cssi/SciSciGPT-SciSciNet huggingface dataset:
Thoracic Aorta and Supra-Aortic Arch Branches

Abstract The thoracic aorta and its supra-aortic arch branches experience physiologic strain induced by cyclic changes in both cardiac and respiratory mechanics. A complex interplay between aging, genetics, environmental factors, and cardiovascular disease yields additional influence on the structural and functional demands of the vascular system over our lifetime. In cases of aortic pathology treated with thoracic aortic stent grafts, segmental aortic wall stiffness is notably increased, with the greatest geometric deformation localized to the ascending aorta. Multiple investigations indicate that the stented descending thoracic aorta exhibits significantly less deformation during both the cardiac and respiratory cycles, including lower axial length, curvature, and diametric changes, as compared to the unstented ascending aorta. The aortic arch branches appear to exhibit less relative motion as compared to the thoracic aorta both acutely and in the long term. Additional investigation is warranted to better elucidate how the augmented mechanical stress and strain observed in the more proximal aorta will impact endografts relative to other aortic segments.
Prediction of Sewer Pipe Deterioration Using Random Forest Classification.

Wastewater infrastructure systems deteriorate over time due to a combination of physical and chemical factors. Failure of this significant infrastructure could affect important social, environmental, and economic impacts. Furthermore, recognizing the optimized timeline for inspection of sewer pipelines are challenging tasks for the utility managers and other authorities. Regular examination of sewer networks is not cost-effective due to limited time and high cost of assessment technologies and a large inventory of pipes. To avoid such obstacles, various researchers endeavored to improve infrastructure condition assessment methodologies to maintain sewer pipe systems at the desired condition. Sewer condition prediction models are developed to provide a framework to forecast the future condition of pipes to schedule inspection frequencies. The main goal of this study is to develop a predictive model for wastewater pipes using random forest classification. Predictive models can effectively predict sewer pipe condition and can increase the certainty level of the predictive results and decrease uncertainty in the current condition of wastewater pipes. The developed random forest classification model has achieved a stratified test set false negative rate, the false positive rate, and an excellent area under the ROC curve of 0.81 in a case study application for the City of LA, California. An area under the ROC curve > 0.80 indicates the developed model is an "excellent" choice for predicting the condition of individual pipes in a sewer network. The deterioration models can be used in the industry to improve the inspection timeline and maintenance planning.
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY IMPROVES SYMPTOMS AFTER FOUR YEARS OF PULMONARY VEIN OCCLUSION

Pulmonary vein stenosis is a known complication of atrial fibrillation ablation. As a result, patients can develop shortness of breath, cough, chest pain, hemoptysis and recurrent lung infections. A 78 year-old female with a history of atrial fibrillation status-post multiple ablations, known left
A systematic review to evaluate the clinical outcomes in COVID -19 patients on angiotensin converting enzyme inhibitors or angiotensin receptor blockers

Abstract Introduction Angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) share their target receptor site with the SARS-CoV-2 virus, that may cause ACE2 receptor upregulation which raised concerns regarding ACEI and ARB use in COVID-19 patients. However, many medical professional societies recommended their continued use given the paucity of clinical evidence but there is need for an updated systematic review of latest clinical studies. Methods A search was conducted on PubMed, Google Scholar, EMBASE and various preprint servers for studies comparing clinical outcomes and mortality in COVID-19 patients on ACEI and/or ARB. Results A total of eight studies were included in the review There were conflicting findings reported in several studies as Meng J. et al, Liu Y. et al and Feng Y. reported that patients on ACE inhibitors/ARB had lower rates of severe outcomes whereas Richardson S. et al reported higher rates of invasive ventilation and intensive care unit (ICU) admissions in patients on ACE inhibitors/ARB as compared to non-users. However, Zhang P. et al found slightly higher rates of ICU admissions in patients on ACE inhibitors and ARB as compared to non-users. Similarly, there were conflicting results in the rate of mortality reported by the various clinical studies as well. Meng J. et al, Li J. et al and Zhang P. et al reported lower rates of mortality in ACE inhibitors/ARB users versus non-users whereas Guo J. et al reported higher rates of mortality in patients on ACE inhibitors/ARB as compared to non-users. Additionally, a large study conducted in New York by Richardson S. et al raised concerns with worse mortality outcomes in patients on ACEI/ ARB. Conclusion It is concluded that ACEI and ARB should be continued in COVID-19 patients, albeit while exercising caution until larger clinical studies and randomized controlled trials confirm their safety. Additionally, the individual patient factors like ACE2 polymorphisms which might confer higher risk of adverse outcomes need to be evaluated further.
Dual sensory impairment in older adults and risk of dementia from the GEM Study.

Introduction Hearing and vision loss are independently associated with dementia, but the impact of dual sensory impairment (DSI) on dementia risk is not well understood. Methods Self-reported measures of hearing and vision were taken from 2051 participants at baseline from the Gingko Evaluation of Memory Study. Dementia status was ascertained using standardized criteria. Cox models were used to estimate risk of dementia associated with number of sensory impairments (none, one, or two). Results DSI was significantly associated with higher risk of all-cause dementia (hazard ratio [HR] = 1.86; 95% confidence interval [CI] = 1.25-2.76) and Alzheimer's disease (HR = 2.12; 95% CI = 1.34-3.36). Individually only visual impairment was independently associated with an increased risk of all-cause dementia (HR = 1.32; 95% CI = 1.02-1.71). Discussion Older adults with DSI are at a significantly increased risk for dementia. Further studies are needed to evaluate whether treatments can modify this risk.
Nitrogen dioxide and asthma emergency department visits in California, USA during cold season (November to February) of 2005 to 2015: A time-stratified case-crossover analysis.

Abstract Nitrogen dioxide (NO2) is responsible for aggravating respiratory diseases, particularly asthma. The aim of this study is to investigate the association between NO2 exposure and asthma emergency department (ED) visits during the cold season (November–February) in five populated locations (Sacramento, San Francisco, Fresno, Los Angeles, and San Diego) of California from 2005 to 2015 (1320 Days). Conditional logistic regression models were used to obtain the odds ratio (OR) and 95% confidence interval (CI) associated with a 5 ppb increase in NO2 concentration for the 19,735 ED visits identified. An increase in NO2 exposure increased the odds of having asthma ED visits for the studied population. The potential effect modification by sex (female and male), race (White, Black, Hispanic, and Asian), and age (2–5, 6–18, 19–40, 41–64, and ≥65) was explored. A 5 ppb increase in the concentration of NO2 during lag 0–30 was associated with a 56% increase in the odds of having an asthma ED visit (OR = 1.560, CI: 1.428–1.703). Sex was not found to be a modifier. Asthma ED visits among all the races/ethnicities (except Asians) were associated with NO2 exposure. Whites had the highest OR 75% (OR = 1.750, CI: 1.417–2.160) at lag 0–30 in response to NO2 exposure. The association between NO2 exposure and asthma ED visits was positive among all age groups except for 19 to 40 years old; the OR was higher among 2 to 18 year old (at lag 0–30: age group 2–5 (OR = 1.699, CI: 1.399–2.062), and age group 6–18 (OR = 1.568, CI 1.348–1.825)). For stratification by location, San Diego and Fresno were found to have the highest OR, compared to the other studied locations.
Reforming International Investment Law for Climate Change Goals

To achieve global climate change mitigation and adaptation goals under the Paris Agreement, international investment law should enable and expedite the transition away from high-emission investment toward low-emission investment. Existing international investment agreements (IIAs) providing for investor–state dispute settlement (ISDS) fail to advance climate goals and can effectively hinder states’ climate action. In this chapter, I discuss the implementation of two main policy options for climate-oriented reform of international investment law – termination of climate-unfriendly IIAs and negotiation of climate-friendly ones – at various governance levels, ranging from unilateral to multilateral action. Given the mounting risks and impacts of IIAs and ISDS, as well as the lack of evidence that they encourage foreign investment flows, terminating IIAs or withdrawing from them appears to be the most effective reform option. States seeking to conclude new climate-friendly treaties or to amend existing IIAs must ensure that the treaties legally distinguish between low-emission and high-emission investments. Climate-friendly IIAs must not hinder climate action (‘do no harm’), by denying treaty protections to high-emission investments, limiting their establishment and expansion, removing incentives such as fossil fuel subsidies, and requiring investments to be made responsibly. In addition, IIAs should leverage the potential contribution of foreign investment to climate goals (‘do good’), by incentivising, promoting, facilitating, and protecting low-emission investments only, and by supporting a just transition to a low-emission world. In line with broader efforts to reform international investment law, climate-aligned IIAs should also exclude or circumscribe controversial provisions (fair and equitable treatment [FET], legitimate expectations, indirect expropriation, and most-favoured-nation [MFN], to name a few), prohibit treaty-based challenges to climate policy measures, and deny substantive rights and access to treaty-based dispute settlement mechanisms to high-emission investments. Climate-unfriendly investors would instead need to rely on substantive rights and procedural avenues based on domestic laws.
Evaluating the Longevity of the Fontan Pathway

Children born with single ventricle physiology who undergo Fontan palliation face a diverse set of long-term complications. However, patient follow-up has in large part been limited to single institutional experiences without uniform application of diagnostic modalities to screen for relevant outcomes. Additionally, the use of different graft materials and variable surgical technique as part of the Fontan procedure has further complicated the evaluation of single ventricle patients. The purpose of this review is to define the changes in the Fontan pathway specific to the graft material used and its relationship to patient outcomes. As a means of introduction, we briefly review the historical evolution of the Fontan procedure with a focus on the intent behind design changes and incorporation of different biomaterials. We further delineate changes to the Fontan pathway which include the development of stenosis, differential growth, thrombosis, and calcification. Ultimately, the recognition of the changes noted within the Fontan pathway need to be assessed relative to their impact on patient hemodynamics, functional capacity, and Fontan-associated comorbidities.
The Inviscid Three Dimensional Quasi-Geostrophic System on Bounded Domains

We present a formal derivation of the inviscid three dimensional quasi-geostrophic system (QG) from primitive equations on a bounded, cylindrical domain. A key point in the derivation is the treatment of the lateral boundary and the resulting boundary conditions it imposes on solutions. To our knowledge, these boundary conditions are new and differentiate our model from closely related models which have been the object of recent study. These boundary conditions are natural for a variational problem in a particular Hilbert space. We construct solutions and prove an elliptic regularity theorem corresponding to the variational problem, allowing us to show the existence of global weak solutions to QG.
Conservation of angular momentum in an elastic medium with spins

Exact conservation of the angular momentum is worked out for an elastic medium with spins. The intrinsic anharmonicity of the elastic theory is shown to be crucial for conserving the total momentum. As a result, any spin-lattice dynamics inevitably involves multiphonon processes and interaction between phonons. This makes transitions between spin states in a solid fundamentally different from transitions between atomic states in a vacuum governed by linear electrodynamics. Consequences for using solid-state spins as qubits are discussed.
ErbB3 is a critical regulator of cytoskeletal dynamics in brain microvascular endothelial cells: Implications for vascular remodeling and blood-brain-barrier modulation:

Neuregulin (NRG)1 - ErbB receptor signaling has been shown to play an important role in the biological function of peripheral microvascular endothelial cells. However, little is known about how NRG1/ErbB signaling impacts brain endothelial function and blood-brain barrier (BBB) properties. NRG1/ErbB pathways are affected by brain injury; when brain trauma was induced in mice in a controlled cortical impact model, endothelial ErbB3 gene expression was reduced to a greater extent than that of other NRG1 receptors. This finding suggests that ErbB3-mediated processes may be significantly compromised after injury, and that an understanding of ErbB3 function would be important in the of study of endothelial biology in the healthy and injured brain. Towards this goal, cultured brain microvascular endothelial cells were transfected with siRNA to ErbB3, resulting in alterations in F-actin organization and microtubule assembly, cell morphology, migration and angiogenic processes. Importantly, a significant increase in barrier permeability was observed when ErbB3 was downregulated, suggesting ErbB3 involvement in BBB regulation. Overall, these results indicate that neuregulin-1/ErbB3 signaling is intricately connected with the cytoskeletal processes of the brain endothelium and contributes to morphological and angiogenic changes as well as to BBB integrity.
The Characters (Χαρακτῆρες) of the Glagolitic Alphabet: New Light on an Old Puzzle

The article calls attention to a neglected source for the over-all “look and feel” of the Glagolitic alphabet as it was first created by Constantine the Philosopher circa 863 ad. This source is the variant forms of the Greek and other alphabets (including Hebrew and Arabic) that consist of so-called Brillenbuchstabe (otherwise characteres a lunettes or ring-letters). These variant alphabets were employed chiefly for esoteric purposes, including astrological and magical ones. Because of their limited use, they have largely been overlooked in standard handbooks of Greek and Oriental paleography. An interest in such subjects as astrology and magic comports poorly with routine assumptions about the inner lives of Medieval Saints such as Constantine. Relying on the extant primary sources for Constantine’s life, however, the article shows that his education, interests and mystical inclinations make a familiarity with some of these esoteric alphabets virtually certain. Thus it is historically plausible that such alphabets were among the inspirations for the general style, that is, the “look and feel”, of the letters of Constantine’s original glagolitic alphabet. (This article supplements the author’s earlier study from 2014, “A New Reconstruction of the Original Glagolitic Alphabet”.)
Bottom-up approaches to engineered living materials: Challenges and future directions

Summary Biomaterials made by living systems, while very diverse, generally share similar organization: different lineages of cells are precisely patterned within a matrix to create a hierarchically defined structure. This meticulous organization allows for their multifunctional properties, which often exceed those of traditional materials. For these reasons, there is growing interest in creating engineered living materials (ELMs) that will have capabilities similar to those of natural living materials yet with tailored functions. This review aims to highlight technologies still missing from the field of ELMs, which currently prevents more impactful applications. We briefly review the existing literature and identify challenges in designing novel protein-based and non-ribosomally synthesized matrix elements, producing and incorporating biominerals, and improving critical material properties such as lifespan, spatial patterning, and cell-cell communication. We also discuss the interplay between these challenges and the need for the development of new chassis and corresponding genetic toolboxes. By overcoming these obstacles, we come ever closer to unlocking the potential and versatility of biomaterials to create designer ELMs.
Rethinking Assumption of Risk and Sports Spectators

In 2002, the puck-related death of thirteen-year-old Brittanie Cecil at a National Hockey League game spurred calls for improved safety measures in professional sports arenas. However, common law tort principles--under which injured fans' claims have traditionally failed - are unlikely to provide the impetus for any such change. Under the “baseball rule,” stadium owners owe the “limited duty” of providing screened seats for as many fans as can reasonably be expected to desire them. However, some courts also applied assumption of risk as an affirmative defense without explicitly differentiating between it and the baseball rule. Uncertainty over the extent to which the two doctrines overlap posed a particular problem in jurisdictions in which the abolition of contributory negligence partially overruled the assumption of risk defense.Recently, in Knight v. Jewett, a plurality of the California Supreme Court held that assumption of risk now operates as an entirely duty-based doctrine. Subsequent California appellate courts opine that Knight replaces the limited duty of the baseball rule with a doctrine in which stadium owners owe fans a mere duty not to increase a sport's inherent risks. In this Comment, David Horton contends that a close examination of Knight and its underlying principles casts doubt on this conclusion. Even though Knight substitutes a duty-based regime for cases previously resolved under the rubric of assumption of risk, its approach is entirely consistent with the application of the duty-based baseball rule to cases of fan injury. To conclude otherwise treats fans and athletes identically, neglecting both the vast difference between their participatory roles, and modern tort law's penchant for allocating the burden of injury prevention entirely to business entities instead of to consumers. Yet, the baseball rule itself allows stadium owners to discharge their legal obligations by taking a single, anachronistic safety measure, thus creating little incentive to examine new methods of keeping fans safe.Horton concludes that stadium owners should instead owe fans a duty of reasonable care. This standard would force stadium owners to link safety measures to the specific manner in which fans are hurt and to update their precautionary measures as sports and technology evolve. In addition, the doctrine of comparative fault would assign liability in accordance with each party's blameworthiness, thus ameliorating concern that a duty of reasonable care would greatly increase stadium owners' liability for fan injuries.
Fast adaptive algorithms using eigenspace projections

Although adaptive gradient algorithms are simple and relatively robust, they generally have poor performance in the absence of "rich" excitation. In particular, it is well known that the convergence speed of the LMS algorithm deteriorates when the condition number of the input autocorrelation matrix is large. This problem has been previously addressed using weighted RLS or normalized frequency-domain algorithms. We present a new approach that employs gradient projections in selected eigenvector sub-spaces to improve the convergence properties of LMS algorithms for colored inputs. We also introduce an efficient method to iteratively update an "eigen subspace" of the autocorrelation matrix. The proposed algorithm is more efficient in terms of computational complexity, than the WRLS and its convergence speed approaches that of the WRLS even for highly correlated inputs. >
Alanine racemase of Pseudomonas: Observations on subtrate and inhibitor specificity

Abstract Systematic studies with purified alanine racemase and a number of substrate analogs permit the generalization that effective competitive inhibition is limited to 2- and 3-carbon compounds. A free α-amino group was not necessary for relatively tight binding; compounds lacking an amino group, or with an α-amino group acylated even by a bulky substituent, were bound as tightly as alanine. Substitution at the α-carbon of alanine (i.e., replacement of the α-H) eliminated binding, while substitution at the β-carbon generally reduced binding. Of several inhibitory compounds tested for substrate activity by H exchange with 3 H 2 O, only glycine appeared active. Covalent binding to the enzyme by halo analogs was not demonstrated.
Trade-offs in Organizational Architecture: Information Systems, Incentives and Work Design

We present a framework and a set of analytical models, which study functional and processoriented organizational design. Drawing from theories of information technology and organizational design, queuing theory, and principal-agent theory, we model simultaneous tradeoffs between different types of information systems, fixed and performance based incentives schemes, and variations in the design of work systems. The effects of crucial parameters such as knowledge intensity, information asymmetry, technology responsiveness, mass customization, and activity rates are also studied. We demonstrate that process-oriented organization is desirable when processes are large, when customers demand significant customization, and when the nature of work is such that information asymmetry is naturally high. However, functional organization is optimal in a number of contexts, particularly when work is knowledge intensive, technology responsiveness is low, when there is high variation in activity rates, and when processes in firms have few steps. While typical changes in work design are complemented by changes in either information technology or employee incentive schemes, we show that the simultaneous introduction of information systems and performance-based pay is not necessarily optimal; rather than being complementary, these changes are substitutable drivers of improved organizational performance. Our framework and results also provide significant context-specific managerial insight into the value of technologies such as intranets, knowledge management systems, expert systems and workflow management systems. In addition, we provide a general formulation and solution technique that will enable the modeling of hitherto intractable problems involving a principalagent problem in a tandem network of queues.
Spartina Revegetation on Dredge Spoil in SE Marshes

Spoil from the dredging of harbors, rivers, and the Inland Waterway when deposited on salt marshes often permanently destroy these important natural resources. Portions of destroyed marsh can be restored through transplantation of the major marsh plant Spartina alterniflora. This was accomplished in a typical silt-clay spoil site along the Intra-coastal Waterway in Georgia for less than –100/acre. Thirty percent of the transplants survived and are continuing to spread 18 months after planting. Elevation of the spoil is of prime importance for transplants and at lower elevations survival rates are as high as 75%. The use of seeds and nursery grown seedlings was not as successful; only 13% of the seeds germinated and none of the seedlings survived.
Thermodynamic analysis of quadrilateral pyroxenes

A thermodynamic model for quadrilateral pyroxene solutions, is developed from the following assumptions: 1) Non-convergent cation-disorder of Fe and Mg occurs over the Ml and M2 sites; 2) Ca is partitioned completely into the M2 site; and 3) Clinopyroxenes unmix to a high-Ca plus low-Ca phase. This ternary model is an extension of Thompson's (1969, 1970) binary model. Model expressions are presented that describe cation distributions, exchange equilibria and chemical potentials of both ternary and quadrilateral components.
Low Wind Speed Turbine Project Phase II: The Application of Medium-Voltage Electrical Apparatus to the Class of Variable Speed Multi-Megawatt Low Wind Speed Turbines; 15 June 2004--30 April 2005

Kilowatt ratings of modern wind turbines have progressed rapidly from 50 kW to 1,800 kW over the past 25 years, with 3.0- to 7.5-MW turbines expected in the next 5 years. The premise of this study is simple: The rapid growth of wind turbine power ratings and the corresponding growth in turbine electrical generation systems and associated controls are quickly making low-voltage (LV) electrical design approaches cost-ineffective. This report provides design detail and compares the cost of energy (COE) between commercial LV-class wind power machines and emerging medium-voltage (MV)-class multi-megawatt wind technology. The key finding is that a 2.5% reduction in the COE can be achieved by moving from LV to MV systems. This is a conservative estimate, with a 3% to 3.5% reduction believed to be attainable once purchase orders to support a 250-turbine/year production level are placed. This evaluation considers capital costs as well as installation, maintenance, and training requirements for wind turbine maintenance personnel. Subsystems investigated include the generator, pendant cables, variable-speed converter, and padmount transformer with switchgear. Both current-source and voltage-source converter/inverter MV topologies are compared against their low-voltage, voltage-source counterparts at the 3.0-, 5.0-, and 7.5-MW levels.
Deadenylation-Dependent and -Independent Decay Pathways for α1-Tubulin mRNA in Chlamydomonas reinhardtii

The alpha- and beta-tubulin mRNAs of Chlamydomonas reinhardtii exhibit different half-lives under different conditions: when expressed constitutively, they degrade with half-lives of about 1 h, whereas when induced by deflagellation, they degrade with half-lives of only 10 to 15 min. To investigate the decay pathway(s) used under these two conditions, an alpha1-tubulin gene construct which included an insert of 30 guanidylate residues within the 3' untranslated region was introduced into cells. This transgene was efficiently expressed in stably transformed cells, and the mRNA exhibited constitutive and postinduction half-lives like those of the alpha1-tubulin mRNA. Northern blot analysis revealed the occurrence of a 3' RNA fragment derived from the poly(G)-containing alpha1-tubulin transcripts. The 3' fragment was shown to accumulate as full-length mRNA disappeared in actinomycin D-treated cells, indicating a precursor-product relationship. Insertion of a second poly(G) tract upstream of the first resulted in accumulation of only a longer 3' fragment, suggesting that the decay intermediate is generated by 5'-to-3' exonucleolytic digestion. A translational requirement for generation of the 3' fragment was demonstrated by experiments in which cells were deflagellated in the presence of cycloheximide. Analysis of fragment poly(A) length revealed that the fragments were, at most, oligoadenylated in nondeflagellated cells but had a long poly(A) tail in deflagellated cells. These findings suggest that the oligoadenylated fragment is a decay intermediate in a deadenylation-dependent, constitutive degradation pathway and that the requirement for deadenylation is bypassed in deflagellated cells. This represents the first example in which a single transcript has been shown to be targeted to different decay pathways under different cellular conditions.
Effects of Aging-Time Reference on the Long Term Behavior of the IM7/K3B Composite

An analytical study was undertaken to investigate the effects of the time-based shift reference on the long term behavior of the graphite reinforced thermoplastic polyimide composite IM7/K3B at elevated temperature. Creep compliance and the effects of physical aging on the time dependent response was measured for uniaxial loading at several isothermal conditions below the glass transition temperture (T\sub{g}). Two matrix dominated loading modes, shear and transverse, were investigated in tension and compression. The momentary sequenced creep/aging curves were collapsed through a horizontal (time) shift using the shortest, middle and longest aging time curve as the reference curve. Linear viscoelasticity was used to characterize the creep/recovery behavior and superposition techniques were used to establish the physical aging related material constants. The use of effective time expressions in a laminated plate model allowed for the prediction of long term creep compliance. The effect of using different reference curves with time/aging-time superposition was most sensitive to the physical aging shift rate at lower test temperatures. Depending on the loading mode, the reference curve used can result in a more accurate long term prediction, especially at lower test temperatures.
Effects of pH on Kinetic Parameters of the Na-HCO3 Cotransporter in Renal Proximal Tubule

The effects of pH on cotransporter kinetics were studied in renal proximal tubule cells. Cells were grown to confluence on permeable support, mounted in an Ussing-type chamber, and permeabilized apically to small monovalent ions with amphotericin B. The steady-state, dinitrostilbene-disulfonate-sensitive current (DeltaI) was Na+ and HCO3- dependent and therefore was taken as flux through the cotransporter. When the pH of the perfusing solution was changed between 6.0 and 8.0, the conductance attributable to the cotransporter showed a maximum between pH 7.25 and pH 7.50. A similar profile was observed in the presence of a pH gradient when the pH of the apical solutions was varied between 7.0 and 8.0 (basal pH lower by 1), but not when the pH of the basal solution was varied between 7.0 and 8.0 (apical pH lower by 1 unit). To delineate the kinetic basis for these observations, DeltaI-voltage curves were obtained as a function of Na+ and HCO3- concentrations and analyzed on the basis of a kinetic cotransporter model. Increases in pH from 7.0 to 8.0 decreased the binding constants for the intracellular and extracellular substrates by a factor of 2. Furthermore, the electrical parameters that describe the interaction strength between the electric field and substrate binding or charge on the unloaded transporter increased by four- to fivefold. These data can be explained by a channel-like structure of the cotransporter, whose configuration is modified by intracellular pH such that, with increasing pH, binding of substrate to the carrier is sterically hindered but electrically facilitated.
Educational Implications of a Social Networking Application, Twitter™, for Anatomical Sciences

Social networking applications have become a ubiquitous part of daily life, especially for the current generation of students. Use of the social networking application, Twitter™, for education is explored in the current study. During a year-long, integrated basic science course, the instructors tweeted a multiple-choice question relating to course content after each lecture, followed by another tweet with the correct answer the following day. A Twitter™ link was made available to first- and second-year dental students with an option to sign up for “push” notifications on their smartphones. The second-year students were invited to take a pre-quiz before the Twitter™ feeds started and then a post-quiz 10 weeks later to attempt to quantify the educational value of the tweets. Further, students were invited to take a survey to measure their perception of the overall value of Twitter™ as an educational tool and to obtain their opinion on the usability of a social networking application for educational purposes. Results indicate that (1) students were not familiar with Twitter™ and voiced their desire for anatomy feeds through Facebook™ initially, (2) many students did not have Twitter™ accounts and had to create one, (3) second-year students preferred to have tweets “pushed” to their phones while most of the first-year students preferred to visit the Twitter™ site before course assessments, (4) most students found the Twitter™ feeds to be a good educational resource and planned to continue following the feeds, and (5) Twitter™ feeds complemented the second-year students’ ability to recall course material.
Polarizability of Solid H 2 and D 2

We have measured the dielectric constant e of solid H2 and D2 at several densities ρ as a function of temperature and have calculated the polarizability α using the Clausius-Mosotti relation $$ \frac{{\varepsilon - 1}} {{\varepsilon + 2}} = \rho \alpha \frac{{4\pi }} {3}\frac{1} {M} $$ (1) The aim of our experiments was to determine the effect on α caused by the orientational ordering of the H2 and D2 molecules with angular momentum J = 1, as predicted by Harris.1 The measurements were expected to show a dependence on the mole fraction X of molecules with J = 1. As a control of our experimental method we have also measured e in solid 4He and Ne, where a priori very little temperature dependence of α is expected.
Nanoparticle building blocks

Monolayer-protected clusters (MPCs) and mixed monolayer-protected clusters (MMPCs)2 provide crucial tools for bridging the gap between ‘bottomup’ synthetic methods and ‘top-down’ fabrication. MPCs are core-shell type systems that feature a metallic or semiconductor core functionalized with a self-assembled monolayer (SAM). This monolayer provides two key functions. Firstly preventing core-core contact that would lead to agglomeration and secondly providing a structured environment for the attachment of functional molecular entities, including devices and sensors. MMPCs feature multiple functionality on the shell monolayer, greatly extending the versatility of these core-shell systems.
Guidelines for human embryonic stem cell research.

Responding to a lack of US government leadership on the conduct of human embryonic stem cell research, a National Academies panel has proposed the creation of new institutional oversight committees.
Characterization of glycogens from mycobacteria

Abstract Glycogens from Mycobacterium phlei, M. smegmatis , and M. tuberculosis at various stages of cellular synthesis and degradation were isolated by a mild cold water procedure, purified and characterized. During glycogen synthesis and accumulation the degree of branching decreased and the outer branch length and the average sedimentation coefficient increased. As the glycogen was degraded by the cells, the degree of branching increased and the outer branch length and the average sedimentation coefficient decreased. At maximal glycogen content, M. phlei glycogen had a weight-average molecular weight of approximately 100 × 10 6 . Although mycobacterial glycogens are not sufficiently constant in physical properties to be characterized by a single set of parameters, they are, in general, more highly branched, with shorter outer branches than previously characterized Ascaris muscle, tapeworm, and mammalian liver and muscle glycogens. Glycogens extracted from M. phlei exhibited sedimentation coefficient distributions indicating a continuum of molecular weights. In electron micrographs, the mycobacterial glycogens appear as particles ranging from 0.02 to 0.15 μ in diameter.
High-Level Expression and Purification of MyoD, Myogenin, and E12

The myogenic regulatory factors (MRFs), MyoD, myogenin, Myf-5, and MRF4, function as transcriptional activators of muscle-specific gene expression by forming heterodimers with the ubiquitously expressed products of the E2A gene, E12 and E47. To enable quantitative biochemical and biophysical analyses of the wild-type proteins, as well as mutants designed to reveal structure-function relationships, we developed protocols for the high-level expression and rapid purification of milligram quantities of MyoD, myogenin, and E12 using conventional biochemical techniques. T7 expression systems were used to direct expression of cDNA encoded proteins in Escherichia coli. Whereas MyoD and E12 were expressed well without alteration, high-level expression of myogenin required changing several rare arginine codons by in vitro mutagenesis to a commonly used E. coli arginine codon. Presumably, inefficient translation of the rare arginine codons inhibited high-level expression of myogenin in the original expression plasmid. Purification protocols are described which involve a simple strategy of cell lysis, ammonium sulfate precipitation, and ion-exchange chromatography. Using this approach, 20 to 50 mg of MyoD, myogenin, or E12 can be purified to 90-95% homogeneity from induced cell pellets in 1 day's time.
Optical Solitons with Time-Dependent Dispersion, Nonlinearity and Attenuation in a Kerr-Law Media

This paper obtains the 1-soliton solution of the nonlinear Schrodinger’s equation with Kerr law nonlinearity and time-dependent dispersion, nonlinearity and attenuation. The solitary wave ansatze is used to obtain this solution. The constraint relation between these time-dependent coefficients is also obtained for the solitons to exist. The variation of the soliton velocity also falls out by this method.
Clinical use of naltrexone (EN-1639A): Part I: Safety and efficacy in pilot studies.

(1974). Clinical Use of Naltrexone (EN-1639A): Part I: Safety and Efficacy in Pilot Studies. The American Journal of Drug and Alcohol Abuse: Vol. 1, No. 2, pp. 253-269.
Paleomagnetic evidence for the age and extent of Middle Tertiary counterclockwise rotation, Dixie Valley Region, west central Nevada

Paleomagnetic data obtained from Oligocene to lower Miocene igneous rocks and middle Miocene basaltic rocks at fifteen localities from a region surrounding Dixie Valley in west central Nevada indicate that parts of the area experienced counterclockwise vertical-axis rotation, and these data provide constraints on the extent and timing of rotation. Counterclockwise vertical-axis rotation probably exceeding 30° is indicated for Oligocene to lower Miocene rocks in the central part of the study area. Calculated rotations increase with increasing age of the Oligocene to lower Miocene rocks, indicating that vertical-axis rotation was concurrent with ash-flow deposition (about 23–33 Ma). Paleomagnetic data indicate that middle Miocene basaltic rocks (about 10–17 Ma) postdate significant counterclockwise vertical-axis rotation, although this interpretation is complicated because the rocks were erupted episodically in pulses that apparently were short lived with respect to geomagnetic secular variation. Counterclockwise rotation was related to a deformation event that predated development of the present basin and range physiography of the area. The total amount of crustal rotation in Tertiary time in the area is poorly known. Rotation estimates calculated from time-averaged mean directions that incorporate data from a broad range of the Oligocene to lower Miocene units probably underestimate total Tertiary rotation because the mean directions include data from units that postdate much of the rotation. For example, a rotation estimate for a composite sequence from the central part of the study area is −23° ± 15°, whereas estimates from older and younger halves of the sequence are −37° ± 21° and −11° ± 16°, respectively. Paleomagnetic data indicate that Oligocene to lower Miocene rocks at some localities in the northern and southern parts of the study area (e.g., the Golconda Canyon locality) probably did not experience significant Tertiary counterclockwise rotation. Although the paleomagnetic data alone are insufficient to fully define the geographic area subjected to Tertiary counterclockwise rotation, the data suggest that a discrete subregion was affected rather than the entire Basin and Range province.
The Impact of CEO Characteristics on Corporate Social Performance

While there are growing bodies of research examining both the differences between strongly and poorly socially performing firms, and the impact of firm leaders on other strategic outcomes, little has been done in examining the effect of firm leaders on corporate social performance (CSP). This study directly addresses this issue by using upper echelon theory, and the KLD Research Analytics CSP ratings, to show that observable CEO characteristics predict differences in CSP between firms, even when firm and industry characteristics are controlled for. Using a sample of 650 public US firms I find that strong or exemplary CSP, as measured by the strengths categories of KLD’s ratings, is positively related to the CEO having a bachelor’s degree in humanities, having a breadth of career experience and being female. I find that KLD strength ratings are negatively related to the CEO having a bachelor’s degree in economics and to their level of short-term compensation. Preliminary tests of causality support the assertion that these effects reflect CEO discretion rather than being an artifact of reverse causality. Significant relationships between the CEO characteristics and poor social performance as measured by the concerns categories of KLD’s ratings are not found. This suggests that CEOs have more discretion in influencing strong and exemplary social performance than in impacting poor CSP. Implications, particularly for economics education, are discussed. While there are many fruitful directions for future research, the benefits and challenges to conducting similar studies in other countries is focused upon to correspond to the global nature of this special issue.
Uptake and metabolism of exogenous γ-aminobutyric acid by subcellular particles in a sodium-containing medium

A morphologically heterogeneous “mitochondrial” fraction was prepared from a sucrose homogenate of whole mouse brain. This particulate fraction, which contains endogenous γ-aminobutyric acid (γABA), was suspended for 10 min in an ice-cold buffered solution which contained Na+ ions and 14C-γABA. During this interval there was a Na+-dependent binding of 14C-γABA to the particles. The suspension was then incubated at 29°. This resulted in a rapid decrease in the total γABA content of the suspending medium and the particles and accumulation of non-volatile radioactive metabolites of γABA in the particles, and the liberation of 14CO2 from the suspension. The major radioactive metabolites were CO2 and aspartate. Glutamate and glutamine were found to a lesser extent. A purified microsomal fraction studied under the same conditions as the crude mitochondrial preparation rapidly released its γABA into the suspending medium at 29° and did not metabolize γABA. When K+ was substituted for Na+ in the test system, the particles of the mitochondrial suspension released γABA into the suspending medium, and some metabolism of endogenous γABA occurred. However, there appeared to be no entry of radioactive γABA into the particles. When the particles were suspended in 0.25 M sucrose, results were obtained similar to those seen in the K+-containing suspension with the exception that there was no decrease in the γABA content of the system.
Raman spectra of the hexahalogenated benzenes in the solid phase

Abstract Solid Raman spectra of the hexahalogenated benzenes are examined at both room and liquid nitrogen temperatures. Tentative assignments for C 6 C1 6 , C 6 Br 6 and C 6 I 6 are proposed on the basis of a puckered ( D 3 d ) geometry.
Duplicate sequences with a similarity to expressed genes in the genome of Arabidopsis thaliana

The proportion of non-tandem duplicated loci detected by DNA hybridization and the segregation of RFLPs using 90 independent randomly isolated cDNA probes was estimated by segregation analysis to be 17%. The 14 cDNA probes showing duplicate loci in progeny derived from a cross between Arabidopsis-thaliana ecotypes 'Columbia x Landsberg erecta' detected an average of 3.6 loci per probe (ranging from 2 to 6). The 50 loci detected with these 14 probes were arranged on a genetic map of 587 cM and assigned to the five A. Thaliana chromosomes. An additional duplicated locus was detected in progeny from a cross between 'Landsberg erecta x Niederzenz'. The majority of duplicated loci were on different chromosomes, and when linkage between duplicate locus pairs was detected, these loci were always separated by at least 15 cM. When partial nucleotide sequence data were compared with GENBANK databases, the identities of 2 cDNA clones which recognized duplicate unlinked sequences in the A. Thaliana genome were determined to encode a chlorophyll a/b-binding protein and a beta-tubulin. Of the 8 loci carrying beta-tubulin genes 6 were placed on the genetic map. These results imply that gene duplication has been an important factor in the evolution of the Arabidopsis genome.
Phylogenetic analysis of the promoter region of the CD40L gene in primates and other mammals.

Abstract CD40L is a type II membrane protein comprised of 261 amino acids. CD40L plays a crucial role in the immune system where it is primarily expressed on activated T cells and triggers immunoglobulin class switching. The genetic disease X-linked hypergammaglobulinemia (HIGM1, XHIGM or XHIM) is caused by mutations in the CD40L gene. Individuals with HIGM1 are susceptible to recurrent infections to pathogens and a relationship has been shown to exist with malaria [Sabeti, P., Usen, S., Farhadian, S., Jallow, M., Doherty, T., Newport, M., Pinder, M., Ward, R., Kwiatkowski, D., 2002a. CD40L association with protection from severe malaria. Genes Immun. 3, 286–291]. In this paper, we phylogenetically examine the promoter region of CD40L in primates and other mammals via phylogenetic shadowing. This analysis revealed several regions of the CD40L promoter that were highly constrained and thereby inferred to be functional. These constrained regions confirmed many known regulatory sites. In addition, a novel, highly constrained upstream region was also identified which had an NF-AT recognition motif. These analyses also showed that the different mammal groups do not share an exactly similar set of promoter binding sites and taxon-specific promoters have evolved.