cssi/SciSciGPT-SciSciNet huggingface dataset:
Effects of brief daily periods of unrestricted vision during early monocular form deprivation on development of visual area 2.

The developing visual system is exquisitely sensitive to degradation of retinal images. Depriving one eye of clear vision soon after birth results in a severe loss of visual sensitivities in the affected eye (form-deprivation amblyopia).1–7 However, recent studies in nonhuman primates showed that the magnitude of form-deprivation amblyopia is dramatically reduced if a brief daily period of unrestricted vision is provided during the deprivation period.8 Similar beneficial effects of brief periods of “normal” vision have been reported in cats.9–11 The neural mechanisms underlying amblyopia or the observed preventive effects of unrestricted vision in amblyopic subjects are not well understood, partly because previous neurophysiological studies of the neural basis of amblyopia in nonhuman primates focused mostly on how the primary visual cortex (V1) is reorganized by early abnormal visual experience. The primate brain has vast cortical areas beyond V1 that process information required for visual perception. Moreover, the functional development of the visual brain is thought to proceed in a hierarchical order and therefore, a higher order visual area (e.g., V2) is likely to be more plastic than a lower area (e.g., V1) at a given developmental age.12–18 For example, our recent study of strabismic amblyopia in macaque monkeys revealed that whereas the ocular dominance distribution of V1 neurons in amblyopic monkeys was balanced between the two eyes, there was a significant ocular dominance shift in V2 neurons away from the deviating eye in these same amblyopic monkeys.18 A previous comprehensive fMRI study on anisometropic and strabismic amblyopia reported that fMRI responses to stimulation of the amblyopic eye were progressively reduced in higher order visual areas.19 Also nearly all neurons in extrastriate visual areas are driven by either eye (i.e., binocular cells) and often exhibit more complex spatial vision processing than V1 neurons.20–24 Moreover binocular signal interactions in V2 are far more robust than in V1, and V2 neurons, unlike V1 neurons, are known to be directly involved in binocular depth perception.25,26 Taken together, studies on higher stages of cortical processing during early development are necessary to better understand the neural basis of amblyopia and therefore, the mechanisms of preventive effects from brief daily periods of unrestricted vision during early monocular form deprivation. In the present study, we asked whether developing V2 neurons are more sensitive than V1 neurons to the protective effects of brief daily periods of unrestricted vision during early monocular form deprivation.
Aqueous free radical chemistry of mercury in the presence of iron oxides and ambient aerosol

Abstract The effect of goethite (α-FeOOH), hematite (α-Fe203) and maghemite (γ-Fe203) on the aqueous photoreduction of divalent mercury with organic acids (oxalate, formate and acetate) is investigated. Laboratory photochemistry experiments with synthetic iron oxides and simulated sunlight were performed to assess the role of the oxides on the photoreduction. Ambient aerosol was also collected and introduced as the solid phase to compare its effect with that of synthetic oxides. It is observed that the presence of various iron oxides or aerosol particles enhances the photoreduction. It is also found that the hydroxyl radicals produced in the hematite-oxalate systems can re-oxidize the reduced mercury back to Hg(II). Based on the experimental observations, mechanisms responsible for the Hg(II) reduction are proposed. The kinetics of Hg0 oxidation by hydroxyl radicals was also studied by a steady-state kinetic technique using nitrate photolysis as the * OH radical source. The second-order rate constant is determined to be 2.0 × 109 M− s−1. The implications of the studied reactions on the atmospheric chemistry of mercury are discussed.
Attitudes Toward Working on Interdisciplinary Healthcare Teams: A Comparison by Discipline

Interdisciplinary teams are important in providing care for older patients, but interdisciplinary teamwork is rarely a teaching focus, and little is known about trainees' attitudes towards it. To determine the attitudes of second-year post-graduate (PGY-2) internal medicine or family practice residents, advanced practice nursing (NP), and masters-level social work (MSW) students toward the value and efficiency of interdisciplinary teamwork and the physician's role on the team, a baseline survey was administered to 591 Geriatrics Interdisciplinary Team Training participants at eight U.S. academic medical centers from January 1997 to July 1999. Most students in each profession agreed that the interdisciplinary team approach benefits patients and is a productive use of time, but PGY-2s consistently rated their agreement lower than NP or MSW students. Interprofessional differences were greatest for beliefs about the physician's role; 73% of PGY-2s but only 44% to 47% of MSW and NP trainees agreed that a team's primary purpose was to assist physicians in achieving treatment goals for patients. Approximately 80% of PGY-2s but only 35% to 40% of MSW or NP trainees agreed that physicians have the right to alter patient care plans developed by the team. Although students from all three disciplines were positively inclined toward medical interdisciplinary teamwork, medical residents were the least so. Exposure to interdisciplinary teamwork may need to occur at an earlier point in medical training than residency. The question of who is ultimately responsible for the decisions of the team may be an "Achilles heel," interfering with shared decision-making.
Formal post-graduate education in automatic control in the United States

American educational institutions have developed an approach to post graduate education which is not common in the rest of the world. This paper reviews the American system of education in automatic control beyond the baccalaureate degree and discusses some of the strengths and weaknesses of this system. In 1969 the Education Committee of the American Automatic Control Council surveyed American educational institutions offering advanced degrees with specialization in automatic control. Some of the facts in the present paper were obtained from this source. A summary of the survey may be found in the author's Ref. 1.
Model based iterative reconstruction for Bright Field electron tomography

Bright Field (BF) electron tomography (ET) has been widely used in the life sciences to characterize biological specimens in 3D. While BF-ET is the dominant modality in the life sciences it has been generally avoided in the physical sciences due to anomalous measurements in the data due to a phenomenon called “Bragg scatter” - visible when crystalline samples are imaged. These measurements cause undesirable artifacts in the reconstruction when the typical algorithms such as Filtered Back Projection (FBP) and Simultaneous Iterative Reconstruction Technique (SIRT) are applied to the data. Model based iterative reconstruction (MBIR) provides a powerful framework for tomographic reconstruction that incorporates a model for data acquisition, noise in the measurement and a model for the object to obtain reconstructions that are qualitatively superior and quantitatively accurate. In this paper we present a novel MBIR algorithm for BF-ET which accounts for the presence of anomalous measurements from Bragg scatter in the data during the iterative reconstruction. Our method accounts for the anomalies by formulating the reconstruction as minimizing a cost function which rejects measurements that deviate significantly from the typical Beer’s law model widely assumed for BF-ET. Results on simulated as well as real data show that our method can dramatically improve the reconstructions compared to FBP and MBIR without anomaly rejection, suppressing the artifacts due to the Bragg anomalies.
Mesangial cell proliferation mediated by PDGF and bFGF is determined by levels of the cyclin kinase inhibitor p27Kip1

Mesangial cell proliferation mediated by PDGF and bFGF is determined by levels of the cyclin kinase inhibitor p27 Kip1 . Mesangial cell proliferation in vitro is regulated by many cytokines. Platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) are potent mesangial cell mitogens, whereas transforming growth factor- β 1 (TGF- β 1) reduces their effects. We examined how these cytokines regulate rat mesangial cell proliferation at the level of the cell-cycle. Quiescent mesangial cells in vitro express the cyclin kinase inhibitor, p27 Kip1 (p27), and PDGF- and bFGF-induced mesangial cell proliferation is associated with a substantial decrease in p27 levels. Consequently there is a marked increase in expression (Western blot analysis, immunostaining) of cyclin A and CDK2. The decline in p27 levels was prevented by TGF- β 1 during inhibition of PDGF- and bFGF-induced mesangial cell proliferation. To determine the functional role of p27 during cytokine-mediated mesangial cell proliferation, the expression of p27 was reduced with specific p27 Kip1 antisense oligodeoxynucleotides. Reducing the levels of p27 resulted in an increased magnitude of mesangial cell proliferation (BrdU and 3 H-thymidine incorporation) induced by PDGF and bFGF compared to non-transfected mesangial cells and mesangial cells transfected with control mismatch oligodeoxynucleotides. Furthermore, the onset of maximal proliferation occurred earlier in mesangial cells transfected with antisense compared to control. The reduction in proliferation by TGF- β 1 were not altered by decreased p27 expression. Reducing p27 expression in the absence of mitogens was not associated with entry into the cell-cycle. These results suggest cytokine mediated mesangial cell proliferation is associated with specific cell-cycle proteins, and that the levels of p27 may be important in determining the mesangial cell's proliferative response to PDGF and bFGF in vitro .
Cystic lung lesions with systemic arterial blood supply: A hybrid of congenital cystic adenomatoid malformation and bronchopulmonary sequestration

Congenital cystic adenomatoid malformation and bronchopulmonary sequestration are congenital lung tumors that are classically described as having distinct embryology, pathology, and natural history. The authors treated six patients who had prenatally diagnosed lung masses that displayed clinicopathologic features of both lesion types. At prenatal diagnosis (19 to 30 weeks' gestation), all six lesions were classified sonographically as congenital cystic adenomatoid malformation, and none of the masses appeared to have a systemic arterial blood supply as seen by color flow Doppler study. Two of the six masses showed size regression antenatally. At the time of surgery, all six lesions had a systemic vessel directly from the aorta--five cases were consistent grossly with an intralobular bronchopulmonary sequestration, and one case was consistent with an extralobular bronchopulmonary sequestration. However, all six lesions displayed congenital cystic adenomatoid malformation histology. Hydrops developed in one fetus with a huge mass, and that fetus underwent successful fetal surgical resection (left lower lobectomy) at 22 weeks' gestation with delivery at 35 weeks' gestation. One neonate with a large extralobular bronchopulmonary sequestration was treated with resection and extracorporeal membrane oxygenation (ECMO) but died of pulmonary hypoplasia. Four other patients who had much smaller masses underwent elective lower lobectomy after birth. These findings emphasize the importance of seeking an anomalous blood supply in patients who have congenital lung lesions. These "hybrid" cases suggest a similar embryological origin for congenital cystic adenomatoid malformation and bronchopulmonary sequestration.
Brain Connectivity: Revealing the Fly Visual Motion Circuit

A new semi-automated method for high-throughput identification of visual neurons and their synaptic partners has been combined with optical recording of activity and behavioral analysis to give the first complete description of an elementary circuit for detecting visual motion.
Measurement of the cesium 7 d D 3 ∕ 2 2 hyperfine coupling constants in a thermal beam using two-photon fluorescence spectroscopy

The hyperfine intervals of the $^{133}\mathrm{Cs}$ $7d\phantom{\rule{0.2em}{0ex}}^{2}D_{3∕2}$ manifold are measured using two-photon resonant laser-induced-fluorescence of an effusive cesium beam. A radio-frequency phase modulation technique directly references the relative frequency scale to the ground hyperfine splitting of $^{87}\mathrm{Rb}$. The $^{133}\mathrm{Cs}$ $7d\phantom{\rule{0.2em}{0ex}}^{2}D_{3∕2}$ hyperfine intervals are used to generate the magnetic dipole coupling constant $A=7.36\ifmmode\pm\else\textpm\fi{}0.03\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ and electric quadrupole coupling constant $B=\ensuremath{-}0.1\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$. The $A$ coupling constant agrees with a previous measurement, but with an improvement in resolution that is sufficient to serve as a benchmark value for testing high-precision theory. The result for the $B$ coupling constant is the first constraint placed on this parameter.
Good libraries are expensive libraries

Purpose – The ideas surrounding which institutional attributes make for good libraries vary radically based on patron review, professional association rankings, size of overall collections, and other measures. The purpose of this article is to provide insight into argumentation for establishing how libraries gain the compliment of “good” in an increasingly digital age.Design/methodology/approach – An analysis of the general effect digital content available on the internet has on the mind of the consumer frames the debate on how libraries can be seen as both relevant and good for their communities despite being expensive.Findings – Library leaders always need to advocate for their services and collections, but it is only through true reflective discourse with key stakeholders and governing bodies that enlightenment on the key advantages of libraries can be found.Originality/value – Library popularity and use rises and falls solely based on the conscious user evaluation of collections and services. Focusing...
Nutrition and somatomedin. XIV. Altered levels of somatomedins and somatomedin inhibitors in rats with streptozotocin-induced diabetes.

Diabetes is associated with poor growth despite elevated levels of growth hormone (GH). Skeletal GH effects are mediated by somatomedins; in diabetes, somatomedins measured by radioassay are normal, yet somatomedin activity measured by bioassay is low. Since bioassay measurements reflect the presence of both somatomedins and somatomedin inhibitors, we asked if diabetes might be associated with discordant regulation of these circulating factors. Graded severity of diabetes was induced in rats by injection of streptozotocin at 37, 73, 146, and 293 mg/kg. After two days, metabolic derangement varied from normal serum beta-hydroxybutyrate with slight increase in glucose and minimal weight loss at 37 mg/kg streptozotocin to beta-hydroxybutyrate 10.6 mmol/L, glucose 447 mg/dL, and 33 g weight loss at 293 mg/kg streptozotocin. After fractionation of serum on Sephacryl S-300 pH 7.0, somatomedins and somatomedin inhibitors were measured by rat cartilage bioassay. Somatomedins (Kav 0.25 to 0.50) were comparable to control levels despite beta-hydroxybutyrate 2 mmol/L, glucose 534 mg/dL, and weight loss 11 g at 73 mg/kg streptozotocin and fell only at higher streptozotocin dosage. In contrast, somatomedin inhibitors (Kav 0.62 to 0.88) began to rise at 37 mg/kg streptozotocin and increased with higher dosage. Levels of somatomedins were correlated weakly only with beta-hydroxybutyrate (r = 0.48, P < 0.05), while somatomedin inhibitors were correlated significantly with all indices, particularly beta-hydroxybutyrate (r= 0.78, P < 0.0001). The early rise in somatomedin inhibitors but late fall in somatomedins could explain low somatomedin activity (and poor growth) despite normal levels of somatomedins measured by radioassay; measurement of somatomedin inhibitors may provide an index of growth potential in diabetes mellitus.
Oxidative interactions between hemoglobin and egg lecithin liposomes.

The oxidative interaction between hemoglobin and unsaturated egg lecithin liposomes, characterized by the consumption of oxygen and the production of methemoglobin over time, was measured and modelled. The oxygen and methemoglobin profiles were fit by a mathematical model, using numerical integration techniques. From the model, it was determined that the catalytic rate constants for the effect of hemoglobin on lipid peroxidation varied with hemoglobin type, as deoxyhemoglobin > oxyhemoglobin = methemoglobin. Under in vivo conditions of oxygen tension, reaction rates were oxyhemoglobin > deoxyhemoglobin > methemoglobin. Vitamin E had about 35 times the antioxidant activity of cholesterol, as determined by the model. Both additives, together, appeared to stabilize the liposomal membrane, as manifested by their ability to prevent oxidation of approximately 95% of the available lipid.
Mixed carbon nanotube bundles for interconnect applications

The increasing resistivity of copper with scaling and demands for higher current density are the driving forces behind the ongoing investigation for new wiring solutions for deep nanometer scale VLSI technologies. Metallic carbon nanotubes (CNTs) are promising candidates that can potentially address the challenges faced by copper, and thereby extend the lifetime of electrical interconnects. This article examines the state of the art in CNT applications with focus on CNT interconnect research. It is observed that individually, single-wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs) exhibit characteristics that can be better exploited when a combination of the two is used – in the form of a CNT bundle that plays a vital role in interconnect applications. The focus here is that the usage of a combination of SWCNT (at the centre area of the bundle) and MWCNT (on the outside) provides great performance boost with lower interaction and crosstalk between neighbouring CNT bundles. Simulatio...
Alternative Waste Management Strategies

The health care industry and, more specifically, the perioperative setting have a 30-year history of acquiring a complete disposable habit. The fast-paced nature of perioperative nursing allows little time to contemplate the costs or impact of these practices; however, nurses are increasingly aware and concerned for their own safety and the safety of those who may be exposed to potential disease-causing materials. It seems to be the time to reconsider the benefits and liabilities of our practice habits. In the absence of definitive, conclusive, and compelling unbiased scientific evidence, we are directed by industry rather than by our own profession.
Photoperiodic activation of brains in castrates and the role of the gonad in reproductive maturation of Limax maximus

Results obtained with castration and gonad implantation verify that a factor(s) from the gonad is required for development of the female accessory sex organs (ASO) inLimax maximus. In addition, they show that a gonadal factor promotes rapid gonadal growth and sperm production, and gradual or incomplete development of the penis. Although an immature slug that is castrated and then switched to inductive photoperiods fails to exhibit reproductive tract maturation, in two differently designed experimental tests, the brains of such animals were able to promote sexual maturation when subsequently paired with an immature gonad. We interpret the results of these experiments as evidence for photoperiodic induction of secretion of maturation-inducing factor (MH) by the brain in the absence of the gonad. One or more gonadal hormones appear to be both necessary and sufficient for production of sperm and for development of ASO, but they are not required for the photoperiodic stimulation of MH release.
Crystal Structure of a Flp Recombinase-Holliday Junction Complex: Assembly of an Active Oligomer by Helix Swapping

Abstract The crystal structure of a Flp recombinase tetramer bound to a Holliday junction intermediate has been determined at 2.65 A resolution. Only one of Flp's two domains, containing the active site, is structurally related to other λ integrase family site-specific recombinases, such as Cre. The Flp active site differs, however, in that the helix containing the nucleophilic tyrosine is domain swapped, such that it cuts its DNA target in trans. The Flp tetramer displays pseudo four-fold symmetry matching that of the square planar Holliday junction substrate. This tetramer is stabilized by additional novel trans interactions among monomers. The structure illustrates how mechanistic unity is maintained on a chemical level while allowing for substantial variation on the structural level within a family of enzymes.
The Effects of Sensory-Based Treatment of Drooling in Children

Drooling has been attributed to the incoordination of the oro-facial muscles. Frequently, children who drool are able to eat and drink normally but do not respond to the sensory information provided by their own secretions in order to swallow in a timely manner. We describe a sensory-based therapy for the management of drooling based upon the hypothesis that drooling is not always due to muscle dysfunction but is often a sensory problem. Three developmentally delayed children, aged 6-7 years, were selected for this pilot study. All demonstrated adequate oral-motor coordination for the management of liquids and solid food consistencies at mealtime and were able to follow simple directions. Two were able to speak in sentences, while the other had limited verbal communication skills due to severe oral apraxia but was able to use sign language. All subjects also exhibited language delays. None were diagnosed with cerebral palsy.Children were clinically treated using a flavored alcohol/propylene glycol stimulu...
Promotion of Germination of Striga asiatica Seed by Coumarin Derivatives and Effects on Seedling Development

OUR efforts to isolate and characterize the Striga germination stimulant in root exudates of maize were accompanied by testing more than 270 compounds for their capacity to stimulate germination. A previous paper1 reported the stimulation of Striga asiatica (witchweed) seed germination and described morphogenic effects on the seedlings induced by kinetin and certain other 6-(substituted) purines. This communication reports the results obtained with 41 coumarin derivatives, two of which stimulated germination of witchweed seeds.
Interactions between neural membrane glycerophospholipid and sphingolipid mediators: A recipe for neural cell survival or suicide

The neural membranes contain phospholipids, sphingolipids, cholesterol, and proteins. Glycerophospholipids and sphingolipids are precursors for lipid mediators involved in signal transduction processes. Degradation of glycerophospholipids by phospholipase A(2) (PLA(2)) generates arachidonic acid (AA) and docosahexaenoic acids (DHA). Arachidonic acid is metabolized to eicosanoids and DHA is metabolized to docosanoids. The catabolism of glycosphingolipids generates ceramide, ceramide 1-phosphate, sphingosine, and sphingosine 1-phosphate. These metabolites modulate PLA(2) activity. Arachidonic acid, a product derived from glycerophospholipid catabolism by PLA(2), modulates sphingomyelinase (SMase), the enzyme that generates ceramide and phosphocholine. Furthermore, sphingosine 1-phosphate modulates cyclooxygenase, an enzyme responsible for eicosanoid production in brain. This suggests that an interplay and cross talk occurs between lipid mediators of glycerophospholipid and glycosphingolipid metabolism in brain tissue. This interplay between metabolites of glycerophospholipid and sphingolipid metabolism may play an important role in initiation and maintenance of oxidative stress associated with neurologic disorders as well as in neural cell proliferation, differentiation, and apoptosis. Recent studies indicate that PLA(2) and SMase inhibitors can be used as neuroprotective and anti-apoptotic agents. Development of novel inhibitors of PLA(2) and SMase may be useful for the treatment of oxidative stress, and apoptosis associated with neurologic disorders such as stroke, Alzheimer disease, Parkinson disease, and head and spinal cord injuries.
Quantum Relations in Photo-Electric Phenomena.

For the past ten years I have been engaged with experiments which were designed for the sake of subjecting Einstein's photo-electric quantum-theory equation to searching experimental tests, and although I have at times thought that I had evidence which was irreconcilable with that equation, the longer I have worked and the more completely I have eliminated sources of error the better has the equation been found to predict the observed results. I shall present herewith the barest sketch of six consequences of that equation and their experimental verification. Preliminary reports on some of these results have already been made (1) and detailed reports will be found in forthcoming numbers of the Physical Review.
Soft-x-ray and x-ray ultraviolet radiation from high-density aluminum plasmas

Radiation emission over a wide range (5--5000 A) of wavelengths in a high-density aluminum plasma has been studied theoretically. The atomic model includes explicit treatment of a large number of states and transitions characterizing the line emission from the Al III--Al XIII ions. The state populations are calculated using a set of atomic rate equations describing a plasma in collisional-radiative equilibrium. The ionization state of the plasma is calculated self-consistently with line and continuum radiation transport using a one-dimensional multicell structure for the plasma. A new radiation transport scheme has been implemented in this model based on probability of escape for both line and continuum photons. The total L- and K-shell radiation emission is described as a function of plasma temperature, density, and source size, and is compared to predictions made from corona and local thermodynamic equilibrium models. It is shown that over a wide range of plasma parameters, neither of these two limiting models accurately describes the plasma emission characteristics. Several line intensity ratios from L-shell lines are studied and shown to be useful diagnostic indicators of the plasma temperature and density. Finally, theoretical spectra are calculated and discussed in the context of their comparability with experimental spectra inmore » order to make contact with real plasma radiation signatures and exploit the predictive capabilities of the model.« less
A systematic review of medical therapy for anal fissure.

Purpose: This is a meta-analysis of randomized, controlled trials to assess the efficacy and morbidity of medical therapies for anal fissure. Methods: Medline and the Cochrane Controlled Trials Register and the Cochrane Colorectal Cancer Review Groups Controlled Trials Register were searched using the terms “anal fissure randomized” from 1966 to 2002. Studies in which participants were randomized to a nonsurgical therapy for anal fissure were the focus of this review. Comparison groups included an operative procedure, an alternate medical therapy, or placebo. Chronic fissure, acute fissure, and fissure in children were included in the review, however, atypical fissure associated with inflammatory bowel disease, cancer, or anal infection were excluded. Data were abstracted from published reports and meeting abstracts, assessing method of randomization, blinding, “intention to treat” and dropouts, therapies, supportive measures, dosing and frequency, and crossovers. Outcome measures included nonhealing of the fissure and adverse events. Results: Twenty one different comparisons of medical therapies to heal anal fissure have been reported in 31 trials, including 9 agents—glyceryl trinitrate, isosorbide dinitrate, botulinum toxin, diltiazem, nifedipine, hydrocortisone, lidocaine, bran, placebo—as well as anal dilators and surgical sphincterotomy. Glyceryl trinitrate was favored in the analysis over placebo (odds ratio =0.55, 95 percent confidence interval, 0.41–0.74). After excluding two studies from analysis because of placebo response rates < 2 standard deviations below the mean for all studies, the advantage of glyceryl trinitrate over placebo was no longer statistically significant (odds ratio = 0.78; 95 percent confidence interval, 0.56–1.08). Nifedipine and diltiazem did not differ from glyceryl trinitrate in their ability to cure fissure (0.66; 0.22–2.01). Botulinum toxin compared with placebo showed no significant efficacy (0.75; 0.32–1.77), and was also no better than glyceryl trinitrate (0.48; 0.21–1.10). Surgery was more effective than medical therapy in curing fissure (0.12; 0.07–0.22). Conclusions: Medical therapy for chronic anal fissure, acute fissure, and fissure in children may be applied with a chance of cure that is only marginally better than placebo, and for chronic fissure, far less effective than surgery.
Cesium Hydroxide Promoted Chemoselective N-Alkylation for the Generally Efficient Synthesis of Secondary Amines

Selective N-alkylation of primary amines was developed using cesium hydroxide to prepare various secondary amines efficiently. A cesium base not only promoted monoalkylations of primary amines but also suppressed overalkylations. Various amines and alkyl bromides were examined, and the preliminary results demonstrated this methodology was highly chemoselective, favoring mono-N-alkylation over dialkylation. In particular, use of amino acid derivatives afforded the desired secondary amines exclusively.
Social structure of Atlantic spotted dolphins, Stenella frontalis, following environmental disturbance and demographic changes

Extreme environmental events and demographic changes can have variable effects on the social structure of animal populations. This study compared the social structure of a community of Atlantic spotted dolphins in the Bahamas before and after two hurricanes. Approximately 36% of the individuals were lost, with no subsequent increase in immigration. The majority of the social structure characteristics were consistent with results from a long-term study covering the previous 12 yr, including community structure with definitive social clusters, sex preferences and overall association patterns. However some changes occurred, though still constrained within sex preferences. Posthurricane there was a decrease in social differentiation and increased cohesion within clusters and across age class. Males retained or made new first order alliances, however, only one second order alliance was evident, revealing a simplified alliance structure. Juvenile individuals made alliance level associations, unprecedented from long-term analysis. Although other studies have shown stark restructuring, this study showed that less drastic changes within overall social structure stability can occur. Persistence and evolutionary changes in populations through environmental and/or demographic perturbations may depend on the social structure of a population or community. Understanding the processes involved in social development is paramount for conservation of diverse populations.
Vesicle Permeabilization by Protofibrillar α-Synuclein Is Sensitive to Parkinson's Disease-Linked Mutations and Occurs by a Pore-like Mechanism†

Two mutations in the protein α-synuclein (A30P and A53T) are linked to an autosomal dominant form of Parkinson's disease. Both mutations accelerate the formation of prefibrillar oligomers (protofibrils) in vitro, but the mechanism by which they promote toxicity is unknown. Protofibrils of wild-type α-synuclein bind and permeabilize acidic phospholipid vesicles. This study examines the relative membrane permeabilizing activities of the wild type, mutant, and mouse variants of protofibrillar α-synuclein and the mechanism of membrane permeabilization. Protofibrillar A30P, A53T, and mouse variants were each found to have greater permeabilizing activities per mole than the wild-type protein. The leakage of vesicular contents induced by protofibrillar α-synuclein exhibits a strong preference for low-molecular mass molecules, suggesting a pore-like mechanism for permeabilization. Under conditions in which the vesicular membrane is less stable (lack of calcium as a phospholipid counterion), protofibril permeabili...
Miocene extension and fault-related folding in the Highland Range, southern Nevada: a three-dimensional perspective

Abstract The Highland Range of southern Nevada contains a major anticline and syncline that constitute the westernmost segments of the Black Mountains accommodation zone in the highly extended Colorado River extensional corridor. The folds are defined by thick tilted sections of Miocene volcanic and sedimentary strata that accumulated immediately prior to and during regional extension. The folds are generally symmetrical, with interlimb angles that exceed 90°, subhorizontal hingelines, and steeply inclined axial surfaces. East- and west-dipping normal faults dominate the west- and east-tilted limbs of the folds, respectively. The limbs of the folds are parts of major half grabens. Tilt fanning within these half grabens and 15 new 40Ar/39Ar dates bracket major extension between about 16.5 and 11 Ma. Tilting of the opposing fold limbs occurred simultaneously and was contemporaneous with extension. The anticline and syncline are therefore interpreted as fault-related extensional folds produced by the partial, along-strike overlap of oppositely dipping normal-fault systems and attendant tilt-block domains. The anticline developed between overlapping listric normal faults that dip toward one another, including the east-dipping McCullough Range and west-dipping Keyhole Canyon faults. Each limb of the anticline is a rollover fold developed in the hanging wall of the inwardly dipping listric normal faults. The syncline formed between overlapping outwardly dipping listric faults, as adjacent fault blocks were tilted toward one another. The dominant folding style was fault-bend folding, with drag-folding and displacement-gradient folding playing subsidiary roles. The anticline and syncline significantly affected depositional patterns, with synextensional units, including two major ash-flow tuffs, thinning toward the anticlinal hinge and thickening toward the synclinal hinge. The Black Mountains accommodation zone is largely composed of intersecting northwest-trending anticlines and northeast-trending synclines, both occurring at a variety of scales depending on the amount of overlap between the opposing normal-fault systems. This three-dimensional geometry contrasts with the typical style of folding in contractional settings and may characterize extensional accommodation zones that include the partial along-strike overlap of multiple, oppositely dipping normal faults. The folds in the Highland Range serve as well-exposed analogues of similar features in hydrocarbon-rich areas of submerged continental margins.
Consequences of supergravity with gauged U (1) R symmetry

Abstract The structure of gauged R - supergravity Lagrangians is reviewed, and we consider models with a hidden sector plus light fields of the MSSM. A simple potential for the hidden sector is presented which has a global minimum with zero cosmological constant and spontaneously broken SUSY and R -symmetry. The U(1) R vector multiplet acquires a Planck scale through the Higgs mechanism, and it decouples at low energy. Due to very interesting cancellations, the U(1) R D -terms also drop out at low energy. Thus no direct effects of the gauging of R -symmetry remain in the low-energy effective Lagrangian, and this result is model independent, requiring only that R -symmetry be broken at the Planck scale and 〈 D 〉 = 0, where D is the auxiliary field of the U(1) R vector multiplet. The low-energy theory is fairly conventional with soft SUSY breaking terms for the MSSM fields. As a remnant of the gauging of R -symmetry, it also contains light fields, some required to cancel R -anomalies and others from the hidden sector.
Resonant tunneling in a multi-channel wire

Abstract We calculate analytically the transmission coefficient through two delta function barriers in a quasi-one-dimensional wire as the Fermi energy and distance between scatterers are varied. In a purely one-dimensional or single-mode system, the transmission coefficient is periodic as a function of distance between scatterers with successive resonances separated by half the wavelength of the incident electron. In a two-mode system we find unusual modifications to this result when the Fermi energy is near the second subband minimum. First, the presence of the evanescent mode causes successive resonances in the transmission coefficient to be separated by a full wavelength rather than by a half wavelength. Furthermore, when the Fermi energy coincides with the second subband minimum, the transmission approaches unity for scatterer separations larger than a few wavelengths and is therefore no longer a periodic function of distance between scatterers.
Understanding nonviral nucleic acid delivery with quantum dot-FRET nanosensors.

Nonviral delivery of nucleic acids is a potentially safe and viable therapeutic modality for inherited and acquired diseases. However, current systems have proven too inefficient for widespread clinical translation. The rational design of improved carriers depends on a quantitative, mechanistic understanding of the rate-limiting barriers to efficient intracellular delivery. Separation of the nucleic acid from the carrier is one of the barriers, which may be analyzed by Forster resonance energy transfer (FRET), a mechanism used to detect interactions between fluorescently labeled molecules. When applied to the molecular components of polymer or lipid-based nanocomplexes, FRET provides information on their complexation status, uptake, release and degradation. Recently, the design of FRET systems incorporating quantum dots as energy donors has led to improved signal stability, allowing prolonged measurements, as well as increased sensitivity, enabling direct detection and the potential for multiplexing. The union of quantum dots and FRET is providing new insights into the mechanisms of nonviral nucleic acid delivery through convergent characterization of delivery barriers, and has the potential to accelerate the design of improved carriers to realize the potential of nucleic acid therapeutics and gene medicine.
Stable transfection of GH3 cells with rat gonadotropin-releasing hormone receptor complementary deoxyribonucleic acid results in expression of a receptor coupled to cyclic adenosine 3',5'-monophosphate-dependent prolactin release via a G-protein.

GH3 cells, which normally release PRL in response to stimulation by TRH, have been stably transfected with rat GnRH receptor complementary DNA (GGH3-1' cells). Unlike the parent line, GGH3-1' cells express GnRH receptor, which can be measured in a radioligand assay using a metabolically stable GnRH analog. The number of receptors (11,000 +/- 2,800 receptors/cell; n = 3) and Kd (4.1 +/- 1.0 x 10(-8) M; n = 3), determined using a radioiodinated GnRH agonist, as well as binding inhibition values for GnRH agonists and antagonists and for unrelated substances suggest that this receptor is similar to those expressed in cell cultures derived from rat pituitaries, although the binding affinity is about 1 log lower in the former. Unlike GnRH-stimulated release of gonadotropins from primary pituitary cultures, which does not require protein synthesis and is not coupled to cAMP production, GnRH-stimulated PRL release from the transfected cell line is absolutely dependent on protein synthesis, and cAMP fulfills the r...
Truncation of the human adenovirus type 5 L4 33-kDa protein: evidence for an essential role of the carboxy-terminus in the viral infectious cycle.

The subgroup C human adenovirus L4 33-kDa protein is a nuclear phosphoprotein that plays a direct, but dispensable, role in virion assembly. The r-strand open reading frame (ORF) for this protein lies opposite to the 5' end of the l-strand E2 early (E2E) transcription units. To facilitate studies of regulation of E2E transcription, we wished to construct a mutant virus in which the 33-kDa ORF was truncated to serve as a background into which specific E2E mutations could be introduced without also altering the 33-kDa protein. We constructed viral DNA (vDNA) containing within the 33-kDa ORF two tandem, premature stop codons that should prevent translation of the C-terminal 47 amino acids of the protein (Delta47). We report here the unanticipated lethality of such truncation of the L4 33-kDa protein. Viral DNA harboring the Delta47 mutations did not produce infectious virus when transfected into cultured cells. In contrast, infectious virus was recovered upon transfection of revertant vDNA, indicating that the Delta47 mutations were responsible for the observed phenotype. The Delta47 mutations did not affect E2E transcription or production of the E2 DNA-binding protein. Transfected Delta47 vDNA was replicated and directed the production of early and late viral proteins, including hexon protein in the trimer conformation. However, no virus particles of any kind were produced. We propose that truncation of the adenovirus 33-kDa protein results in a lethal, late block in the infectious cycle during the assembly of progeny virions and discuss the implications of this phenotype for the mechanism of virion assembly.
Structure-activity relationship of the beta adrenoreceptor blocking agents

Abstract The β-adrenoreceptor blocking activity of the nitro and the methyl substituted phenylethanolamine and phenoxypropanolamine series of agents was determined in the isolated turtle heart preparation. The pA2 values for both INPEA and para-methylisoproterenol were found to be 6.9. In the n-isopropylphenoxypropanol derivatives, substitution with a methyl group in the meta position of the phenolic nucleus yielded the most active compound (Ko 592) which has a pA2 value of 8.3. The adrenoreceptor blocking activity was greatly reduced when the methyl substitution was made in either para or ortho positions in this series. In the nitro substituted compounds, however, the blocking activity is markedly reduced in the phenoxypropanolamine series of agents as compared to the phenylethanolamine derivative (INPEA). The structural requirements for the two groups of β-adrenoreceptor blocking agents are different.
Nature and origin of matrix in the unique type 3 chondrite, Kakangari

The characteristics of the matrix of the Kakangari type-3 chondrite were investigated using high-resolution TEM and AEM. It was found that the textural and mineralogical characteristics of the fine-grained matrix of Kakangari are different from those of the other chondrite groups. Unlike the matrix phases present in the CV3 and CO3 chondrites, the matrix mineralogy of Kakangari contains clear information regarding its possible origin and thermal history. Data obtained are most consistent with an origin of Kakangari by annealing, without melting at high temperature (possibly during a chondrule-forming thermal event), of clusters or aggregates of ultrafine-grained amorphous or crystalline phases. The precursor materials were most likely to have been a mixture of nebula and presolar dust. Chondrules in Kakangari were probably formed from identical precursors to the matrix, but reached temperatures sufficiently high to produce melting.
Let's get practical

Chemistry needs an overhaul if it is to solve big global problems and advance fundamental understanding, say George M. Whitesides and John Deutch.
Alkali metal derivatives of sucrose. IV. The problem of ‘firmly bound’ ammonia

Liquid monomethylamine is inferior to liquid ammonia as a medium for the preparation of alkali metal derivatives of sucrose. Sodium is insoluble; lithium dissolves slowly to form a monolithium sucrate which still retains approximately one molecule of methylamine. All but 0·2% of the firmly bound ammonia was removed from a sample of trisodium sucrate by Soxhlet extraction with dimethoxyethane, although part of the sucrate was converted to the sodium hydroxide addition compound. Benzene under strictly anhydrous conditions extracts 44·8% of the bound ammonia without any decrease in sodium content. Optically active sucrose derivatives have been prepared by condensing benzene-and dimethoxyethane-extracted trisodium sucrose derivatives with 2-chloro-4, 6-bis-(2′-chloro-4′-nitrophenoxy)-s-triazine. Penta- and trisodium sucrates, which have not been extracted, give products with a low rotation. The presence of ammonia in sodium sucrate appears to have no effect on the polymerisation reaction with epichlorohydrin. γ-Irradiation of a polymer from monosodium sucrate causes a small but definite degradation to water-soluble products containing glucose, fructose and possibly organic acids.
27Al Solid-state nuclear magnetic resonance study of five-coordinate aluminum in augelite and senegalite

This is a report of 27Al magic-angle spinning, nuclear magnetic resonance spectroscopy of 5- and 6-coordinate aluminum in the aluminophosphate minerals augelite and senegalite. We have determined the quadrupolar coupling constants, asymmetry parameters and chemical shifts corrected for quadrupolar-induced shift for both aluminum coordination sites in each mineral. The quadrupolar coupling constants are significantly less in senegalite than in augelite. Structural analysis (viz., longitudinal- and shear-strain of the aluminum coordination polyhedra; coefficient-of-variation for both Al-O bond lengths and <O-Al-O bond angles) shows that both 5- and 6-coordinate aluminum sites in senegalite are less distorted than in augelite.
Short note on the scaling behavior of communication by ‘slithering’ on a supercoiled DNA

Abstract The first passage time τ for two sites on a supercoiled DNA molecule is analyzed as a function of both overall molecule length N and the length between the two sites n, using a previously introduced theory [J.F. Marko, Physica A 244 (1997) 263]. This time is shown to have the scaling form τ(n,N)∝n2f(n/N) where f(x) smoothly runs from 5.6 to 1 as x runs from 0 to 0.5. Therefore τ(n,N) has a strong dependence on intersite distance n and a much weaker dependence on molecular length N.
Rate of equilibration of a one-dimensional Wigner crystal

Abstract We consider a system of one-dimensional spinless particles interacting via long-range repulsion. In the limit of strong interactions the system is a Wigner crystal, with excitations analogous to phonons in solids. In a harmonic crystal the phonons do not interact, and the system never reaches thermal equilibrium. We account for the anharmonism of the Wigner crystal and find the rate at which it approaches equilibrium. The full equilibration of the system requires umklapp scattering of phonons, resulting in exponential suppression of the equilibration rate at low temperatures.
Transitions in immune responses to Mycobacterium paratuberculosis

The host immune response to infection with Mycobacterium paratuberculosis is paradoxical, with strong cell-mediated immune responses during the early, subclinical stages of infection and strong humoral responses during the late clinical stages of the disease. Cell-mediated immune responses modulated by various T cell subsets are essential to provide protective immunity and prevent progression of the disease. Secretion of cytokines by T cell populations serves to activate macrophages to kill ingested M. paratuberculosis as well as activate other T cell subsets to contain the infection. This paper reviews the current knowledge of T cell immune responses in M. paratuberculosis infection based upon clinical studies and research using mouse models.