cssi/SciSciGPT-SciSciNet huggingface dataset:
Conformational Transition between Four and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction.

Alpha-helical coiled coils play a crucial role in mediating specific protein–protein interactions. However, the rules and mechanisms that govern helix–helix association in coiled coils remain incompletely understood. Here we have engineered a seven heptad “Phe-zipper” protein (Phe-14) with phenylalanine residues at all 14 hydrophobic a and d positions, and generated a further variant (Phe-14M) in which a single core Phe residue is substituted with Met. Phe-14 forms a discrete α-helical pentamer in aqueous solution, while Phe-14M folds into a tetrameric helical structure. X-ray crystal structures reveal that in both the tetramer and the pentamer the a and d side-chains interlock in a classical knobs-into-holes packing to produce parallel coiled-coil structures enclosing large tubular cavities. However, the presence of the Met residue in the apolar interface of the tetramer markedly alters its local coiled-coil conformation and superhelical geometry. Thus, short-range interactions involving the Met side-chain serve to preferentially select for tetramer formation, either by inhibiting a nucleation step essential for pentamer folding or by abrogating an intermediate required to form the pentamer. Although specific trigger sequences have not been clearly identified in dimeric coiled coils, higher-order coiled coils, as well as other oligomeric multi-protein complexes, may require such sequences to nucleate and direct their assembly.
Leakage of Microwave Ovens.

Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment investigates leaked electromagnetic radiation from microwave ovens. We compare the data that are obtained to national standards in order to relate the fields of physics, health and engineering. The experiment is designed to provide for added enquiry and stimulation of thought-provoking questions.
A functional and structural study of troponin C mutations related to hypertrophic cardiomyopathy.

Recently four new hypertrophic cardiomyopathy mutations in cardiac troponin C (cTnC) (A8V, C84Y, E134D, and D145E) were reported, and their effects on the Ca2+ sensitivity of force development were evaluated (Landstrom, A. P., Parvatiyar, M. S., Pinto, J. R., Marquardt, M. L., Bos, J. M., Tester, D. J., Ommen, S. R., Potter, J. D., and Ackerman, M. J. (2008) J. Mol. Cell. Cardiol. 45, 281–288). We performed actomyosin ATPase and spectroscopic solution studies to investigate the molecular properties of these mutations. Actomyosin ATPase activity was measured as a function of [Ca2+] utilizing reconstituted thin filaments (TFs) with 50% mutant and 50% wild type (WT) and 100% mutant cardiac troponin (cTn) complexes: A8V, C84Y, and D145E increased the Ca2+ sensitivity with only A8V demonstrating lowered Ca2+ sensitization at the 50% ratio when compared with 100%; E134D was the same as WT at both ratios. Of these four mutants, only D145E showed increased ATPase activation in the presence of Ca2+. None of the mutants affected ATPase inhibition or the binding of cTn to the TF measured by co-sedimentation. Only D145E increased the Ca2+ affinity of site II measured by 2-(4′-(2″-iodoacetamido)phenyl)aminonaphthalene-6-sulfonic acid fluorescence in isolated cTnC or the cTn complex. In the presence of the TF, only A8V was further sensitized to Ca2+. Circular dichroism measurements in different metal-bound states of the isolated cTnCs showed changes in the secondary structure of A8V, C84Y, and D145E, whereas E134D was the same as WT. PyMol modeling of each cTnC mutant within the cTn complex revealed potential for local changes in the tertiary structure of A8V, C84Y, and D145E. Our results indicate that 1) three of the hypertrophic cardiomyopathy cTnC mutants increased the Ca2+ sensitivity of the myofilament; 2) the effects of the mutations on the Ca2+ affinity of isolated cTnC, cTn, and TF are not sufficient to explain the large Ca2+ sensitivity changes seen in reconstituted and fiber assays; and 3) changes in the secondary structure of the cTnC mutants may contribute to modified protein-protein interactions along the sarcomere lattice disrupting the coupling between the cross-bridge and Ca2+ binding to cTnC.
Should Sensitive Information From Clinical Trials Be Included in Electronic Medical Records

Medical institutions are rapidly moving to ward electronic medical records (EMRs) because of regulatory pressures and perceived benefits in efficiency and quality of patient care. The federal stimulus bill of 2009 included $36 billion to incentivize medical institutions to adopt EMRs, and President Obama has declared it a goal that every patient have an EMR by 2014.1
Social development in nursery-reared pigtailed macaques (Macaca nemestrina)

The social development of 240 nursery-reared pigtailed macaques (Macaca nemestrina) was studied from postnatal weeks 4 to 32. The objectives of the study were to document developmental trends and evaluate social behavior in laboratory-reared M. nemestrina raised at the University of Washington Infant Primate Laboratory, and to identify husbandry factors that might affect early social development. Only infants who had not undergone invasive postnatal experimental manipulation and had no chronic illness or injuries were included in the study. Infants were separated from their mothers and housed singly, but had access to peers for 30 min a day, 5 days a week, in a large playroom. Play and social behaviors emerged early in development, increased during the developmental period studied and occupied a large portion of the infants' time budgets. Although disturbance behaviors occurred with some frequency and duration early in development, they occupied a very small portion of the infants' time budget at 8 months of age. Weaning from infant formula at 16-19 weeks retarded development of play behavior. Permanent removal of a cloth comforter (diaper) during weeks 20-24 had no long-term behavioral effects. It was concluded that at 8 months of age these infants showed relatively normal species-typical behavioral repertoires.
SIGNIFICANCE OF THE ATRIAL CONTRIBUTION TO VENTRICULAR FILLING.

Abstract The contributions of atrial systole to ventricular filling are emphasized by analyses of pressure curve data in (1) patients with complete heart block studied by right and left heart catheterization, (2) patients with sinus rhythm and atrial fibrillation and (3) sinus rhythm and ventricular premature beats. The level of systolic and diastolic right and left heart pressures varies with the temporal relation between the P and QRS complexes in patients with complete heart block. Peak pressures are recorded when there is a normal temporal relation between the P and QRS complexes. The rate of rise of the systemic arterial pressure curve is also at a maximum when the normal P-QRS relation is maintained. Comparison of left ventricular and systemic arterial pressures during sinus rhythm and ventricular premature beats demonstrates higher systolic peak pressures during sinus rhythm with normal atrioventricular conduction; of equal importance is the observation that left ventricular end-diastolic pressures are higher during sinus rhythm than during a series of ventricular premature beats. One subject was studied during both atrial fibrillation and normal sinus rhythm in the course of left heart catheterization. Left ventricular. systolic and end-diastolic pressures were higher during normal sinus rhythm than during atrial fibrillation. The development of mitral regurgitation during ectopic ventricular beats is also illustrated. These data demonstrate the physiologic importance of maintaining the normal temporal sequence of atrioventricular activity.
Influence of solvent conditions on refolding of bovine serum albumin

Abstract The effect of solvent conditions on the refolding of bovine serum albumin was studied. The rate and extent of refolding was affected by the type of monovalent salt used in the medium. While NaCl and NaBr promoted refolding, NaClO4 and NaSCN decreased the rate and extent of refolding at 0.2 M concentration. In this respect the relative order in which various anions influenced the refolding process followed the lyotropic series Cl−, Br−, I−, ClO4−, SCN−. Urea exhibited two opposite effects on the refolding of albumin: whereas at low concentrations urea increased the extent of refolding, at concentrations above 2.0 M the rate and extent of refolding were dramatically decreased. Addition of ethanol to the medium greatly decreased the refolding even at concentrations as low as 4% (v / v). The effects of these various additives on the refolding behavior of serum albumin is interpreted in tems of subtle changes in the structure of water. It is also shown that, while such changes in the solvent structure affected the rate and extent of refolding, they did not affect the pathway of refolding.
Hairy cell leukemia diagnostic criteria and differential diagnosis

Hairy cell leukemia (HCL) is a disease with distinctive clinical findings, as well as a unique morphology and immunophenotype. These features typically allow for a reliable and reproducible diagnosis in nearly all situations. However, certain morphological features of HCL, such as villous cytoplasmic projections or characteristic tissue specific infiltrative patterns, including red pulp expansion with pseudosinuses, may be seen in other B-cell lymphoproliferative disorders. A methodical and thorough approach evaluating the clinical, cytological, histological, architectural, and immunophenotypic features is described and will aid in rendering the appropriate diagnosis. This is paramount as current data indicate that hairy cell leukemia - variant and other splenic B-cell lymphomas must be distinguished from HCL, as the response to therapy differs in these disorders.
Ischemic optic neuropathy associated with idiopathic dilated episcleral veins

A man had acute, painful vision loss due to nonarteritic anterior ischemic optic neuropathy. Although he initially had a mildly elevated intraocular pressure, he later was found to be experiencing large fluctuations in intraocular pressure. He had dilated, tortuous episcleral veins in that eye, which were thought to be the cause of his elevated intraocular pressure.
Activation of K + channels and suppression of neuronal activity by secreted β-amyloid-precursor protein

THE Alzheimer's β-amyloid precursor protein (β-APP) is widely expressed in neural cells, and in neurons secreted forms of β-APP (sAPPs) are released from membrane-spanning holo-βAPP in an activity-dependent manner1,2. Secreted APPs can modulate neur-ite outgrowth, synaptogenesis, synaptic plasticity and cell survival3–9; a signal transduction mechanism of sAPPs may involve modulation of intracellular calcium levels ([Ca2+]i)4,10. Here we use whole-cell perforated patch and single-channel patch-clamp analysis of hippocampal neurons to demonstrate that sAPPs suppress action potentials and hyperpolarize neurons by activating high-conductance, charybdotoxin-sensitive K+ channels. Activation of K+ channels by sAPPs was mimicked by a cyclic GMP analogue and sodium nitroprusside and blocked by an antagonist of cGMP-dependent kinase and a phosphatase inhibitor, suggesting that the effect is mediated by cGMP and protein dephosphorylation. Calcium imaging studies indicate that activation of K+ channels mediates the ability of sAPPs to decrease [Ca2+]i. Modulation of neuronal excitability may be a major mechanism by which β-APP regulates developmental and synaptic plasticity in the nervous system.
Criteria for the Existence and Lower Bounds of Principal Eigenvalues of Time Periodic Nonlocal Dispersal Operators and Applications

The current paper is concerned with the spectral theory, in particular, the principal eigenvalue theory, of nonlocal dispersal operators with time periodic dependence, and its applications. Nonlocal and random dispersal operators are widely used to model diffusion systems in applied sciences and share many properties. There are also some essential differences between nonlocal and random dispersal operators, for example, a smooth random dispersal operator always has a principal eigenvalue, but a smooth nonlocal dispersal operator may not have a principal eigenvalue. In this paper, we first establish criteria for the existence of principal eigenvalues of time periodic nonlocal dispersal operators with Dirichlet type, Neumann type, or periodic type boundary conditions. It is shown that a time periodic nonlocal dispersal operator possesses a principal eigenvalue provided that the nonlocal dispersal distance is sufficiently small, or the time average of the underlying media satisfies some vanishing condition with respect to the space variable at a maximum point or is nearly globally homogeneous with respect to the space variable. Next we obtain lower bounds of the principal spectrum points of time periodic nonlocal dispersal operators in terms of the corresponding time averaged problems. Finally we discuss the applications of the established principal eigenvalue theory to time periodic Fisher or KPP type equations with nonlocal dispersal and prove that such equations are of monostable feature, that is, if the trivial solution is linearly unstable, then there is a unique time periodic positive solution which is globally asymptotically stable.
Phosphodiesterase 4D Deficiency in the Ryanodine-Receptor Complex Promotes Heart Failure and Arrhythmias

Phosphodiesterases (PDEs) regulate the local concentration of 3',5' cyclic adenosine monophosphate (cAMP) within cells. cAMP activates the cAMP-dependent protein kinase (PKA). In patients, PDE inhibitors have been linked to heart failure and cardiac arrhythmias, although the mechanisms are not understood. We show that PDE4D gene inactivation in mice results in a progressive cardiomyopathy, accelerated heart failure after myocardial infarction, and cardiac arrhythmias. The phosphodiesterase 4D3 (PDE4D3) was found in the cardiac ryanodine receptor (RyR2)/calcium-release-channel complex (required for excitation-contraction [EC] coupling in heart muscle). PDE4D3 levels in the RyR2 complex were reduced in failing human hearts, contributing to PKA-hyperphosphorylated, "leaky" RyR2 channels that promote cardiac dysfunction and arrhythmias. Cardiac arrhythmias and dysfunction associated with PDE4 inhibition or deficiency were suppressed in mice harboring RyR2 that cannot be PKA phosphorylated. These data suggest that reduced PDE4D activity causes defective RyR2-channel function associated with heart failure and arrhythmias.
Macroscopic assessment of nanosilver toxicity to soil denitrification kinetics.

A large increase in commercial and home use of silver nanoparticle (AgNP) products and technologies has raised concerns about their impact on environmental health. While several sources cite soils and sediments as the predominant sink for AgNPs in natural environments, few studies contribute to risk assessment of AgNPs in terrestrial environments. In this study, the effect of AgNPs ([Ag] total: 1–100 mg/kg, 15–50 nm with 0–90% polyvinylpyrrolidone [PVP] capping agent) on soil denitrification processes was investigated with batch kinetic experiments using well-characterized AgNPs. Although the effects on denitrification kinetics and equilibrium end-points were variable among the AgNPs, denitrification kinetics were limited under certain conditions (e.g., PVP-coated AgNPs ≥ 10 mg/kg). In assessing the impact of AgNPs on ecosystem processes, it is important to consider the interactions of AgNPs with soils and sediments in addition to the physicochemical properties (size, coating agents, sedimentation rate, solubility, surface charge properties, dispersibility) of AgNPs.
MODELING A RIGHTS-BASED APPROACH FOR MANAGING HABITAT IMPACTS OF FISHERIES

. Limiting adverse consequences of fishing on essential fish habitat has emerged as a key fishery management objective. The conventional approach to providing habitat protection is to create MPAs or marine reserves that prohibit all or certain types of fishing in specific areas. However, there may be more cost-effective and flexible ways to provide habitat protection. We propose an individual habitat quota (IHQ) system for habitat conservation that would utilize economic incentives to achieve habitat conservation goals cost-effectively. Individual quotas of habitat impact units (HIU) would be distributed to fishers with an aggregate quota set to maintain a target habitat “stock.” HIU use would be based on a proxy for marginal habitat damage. We use a dynamic, explicitly spatial fishery and habitat simulation model to explore how such a system might work. We examine how outcomes are affected by spatial heterogeneity in the fishery and the scale of habitat regulation. We find that the IHQ system is a highly cost-effective means of ensuring a given level of habitat protection, but that spatial heterogeneity and the scale of regulation can have significant effects on the distribution of habitat protection.
Influence of increasing 2′-O-methylation on the interferon stimulating capacity of poly(rI) · poly(rC)

Abstract A set of 2′- O -methylated derivatives of poly(rI) · poly(rC) have been prepared and studied for interferon inducing and antiviral activities. Introduction of 2′- O -methyl groups in the polycytidylic strand of this duplex impairs the interferon stimulation capacity more than similar modification of the polyinosinic strand.
Effects of a fourth family on b→sγ and a useful parametrization of quark mixing for rare B decays

Abstract The effects of a fourth family on the decays b→s(d)γ are reported. The BR(b→sγ) can become ∼10−3, i.e., a gain from the three-generation result by an order of magnitude. For very massive t′ (mt > 200GeV) the four-generation result is not sensitive to mt, making the reaction usuful for probing the new mixing angles of the fourth generation. We emphasize that combined information from b→sγ, sl+l− and the hadronic b→s transition without charmed particles would be useful for constraining mass scales and mixing parameters of a fourth generation. In view of the importance of B decays we present a new parametrization of the 4×4 mixing matrix that appears to be better suited for the study of B physics.
Seeing through a different lens: What do interns learn when they make video cases of their own teaching?

This study included four preservice interns at a Midwestern university in the United States who were learning to facilitate interactive discussions in English language arts. The authors investigated how the interns' perceptions of their self-selected audience influenced what they noticed, talked about, and learned as they constructed a video case about their teaching. Two interns identified themselves as the audience and problematized specific aspects of their lesson, whereas two others “showcased” themselves in a positive light for a public audience. All interns gained insights about their teaching as they constructed their case. Implications for teacher education and future research directions are discussed.
Development of an interactive textbook for introductory mechanical design

The tremendous success of the iPad has led to a revolution in portable computing. Many universities, high schools, and elementary schools are attempting to capitalize on this revolution by generating curricula that exploit such portable touchscreen computers. One aspect of this effort is the development of interactive textbooks that go beyond the static display of printed words, equations, and figures. Features that distinguish interactive textbooks include: embedded videos that can be viewed with the tap of a finger, picture slideshows, user-controlled simulations, and interactive forms that accept user input and provide immediate feedback. Unfortunately, the skill sets required to generate such books usually do not reside in one person. Professors have the knowledge and skills to produce traditional textbooks, but they usually lack the knowledge, skill, and time to make the interactive elements. Undergraduate and graduate students can be trained to develop the programming skills to develop the interactive elements, but they lack the knowledge and experience to create the traditional aspects of a textbook. This paper describes how a team was formed to produce an interactive textbook, and it documents the features of such a book created for introductory mechanical design students.
5-Hydroxytryptophan: An absorption and fluorescence probe which is a conservative replacement for [A14 tyrosine] in insulin

Use of insulin's intrinsic tyrosine absorption and fluorescence to monitor its interaction with the insulin receptor is limited because the spectral properties of the receptor tryptophan residues mask the spectral properties of the hormone tyrosine residues. We describe the synthesis of an insulin analog where A14 tyrosine is replaced by a tryptophan analog, 5-hydroxytryptophan. This insulin is spectrally enhanced since 5-hydroxytryptophan has an absorption band above 300 nm which is at lower energies than the absorption of tryptophan. Steady-state and time-resolved fluorescence parameters indicate that 5-hydroxytryptophan reports the same information about the environment of the A14 side chain as does the corresponding tryptophan-containing insulin. The synthetic hormone is a full agonist compared to porcine insulin, but has slightly reduced specific activity. Consequently, this spectrally enhanced insulin analog will be useful for hormone-receptor interaction studies since it can be observed by both absorption and fluorescence even in the presence of the tryptophan-containing receptor.
An exact mapping of the t-J model to the unrestricted Hilbert space

We present an exact mapping of the thermodynamical properties of the t-J model to the unrestricted fermionic Hilbert space. At half filling this is accomplished by the introduction of a complex chemical potential. At finite hole concentration we generalize the t-J model to a particle-hole symmetric form. Identifying a symmetrized combination of a hole and a doubly-occupied site with the charge carrier, we prove that the thermodynamical properties of original and the generalized t-J model are identical.
Structures of Neuroligin-1 and the Neuroligin-1/Neurexin-1β Complex Reveal Specific Protein-Protein and Protein-Ca2+ Interactions

Neurexins and neuroligins provide trans-synaptic connectivity by the Ca2+-dependent interaction of their alternatively spliced extracellular domains. Neuroligins specify synapses in an activity-dependent manner, presumably by binding to neurexins. Here, we present the crystal structures of neuroligin-1 in isolation and in complex with neurexin-1 beta. Neuroligin-1 forms a constitutive dimer, and two neurexin-1 beta monomers bind to two identical surfaces on the opposite faces of the neuroligin-1 dimer to form a heterotetramer. The neuroligin-1/neurexin-1 beta complex exhibits a nanomolar affinity and includes a large binding interface that contains bound Ca2+. Alternatively spliced sites in neurexin-1 beta and in neuroligin-1 are positioned nearby the binding interface, explaining how they regulate the interaction. Structure-based mutations of neuroligin-1 at the interface disrupt binding to neurexin-1 beta, but not the folding of neuroligin-1 and confirm the validity of the binding interface of the neuroligin-1/neurexin-1 beta complex. Our results provide molecular insights for understanding the role of cell-adhesion proteins in synapse function.
Infection of primary cultures of aphid cells with a plant virus.

Abstract Primary cell cultures of ovarian and embryonic tissues of the aphid Hyperomyzus lactucae L. were prepared. These cultures were inoculated with purified samples of sowthistle yellow vein virus (SYVV). Infection of cells with SYVV was demonstrated by direct fluorescent antibody staining. The first infection was noticed 37 hours after inoculation and the number of infected cells reached a maximum after 48 hours. As many as 1700 infected cells were obtained in a single coverslip culture.
KEY ISSUES IN THE ETHICS OF DEMENTIA CARE

This article discusses nine important medical ethical issues following the progression of irreversible dementia from diagnosis to dying. Issues include prevention, research, truth telling, advance planning, cognitive-enhancing drugs, driving restrictions, respectful caring, distribution, justice, and natural dying.
Neprilysin regulates amyloid Beta peptide levels.

That neprilysin (NEP) is a major Aβ peptide-degrading enzyme in vivo is shown by higher Aβ peptide levels in the brain of an NEP knockout mouse. In addition, we show that infusion of an NEP inhibitor, but not inhibitors of other peptidases, into the brains of an APP transgenic mouse elevates Aβ levels. We have investigated the use of NEP as a potential therapeutic agent to prevent the accumulation of Aβ peptides in the brain. Lentivirus expressing NEP was initially used to demonstrate the ability of the enzyme to reduce Aβ levels in a model CHO cell line and to make primary hippocampal neurons resistant to Aβ-mediated neurotoxicity. Injection of NEP-expressing lentivirus, but not inactive NEP-expressing lentivirus, GFP-expressing lentivirus, or vehicle, into the hippocampus of 12–20-mo-old hAPP transgenic mice led to an approx 50% reduction in the number of amyloid plaques. These studies provide the impetus for further investigating of the use of NEP in a gene transfer therapy paradigm to prevent the accumulation of Aβ and prevent or delay the onset of Alzheimer’s disease.
Fluorescence detection and characterization of packing defects in lyotropic liquid crystals

Lyotropic liquid crystals belong to a class of self-assembling nanomaterials. Packing defects among molecules play an important role in the physical properties and dynamics of lyotropic liquid crystals. Time-resolved fluorescence depolarization technique has been used to detect and characterize the onset of packing defects in lyotropic liquid crystals (lipid/water mixtures). Fully hydrated binary mixtures of phosphatidylethanolamine/phosphatidylcholine (PE/PC) exhibit mesoscopic packing defect state (D) as well as 1-dimensional lamellar liquid crystalline (L(alpha )) and 2-dimensional inverted hexagonal (HII) phases. Based on previous electron microscopic investigations, the presence of this D state is characterized by the presence of interlamellar attachments and precursors of HII phase between the lipid layers. Using a rotational diffusion model for rod-shape fluorophore in a curved matrix, rotational dynamics parameters, 2nd and 4th rank order parameters, localized wobbling diffusion and curvature-dependent rotational diffusion constants of rod-shape dipyenylhexatriene (DPH) labeled PC (DPH-PC) in the host PE/PC matrix were calculated from the measured fluorescence depolarization decays of DPH fluorescence. At the onset of packing defects, abrupt increases in the rotational dynamics parameters were observed. Our results suggest that rotational dynamics parameters are very sensitive in detecting packing defects in lyotropic liquid crystals. In addition, the presence of D state can be characterized by enhanced wobbling diffusional motion and order packing of lipid molecules and the presence of localized curvatures in the lipid layers.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The learning curve associated with pediatric laparoscopic splenectomy.

Abstract Background: Laparoscopic splenectomy (LS) is technically difficult compared with open splenectomy. This report examines our experience with LS to define the learning curve. Methods: The first 49 consecutive laparoscopic splenectomies were reviewed. Indications, complications, operative time, and costs were recorded. Results: Indications included hereditary spherocytosis, immune thrombocytopenia purpura, beta-thalassemia, lymphoma, splenic cysts, and abscesses. Surgical time averaged 196 minutes for the first 10 patients, decreasing to 105 minutes for the last 10. Blood loss for the first 10 patients averaged 50 cc and less than 5 cc for the last 10. There were 3 complications and 1 conversion to open operation. Operative and hospital charges averaged $6,670 and $13,402, respectively, for the first 10 cases compared with $5,278 and $10,863 for the last 10. Conclusions: LS can be performed safely with few complications. LS has a steep learning curve in the first 20 patients after which operative times decrease along with overall costs.
Molecular dynamics simulations of the hexagonal structure of crystals with long methylene sequences

An unconstrained polymethylene crystal, consisting of 9600 CH 2 groups, in which each CH 2 is permitted to carry out stretching, bending, and torsional motion, has been studied at various temperatures using molecular dynamics simulations. Information about the atomistic details of the dynamics and structure of these crystals is presented. A significant disorder exists at temperatures well below the melting point. Close to melting, the disordered crystals have about 2% of gauche bonds that are distributed mainly at positions close to the surface of the crystal. The major disorder consists, however, of a collective twisting of the chains leading to a hexagonal crystal structure. The hexagonal structure of the symmetric motifs is caused by a dynamic multidomain arrangement of the chains
Teachers and Educational Reform

n response to two reports issued in 1986 which called for the professionalization of teaching-Tomorrow's Teachers: A Report of the Holmes Group (Holmes Group, 1986) and A Nation Prepared: Teachers for the Twenty-first Century (Carnegie Forum, 1986)-Herbst wrote, "The historian cannot but feel a sense of dj'a vu" (1989, p. 213). He was referring to a persistent, recurring theme which has been in existence since the 1830s demanding that teaching be recognized as a profession. In 1986, recommendations to professionalize teaching focused on creating better and more qualified teachers through more education, certification requirements, and adherence to national standards. It was assumed that if teachers were more highly credentialed then public trust in them and in schools would be restored. As a result, teachers would gain status because they would be "professionalized." In September 1996, Herbst must have felt dfdja' vu all over again when he read the recommendations of the National Commission on Teaching and America's Future to professionalize teachers by setting higher standards and increasing their education and training. Of particular note, however, was the malevolent tone taken. Although few would argue with the idea that teachers should be highly trained and adhere to professional standards, it is still a curious phenomenon when educators attack their own with such vengeance. Some speculations about the issue of teacher "bashing" are addressed here before turning to the issues of the professionalization of teaching, and of the role of teachers in educational reform.
A consumption-based theory of the environmental Kuznets curve

Abstract Most theories about the inverted-U relationship between pollution and income, termed the environmental Kuznets curve (EKC), are production-side theories emphasizing pollution and abatement technologies. Production-side theories are implicitly based on the assumption of low factor mobility, and the absence of pollution as a variable in the utility function. Both assumptions are called into question by the empirical evidence of EKCs for (i) pollutants that are long-lived and not easily shiftable and (ii) regional cross-sections with free labor mobility. Hazardous waste sites are a prime example. This paper develops a stylized model of the EKC based on perfect mobility of households and labor. It represents the first attempt at developing a consumption-side model of the EKC.
The books of Phaedrus requested by Cicero (Att. 13.39)

Around 16 August of 45 B.C. Cicero wrote a brief letter to Atticus (Alt. 13.39) in which he reminds Atticus to send the books of the Epicurean scholarch Phaedrus that he had requested. The Greek words in the text of his request have been corrupted through the centuries
Epidemiology of bacterial meningitis in the USA from 1997 to 2010: a population-based observational study

Summary Background Bacterial meningitis continues to be a substantial cause of morbidity and mortality, but the epidemiological trends after adjunctive dexamethasone recommendations are unknown in the USA. We aimed to describe the changing patterns among the most common bacterial causes in the USA after conjugate vaccination and to assess the association between adjunctive dexamethasone and mortality. Methods For this population-based observational study, we searched information available from hospital discharges about incidence and inpatient mortality for the most important causes of community and nosocomial bacterial meningitis based on International Classification of Diseases coding across all hospitals in the USA between 1997 and 2010 with the HealthCare Cost Utilization Project (HCUP) network database. We calculated incidences according to US Census Bureau data and used a negative binomial regression model to evaluate the significance of changes over time. We assessed mortality from pneumococcus for three periods 1997–2001 (baseline), 2002–04 (transition years), and 2005–08 (after corticosteroid recommendations were available). Findings Streptococcus pneumoniae incidence fell from 0·8 per 100 000 people in 1997, to 0·3 per 100 000 people by the end of 2010 (RR 0·3737, 95% CI 0·1825–0·7656). Mortality from pneumococcal meningitis decreased between 2005 (0·049 per 100 000 people) and 2008 (0·024 per 100 000 people) compared with between 2002 (0·073 per 100 000 people) and 2004 (0·063 per 100 000 people; RR 0·5720, 95% CI 0·4303–0·7582). The incidence of Neisseria meningitidis infection decreased from 0·721 per 100 000 people in 1997, to 0·123 per 100 000 people in 2010 (RR 0·1386, 95% CI 0·048–0·4284), which has placed this pathogen close to common bacterial causes of nosocomial meningitis such as staphylococcus and Gram-negative bacteria and to Haemophilus influenzae. Interpretation S pneumoniae continues to be the leading identifiable cause of bacterial meningitis in the USA, but with a significant decrease in incidence and mortality associated with the introduction of conjugated vaccines and a mortality decrease that is associated with the introduction of recommendations for use of adjunctive dexamethasone for pneumococcal meningitis. Funding National Center for Research Resources.
Performance under design and test of the 20,500 hp TEAAC synchronous motors for the Shaybah Project in the Rub-Al-Khali desert, Saudi Arabia

In July of 1998, a large oil company successfully started up the ambitious Shaybah oil production project. The largest motors that were procured for this undertaking had to be designed to operate in one of the most forbidding environments on Earth. The project location in the Saudi Arabian Rub-Al-Khali (Empty Quarter) desert experiences daily heat extremes in excess of 50/spl deg/C, extensive periods of wind-borne dust and exposure to relentless solar radiation. Totally Enclosed Air to Air Cooling (TEAAC) was and continues to be specified for all large motors. The motor standards that were applied during procurement were based upon NEMA MG-1, which clearly stated that for operation in an ambient that exceeds 50/spl deg/C the allowable temperature rise is to be reduced by 20/spl deg/C. This paper reviews the performance issues that were raised during design and testing in order to meet the requirements of this very difficult TEAAC application. Engineering tradeoffs that had to be thoroughly justified by both the motor manufacturer and the motor user are also highlighted.
Should we be on the fence or can we open the gate? Evidence that QRS gating in FMD analysis is not essential

the function of arterial endothelial cells is now recognized as an important factor in the pathogenesis of atherosclerosis. Almost two decades ago, Celermajer and colleagues ([2][1]) introduced a noninvasive assessment technique to evaluate endothelial function in humans. In this test, the magnitude
Wound induced changes in phenolic metabolism and tissue browning are altered by heat shock

Wounding is one of many abiotic stresses that produce signals that propagate from injured into adjacent non-injured tissues and induce the de novo synthesis of specific wound-induced proteins. Some of these induced proteins are enzymes of phenolic metabolism, such as phenylalanine ammonia-lyase (PAL), whose increased activity leads to the accumulation of phenolic compounds (e.g., chlorogenic acid, dicaffeoyl tartaric acid and isochlorogenic acid) and tissue browning. Wounding of iceberg lettuce leaves increases PAL activity six- to 12-fold over 24 h at 10°C and leads to a three-fold increase in the total phenolic content within 3 days. There may be a hierarchical order to the plant's response to different abiotic stresses. Plant tissue simultaneously exposed to a heat shock and wounding responds to the heat shock in preference to wounding by producing heat shock proteins instead of PAL. A 90 s, 45°C heat shock prevents an increase in PAL activity if administered either 4 h before or 2 h after wounding. This diversion of wound-induced protein synthesis by heat shock might be used to prevent browning in other crops that normally have low phenolic content; e.g., celery and lettuce. The persistence of the ability of a heat shock to preferentially induce the synthesis of heat shock proteins (hsps) in place of wound-induced enzymes of phenylpropanoid metabolism offers a new way to control browning in lightly processed fruits and vegetables. The design of processing lines using a heat shock to extend the shelf-life of fresh-cut lettuce will need to be modified from existing designs to take full advantage of the effect of the heat treatment.
The Protective Role of TLR3 and TLR9 Ligands in Human Pharyngeal Epithelial Cells Infected with Influenza A Virus

In this study we aim to extensively investigate the anti-influenza virus immune responses in human pharyngeal epithelial cell line (Hep-2) and evaluate the protective role of Toll-like receptor (TLR) ligands in seasonal influenza A H1N1 (sH1N1) infections in vitro. We first investigated the expression of the TLRs and cytokines genes in resting and sH1N1 infected Hep-2 cells. Clear expressions of TLR3, TLR9, interleukin (IL)-6, tumour necrosis factor (TNF)-α and interferon (IFN)-β were detected in resting Hep-2 cells. After sH1N1 infection, a ten-fold of TLR3 and TLR9 were elicited. Concomitant with the TLRs activation, transcriptional expression of IL-6, TNF-α and IFN-β were significantly induced in sH1N1-infected cells. Pre-treatment of cells with poly I:C (an analog of viral double-stranded RNA) and CpG-ODN (a CpG-motif containing oligodeoxydinucleotide) resulted in a strong reduction of viral and cytokines mRNA expression. The results presented indicated the innate immune response activation in Hep-2 cells and affirm the antiviral role of Poly I:C and CpG-ODN in the protection against seasonal influenza A viruses.
septicemia mortality reduction in neonates in a heart rate characteristics monitoring trial

Abnormal heart rate characteristics (HRC) wax and wane in early stages of culture-positive, late-onset septicemia (LOS) in patients in the neonatal intensive care unit (NICU). Continuously monitoring an HRC index leads to a reduction in mortality among very low birth weight (VLBW) infants. We hypothesized that the reduction in mortality was due to a decrease in septicemia-associated mortality. This is a secondary analysis of clinical and HRC data from 2,989 VLBW infants enrolled in a randomized clinical trial of HRC monitoring in nine NICUs from 2004 to 2010. LOS was diagnosed 974 times in 700 patients, and the incidence and distribution of organisms were similar in HRC display and nondisplay groups. Mortality within 30 d of LOS was lower in the HRC display as compared with the nondisplay group (11.8 vs. 19.6%; relative risk: 0.61; 95% confidence interval: 0.43, 0.87; P < 0.01), but mortality reduction was not statistically significant for patients without LOS. There were fewer large, abrupt increases in the HRC index in the days leading up to LOS diagnosis in infants whose HRC index was displayed. Continuous HRC monitoring is associated with a lower septicemia-associated mortality in VLBW infants, possibly due to diagnosis earlier in the course of illness.
The Failure of Practical Intuition: How Forward-Coverage Inventory Targets Cause the Landslide Effect

Seasonal demand for products is common at many companies including Kraft Foods, Case New Holland, and Elmer's Products. This study documents how these, and many other companies, experience bloated inventories as they transition from a low season to a high season and a severe drop in service levels as they transition from a high season to a low season. Kraft has termed this latter phenomenon the �landslide effect.� In this study, we present real examples of the landslide effect and attribute its root cause to a common industry practice employing forward days of coverage when setting inventory targets. While inventory textbooks and academic articles prescribe correct ways to set inventory targets, forward coverage is the dominant method employed in practice. We investigate the magnitude and drivers of the landslide effect through both an analytical model and a case study. We find that the effect increases with seasonality, lead time, and demand uncertainty and can lower service by an average of ten points at a representative company. While the logic is initially counterintuitive to many practitioners, companies can avoid the landslide effect by using demand forecasts over the preceding lead time to calculate safety stock targets.
Design of the Intel Pentium processor

The Intel Pentium processor is the next generation high-performance processor, fully compatible with its predecessor, the i486. The Pentium processor integrates 3.1 million transistors on 0.8 /spl mu/m BiCMOS process technology and has 2-5 times higher performance than the i486 CPU at the same frequency. Techniques used to achieve this level of performance are described. >
PHD Inhibition Mitigates and Protects Against Radiation-Induced Gastrointestinal Toxicity via HIF2

Radiation-induced gastrointestinal (GI) toxicity can be a major source of morbidity and mortality after radiation exposure. There is an unmet need for effective preventative or mitigative treatments against the potentially fatal diarrhea and water loss induced by radiation damage to the GI tract. We report that prolyl hydroxylase inhibition by genetic knockout or pharmacologic inhibition of all PHD (prolyl hydroxylase domain) isoforms by the small-molecule dimethyloxallyl glycine (DMOG) increases hypoxia-inducible factor (HIF) expression, improves epithelial integrity, reduces apoptosis, and increases intestinal angiogenesis, all of which are essential for radioprotection. HIF2, but not HIF1, is both necessary and sufficient to prevent radiation-induced GI toxicity and death. Increased vascular endothelial growth factor (VEGF) expression contributes to the protective effects of HIF2, because inhibition of VEGF function reversed the radioprotection and radiomitigation afforded by DMOG. Additionally, mortality from abdominal or total body irradiation was reduced even when DMOG was given 24 hours after exposure. Thus, prolyl hydroxylase inhibition represents a treatment strategy to protect against and mitigate GI toxicity from both therapeutic radiation and potentially lethal radiation exposures.
Sintering Reactions in MgO‐Tic Mixtures

Mixtures of MgO and Tic were sintered at four temperatures in an induction furnace using a helium atmosphere. X-ray patterns of the sinters were made and interpreted. Colors and appearance were noted and weight losses determined for some samples. Observed changes in lattice dimensions are explained on the basis of the formation of titanium monoxide resulting from the partial reduction of magnesia by titanium carbide.
TPMT, UGT1A1 and DPYD: genotyping to ensure safer cancer therapy?

The Food and Drug Administration (FDA) has approved label changes for two anticancer drugs, 6-mercaptopurine (6-MP) and irinotecan, to include pharmacogenetic testing as a potential means to reduce the rate of severe toxic events. Comprehensive evaluation of the clinical benefit and cost effectiveness of screening strategies with these tests has not been completed. However, the FDA decided that evidence indicates sufficient benefit to warrant informing prescribers, pharmacists and patients of the availability of pharmacogenetic tests and their possible role in the selection and dosing of these anticancer agents. Reviewing the gene–drug-phenotype relationships of 6-MP, irinotecan and 5-fluorouracil reveals properties of these relationships that lead to a clinically useful pharmacogenetic test. Research in the near future should clarify the role of pharmacogenetic testing in reducing the risk of severe toxicity and determine how these same tests might identify a subset of patients who should safely receive higher doses of treatment to derive the same benefit as the rest of the patient population.
To ‘errrr’ is human: ecology and acoustics of speech disfluencies

Unlike read or laboratory speech, spontaneous speech contains high rates of disuencies (e.g. repetitions, repairs, ®lled pauses, false starts). This paper aims to promotedisuency awareness' especially in the ®eld of phonetics ± which has much to offer in the way of increasing our understanding of these phenomena. Two broad claims are made, based on analyses of disuencies in different corpora of spontaneous American English speech. First, an Ecology Claim suggests that disuencies are related to aspects of the speaking environments in which they arise. The claim is supported by evidence from task effects, location analyses, speaker effects and sociolinguistic effects. Second, an Acoustics Claim argues that disuency has consequences for phonetic and prosodic aspects of speech that are not represented in the speech patterns of laboratory speech. Such effects include modi®cations in segment durations, intonation, voice quality, vowel quality and coarticulation patterns. The ecological and acoustic evidence provide insights about human language production in real-world contexts. Such evidence can also guide methods for the processing of spontaneous speech in automatic speech recognition applications.
The Study of Mercury

When the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft enters orbit about Mercury in March 2011 it will begin a new phase in an age-old scientific study of the innermost planet. Despite being visible to the unaided eye, Mercury's proximity to the Sun makes it extremely difficult to observe from Earth. Nonetheless, over the centuries man has pursued a quest to understand the elusive planet, and has teased out information about its motions in the sky, its relation to the other planets, and its physical characteristics. A great leap was made in our understanding of Mercury when the Mariner 10 spacecraft flew past it three times in the mid-1970s, providing a rich set of close-up observations. Now, three decades later, The MESSENGER spacecraft has also visited the planet three times, and is poised to add significantly to the study with a year-long orbital observation campaign.