial genetic differentiation was detected among the populations tested; no clear relationship was found between patterns of genetic variability and hydrological basin. The RAPD markers showed the degree of genetic variability of these populations to be similar to, and in some cases slightly higher than, that reported in previous studies on other Spanish and European populations of A. pallipes.
The results offer hope for the recovery of this species in Spain, and provide information that might be useful in the management of crayfish reintroduction programmes.
Copyright © 2007 John Wiley & Sons, Ltd.
Supporting elementary‐age children's searching and browsing: Design and evaluation using the international children's digital library
Authors: Hutchinson Hilary Browne , Druin Allison , Bederson Benjamin B. 
Published: July 2007

AbstractElementary‐age children (ages 6–11) are among the largest user groups of computers and the Internet. Therefore, it is important to design searching and browsing tools that support them. However, many interfaces for children do not consider their skills and preferences. Children are capable of creating Boolean queries using category browsers, but have difficulty with the hierarchies used in many category‐browsing interfaces because different branches of the hierarchy must be navigated sequentially and top‐level categories are often too abstract for them to understand. Based on previous research, the authors believe using a flat category structure, where only leaf‐level categories are available and can be viewed simultaneously, might better support children. However, this design introduces many more items on the screen and the need for paging or scrolling, all potential usability problems. To evaluate these tradeoffs, the authors conducted two studies with children searching and browsing using two types of category browsers in the International Children's Digital Library. Their results suggest that a flat, simultaneous interface provides advantages over a hierarchical, sequential interface for children in both Boolean searching and casual browsing. These results add to our understanding of children's searching and browsing skills and preferences, and possibly serve as guidelines for other children's interface designers.