Kinetic Model for Layer-by-Layer Crystal Growth in Chain Molecules

A kinetic model is proposed to describe the structure and rate of advancement of the growth front during crystallization. Solidification occurs through the mechanisms of surface nucleation and lateral spreading of the solid phase within layers in the vicinity of the growth front. The transformation from liquid to solid within each layer is described by an equation similar to the two-dimensional variant of the Johnson–Mehl–Avrami (JMA) equation, but in which the finite size and shape of the critical nucleus and the dynamic evolution of the solid fraction of the underlying layers are taken into account. Connection to the regime theory of Hoffman and co-workers, for surface nucleation and spreading in one or two dimensions, is also made. Given only molecular level information regarding surface nucleation rates, lateral spreading rates, and critical surface nucleus geometry, the resulting set of coupled nonlinear equations for solidification in each layer is numerically integrated in time to obtain the structure and rate of advancement of the growth front, for arbitrarily large systems and long times. Using this kinetic model with input parameters obtained from molecular dynamics simulations, a multiscale modeling analysis of crystal growth in n-pentacontane (C50) is performed.National Science Foundation (U.S.) Division of Civil, Mechanical and Manufacturing Innovation (CMMI-1235109

Reinforcement of graphene nanoplatelets on plasticized poly (lactic acid) nanocomposites: mechanical, thermal, morphology, and antibacterial properties

Plasticized poly(lactic acid) (PLA)‐based nanocomposites filled with graphene nanoplatelets (xGnP) and containing poly(ethylene glycol) (PEG) and epoxidized palm oil (EPO) with ratio 2 : 1 (2P : 1E) as hybrid plasticizer were prepared by melt blending method. The key objective is to take advantage of plasticization to increase the material ductility while preserving valuable stiffness, strength, and toughness via addition of xGnP. The tensile modulus of PLA/2P : 1E/0.1 wt % xGnP was substantially improved (30%) with strength and elasticity maintained, as compared to plasticized PLA. TGA analysis revealed that the xGnP was capable of acting as barrier to reduce thermal diffusion across the plasticized PLA matrix, and thus enhanced thermal stability of the plasticized PLA. Incorporation of xGnP also enhanced antimicrobial activity of nanocomposites toward Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes

Plasticized poly(lactic acid) with low molecular weight poly(ethylene glycol) : mechanical, thermal, and morphology properties

Poly(lactic acid) PLA was plasticized with low molecular weight poly(ethylene glycol) PEG-200 to improve the ductility of PLA, while maintaining the plasticizer content at maximum 10 wt%. Low molecular weight of PEG enables increased miscibility with PLA and more efficient reduction of glass transition temperature (Tg). This effect is enhanced not only by the low molecular weight but also by its higher content. The tensile properties demonstrated that the addition of PEG-200 to PLA led to an increase of elongation at break (>7000%), but a decrease of both tensile strength and tensile modulus. The plasticization of the PLA with PEG-200 effectively lowers Tg as well as cold-crystallization temperature, increasing with plasticizer content. SEM micrographs reveal plastic deformation and few long threads of a deformed material are discernible on the fracture surface. The use of low molecular weight PEG-200 reduces the intermolecular force and increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA

Differences in carotid artery atherosclerosis between men and women in the early phase after ischemic event

Objectives There is little data about sex differences in carotid atherosclerosis in the early phase after an ischemic event. The aim of this study was to examine the carotid artery atherosclerosis differences between men and women in early phase after TIA or stroke. Methods Consecutive patients with recent ischemic event, admitted during the first week after symptom onset were examined with ultrasound. Sex differences in degree of stenosis, number of plaques and plaque morphology were compared. Plaque morphology was assessed by gray-scale median (GSM), according to which lower values were associated with hemorrhagic/necrotic core indicating plaque instability. Results Of the 316 patients with ischemic events, 196 (50.5% male) entered the study. Men had more often moderate as well as severe ipsilateral carotid stenosis (12.1% vs 7.2% for moderate and 12.1% vs 2.1% for severe; p=0.024). Men had more often the largest plaque hypoechogenic contralateral (62.6% vs 37.1%, p=0.0008), but not ipsilateral. Men had 3 or more hypoechogenic plaques (24.2% vs 4.1%, p=0.0001; 17.2% vs 4.1%, p<0.0001) both ipsi and contralateral respectively. Male sex was a risk factor for having 3 or more ipsilateral hypoechogenic plaques (p=0.002, OR=20 CI 95% [5.5–75]. Conclusions Men had more often carotid stenosis and higher number of hypoechogenic plaques

An effector-reduced anti-β-amyloid (Aβ) antibody with unique aβ binding properties promotes neuroprotection and glial engulfment of Aβ.

Passive immunization against β-amyloid (Aβ) has become an increasingly desirable strategy as a therapeutic treatment for Alzheimer's disease (AD). However, traditional passive immunization approaches carry the risk of Fcγ receptor-mediated overactivation of microglial cells, which may contribute to an inappropriate proinflammatory response leading to vasogenic edema and cerebral microhemorrhage. Here, we describe the generation of a humanized anti-Aβ monoclonal antibody of an IgG4 isotype, known as MABT5102A (MABT). An IgG4 subclass was selected to reduce the risk of Fcγ receptor-mediated overactivation of microglia. MABT bound with high affinity to multiple forms of Aβ, protected against Aβ1-42 oligomer-induced cytotoxicity, and increased uptake of neurotoxic Aβ oligomers by microglia. Furthermore, MABT-mediated amyloid plaque removal was demonstrated using in vivo live imaging in hAPP((V717I))/PS1 transgenic mice. When compared with a human IgG1 wild-type subclass, containing the same antigen-binding variable domains and with equal binding to Aβ, MABT showed reduced activation of stress-activated p38MAPK (p38 mitogen-activated protein kinase) in microglia and induced less release of the proinflammatory cytokine TNFα. We propose that a humanized IgG4 anti-Aβ antibody that takes advantage of a unique Aβ binding profile, while also possessing reduced effector function, may provide a safer therapeutic alternative for passive immunotherapy for AD. Data from a phase I clinical trial testing MABT is consistent with this hypothesis, showing no signs of vasogenic edema, even in ApoE4 carriers

Die Nachkommen von prominenten Nazis und ihr schweres Erbe

Gegenstand der vorliegenden Arbeit sind die autobiographischen Berichte von Kindern ausgewählter Nazigrößen (Margret Nissen, Richard von Schirach, Rolf Mengele, Barbara Bronnen, Katrin Himmler, Claudia Brunner, Uwe von Seltmann). Die Autoren berichten von ihrer Kindheit, von der Beziehung zu den Eltern und wie sich diese Beziehung im Laufe der Zeit geändert hat. Vor allem ist hier der väterliche Elternteil gemeint, der oft in die Verbrechen des "Dritten Reiches" verstrickt war. Die Analyse der ausgewählten Texte umfasst die Verarbeitung der Erfahrungen von Autoren sowie die Ähnlichkeiten und Unterschiede zwischen den einzelnen Berichten. Anhand der angeführten Beispiele wird das Thema der Arbeit bestätigt, indem die Kinder und Enkel prominenter Nazis ein schweres Erbe zu tragen haben. Schon in ihrer Kindheit, als der väterliche Elternteil entweder verhaftet oder getötet wurde, hatten sie mit vielen Schicksalsschlägen zu kämpfen, indem die ganze Familie mittellos zurückgelassen wurde. Im Erwachsenenleben setzte sich das fort, als sie die Last des eigenen Familiennamens tragen mussten

Economic, Social and Cultural Changes in the Polish Village

Preobražaj agrarne, klasne i socijalno-profesionaine strukture u poljskom selu nakon drugoga svetskog rata uslovljen .je, pre svega, društveno-političkim promenama i intenzivnim procesom industrijalizacije i urbanizacije zemlje. Promene u agraru nastale su provedbom poljoprivredne reforme koja je obuhvatila četiri važna problema: zemlja seljaka (društvena struktura seljaka i njihov socijalno-politički status), poljoprivreda i odnos sela i grada, odnosno poljoprivrede i industrije. Razvoj sela nastavlja se i dalje u skladu sa politikom tehničkoga i društvenog preobražaja sela. Posebno se očei<uje poboljšanje agrarne strukture individualne proizvodnje zahvaljujući povećanju površine pojedinih imanja i organizovanju individualnih zemljoradnika u proizvodne kolektive. U vreme izgradnje narodne Poljske došlo je takođe do burnih promena u kulturno-prosvetnom životu seoskog stanovništva. Prvi zadatak nove vlade bio je likvidacija nepismenosti i uspostavljanje obaveznog školovanja za svu decu do četrnaest godina (posle do petnaest godina). I dalje se vodi dosledna politika u oblasti razvoja kulture, usmerena prevazilaženju razlika u razvoju kulture na selu i u gradu. Pojačava se mreža već postojećih biblioteka, bioskopa, domova kulture, klubova i drugih ustanova tog tipa.The transformation of the agrarian, class and socio-professional structure of the Polish village after World War II primarily results from socio-political change and the intense process of industrialization and urbanization that swept over the whole country. Changes in agriculture resulted from the agricultural reform which included four important problems: peasant land, (the social structure of the peasants and their socio-political status), agriculture and the relationship between the village and the town, and between agriculture and industry. The village continues to develop in harmony with the policy of its technological and social transformation. An improvement of the agrarian structure of individual production is especially to be expected thanks to an increase of the area of private farms and the organization of farmers into production collectives. During the development of national Poland there were also great changes in the cultural and educational life of the rural population. The first task of the new government was to get rid of illiteracy and it introduced compulsory education for all children up to the age of 14 (later 15). This consistent policy in the field of cultural development is continuing, and its main aim is to overcome cultural diferences between the village and the town. The already existing network of libraries, cinemas, halls of culture, clubs and other institutions of that type is being expanded

Solution electrospinning and properties of poly(ethylene 2,5-furandicarboxylate) fibers

Abstract: Poly(ethylene 2,5-furandicarboxylate) (PEF) is an attractive bio-based alternative to petroleum-based polymers. In this work, novel PEF-based nonwovens were obtained by the solution electrospinning, using as solvents: trifluoroacetic acid, its mixtures with dichloromethane and dichloroethane, and also 1,1,1,3,3,3-hexafluoro-2-propanol. The effect of the solvent type and PEF concentration on the fiber thickness and the properties of nonwovens was studied. The average thickness of nonwoven fibers ranged from 180 nm to 2.3 μm. The fibers were amorphous with the glass transition temperature of 85–87 °C. The nonwovens were strongly hydrophobic, with water contact angles of 144–146° although they exhibited the rose petal effect. The mechanical properties of the materials were influenced by their porosity and fiber thickness. The nonwoven electrospun from 20 wt% PEF solution in trifluoroacetic acid, with an average fiber diameter of 2.13 μm and a porosity of 74%, exhibited the highest tensile strength and elongation at break, 10.8 MPa and 190%, respectively