bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of fallback foods on great ape tooth enamel
Authors: Constantino Paul J. , Lucas Peter W. , Lee James J.‐W. , Lawn Brian R.
Published: November 2009

Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30 2008 374‐385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of this conclusion on the evolution of the dentition of extinct hominins. Am J Phys Anthropol 140:653–660, 2009. © 2009 Wiley‐Liss, Inc.
Fallback foods, eclectic omnivores, and the packaging problem
Authors: Altmann Stuart A.
Published: November 2009

For omnivorous primates, as for other selective omnivores, the array of potential foods in their home ranges present a twofold problem: not all nutrients are present in any food in the requisite amounts or proportions and not all toxins and other costs are absent. Costs and benefits are inextricably linked. This so‐called packaging problem is particularly acute during periods, often seasonal, when the benefit‐to‐cost ratios of available foods are especially low and animals must subsist on fallback foods. Thus, fallback foods represent the packaging problem in extreme form. The use of fallback foods by omnivorous primates is part of a suite of interconnected adaptations to the packaging problem, the commingling of costs and benefits in accessing food and other vital resources. These adaptations occur at every level of biological organization. This article surveys 16 types of potential adaptations of omnivorous primates to fallback foods and the packaging problem. Behavioral adaptations, in addition to finding and feeding on fallback foods, include minimizing costs and requirements, exploiting food outbreaks, living in social groups and learning from others, and shifting the home range. Adaptive anatomical and physiological traits include unspecialized guts and dentition, binocular color vision, agile bodies and limbs, Meissner's corpuscles in finger tips, enlargement of the neocortex, internal storage of foods and nutrients, and ability internally to synthesize compounds not readily available in the habitat. Finally, during periods requiring prolonged use of fallback foods, life history components may undergo changes, including reduction of parental investment, extended interbirth intervals, seasonal breeding or, in the extreme, aborted fetuses. Am J Phys Anthropol 140:615–629, 2009. © 2009 Wiley‐Liss, Inc.
Male and female western gorilla diet: Preferred foods, use of fallback resources, and implications for ape versus old world monkey foraging strategies
Authors: Doran‐Sheehy D. , Mongo P. , Lodwick J. , Conklin‐Brittain N.L.
Published: November 2009

Most of what is currently known about western gorilla (Gorilla gorilla) diet is based on indirect studies using fecal samples and trail signs rather than measures based on direct observations. Here we report results on adult male and female western gorilla foraging behavior, based on systematic focal observations and nutritional analyses of foods. We found that western gorillas, like other apes, are highly selective ripe fruit specialists, seeking fruit high in energy, low in antifeedants, and rare in the environment. During seasonal fruiting peaks, fruit accounted for up to 70% of feeding time. When ripe fruit was scarce, gorillas increased time spent feeding on leaves and nonpreferred fruits and herbs. Leaves were the major fallback food, accounting for up to 70% of feeding time in males and 50% in females during periods of fruit scarcity. In spite of large differences in body size, the sexes were remarkably similar in their overall diet, not differing in time spent feeding on fruit or preferred herbs. However, the male consistently fed more often and on a greater variety of leaves than did females, whereas females fed more often on fallback herbs and termites. Our findings, when considered in light of previous findings on sympatric mangabeys, indicate that the foraging strategy of western gorillas is broadly similar to that of chimpanzees and orangutans, and distinct from that of old world monkeys. Am J Phys Anthropol 140:727–738, 2009. © 2009 Wiley‐Liss, Inc.
Foraging and ranging behavior during a fallback episode:Hylobates albibarbisandPongo pygmaeus wurmbiicompared
Authors: Vogel Erin R. , Haag Livia , Mitra‐Setia Tatang , van Schaik Carel P. , Dominy Nathaniel J.
Published: November 2009

Periodic episodes of food scarcity may highlight the adaptive value of certain anatomical traits, particularly those that facilitate the acquisition and digestion of exigent fallback foods. To better understand the selective pressures that favored the distinctive dental and locomotor morphologies of gibbons and orangutans, we examined the foraging and ranging behavior of sympatricHylobates albibarbisandPongo pygmaeus wurmbiiduring an episode of low fruit availability at Tuanan, Kalimantan Tengah, Indonesia. We found thatHylobatesranged 0.5 km day−1or 33% farther than didPongo, but the overall daily ranging of both species did not vary as fruit availability decreased by as much as 50%. Among gibbons, we observed dietary switching to fallback foods; in particular, there was a progressively greater reliance on figs, liana products, and unripe fruit. Orangutans relied heavily on unripe fruit and fracture‐resistant bark and pith tissues. Despite these divergent fallback patterns, the stiffness of fruit mesocarp consumed byHylobatesandPongodid not differ. We discuss canine and molar functional morphology with respect to dietary mechanics. Next, to contextualize these results, we discuss our findings with respect to forest structure. The rain forests of Southeast Asia have been described as having open, discontinuous canopies. Such a structure may inform our understanding of the ranging behavior and distinctive locomotion of apes in the region, namely richochetal brachiation and quadrumanous clambering. Our approach of integrating behavioral ecology with physical measures of food may be a powerful tool for understanding the functional adaptations of primates. Am J Phys Anthropol 140:716–726, 2009. © 2009 Wiley‐Liss, Inc.
Shallow‐water habitats as sources of fallback foods for hominins
Authors: Wrangham Richard , Cheney Dorothy , Seyfarth Robert , Sarmiento Esteban
Published: November 2009

Underground storage organs (USOs) have been proposed as critical fallback foods for early hominins in savanna, but there has been little discussion as to which habitats would have been important sources of USOs. USOs consumed by hominins could have included both underwater and underground storage organs, i.e., from both aquatic and terrestrial habitats. Shallow aquatic habitats tend to offer high plant growth rates, high USO densities, and relatively continuous USO availability throughout the year. Baboons in the Okavango delta use aquatic USOs as a fallback food, and aquatic or semiaquatic USOs support high‐density human populations in various parts of the world. As expected given fossilization requisites, the African early‐ to mid‐Pleistocene shows an association of Homo and Paranthropus fossils with shallow‐water and flooded habitats where high densities of plant‐bearing USOs are likely to have occurred. Given that early hominins in the tropics lived in relatively dry habitats, while others occupied temperate latitudes, ripe, fleshy fruits of the type preferred by African apes would not normally have been available year round. We therefore suggest that water‐associated USOs were likely to have been key fallback foods, and that dry‐season access to aquatic habitats would have been an important predictor of hominin home range quality. This study differs from traditional savanna chimpanzee models of hominin origins by proposing that access to aquatic habitats was a necessary condition for adaptation to savanna habitats. It also raises the possibility that harvesting efficiency in shallow water promoted adaptations for habitual bipedality in early hominins. Am J Phys Anthropol 140:630–642, 2009. © 2009 Wiley‐Liss, Inc.
The impact of fallback foods on wild ring‐tailed lemur biology: A comparison of intact and anthropogenically disturbed habitats
Authors: Sauther Michelle L. , Cuozzo Frank P.
Published: November 2009

Fallback foods are often viewed as central in shaping primate morphology, and influencing adaptive shifts in hominin and other primate evolution. Here we argue that fruit of the tamarind tree (Tamarindus indica) qualifies as a fallback food of ring‐tailed lemurs (Lemur catta) at the Beza Mahafaly Special Reserve (BMSR), Madagascar. Contrary to predictions that fallback foods may select for dental and masticatory morphologies adapted to processing these foods, consumption of tamarind fruit by these lemurs leaves a distinct pattern of dental pathology among ring‐tailed lemurs at BMSR. Specifically, the physical and mechanical properties of tamarind fruit likely result in a high frequency of severe tooth wear, and subsequent antemortem tooth loss, in this lemur population. This pattern of dental pathology is amplified among lemurs living in disturbed areas at Beza Mahafaly, resulting from a disproportionate emphasis on challenging tamarind fruit, due to few other fruits being available. This is in part caused by a reduction in ground cover and other plants due to livestock grazing. As such, tamarind trees remain one of the few food resources in many areas. Dental pathologies are also associated with the use of a nonendemic leaf resource Argemone mexicana, an important food during the latter part of the dry season when overall food availability is reduced. Such dental pathologies at Beza Mahafaly, resulting from the use or overemphasis of fallback foods for which they are not biologically adapted, indicate that anthropogenic factors must be considered when examining fallback foods. Am J Phys Anthropol 140:671–686, 2009. © 2009 Wiley‐Liss, Inc.
Numerical simulation of aggregate dispersion in different flow fields using discrete element method
Authors: Hosseini M. Salami , Nazockdast H. , Dabir B.
Published: November 2009

An attempt was made to study the aggregate dispersion process in three different flow fields namely; steady shear, elongation flow, and combined shear and elongational flows using the discrete element method. The simulation was performed on two aggregate structures characterized by their fractal dimensions. The predicted results showed that the aggregate break‐up process evaluated in terms of weighted average fragment size 〈w〉 follows a power–law type relation as 〈w〉 = kt−m in all the three flow fields. The dispersion performance of different flow fields evaluated by dispersing rate and a final steady‐state fragment size was found to be dependent upon the extent of applied stress and flow fields such that at low applied stress levels much smaller steady state values of 〈w〉 could be obtained for the elongational flow. The aggregate structure, characterized by its fractal dimension, was found to have different effects on the aggregate dispersion process depending on the flow field and applied stress level. The results predicted from this simulation could be explained in terms of ability of flow fields in rotating the aggregates and fragments in appropriate position to be broken up and the fractal dimensions of aggregates. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Isotactic polypropylene composites reinforced with multiwall carbon nanotubes, part 2: Thermal and mechanical properties related to the structure
Authors: Kotsilkova Rumiana , Ivanov Evgeni , Krusteva Ekaterina , Silvestre Clara , Cimmino Sossio , Duraccio Donatella
Published: November 2009

Polypropylene nanocomposites containing multiwall carbon nanotubes (MWCNT), from 0.1 to 3 wt %, are prepared by dilution of a polypropylene based masterbatch (20% MWCNT) with isotactic polypropylene (iPP) using extrusion processing. CNT are found to enhance significantly the thermal stability of iPP in nitrogen and air atmosphere. Dynamic mechanical analysis and tensile tests confirm the reinforcement effect of small amount of nanotubes in iPP. Rheology, structure, and properties are correlated determine the optimal limits of nanofiller content required for improving the performance of nanocomposites. The rheological flocculation threshold of φ* = 0.5% is found as a critical concentration for the formation of a flocculated type of structure in the dispersions. It is proposed, that the flocculated structure is responsible for the maximal improvement of nanocomposite mechanical and thermal properties. The MWCNT additive slightly enhances the local dynamics of iPP molecules in the glass transition region and suppresses the global relaxation of the chain segments in the amorphous regions, resulting in a reinforcement effect. The fracture mechanism is discussed and associated with the hierarchy of the flocculated nanocomposite morphology and the bridging of matrix cracks by CNT. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of in situ surface‐modified nano‐SiO2 on the thermal and mechanical properties and crystallization behavior of nylon 1010
Authors: Xiuwei Fang , Xiaohong Li , Laigui Yu , Zhijun Zhang
Published: November 2009

Nylon 1010 composites filled with two types of surface‐modified SiO2 nanoparticles (RNS and DNS) were prepared by melt blending. The mechanical properties of the composites were evaluated. The influences of the surface‐modified nano‐SiO2 on the thermal stability, crystallization behavior, and microstructure of nylon 1010 were investigated by thermogravimetric analysis, differential scanning calorimetry (DSC), X‐ray diffraction, and transmission electron microscopy. And the interfacial interactions between the fillers and polymer matrix were examined using a Fourier transformation infrared spectrometer. It was found that the addition of the surface‐modified nano‐SiO2 had distinct influences on the thermal stability, mechanical properties, and crystallization behavior of nylon 1010. RNS and DNS as the fillers had different effects on the mechanical properties of nylon 1010. The composites filled with RNS at a mass fraction of 1–5% showed increased break elongation, Young's modulus, and impact strength but almost unchanged or even slightly lowered tensile strength than the unfilled matrix. The DNS‐filled nylon 1010 composites had obviously decreased tensile strength, whereas the incorporation of DNS also contributed to the increase in the Young's modulus of nylon 1010, but less effective than RNS. Moreover, the nylon 1010 composites had better thermal stability than the neat polymer matrix, and the composites filled with RNS were more thermally stable than those filled with DNS. The difference in the crystallinity of neat nylon 1010 and its composites filled with RNS and DNS was subtle, although the surface‐modified nano‐SiO2 could induce or/and stabilize the γ‐crystalline formation of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Novel methyl cellulose‐grafted‐acrylamide/gelatin microspheres for controlled release of nifedipine
Authors: Babu V. Ramesh , Kanth V. Rajinee , Mukund Jadhav M. , Aminabhavi Tejraj M.
Published: November 2009

Naturally available carbohydrate polymers such as methylcellulose (MC) and gelatin (Ge) have been widely studied in the previous literature for controlled release (CR) applications. In this study, methyl cellulose‐g‐acrylamide/gelatin (MC‐g‐AAm/Ge) microspheres were prepared by water‐in‐oil (W/O) emulsion method and crosslinked with glutaraldehyde to encapsulate with nifedipine (NFD), an antihypertensive drug. The microspheres prepared were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and laser particle size analyzer. DSC thermograms of NFD‐loaded AAm‐MC/Gel microspheres confirmed the molecular level distribution of NFD in the matrix. SEM indicated the formation of spherical particles. Swelling experiments supported the drug diffusion characteristics and release data of the matrices. Cumulative release data were analyzed using an empirical equation to understand the nature of transport of drug through the matrices. Controlled release characteristics of the matrices for NFD were investigated in pH 7.4 media. Drug was released in a controlled manner up to 12 h. Particle size and size distribution of the microspheres as studied by laser light diffraction particle size analyzer indicated their sizes to be around 120 μm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Investigation of factors affecting synthesis of polyvinyl butyral by Taguchi method
Authors: Hajian Morteza , Koohmareh Gholam Ali , Rastgoo Mahdi
Published: November 2009

Polyvinyl butyral (PVB) was prepared by condensation reaction of butyral with polyvinyl alcohol (PVA) in aqueous phase containing an acid as a catalyst and an emulsifying agent. Properties of the polymer were a function of the relative amounts of the three randomly distributed units of acetal, acetate and vinyl alcohol groups, and the molecular weight. In this work, some effective factors in synthesis of PVB have been investigated by Taguchi method. The percent of the acetalization has been determined according to the ASTM D1396, and the polymer was characterized by IR, TG, and DTG techniques. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Surface chemical modification of polypropylene fiber waste by H2SO4: Mechanistic investigation and application as cation‐exchange adsorbent
Authors: Matos Jamerson Peixoto , Sansiviero Maria Terezinha Caruzo , Lago Rochel Montero
Published: November 2009

In this work, polypropylene (PP) fiber waste was modified by the reaction with concentrated H2SO4. IR, TG, Raman, CHN, acid titration, SEM, and XRD suggested that sulfuric acid at about 105°C reacts with PP to produce mainly surface sulfonic groups. The kinetic experiments showed that these SO3H groups decompose to form SO2 gas leading to an aromatization of the polymer to form amorphous and graphitic carbon. Adsorption isotherms of the cationic model molecule methylene blue showed that the modified PP fibers have a great potential as ion‐exchange adsorbent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of biodegradable thermoplastic films based on collagen hydrolyzate
Authors: Haroun A. A.
Published: November 2009

The increasing use of plastics and their nonbiodegradability have raised environmental awareness and hence there is a need for the development of environmentally friendly degradable materials. One of the ways to reach this goal is via the modification of the synthetic polymer, modified polyethylene (MPE), with protein, collagen hydrolyzate (CH). CH is a biopolymer isolated from hide/skin fleshing of untanned solid waste from the leather industry after enzymatic hydrolysis. An investigation on the blending of MPE with CH using polymer melt technique is reported. The resulting thermoplastic films were evaluated using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTA), and scanning electron microscope (SEM), in addition to simulated soil burial respirometric testing. It is interesting to note that CH easily blends with MPE, but like other biopolymers, it also has effects on the original mechanical properties of the MPE. The CH addition in the blend significantly increases the biodegradation rate. The effect of CH on MPE biodegradability has been investigated. About 53% biodegradation is observed, after 24 days, when the polymer is blended with 5% CH and about 63% biodegradation is found in the case of polymer blended with 20% CH. Although MPE/CH thermoplastic film with 40% CH have shown better performance in biodegradation, the mechanical strength properties were rather poor in this case. The optimum thermoplastic film composition for blending of CH with MPE is about 10–20 wt % CH, which retains an acceptable range of compatibility, mechanical strength, and biodegradability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Polyamide 6 composites reinforced with silicon nitride whiskers: Synthesis, interface interaction, and mechanical properties
Authors: Li Lanjie , Yang Guisheng
Published: November 2009

In this study, polyamide 6 (PA6)/silicon nitride whisker (SNW) composites were fabricated via in situ hydrolytic ring‐opening polymerization of ε‐caprolactam. By this novel method, SNWs can be dispersed uniformly in PA6 matrix. The interface interaction between SNW and PA6 was investigated, and the reinforcing efficiency of SNW on PA6 was evaluated. It was revealed by Fourier transform infrared spectroscopy that a large amount of polar groups, such as SiOH, NH, and NH2, were present on the SNWs, by which hydrogen bonding and covalent bonding can be formed at interface. Mechanical test showed that at a loading of 5.0 wt % SNW, the tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength of PA6/SNW composite were 37.9, 80.5, 60.3, 73.9, and 64% higher than those of neat PA6, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Controlled release of carbamazepine from carboxymethyl chitosan‐grafted‐ 2‐hydroxyethylmethacrylate matrix tablets
Authors: Patel Nirmal K. , Joshi Jigar , Mishra Deepak , Patel Vishnu A. , Sinha Vijay Kumar
Published: November 2009

The aim of the study was to prepare the controlled release dosage of carbamazepine matrix tablets using wet granulation technique. The graft copolymerization of carboxymethyl chitosan (CMCH) with 2‐hydroxyethylmethacrylate (HEMA) was carried out. The product was characterized by Fourier‐transform infrared, scanning electron microscopy, transmission electron micrograph, and X‐ray diffraction anayses. CMCH‐g‐HEMA was used as binder to prepare the matrix tablets containing carbamazepine. The properties of tablets like hardness, friability, and dissolution influenced by binder were studied. In vitro release of the matrix tablets was carried out with the phosphate‐buffered solution (pH 7.4) at 37°C and 100 × g using USP dissolution test apparatus. Release rate of carbamazepine from controlled release matrix tablets was compared with the commercially marketed tablet, Tagretol 200. Results show that after 6 hrs percentage drug release of formulated tablet CGH5 was 20.42% and that of Tegretol 200 was 18.32%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Hydrogels from scleroglucan and ionic crosslinkers: Characterization and drug delivery
Authors: Coviello Tommasina , Matricardi Pietro , Balena Alessandra , Chiapperino Bicemaria , Alhaique Franco
Published: November 2009

The polysaccharide scleroglucan (Sclg), exploited as a matrix suitable for modified drug delivery, was crosslinked in the presence of three ions: borate, aluminum, and iron. A rheological investigation indicated the main differences between the hydrogels in their viscoelastic linear response: the Sclg/borax system showed the highest strength when deformed by elongation, whereas the strength of the other systems broke down, in terms of viscosity, at much lower values of the imposed strain. Tablets prepared from the gels showed remarkable differences in their water uptake and dimensional swelling. On the other hand, the tablets, loaded with drugs of different steric hindrances, showed similar release behavior, regardless of the crosslinking agent. Scanning electron microscopy analysis was related to the delivery and rheological profiles. Texture analysis, carried out on tablets swollen for 5 h, showed different values of cohesion. Furthermore, when the generalized Maxwell model was applied to the relaxation data, the obtained mechanical spectra showed a more pronounced solidlike character of the Sclg/iron network in comparison with the prevailing viscous behavior of the other matrices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Direct‐current and alternating‐current analysis of the humidity‐sensing properties of nickel oxide doped polypyrrole encapsulated in mesoporous silica SBA‐15
Authors: Wang Rui , Zhang Tong , He Yuan , Li Xiaotian , Geng Wangchang , Tu Jinchun , Yuan Qing
Published: November 2009

Nickel oxide (NiO) doped polypyrrole (PPy) was encapsulated in mesoporous SBA‐15. All of the synthesized samples were characterized by infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. They were investigated as humidity‐sensor materials at room temperature. The sensor showed excellent humidity sensitivity in the relative humidity range 11–95%. The humidity‐sensing properties were very much improved by encapsulation of the NiO‐doped PPy into mesoporous silica SBA‐15. Finally, the sensitivity mechanism was investigated by direct‐current (dc) and alternating‐current (ac) analysis. The dc circuit with the instantaneous polarity reversion method was designed by us to study the dc response in different humidity environments. The conductive mechanism was established through the dc and ac investigation, and the conductive particles were identified as ions and electrons. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of spinning conditions on the mechanical properties of polyacrylonitrile fibers modified with carbon nanotubes
Authors: Mikolajczyk T. , Szparaga G. , Bogun M. , Fraczek‐Szczypta A. , Blazewicz S.
Published: November 2009

Carbon nanotubes (CNTs) were used to modify polyacrylonitrile (PAN) polymer. The PAN/CNT composite fibers were spun from dimethylformamide solutions containing different types of CNTs. The effect of nanotube addition to the fiber precursor on the resulting mechanical properties is discussed. In this study, we examined the relationship of the rheological properties of PAN spinning solutions containing various types of CNTs and the tensile strength of the resulting PAN fibers. The presence of CNTs in the PAN spinning solution enhanced its deformability during the drawing stage. This effect resulted in a higher tensile strength in the fibers containing nanotubes, as compared to the pure fibers. The use of a three‐stage drawing process resulted in a significant increase in the tensile strength of PAN fibers modified with multiwalled nanotubes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of silane‐grafting on water tree resistance of XLPE cable insulation
Authors: Ma Zhishen , Huang Xingyi , Jiang Pingkai , Wang Genlin
Published: November 2009

Water treeing is one of the main deterioration phenomena observed in the polymeric insulation of extruded crosslinked polyethylene (XLPE) cables, which can affect the service life of power cables. In this work, we investigated the effect of grafting of a silane (vinyl trimethoxysilane, VTMS) on the resistance of XLPE to water treeing. A series of water‐treeing tests, the mechanical and dielectric measurements indicated that the silane‐grafting could significantly improve the water tree resistance of the conventional XLPE cable insulation with little influences on its dielectric properties, e.g., the dielectric breakdown strength, dielectric constant and loss tangent, and its mechanical performance. It was found that there exists an optimum value of VTMS concentration (about 0.6 phr) corresponding to the minimum water tree length. The water tree resistance mechanism of silane‐grafted XLPE was proposed on the basis of the process of silane hydrolysis and crosslinking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A head in virtual reality: Development of a dynamic head and neck model
Authors: Nguyen Ngan , Wilson Timothy D.
Published: November 2009

Advances in computer and interface technologies have made it possible to create three‐dimensional (3D) computerized models of anatomical structures for visualization, manipulation, and interaction in a virtual 3D environment. In the past few decades, a multitude of digital models have been developed to facilitate complex spatial learning of the human body. However, there is limited empirical evidence to guide the development and integration of effective computer models for teaching and learning. The purpose of this article is to describe the development of a dynamic head and neck model with flexible displays (2D, 3D, and stereoscopic 3D) and interactive control features that can be later used to design and test the efficacy of computer models as a means of improving student learning. The model was created using computer tomography scans of a human cadaver. Anatomical structures captured on the scans were segmented into discreet areas, and then reconstructed in three‐dimensions using specialized software. The final model consists of 70 distinct anatomical structures that can be displayed in 2D, 3D, or stereoscopic 3D. In 3D mode, a mouse can be used to actively and continuously interact with the model by manipulating viewer orientation, altering surface transparency, superimposing 2D scans with 3D reconstructions, removing or adding structures sequentially, and customizing animated scenes to show complex anatomical pathways or relationships. Anat Sci Educ 2: 294–301, 2009. © 2009 American Association of Anatomists.
Medical education in the anatomical sciences: The winds of change continue to blow
Authors: Drake Richard L. , McBride Jennifer M. , Lachman Nirusha , Pawlina Wojciech
Published: November 2009

At most institutions, education in the anatomical sciences has undergone several changes over the last decade. To identify the changes that have occurred in gross anatomy, microscopic anatomy, neuroscience/neuroanatomy, and embryology courses, directors of these courses were asked to respond to a survey with questions pertaining to total course hours, hours of lecture, and hours of laboratory, whether the course was part of an integrated program or existed as a stand‐alone course, and what type of laboratory experience occurred in the course. These data were compared to data obtained from a similar survey in 2002. Comparison between the data sets suggests several key points some of which include: decreased total hours in gross anatomy and neuroscience/neuroanatomy courses, increased use of virtual microscopy in microscopic anatomy courses, and decreased laboratory hours in embryology courses. Anat Sci Educ 2: 253–259, 2009. © 2009 American Association of Anatomists.
Dust‐enshrouded star formation in XMM‐LSS galaxy clusters
Authors: Temporin S. , Duc P.‐A. , Ilbert O. , XMM‐LSS/SWIRE collaboration
Published: November 2009

In recent years, infrared studies of individual galaxy clusters at intermediate redshifts led to the identification of several luminous infrared galaxies (LIR > 1011 L⊙). These findings were interpreted as an evidence ofvigorous, dust‐enshrouded star formation activity, hinting at the presence of an infrared Butcher‐Oemler effect. In order to explore this effect, we have undertaken a statistical investigation based on a cluster sample drawn from the XMM‐Newton Large Scale Structure survey (XMM‐LSS) and exploiting the contiguous coverage of the XMM‐LSS field by the Spitzer SWIRE legacy survey. We adopted a stacking technique to investigate the distribution of 24‐μ m sources out to the cluster periphery and compare it with the distribution of sources in a sample of control fields. Among putative cluster members, selected by means of photometric redshifts, we identified surprisingly high numbers of bright 24‐μ m sources toward intermediate redshift clusters (z > 0.3). Our analysis indicates the presence of an excess of bright mid‐IR sources at redshift z > 0.3 at clustercentric radii ∼200–500 kpc (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A composite K ‐band luminosity function for cluster galaxies
Authors: De Propris R. , Christlein D.
Published: November 2009

We present a composite K ‐band luminosity function for 10 clusters at low redshift, where member galaxies are identified from an existing spectroscopic survey (the 2dF galaxy redshift survey). Our kinematically selected K ‐band luminosity function is well fitted by a Schechter function with MK * = –24.50 + 5 log h and α = –0.98 over –27 ≪ MK –5 log h < –22. This is very similar to the 2dF field value and suggests that the integrated mass accretion history of galaxies does not vary strongly with environment (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Early‐type dwarf galaxies with spiral structure
Authors: Lisker T. , Brunngräber R. , Grebel E.K.
Published: November 2009

A significant fraction of Virgo cluster early‐type dwarf (dE) galaxies exhibit disk substructure, like spiral arms and bars. Are these disks the still visible remnants of late‐type progenitor galaxies that harassment transformed into dEs? Simulations of harassment predict tidal debris arcs around the remnants, as well as a distorted outer structure. We aimed at detecting such signatures by means of very deep ESO 2.2m/WFI images of dEs with weak spiral structure. Here, we present a preliminary analysis of these images and their implications (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Metallicity gradients: Mass dependency in dwarf elliptical galaxies
Authors: Koleva M. , Prugniel Ph. , De Rijcke S. , Zeiinger W. W. , Michielsen D.
Published: November 2009

The formation and evolution of galaxies is imprinted on their stellar population radial gradients. Two recent articles present conflicting results concerning the mass dependence of the metallicity gradients for early‐type dwarf galaxies. On one side, Spolaor et al. (2009) show a tight positive correlation between the total metallicity [Z /H] and the mass. On the other side, in a distinct sample, we do not find any trend involving [Fe/H] (Koleva et al. 2009). In order to investigate the origin of the discrepancy, we examine various factors that may affect the determination of the gradients: namely the sky subtraction and the signal‐to‐noise ratio. We conclude that our detection of gradients are well above the possible analysis biases. Then, we measured the [Mg/Fe] relative abundance profile and found moderate gradients. The derived [Z /H] gradients scatter around –0.4 dex/re. The two samples contain the same types of objects and the reason of the disagreement is still not understood (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultraviolet color‐magnitude relation of early‐type dwarf galaxies in the Virgo cluster
Authors: Kim S. , Rey S.‐C. , Lisker T.
Published: November 2009

We present ultraviolet (UV) color‐magnitude relations (CMRs) for dwarf ellipticals (dEs) and dwarf lenticulars (dS0s) in the Virgo cluster. We used the Galaxy Evolution Explorer (GALEX) GR3 photometric data in far‐ultraviolet (FUV) and near‐ultraviolet (NUV) passbands combined with SDSS DR5 data. We found that dS0s as well as peculiar dEs (dEs with blue center and disk) found by Lisker et al. (2006a, b) show distinct locus from that of ordinary dEs in UV CMRs. The dS0s and peculiar dEs have bluer UV colors than ordinary dEs at a fixed optical luminosity. Furthermore, UV colors of dEs in outer region of the cluster are systematically bluer than those in inner region. Since UV flux is sensitive to the presence of young stellar population from recent star formation activity, our results suggest that there are different star formation histories among different subsample of early‐type dwarf galaxies in Virgo cluster concerning their morphology and environmental effect (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How to disentangle the group of dwarf elliptical galaxies in the Virgo cluster
Authors: Gotthart T. , Jäger M. , Hensler G. , Zeilinger W.W. , Boselli A.
Published: November 2009

A sample of early‐type dwarf galaxies of the Virgo cluster extracted from the Sloan Digital Sky Survey is analyzed to search for two different populations: galaxies which were formed in the cluster and galaxies which were accreted at a later stage and which were stripped during this process. Photometric and spectroscopic data has been used for the analysis. Due to the low signal‐to‐noise ratios of the data, the results are however inconclusive (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncover the conserved property underlying sequence‐distant and structure‐similar proteins
Authors: Gao Jun , Li Zhijun
Published: November 2009

It is widely accepted that a protein's sequence determines its structure. The surprising finding that proteins of distant sequence can adopt similar 3D structures has raised interesting questions regarding underlying conserved properties that are essential for protein folding and stability. Uncovering the conserved properties may shed light on the folding mechanism of proteins and help with the development of computational tools for protein structure prediction. We compiled and analyzed a structure pair dataset of 66 high‐resolution and low sequence identity (16–38%) soluble proteins. Structure deviation for each pair was confirmed by calculating its Cα SiMax value and comparing its potential energy per residue. Analysis of favorable inter‐residue interactions for each structure pair indicated that the average number of inter‐residue interactions within each structure represents a conserved feature of homologous structures of distant sequence. Detailed comparison of individual types of interactions showed that the average number of either hydrophobic or hydrogen bonding interactions remains unchanged for each structure pair. These findings should be of help to improving the quality of homology models based on templates of low sequence identity, thus broadening the application of homology modeling techniques for protein studies. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 340–347, 2010.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Computational Study of the Lipase‐Mediated Desymmetrisation of 2‐Substituted‐Propane‐1,3‐Diamines
Authors: García‐Urdiales Eduardo , Busto Eduardo , Ríos‐Lombardía Nicolás , Gotor‐Fernández Vicente , Gotor Vicente
Published: November 2009

The enantioselectivity displayed by the lipase from Pseudomonas cepacia towards a wide range of prochiral 2‐substituted‐propane‐1,3‐diamines was studied by means of molecular dynamics simulations (MDS). In all cases the enzyme allows the recovery of the corresponding amino carbamates of R configuration. However, the enantioselectivity is only synthetically useful if no ortho substituent is present and the aromatic ring is directly bonded to the 2‐carbon of the 1,3‐diamine core. Analysis of the MDS trajectories revealed that the homologation of 2‐aryl substituents by means of a methylene group lowers enantioselectivity by alleviating the conformational tension of the slow‐reacting orientations due to unfavourable intramolecular contacts between the ortho carbons of the aryl group and the nucleophilic nitrogen, as well as between the chiral carbon and the oxyanion. Additionally, the relative solvent accessible surfaces of the atoms of the aryl ring nicely correlate with the effect of the location of the substituent on enantioselectivity.
An animal model for chemotherapy‐associated steatohepatitis and its prevention by the oral administration of fatty acid bile acid conjugate
Authors: Keizman Daniel , Maimon Natalie , Ish‐Shalom Maya , Buchbut Dana , Inbar Moshe , Klein Baruch , Bernheim Joelle , Goldiner Ilana , Leikin‐Frenkel Alicia , Konikoff Fred
Published: November 2009

BACKGROUND:

Preoperative chemotherapy for hepatic resection of colorectal liver metastases is associated with the development of chemotherapy‐associated steatohepatitis (CASH). This increases the risk of perioperative morbidity and mortality. To the authors' knowledge, an animal model for CASH has not been described previously. It has been established that fatty acid bile acid conjugates (FABACs) prevent the formation of diet‐induced fatty liver. The current study was designed to establish an animal model of CASH and to use that model to study the effect of FABACs on its occurrence.

METHODS:

C57BL/6 mice were given different doses of oxaliplatin and irinotecan. Oxaliplatin administered once weekly at a dose of 6 mg/kg for a total dose of 24 mg/kg was tolerated best and was associated most consistently with CASH. Thus, that dose was chosen as the induction model for CASH. Subsequently, mice were divided into a control group (no treatment), an oxaliplatin group, and a CASH‐prevention group, which received oxaliplatin and C20‐FABAC at a dose of 150 mg/kg daily. The animals were killed after 28 days.

RESULTS:

Liver fat content was significantly lower (P < .0001) in the control group (51.63 mg/g) and the prevention group (62.13 mg/g) compared with the oxaliplatin group (95.35 mg/g). This difference was mainly because of the accumulation of liver triglycerides in the oxaliplatin group.

CONCLUSIONS:

The current results indicated that C57BL/6 mice receiving weekly oxaliplatin can be used as a model for CASH. Oral FABAC therapy reduced the development of CASH in animals that received oxaliplatin. To the authors' knowledge, this report is the first description of a model and a potential preventive treatment for CASH. Cancer 2010. © 2010 American Cancer Society.
Reduced microRNA‐218 expression is associated with high nuclear factor kappa B activation in gastric cancer
Authors: Gao Caiping , Zhang Zhiyu , Liu Wenzhong , Xiao Shudong , Gu Weiqi , Lu Hong
Published: November 2009

BACKGROUND:

Poor expression of microRNAs (miRs) reportedly plays an important role in gastric carcinogenesis. Large‐scale microarray assays have indicated that there is significant down‐regulation of miR‐218 in gastric cancer. miR‐218 also was decreased specifically in human papillomavirus‐positive cell lines, cervical lesions, and cervical cancer tissues and in bronchial airway epithelium in smokers. However, its role in carcinogenesis remains unclear, especially in Helicobacter pylori (H. pylori)‐associated gastric cancer.

METHODS:

miR‐218 levels were evaluated in 20 noncardia gastric cancer tissues, in 10 H. pylori‐infected and 8 uninfected normal gastric biopsies, and in the human gastric epithelial cancer cell line AGS using TaqMan quantitative real‐time polymerase chain reaction analysis. Pre‐miR‐218 and anti‐miR‐218 inhibitors were used to examine the effects of miR‐218 expression on cell proliferation and apoptosis. A luciferase reporter assay was used to examine the potential target genes and related pathways.

RESULTS:

miR‐218 expression was reduced significantly in gastric cancer tissues, in H. pylori‐infected gastric mucosa, and in H. pylori‐infected AGS cells. Overexpression of miR‐218 inhibited cell proliferation and increased apoptosis in vitro. Epidermal growth factor receptor‐coamplified and overexpressed protein (ECOP), which regulates nuclear factor kappa B (NF‐κB) transcriptional activity and is associated with apoptotic response, was a direct target of miR‐218. Overexpression of miR‐218 also inhibited NF‐κB transcriptional activation and transcription of cyclooxygenase ‐2, a proliferative gene regulated by NF‐κB.

CONCLUSIONS:

H. pylori infection resulted in a decrease in miR‐218 expression. The down‐regulation of miR‐218 has the potential to increase carcinogenesis by losing control of its targets, and it may be correlated with the high transcriptional activity of NF‐κB that results from H. pylori infection. Cancer 2010. © 2010 American Cancer Society.
Solvothermal Synthesis and Characterization of Hierarchically Nanostructured Hydroxyapatite Hollow Spheres
Authors: Ma Ming‐Guo , Zhu Jie‐Fang
Published: November 2009

Hierarchically nanostructured hydroxyapatite (HA) hollow spheres assembled from nanorods have been successfully synthesized using CaCl2, NaH2PO4, and potassium sodium tartrate via a solvothermal method at 200 °C for 24 h in water/N,N‐dimethylformamide (DMF) mixed solvents. The ratio of water to DMF plays a key role in the formation of hierarchically nanostructured HA hollow spheres. The potassium sodium tartrate was used as a chelating ligand and a template molecule in the synthesis and self‐assembly of HA nanorods. The products were characterized by X‐ray powder diffraction, and field‐emission scanning electron microscopy (FESEM), transmission electron microscopy, high‐resolution transmission electron microscopy (HRTEM), energy‐dispersive X‐ray spectra (EDS), Brunauer–Emmett–Teller (BET), and Fourier transform infrared spectrometry. FESEM and TEM images indicated that hollow spheres of about 3.6 μm in diameter were built by HA nanorods. On the basis of experimental results, a possible formation mechanism of these hierarchically nanostructured HA hollow spheres in the growth processes was proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Rotationally Restricted and Modular Biphenyl Building Blocks
Authors: Vonlanthen David , Rotzler Jürgen , Neuburger Markus , Mayor Marcel
Published: November 2009

A series of modular biphenyl building blocks with stepwise adjusted torsion angles and terminally functionalized with leaving groups have been synthesized. The two phenyl rings of the biphenyl synthon are clamped by alkyl chains of various lengths. The desired building blocks 3 and 4 were obtained by copper‐mediated C–C biaryl coupling reactions followed by the construction of interlinking alkyl bridges. The key intermediates 14 and 15 were transformed into the corresponding cycloheptadienones 16 and 17, which were reduced to the desired propyl‐bridged biphenyls 3b and 3c. The butyl‐bridged derivatives 4b and 4c were obtained from 14 and 15 by an allylation reaction followed by ring‐closing metathesis (RCM) and hydrogenation. The pentyl chain in precursor 24 was obtained by two aldol C–C bond‐forming reactions followed by a sequence of reduction steps. It was subsequently cyclized in an aryl–aryl coupling reaction to the pentyl‐bridged biphenyl 26 along with the macrocyclic dimer 25. The UV absorption spectra of the acetylsulfanyl‐functionalized series 1a–8a were recorded and analyzed: A linear correlation between the conjugation band in the UV absorption spectra and the cos2 Φ values (Φ is the interplanar torsion angle) is observed.
Highly Efficient Fluorine‐Promoted Intramolecular Condensation of Benzo[c]phenanthrene: A New Prospective on Direct Fullerene Synthesis
Authors: Amsharov Konstantin Yu. , Kabdulov Mikhail A. , Jansen Martin
Published: November 2009

Various functional groups have been tested as alternative promoters of the intramolecular condensation of benzo[c]phenanthrene under flash vacuum pyrolysis conditions. Methyl and fluorine functionalization were found to be promising approaches. Unexpectedly high selectivity was observed in the cyclization of fluorinated benzo[c]phenanthrenes. The mechanism for the condensation reaction and the advantages of fluorine as a promoter for the rational synthesis of fullerenes are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)