bluuebunny/crossref_metadata_2025 huggingface dataset:
Idiopathic granulomatous mastitis, erythema nodosum and bilateral ankle arthritis in an Iranian woman
Authors: Binesh Fariba , Shiryazdi Mostafa , Bagher Owlia Mohammad , Azimi Soheila
Published: January 2013

Here we report a case of idiopathic granulomatous mastitis (IGM) associated with erythema nodosum (EN) and ankle arthritis. The skin, joint and mammary symptoms improved with corticosteroid. Coincidence of granulomatous mastitis, EN and arthritis is a rare feature.
Modeling co-occurring species: a simulation study on the effects of spatial scale for setting management targets
Authors: Dougherty Dawn T. , Hilborn Ray , Punt André E. , Stewart Ian J.
Published: January 2013

Many species of marine fish are found in similar habitats and display similar vulnerability to fishing pressure, although their sustainable exploitation rates may differ considerably. Managing and setting harvest limits is challenging for such co-occurring species because the management targets for the less productive species may affect the fishing opportunities for the more productive species. We used simulation modeling to explore the effects of setting multi-species management targets and harvest regulations at local area or coast-wide levels. Setting management targets over the entire coast, and identifying optimal harvest rates within each local area, consistently led to the same or higher yields than setting management targets for each area. Essentially, the global conservation goal can be achieved by protecting areas in which the less productive species is abundant and by taking most of the harvest from other areas. The increases in yield do not increase the coast-wide probabilities of either species being overfished or severely depleted, but do increase these probabilities at the local area level for the less productive species. These results are magnified with increased spatial variation in the ratio of abundance and differences in intrinsic rates of growth among the fished species.
Use of Molecular Biomarkers to Quantify the Spatial Distribution of Effects of Anticancer Drugs in Solid Tumors
Authors: Saggar Jasdeep K. , Fung Andrea S. , Patel Krupa J. , Tannock Ian F.
Published: January 2013

Poor distribution of anticancer drugs within solid tumors may limit their effectiveness. Here, we characterize the distribution within solid tumors of biomarkers of drug effect. γ-H2AX, cleaved-caspase-3 or -6, and Ki67 were quantified in tumor sections in relation to blood vessels (recognized by CD31) using monoclonal antibodies and immunohistochemistry. To validate their use, we compared their time-dependent distribution with that of (i) fluorescent doxorubicin and (ii) a monoclonal antibody that detects melphalan-induced DNA adducts. The biomarkers were then used to quantify the distribution of docetaxel in relation to tumor blood vessels. Activation of γ-H2AX was evaluated following in vitro exposure of tumor cells to multiple drugs. Distributions of doxorubicin in MDA-MB-231 and MCF-7 xenografts and of melphalan-induced DNA adducts in MCF-7 and EMT-6 tumors decreased with distance from blood vessels, similar to the distributions of (i) γ-H2AX at 10 minutes, (ii) cleaved caspase-3 or -6, and (iii) change in Ki67 at 24 hours following treatment. The distribution of these biomarkers following treatment with docetaxel also decreased with increasing distance from tumor blood vessels. Activation of γ-H2AX occurred within 1 hour after exposure to several drugs in culture. Multiple anticancer drugs show a decrease in activity with increasing distance from tumor blood vessels; poor drug distribution is an important cause of drug resistance. The above biomarkers may be used in designing strategies to overcome therapeutic resistance by modifying or complementing the limited spatial distribution of drug activity in solid tumors. Mol Cancer Ther; 12(4); 542–52. ©2013 AACR.
AML cells are differentially sensitive to chemotherapy treatment in a human xenograft model
Authors: Wunderlich Mark , Mizukawa Benjamin , Chou Fu-Sheng , Sexton Christina , Shrestha Mahesh , Saunthararajah Yogen , Mulloy James C.
Published: January 2013

Key Points

A relevant xenograft chemotherapy model was developed by using standard AML induction therapy drugs and primary human AML patient samples. Human AML cells show significantly increased sensitivity to in vivo chemotherapy treatment compared with murine LSK and total bone marrow cells.
Identification of mimotopes of Mycobacterium leprae as potential diagnostic reagents
Authors: Alban Silvana M , de Moura Juliana Ferreira , Minozzo João Carlos , Mira Marcelo Távora , Soccol Vanete Thomaz
Published: January 2013

Background

An early diagnostic test for detecting infection in leprosy is fundamental for reducing patients’ sequelae. The currently used lepromin is not adequate for disease diagnosis and, so far, no antigen to be used in intradermoreaction has proved to be sensitive and specific for that purpose. Aiming at identifying new reagents to be used in skin tests, candidate antigens were investigated.

Methods

Random peptide phage display libraries were screened by using antibodies from leprosy patients in order to identify peptides as diagnostic reagents.

Results

Seven different phage clones were identified using purified antibodies pooled from sera of leprosy patients. When the clones were tested with serum samples by ELISA, three of them, 5A, 6A and 1B, allowed detecting a larger number of leprosy patients when compared to controls. The corresponding peptides expressed by selected phage clones were chemically synthesized. A pilot study was undertaken to assess the use of peptides in skin tests. The intradermal challenge with peptides in animals previously sensitized with Mycobacterium leprae induced a delayed-type hypersensitivity with peptide 5A (2/5) and peptide 1B (1/5). In positive controls, there was a 3/5 reactivity for lepromin and a 4/5 reactivity of the sensitized animals with soluble extract of M. leprae.

Conclusions

The preliminary data suggest that may be possible to develop reagents with diagnostic potential based on peptide mimotopes selected by phage display using polyclonal human antibodies.
Career choices for cardiology: cohort studies of UK medical graduates
Authors: Smith Fay , Lambert Trevor W , Pitcher Alex , Goldacre Michael J
Published: January 2013

Background

Cardiology is one of the most popular of the hospital medical specialties in the UK. It is also a highly competitive specialty in respect of the availability of higher specialty training posts. Our aims are to describe doctors’ early intentions about seeking careers in cardiology, to report on when decisions about seeking a career in cardiology are made, to compare differences between men and women doctors in the choice of cardiology, and to compare early career choices with later specialty destinations.

Methods

Questionnaire surveys were sent to all UK medical graduates in selected qualification years from 1974–2009, at 1, 3, 5, 7 and 10 years after graduation.

Results

One year after graduation, the percentage of doctors specifying cardiology as their first choice of long-term career rose from the mid-1990s from 2.4% (1993 cohort) to 4.2% (2005 cohort) but then fell back to 2.7% (2009 cohort). Men were more likely to give cardiology as their first choice than women (eg 4.1% of men and 1.9% of women in the 2009 cohort). The percentage of doctors who gave cardiology as their first choice of career declined between years one and five after qualification: the fall was more marked for women. 34% of respondents who specified cardiology as their sole first choice of career one year post-graduation were later working in cardiology. 24% of doctors practising as cardiologists several years after qualification had given cardiology as their sole first choice in year one. The doctors’ ‘domestic circumstances’ were a relatively unimportant influence on specialty choice for aspiring cardiologists, while ‘enthusiasm/commitment’, ‘financial prospects’, ‘experiences of the job so far’ and ‘a particular teacher/department’ were important.

Conclusions

Cardiology grew as a first preference one year after graduation to 2005 but is now falling. It consistently attracts a higher percentage of men than women doctors. The correspondence between early choice and later destination was not particularly strong for cardiology, and was less strong than that for several other specialties.
Gastrointestinal and renal responses to variable water intake in whitebellied sunbirds and New Holland honeyeaters
Authors: Purchase Cromwell , Napier Kathryn R. , Nicolson Susan W. , McWhorter Todd J. , Fleming Patricia A.
Published: January 2013

Nectarivores face a constant challenge in terms of water balance, experiencing water loading or dehydration when switching between food plants or between feeding and fasting. To understand how whitebellied sunbirds and New Holland honeyeaters meet the challenges of varying preformed water load, we used the elimination of Intramuscular-injected [14C]-L-glucose and 3H2O to quantify intestinal and renal water handling on diets varying in sugar concentration. Both sunbirds and honeyeaters showed significant modulation of intestinal water absorption, allowing excess water to be shunted through the intestine on dilute diets. Despite reducing their fractional water absorption, both species showed linear increases in water flux and fractional body water turnover as water intake increased (both afternoon and morning), suggesting that the modulation of fractional water absorption was not sufficient to completely offset dietary water loads. In both species, glomerular filtration rate (GFR) was independent of water gain (but was higher for the afternoon), as was renal fractional water reabsorption (measured in the afternoon). During the natural overnight fast, both sunbirds and honeyeaters arrested whole kidney function. Evaporative water loss in sunbirds was variable but correlated with water gain. Both sunbirds and honeyeaters appear to modulate intestinal water absorption as an important component of water regulation to help deal with massive preformed water loads. Shutting down GFR during the overnight fast is another way of saving energy for osmoregulatory function. Birds maintain osmotic balance on diets varying markedly in preformed water load by varying both intestinal water absorption and excretion through the intestine and kidneys.
Antifreeze proteins in the primary urine of larvae of the beetle Dendroides canadensis (Latreille)
Authors: Nickell Philip K. , Sass Sandra J. , Verleye Dawn M. , Blumenthal Edward M. , Duman John G.
Published: January 2013

To avoid freezing while overwintering beneath the bark of fallen trees, Dendroides canadensis (Coleoptera: Pyrochroidae) larvae produce a family of antifreeze proteins (DAFPs) that are transcribed in specific tissues and have specific compartmental fates. DAFPs and associated thermal hysteresis activity (THA) have been shown previously in hemolymph and midgut fluid, but the presence of DAFPs has not been explored in primary urine, a potentially important site that can contain endogenous ice nucleating compounds that could induce freezing. A maximum mean thermal hysteresis activity of 2.65±0.33°C was observed in primary urine of winter collected D. canadensis larvae. Thermal hysteresis activity in primary urine increased significantly through autumn, peaked in the winter and decreased through spring to levels of 0.2-0.3°C in summer, in a pattern similar to that of hemolymph and midgut fluid. Thermal hysteresis activity was also found in hindgut fluid and excreted rectal fluid suggesting that these larvae not only concentrate AFPs in the hindgut, but also excrete AFPs from the rectal cavity. Based on dafps isolated from Malpighian tubule epithelia, cDNAs were cloned and sequenced, identifying the presence of transcripts encoding 24 DAFP isoforms. Six of these Malpighian tubule DAFPs were known previously, but 18 are new. We also provide functional evidence that DAFPs can inhibit ice nucleators present in insect primary urine. This is potentially critical because D. canadensis larvae die if frozen, and therefore ice formation in any body fluid, including the urine, would be lethal.
Effects of low temperatures on proliferation-related signaling pathways in the hippocampus after traumatic brain injury
Authors: Wang Yang , Guo Fei , Pan Changfu , Lou Yuanlei , Zhang Pengqi , Guo Shangchun , Yin Junhui , Deng Zhifeng
Published: January 2013

To evaluate the influence of low temperatures on the proliferation of neural stem cells (NSCs) and the regulation of their signaling pathways after brain trauma, we examined changes in the expression levels of specific miRNAs and their target genes. We also evaluated NSC proliferation in the hippocampus after brain trauma under low-temperature conditions. We found that the expression profile of miRNAs in the hippocampus after trauma changed at both normal and low temperatures, and the expression of miR-34a decreased significantly lower in rats exposed to low temperatures. There was significant proliferation of endogenous NSCs in the hippocampus after brain trauma at both temperatures, but NSC proliferation was slower at low temperatures. In addition, the expression of Notch1 significantly increased in the hippocampus after brain trauma at both temperatures. However, at low temperatures, the degree of up-regulation of Notch signaling molecules was significantly lower. We conclude that low-temperature environments can inhibit the proliferation of endogenous NSCs in the hippocampus, possibly by alleviating the effects of miR-34a down-regulation and Notch signaling up-regulation induced by traumatic brain injury.
‘Seeing’ is ‘trying’: The relation of visual perception to attemptive modality in the world's languages
Authors: Voinov Vitaly
Published: January 2013

This paper examines the relationship between the concepts of ‘seeing’ and ‘attempting/trying’ in various languages. These concepts have so far been found to be co-lexified in languages spoken in Eurasia, Papua New Guinea, India and West Africa, with an added implicature of politeness present in some languages when this lexical item is used in directives. After establishing a cross-linguistic sample, the paper proposes a specific grammaticalization mechanism as responsible for producing this semantic relationship. The explanation centers on a process involving metaphorical transfer, the loss of semantic features, generalization, and a specific syntactic context conducive to this meaning shift. First, the Mind-as-Body metaphor is applied to the mind-related notion of ‘seeing an object’ to derive the body-related notion of ‘controlling an object’, as has previously been demonstrated to be the case in the history of certain Indo-European languages. Second, semantic bleaching causes the meaning component of physical sight to be lost from the overall meaning of the morpheme, and semantic generalization allows attempted actions to be mentally treated the same as physical objects that are manipulated. Finally, the context in which this meaning shift occurs is posited as constructions involving multiverbs, such as serial verbs or converbs.
Aktive Schwingungsdämpfung eines Weißlichtinterferometers
Authors: Schäfer Patrick , Broschart Daniel , Seewig Jörg
Published: January 2013

In der Oberflächenmesstechnik sind mechanische Umgebungsschwingungen problematisch. Eine aktive Dämpfung von Messgeräten kann aus diesem Grund ein wichtiger Bestandteil für eine hohe Ergebnisgüte sein. Beispielhaft ist hier die praktische Umsetzung der Dämpfung eines Weißlichtinterferometers (WLI) vorgestellt. Als Referenzmessgerät dient ein Quadraturinterferometer (QI), welches die Schwingungen zwischen WLI-Messkopf und Messtisch aufzeichnet. Ein Regelalgorithmus nutzt diese Information um eine Stellgröße zu erzeugen, welche den WLI-Messkopf mit Hilfe eines Piezoelementes stabilisiert.
Messsystem zur Bestimmung akustischer Kenngrößen stark absorbierender, transversal isotroper Kunststoffe
Authors: Rautenberg Jens , Bause Fabian , Henning Bernd
Published: January 2013

Es wird ein wellenleiterbasierter Ansatz zur Bestimmung von Modellparametern für die numerische Simulation der Schallausbreitung in stark absorbierenden, transversal isotropen Kunststoffen vorgestellt. Aufbauend auf einer ersten strahlentheoretischen Schätzung wird innerhalb eines inversen Ansatzes eine multimodale wellentheoretische Simulation der Schallausbreitung im Wellenleiter realisiert.
A Semianalytic Solution for Flow in Finite-Conductivity Vertical Fractures by Use of Fractal Theory
Authors: Cossio M.. , Moridis G.J.. J. , Blasingame T.A.. A.
Published: January 2013

The exploitation of unconventional reservoirs complements the practice of hydraulic fracturing, and with an ever-increasing demand in energy, this practice is set to experience significant growth in the coming years. Sophisticated analytic models are needed to accurately describe fluid flow in a hydraulic fracture, and the problem has been approached from different directions in the past 3 decades—starting with the work of Gringarten et al. (1974) for an infinite-conductivity case, followed by contributions from Cinco-Ley et al. (1978), Lee and Brockenbrough (1986), Ozkan and Raghavan (1991), and Blasingame and Poe (1993) for a finite-conductivity case. This topic remains an active area of research and, for the more-complicated physical scenarios such as multiple transverse fractures in ultratight reservoirs, answers are currently being sought.

Starting with the seminal work of Chang and Yortsos (1990), fractal theory has been successfully applied to pressure-transient testing, although with an emphasis on the effects of natural fractures in pressure/rate behavior. In this paper, we begin by performing a rigorous analytical and numerical study of the fractal diffusivity equation (FDE), and we show that it is more fundamental than the classic linear and radial diffusivity equations. Thus, we combine the FDE with the trilinear flow model (Lee and Brockenbrough 1986), culminating in a new semianalytic solution for flow in a finite-conductivity vertical fracture that we name the “fractal-fracture solution (FFS).” This new solution is instantaneous and comparable in accuracy with the Blasingame and Poe solution (1993). In addition, this is the first time that fractal theory is used in fluid flow in a porous medium to address a problem not related to reservoir heterogeneity. Ultimately, this project is a demonstration of the untapped potential of fractal theory; our approach is flexible, and we believe that the same methodology could be extended to different applications.

One objective of this work is to develop a fast and accurate semianalytical solution for flow in a single vertical fracture that fully penetrates a homogeneous infinite-acting reservoir. This would be the first time that fractal theory is used to study a problem that is not related to naturally fractured reservoirs or reservoir heterogeneity. In addition, as part of the development process, we revisit the fundamentals of fractals in reservoir engineering and show that the underlying FDE possesses some interesting qualities that have not yet been comprehensively addressed in the literature.
Activation of PPARα Ameliorates Hepatic Insulin Resistance and Steatosis in High Fructose–Fed Mice Despite Increased Endoplasmic Reticulum Stress
Authors: Chan Stanley M.H. , Sun Ruo-Qiong , Zeng Xiao-Yi , Choong Zi-Heng , Wang Hao , Watt Matthew J. , Ye Ji-Ming
Published: January 2013

Endoplasmic reticulum (ER) stress is suggested to cause hepatic insulin resistance by increasing de novo lipogenesis (DNL) and directly interfering with insulin signaling through the activation of the c-Jun N-terminal kinase (JNK) and IκB kinase (IKK) pathway. The current study interrogated these two proposed mechanisms in a mouse model of hepatic insulin resistance induced by a high fructose (HFru) diet with the treatment of fenofibrate (FB) 100 mg/kg/day, a peroxisome proliferator–activated receptor α (PPARα) agonist known to reduce lipid accumulation while maintaining elevated DNL in the liver. FB administration completely corrected HFru-induced glucose intolerance, hepatic steatosis, and the impaired hepatic insulin signaling (pAkt and pGSK3β). Of note, both the IRE1/XBP1 and PERK/eIF2α arms of unfolded protein response (UPR) signaling were activated. While retaining the elevated DNL (indicated by the upregulation of SREBP1c, ACC, FAS, and SCD1 and [3H]H2O incorporation into lipids), FB treatment markedly increased fatty acid oxidation (indicated by induction of ACOX1, p-ACC, β-HAD activity, and [14C]palmitate oxidation) and eliminated the accumulation of diacylglycerols (DAGs), which is known to have an impact on insulin signaling. Despite the marked activation of UPR signaling, neither JNK nor IKK appeared to be activated. These findings suggest that lipid accumulation (mainly DAGs), rather than the activation of JNK or IKK, is pivotal for ER stress to cause hepatic insulin resistance. Therefore, by reducing the accumulation of deleterious lipids, activation of PPARα can ameliorate hepatic insulin resistance against increased ER stress.
Carbonised polyaniline and polypyrrole: towards advanced nitrogen-containing carbon materials
Authors: Ćirić-Marjanović Gordana , Pašti Igor , Gavrilov Nemanja , Janošević Aleksandra , Mentus Slavko
Published: January 2013

Polyaniline (PANI) and polypyrrole (PPY) undergo carbonisation in an inert/reduction atmosphere and vacuum, yielding different nitrogen-containing carbon materials. This contribution reviews various procedures for the carbonisation of PANI and PPY precursors, and the characteristics of obtained carbonised PANI (C-PANI) and carbonised PPY (C-PPY). Special attention is paid to the role of synthetic procedures in tailoring the formation of C-PANI and C-PPY nanostructures and nanocomposites. The review considers the importance of scanning and transmission electron microscopies, XPS, FTIR, Raman, NMR, and EPR spectroscopies, electrical conductivity and adsorption/desorption measurements, XRD, and elemental analyses in the characterisation of C-PANIs and C-PPYs. The application of C-PANI and C-PPY in various fields of modern technology is also reviewed.
The Referee as Educator: Hermeneutical and Pedagogical Perspectives
Authors: Isidori Emanuele , Müller Arno , Kaya Sabri
Published: January 2013

Nowadays, in contemporary sports studies scarce attention is devoted to studying the referee and his/her functions in light of the philosophical and pedagogical approach. For this reason, the main aim of this study is to use a hermeneutical philosophic methodology to reflect on the role and functions of this figure, and to show his or her importance in preserving the intrinsic values of sport in front of youth and society. Starting with a historical analysis of the referee and the sport judge in ancient Greek athletics, this study will highlight how such this important figure has always been a key element of competitive sport. This study will demonstrate that refereeing is a practice that needs a specific set of hermeneutical skills and the development of complex pedagogical knowledge and ways of acting. It will also define the concept of “refereeing” in light of a pedagogical approach demonstrating that this practice is, fundamentally, a communicative action implying an ethical and hermeneutical dimension of the referee as a critical-reflective professional committed to enforcing sport’s rules and values. In conclusion, the study will stress the importance of looking at referees and sport judges not as a mere technicians and evaluators of performances in competitions but as educators whose specific knowledge must be developed in all of the courses for their training and education.
The Yin-Yang of DNA Damage Response: Roles in Tumorigenesis and Cellular Senescence
Authors: Li Xiaoman , Xu Hongde , Xu Chongan , Lin Meina , Song Xiaoyu , Yi Fei , Feng Yanling , Coughlan Kathleen , Cho William , Kim Sang , Cao Liu
Published: January 2013

Senescent cells are relatively stable, lacking proliferation capacity yet retaining metabolic activity. In contrast, cancer cells are rather invasive and devastating, with uncontrolled proliferative capacity and resistance to cell death signals. Although tumorigenesis and cellular senescence are seemingly opposite pathological events, they are actually driven by a unified mechanism: DNA damage. Integrity of the DNA damage response (DDR) network can impose a tumorigenesis barrier by navigating abnormal cells to cellular senescence. Compromise of DDR, possibly due to the inactivation of DDR components, may prevent cellular senescence but at the expense of tumor formation. Here we provide an overview of the fundamental role of DDR in tumorigenesis and cellular senescence, under the light of the Yin-Yang concept of Chinese philosophy. Emphasis is placed on discussing DDR outcome in the light of in vivo models. This information is critical as it can help make better decisions for clinical treatments of cancer patients.
Regulation of Phosphatidylethanolamine Homeostasis — The Critical Role of CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2)
Authors: Pavlovic Zvezdan , Bakovic Marica
Published: January 2013

Phosphatidylethanolamine (PE) is the most abundant lipid on the protoplasmatic leaflet of cellular membranes. It has a pivotal role in cellular processes such as membrane fusion, cell cycle regulation, autophagy, and apoptosis. CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme in de novo biosynthesis of PE from ethanolamine and diacylglycerol by the CDP-ethanolamine Kennedy pathway. The following is a summary of the current state of knowledge on Pcyt2 and how splicing and isoform specific differences could lead to variations in functional properties in this family of enzymes. Results from the most recent studies on Pcyt2 transcriptional regulation, promoter function, autophagy, and cell growth regulation are highlighted. Recent data obtained from Pcyt2 knockout mouse models is also presented, demonstrating the essentiality of this gene in embryonic development as well as the major physiological consequences of deletion of one Pcyt2 allele. Those include development of symptoms of the metabolic syndrome such as elevated lipogenesis and lipoprotein secretion, hypertriglyceridemia, liver steatosis, obesity, and insulin resistance. The objective of this review is to elucidate the nature of Pcyt2 regulation by linking its catalytic function with the regulation of lipid and energy homeostasis.
Convergent Overdetermined-RBF-MLPG for Solving Second Order Elliptic PDEs
Authors: Shirzadi Ahmad , Ling Leevan
Published: January 2013

This paper deals with the solvability and the convergence of a class of unsymmetric Meshless Local Petrov-Galerkin (MLPG) method with radial basis function (RBF) kernels generated trial spaces. Local weak-form testings are done with step-functions. It is proved that subject to sufficiently many appropriate testings, solvability of the unsymmetric RBF-MLPG resultant systems can be guaranteed. Moreover, an error analysis shows that this numerical approximation converges at the same rate as found in RBF interpolation. Numerical results (in double precision) give good agreement with the provided theory.
The Role of Education in Transforming the Potential Social Skills of College Students
Authors: New Kuwi Hoi , Abdul Ghafar Mohamed Najib
Published: January 2013

This study advances “transformation” as the role of education in changing individual lives, and offers it as central to a theoretical framework that enables one to understand college education and the development of students in institutions of higher learning. Using a qualitative analytical approach, with in-depth field interviews, this research proposes a model that clarifies the process by which students are transformed into fully potential individuals as a consequence of their college experience. Education transforms both societies and people in a particular direction by shaping and reshaping their patterns of thoughts, means of problem solving and ways of life. This will then contribute to further individual and social transformation. This study finds that the process of education enables significant changes in students by contributing to the social skills that transform their identity and ultimately their society.
Refractometry
Authors: Pepper Randy E. , Samuels Robert J.
Published: January 2013

Polymers are an integral part of our everyday life as they are used in products from clothing to car dashboards, toys to aircraft wings, and hundreds of other products that reflect their high strength, low weight, and manufacturing versatility. To use polymers most efficiently, knowledge of both their processed structure and how that structure affects their performance is required. The processed structure signifies either the molecular orientation in a single‐phase polymer system or the amount and orientation of each phase in a multiphase polymer. One particularly useful and simple technique for quantifying the structural state of a polymer sample is polarized refractometry using an Abbe refractometer. This technique is important because it is nondestructive, inexpensive, simple to use, easy to understand, and generates considerable information about the structural state of the polymer. A partial list of the structural information derivable from the refractive index(es) measured with an Abbe refractometer using polarized monochromatic light includes the three principal refractive indexes (

N
x

,

N
y

, and

N
z

), axiality (isotropic, uniaxial, multiaxial), average refractive index, density, crystallinity, molecular weight, glass‐transition temperature, copolymer composition, and three‐dimensional molecular orientation. This article presents the theory and practical aspects of polarized refractometry along with applications to real polymer systems.
Zwitterionic Polymerization
Authors: Suzuki Masato
Published: January 2013

A zwitterion conducts the polymerization as the key intermediate, which is formed by the reaction between neutral electrophile and nucleophile, or as the monomer itself, which is prepared and isolated before use. The latter case is known in a limited number of articles. On the other hand, a number of examples have been reported for the former case, which is categorized into the following three patterns: (1) Propagation takes place from one site of a zwitterion, accordingly, which is the initiating species to give homopolymer. There is a case that a cyclic polymer is produced by the backbiting. (2) A zwitterion is formed to activate a monomer and reacts with a neutral initiator as well as the same functional group at the polymer terminal for the propagation reaction. In these two patterns, amine, phosphine, orN‐heterocyclic carbene work as the initiator and the activator, respectively. (3) No catalyst copolymerization takes place by the reactions between zeitterionic intermediates, which are produced by the combination of a nucleophilic monomer with an electrophilic monomer. The monomers that appear in these three patterns involve electron‐deficient and electron‐rich olefinic compounds including qiunone and allene, heterocumulenes such as isocyanate and carbon disulfide, and heterocyclic compounds such as lactone, oxirane, amino acidN‐carboxyanhydride, cyclic imino ether, cyclic phosphite, and cyclic phophonite.
Polycondensation
Authors: Higashihara Tomoya , Ueda Mitsuru
Published: January 2013

There are many technological challenges of the twenty‐first century including energy, information, and transportation. During the continuous innovations, polycondensates have been supporting our modern life in the global society. The synthetic methodology of polycondensation allows for a wide variety of available monomers and polymer structures than any other synthetic polymerization technique, which are derived from almost infinite kinds of designing structures in monomers compared to vinyl monomers. In addition, the high performance of specially designed polycondensates (eg, high thermal, chemical, mechanical, and dimensional stability) have provided a breakthrough, especially in material science and industry, as represented by the developments of superengineering plastics, such as wholly aromatic polyamides, polyimides, poly(phenylene ether)s, poly(ether sulfone)s, poly(ether ketone)s, and poly(ether ether ketone)s. Polycondensation chemistry is also used for preparing recent optoelectronic applications including organic electroluminescence, field–effect transistors, organic solar cells, polymer memories, and so forth. This article, details the basic principles of polycondensation and recent advances in polycondensation.
Two‐Dimensional Correlation Spectroscopy: A Polymer‐Related Issue
Authors: Sun Shengtong , Wu Peiyi
Published: January 2013

Two‐dimensional correlation spectroscopy (2DCOS) is a mathematical method whose basic principles were first proposed by Noda in 1986. Up to the present, 2DCOS has been widely used to study spectral variations of different chemical species under various external perturbations (eg, temperature, pressure, concentration, time, electromagnetic). By spreading peaks along a second dimension, 2DCOS can sort out complex or overlapped spectral features and get an enhanced spectral resolution. Owing to the different response of different species to external variable, additional useful information about molecular motions or conformational changes can be extracted, which cannot be obtained directly from conventional one‐dimensional spectra. Perturbation‐correlation moving window (PCMW) is a newly developed technique based on 2DCOS. Except for its original ability in determining transition points, PCMW can additionally monitor complicated spectral variations along the perturbation direction. In this critical review, we focus on the application of 2DCOS and PCMW to the characterization of polymers, which are classified in six specific topics: synthetic functional polymers, bio‐ and natural polymers, glass transition, crystallization and melting of polymers, water diffusion in polymer films, polymer blends and nanocomposites, and polymer‐related reactions.
Discovery and Evaluation of a Functional Ternary Polymer Blend for Bone Repair: Translation from a Microarray to a Clinical Model
Authors: Khan Ferdous , Smith James O. , Kanczler Janos M. , Tare Rahul. S. , Oreffo Richard O.C. , Bradley Mark
Published: January 2013

Skeletal tissue regeneration is often required following trauma, where substantial bone or cartilage loss may be encountered and is a significant driver for the development of biomaterials with a defined 3D structural network. Solvent blending is a process that avoids complications associated with conventional thermal or mechanical polymer blending or synthesis, opening up large areas of chemical and physical space, while potentially simplifying regulatory pathways towards in vivo application. Here ternary mixtures of natural and synthetic polymers were solvent blended and evaluated as potential bone tissue engineering matrices for osteoregeneration by the assessment of growth and differentiation of STRO‐1+ skeletal stem cells. Several of the blend materials were found to be excellent supports for human bone marrow‐derived STRO‐1+ skeletal cells and fetal skeletal cells, with the optimized blend exhibiting in vivo osteogenic potential, suggesting that these polymer blends could act as suitable matrices for bioengineering of hard tissues.
Ligandless Copper‐Catalyzed Coupling of Heteroaryl Bromides with Gaseous Ammonia
Authors: Fantasia Serena , Windisch Johannes , Scalone Michelangelo
Published: January 2013

A range of different N‐ and S‐containing heterocyclic bromides can be efficiently coupled with gaseous ammonia in the presence of copper(II) acetylacetonate [Cu(acac)2] as catalyst and in the absence of additional ligands. Unstable aminothiophenes and aminobenzothiophenes can be further reacted in situ to afford functionalized derivatives.
An Efficient and Reliable Procedure for the Preparation of Highly Reactive Rieke Zinc
Authors: Kudret Suleyman , Haen Jan D‘ , Lutsen Laurence , Vanderzande Dirk , Maes Wouter
Published: January 2013

Rieke zinc has a wide potential for applications in organic chemistry, notably for the synthesis of highly chemoselective organozinc reagents. However, due to the rather unreliable preparation method, leading to large batch to batch variations, its use has been rather limited. Rieke zinc is commonly prepared by the reduction of zinc chloride with lithium using a stoichiometric amount of naphthalene. In our hands, it was observed that the reaction outcome was highly dependent on the naphthalene source and purity grade. The presence of benzothiophene seems crucial to avoid coagulation of the zinc particles and the amount of benzothiophene has a large effect on the physical properties and the reactivity of the resulting zinc powder. Accordingly, highly reactive Rieke zinc was easily prepared from zinc chloride by adding an optimum amount (3 mol% with regard to ZnCl2) of benzothiophene into the lithium naphthalenide solution (prepared in situ). The Rieke zinc obtained in this way was successfully employed in the so‐called “Rieke method” to prepare regioregular poly(3‐hexylthiophene) (P3HT). The novel approach enables preparation of Rieke zinc in a reproducible manner, which considerably facilitates its use in both small molecule and polymer synthesis.
The evolutionary paradox and the missing heritability of schizophrenia
Authors: van Dongen Jenny , Boomsma Dorret I.
Published: January 2013

Schizophrenia is one of the most detrimental common psychiatric disorders, occurring at a prevalence of approximately 1%, and characterized by increased mortality and reduced reproduction, especially in men. The heritability has been estimated around 70% and the genome‐wide association meta‐analyses conducted by the Psychiatric Genomics Consortium have been successful at identifying an increasing number of risk loci. Various theories have been proposed to explain why genetic variants that predispose to schizophrenia persist in the population, despite the fitness reduction in affected individuals, a question known as the evolutionary paradox. In this review, we consider evolutionary perspectives of schizophrenia and of the empirical evidence that may support these perspectives. Proposed evolutionary explanations include balancing selection, fitness trade‐offs, fluctuating environments, sexual selection, mutation‐selection balance and genomic conflicts. We address the expectations about the genetic architecture of schizophrenia that are predicted by different evolutionary scenarios and discuss the implications for genetic studies. Several potential sources of “missing” heritability, including gene–environment interactions, epigenetic variation, and rare genetic variation are examined from an evolutionary perspective. A better understanding of evolutionary history may provide valuable clues to the genetic architecture of schizophrenia and other psychiatric disorders, which is highly relevant to genetic studies that aim to detect genetic risk variants. © 2013 Wiley Periodicals, Inc.
Molecular Basis for Sequence‐Dependent Induced DNA Bending
Authors: Rettig Michael , Germann Markus W. , Wang Shuo , Wilson W. David
Published: January 2013

With a growing understanding of the microstructural variations of DNA, it has become apparent that subtle conformational features are essential for specific DNA molecular recognition and function. DNA containing an A‐tract has a narrow minor groove and a globally bent conformation but the structural features of alternating AT DNA are less well understood. Several studies indicate that alternating AT sequences are polymorphic with different global and local properties from A‐tracts. The mobility of alternating AT DNA in gel electrophoresis is extensively reduced upon binding with minor‐groove binding agents such as netropsin. Although this suggests that such complexes are bent, similarly to A‐tract DNA, direct evidence and structural information on AT DNA and the induced conformational change is lacking. We have used NMR spectroscopy and residual dipolar coupling together with restrained molecular‐dynamics simulations to determine the solution structures of an alternating AT DNA segment, with and without netropsin, in order to evaluate the molecular basis of the binding‐induced effects. Complex formation causes a significant narrowing of the minor groove and a pronounced change in bending, from a slight bend towards the major groove for the free DNA to a pronounced bend towards the minor groove in the complex. This observation demonstrates that conformational features and the inherent malleability of AT sequences are essential for specific molecular recognition and function. These results take the field of DNA structures into new areas while opening up avenues to target novel DNA sequences.
Control of the Helical Chirality of Enantiopure Sulfinyl (Z)‐Azobenzene‐Based Photoswitches
Authors: Núñez Irene , Merino Estíbaliz , Lecea Mercedes , Pieraccini Silvia , Spada Gian Piero , Rosini Carlo , Mazzeo Giuseppe , Ribagorda María , Carreño M. Carmen
Published: January 2013

A new class of enantiopure ortho,ortho‐disubstituted azobenzene photoswitches has been synthesized from (S)‐2‐(p‐tolylsulfinyl)benzoquinone and arylhydrazines. The sulfoxide acts as a unidirectional controller of the helical chirality that arises in the Z isomer after photoisomerization. Highly congested E‐azobenzenes 5 c showed two atropisomeric diastereoconformers in the solid state that converged upon irradiation into a unique Z isomer with defined helicity (M), as evident in the X‐ray structure. The chiroptical properties of this three‐state enantiopure switch can be externally tuned both photochemically and/or thermally. Theoretical CD spectra calculated by using time‐dependent DFT methods support the existence of two atropoisomeric E isomers and only one Z isomer with (M) helicity. Complementary to the classical azobenzene‐based switches, the photoswiching event is promoted under green/blue light and do not occur under UV irradiation.
Efficient Stacking on Protein Amide Fragments
Authors: Harder Michael , Kuhn Bernd , Diederich François
Published: January 2013

The less polar π‐surface of protein amide groups is exposed in many receptor binding sites, either as part of the backbone or in Gln/Asn side chains. Using quantum chemical calculations and Protein Data Bank (PDB) searches on model systems, we investigate the energetics and geometric preferences for the stacking on amide groups of a large number of heteroarenes that are relevant to medicinal chemistry. From this study, we discern that the stacking energy of an aromatic ligand substituent can be improved by: 1) orienting the fragment dipole vector such that it is aligned in an antiparallel fashion with the dipole of the interacting protein amide group, 2) increasing its dipole moment, and 3) decreasing its π‐electron density. These guidelines should be helpful to more rationally exploit this interaction type in future structure‐based drug design.
Three‐Component (Domino) Reaction Affording Substituted Pyrroloquinazolines: Cyclization Regioselectivity and Stereoselectivity
Authors: Paleta Oldřich , Dolenský Bohumil , Paleček Jiří , Kvíčala Jaroslav
Published: January 2013

The cyclization involving 2‐(aminomethyl)aniline, methyl 3,3,3‐trifluoropyruvate, and various oxo compound afforded linearly annulated pyrroloquinazolines, for example, (2R*,3aS*)‐2‐hydroxy‐3a‐phenyl‐2‐trifluoromethyl‐3,3a,4,9‐tetrahydropyrrolo[2,1‐b]quinazolin‐1(2H)‐one (cis‐8), as the major product, possessing the skeleton of the alkaloids of the vasicine group, along with angularly annulated products, for example, (2S*,3aR*)‐2‐hydroxy‐3a‐phenyl‐2‐trifluoromethyl‐3,3a,4,5‐tetrahydropyrrolo[1,2‐a]quinazolin‐1(2H)‐one(cis‐18). The effects of the nature of the oxo compound and the temperature on the ratio of the linear and angular cyclization products, as well as the diastereoselectivity of the product formation, were studied, with an increase in temperature leading to improved selectivity. Some of the linear pyrroloquinazolines were stereoselectively didehydrogenated at the quinazoline ring by the trifluoropyruvate.
Dielectrophoresis of lambda‐DNA using 3D carbon electrodes
Authors: Martinez‐Duarte Rodrigo , Camacho‐Alanis Fernanda , Renaud Philippe , Ros Alexandra
Published: January 2013

Carbon electrodes have recently been introduced as an alternative to metal electrodes and insulator structures for dielectrophoretic applications. Here, an experimental and theoretical study employing an array of 3D carbon electrodes contained in a microfluidic channel for the dielectrophoretic manipulation of DNA is presented. First evidence that carbon‐electrode DEP can be used for the manipulation and trapping of biomolecules such as DNA is reported. In particular, the dielectrophoretic response of λ‐DNA (48.5 kbp) under various frequencies and flow conditions necessary for retention of λ‐DNA are studied. Negative DEP is observed at frequencies above 75 kHz and positive DEP is present in the range below 75 kHz and down to 5 kHz. We further implement a theoretical model to capture the experimental findings in sufficient detail. Our theoretical considerations based on reported scaling laws for linear and supercoiled DNA further suggest that carbon‐electrode DEP devices could be employed in future analytical applications such as DNA preconcentration and fractionation.
The performance of grass filter strips in controlling high‐concentration suspended sediment from overland flow under rainfall/non‐rainfall conditions
Authors: Ma Lan , Pan Chengzhong , Teng Yanguo , Shangguan Zhouping
Published: January 2013

There is little information on the performance of vegetative filter strips (VFS) in filtering high‐concentration sediment from subcritical overland flow. Flume experiments on simulated grass strips were conducted using combinations of three slope gradients (3°, 9° and 15°), five 1‐m‐wide slope positions (from upslope to downslope), two flow rates (60 and 20 L min‐1 m‐1) and sediment concentrations of 100–300 kg m‐3 under simulated rainfall and non‐rainfall conditions. The results showed that sediment deposition efficiency increased with VFS width as a power function. Rainfall significantly reduced sediment deposited within VFS. Higher sediment concentration corresponded to a larger sediment deposition load but reduced deposition efficiency. Flow rate had a negative effect on deposition efficiency but no effect on deposition load. Sediments were more easily deposited at the upper slope position than downslope, and the upper slope position had a higher percentage of coarse sediments. The deposited sediment had significantly greater median diameters (D50) than the inflow sediment. A greater proportion of coarse sediments larger than 25 µm in diameter were deposited, and particles smaller than 1 µm and of 10–25 µm had a better deposition performance than particles of 1–10 µm. Rainfall reduced the deposited sediment D50 at a slope gradient of 3° and had no significant influence on it at 9° or 15°. A higher sediment concentration led to a smaller D50 of the deposited sediment. Rainfall had no significant effect on overland flow velocity. Both the deposited sediment load and D50 decreased with increasing flow velocity, and flow velocity was the most sensitive factor impacting sediment deposition. The results from this study should be useful to control sediment flowing into rivers in areas with serious soil erosion. Copyright © 2013 John Wiley & Sons, Ltd.