cssi/SciSciGPT-SciSciNet huggingface dataset:
The role of white matter microstructure in inhibitory deficits in patients with schizophrenia.

Abstract Background Inhibitory-excitatory (I-E) imbalance has increasingly been proposed as a fundamental mechanism giving rise to many schizophrenia-related pathophysiology. The integrity of I-E functions should require precise and rapid electrical signal transmission. Objective/Hypothesis We hypothesized that part of the I-E abnormality in schizophrenia may originate from their known abnormal white matter connectivity that may interfere the I-E functions. Methods We test this using short-interval intracortical inhibition (SICI) vs. intracortical facilitation (ICF) which is a non-invasive measurement of I-E signaling. SICI-ICF from left motor cortex and white matter microstructure were assessed in schizophrenia patients and healthy controls. Results Schizophrenia patients showed significantly reduced SICI but not ICF. White matter microstructure as measured by fraction anisotropy (FA) in diffusion tensor imaging had a significant effect on SICI in patients, such that weaker SICI was associated with lower FA in several white matter tracts, most strongly with left corona radiata (r = −0.68, p = 0.0002) that contains the fibers connecting with left motor cortex. Left corticospinal tract, which carries the motor fibers to peripheral muscular output, also showed significant correlation with SICI (r = −0.54, p = 0.005). Mediation analysis revealed that much of the schizophrenia disease effect on SICI can be accounted for by mediation through left corona radiata. SICI was also significantly associated with the performance of processing speed in patients. Conclusion This study demonstrated the importance of structural circuitry integrity in inhibitory signaling in schizophrenia, and encouraged modeling the I-E dysfunction in schizophrenia from a circuitry perspective.
Hypoxic Preconditioning Increases Blood-Brain Barrier Disruption in the Early Stages of Cerebral Ischemia

Even though hypoxic preconditioning has been reported to produce neuroprotection, its effect on blood-brain barrier (BBB) disruption in the early stages of cerebral ischemia within the therapeutic window is not clear. Since hypoxic preconditioning increases expression of vascular endothelial growth factor (VEGF) that modulates vascular permeability, the effects of hypoxic preconditioning and VEGF on BBB permeability were investigated after one hour of focal cerebral ischemia. Rats were exposed to 8% of oxygen for two hours or room air and then 24 hours later, permanent middle cerebral artery (MCA) occlusion was performed. In some of the hypoxic preconditioned rats, a VEGF-A antibody was applied to the ischemic cortex one hour before MCA occlusion. One hour after MCA occlusion, the transfer coefficient (Ki) of 14C-α-aminoisobutyric acid was determined to measure the degree of BBB disruption. MCA occlusion increased the Ki when compared with the contralateral cortex (14.1 ± 4.0 vs 4.2 ± 1.9 μL/g/min, p < 0.0001). Hypoxic preconditioning further increased the Ki in the ischemic cortex when compared with the control rats (25.1 ± 8.7 μL/g/min, p < 0.01). Application of VEGF antibody to the ischemic cortex of the hypoxic preconditioned animals reduced the Ki to the level of the control rats (13.6 ± 5.1 μL/g/min, p < 0.01). Our data demonstrated that hypoxic preconditioning increased BBB disruption through a VEGF related pathway and suggest the possibility of aggravation of brain edema by hypoxic preconditioning in the early stages of cerebral ischemia.
Inter- and intra-seasonal changes in anthocyanin accumulation and global metabolite profiling of six blueberry genotypes

Abstract Anthocyanin content in six blueberry genotypes was evaluated across two harvest seasons. Three southern highbush (hybrids of Vaccinium corymbosum) genotypes (Legacy, Sampson, SHF2B1-21:3) showed a dramatic and almost linear increase in total anthocyanin content across each harvest season, with an increase of up to 20 mg/g dry weight (DW). The three rabbiteye (V. virgatum) genotypes (Ira, Montgomery, Onslow) showed no trend in anthocyanin content, fluctuating by up to 15 mg/g DW. The relative proportions of each individual anthocyanin were also investigated. Rabbiteye genotypes contained higher percentages of cyanidin glycosides than the southern highbush genotypes, while the reverse was found for the levels of delphinidin glycosides present. For southern highbush genotypes, the percentages of malvidin and delphinidin glycosides were inversely proportional across each harvest season. Principal component analysis on the data obtained by HPLC–MS of the crude extracts clearly separated rabbiteyes and southern highbush into two discrete sets based on global metabolite profiling. Within the southern highbush grouping, genotypes were easily distinguished from one another across each harvest season, due to their separation on the scores plot, indicating that each genotype had distinctly different metabolite profile, whereas each of the rabbiteye genotypes overlapped on the scores plot, indicating commonalities in metabolite profiles.
CUSP Properties for B y Domainant IMF

Cusp properties during periods of By dominant IMF are investigated, since previous studies focus mostly on IMF Bz. The model-data comparisons for various IMF configurations show that the model captures the large-scale features of the particle precipitation very well, not only in the cusp region, but also in other open-field line regions such as the mantle, polar rain, and open-field line low-altitude boundary layer (LLBL). When the IMF is strongly duskward/dawnward and weakly southward, the model predicts the occurrence of a double cusp near noon: one cusp at lower latitude and one at higher latitude. The lower latitude cusp ions originate from the low-latitude magnetosheath whereas the higher latitude ions originate from the high-latitude magnetosheath. The lower latitude cusp is located in the region of weak azimuthal E×B drift, resulting in a dispersionless cusp. The higher latitude cusp is located in the region of strong azimuthal and poleward E×B drift. Because of a significant poleward drift, the higher latitude cusp dispersion has some resemblance to that of the typical southward IMF cusp. Occasionally, the two parts of the double cusp have such narrow latitudinal separation that they give the appearance of just one cusp with extended latitudinal width. From the 40 DMSP passes selected during periods of large (positive or negative) IMF By and small negative IMF Bz, 30 (75%) of the passes exhibit double cusps or cusps with extended latitudinal width. The double cusp result is consistent with the following statistical results: (1) the cusp’s latitudinal width increases with ∣IMF By∣ and (2) the cusp’s equatorward boundary moves to lower latitude with increasing ∣IMF By∣.
Stacking sequence optimization for maximizing the first failure initiation load followed by progressive failure analysis until the ultimate load

Abstract For laminated plates deformed statically with transverse normal tractions applied on a major surface, we use honeybees inspired Nest-Site Selection (NeSS) optimization algorithm, a third order shear and normal deformable plate theory (TSNDT), and the finite element method to find an optimum stacking sequence that maximizes the first failure load according to the Tsai-Wu criterion. An optimum lay-up of fibers in different layers depends upon the starting estimate and is not unique. In the TSNDT, we express each displacement component at a point as a complete polynomial of degree three in the thickness coordinate. Subsequent to finding an optimum stacking sequence, we perform progressive failure analysis to determine the ultimate load by degrading elasticities of the material at an integration point where the failure criterion has just been satisfied. Without incrementing the load, we repeat the analysis to find if the failure at one integration point has led to failure at other integration points. When the failure ceases to propagate, we increase the load and repeat the analysis. We take the degradation of material properties to be permanent. At the ultimate load deflections of one or more points become extremely large with a minute increment in the applied load. We also find the ultimate load for different load distributions on a major surface, boundary conditions and plate geometries. It is found that for a clamped plate, the ultimate load can be 40% more than the first ply failure load. However, for a simply supported plate, the ultimate load essentially equals the first failure load. The stacking sequence for the optimal first failure load need not have the maximum ultimate load.
Augmenting word embeddings through external knowledge-base for biomedical application

The technological advancements in biomedical domain has led to a tremendous growth of unstructured data; primarily a result of increased publication of findings. At the same time, a corresponding interest in the Natural Language Processing (NLP) community to develop scalable methodologies to exploit such massive unlabeled corpora for unsupervised language processing has resulted in new opportunities towards developing semantic sensitive models. Amongst them, the field of word embeddings has garnered significant attention due to its capability to understand implicit semantics. However such data driven models are largely agnostic of the rich explicit semantic knowledge available in the biomedical domain in the form of vocabularies and ontologies. This is problematic because it leads to a poor representation of words with little local context and its effect is acute in biomedical domain. In this paper, we propose a novel model (MeSH2Vec) that jointly exploits both contextual information and available explicit semantic knowledge to learn externally augmented word embeddings. Unlike existing approaches, the proposed methodology is more dexterous in its ability to handle relationships between indirectly related concepts. The 13% improvement in the correlation to experts, shown on experiments involving biomedical concept similarity and relatedness task validates the effectiveness of the proposed approach and demonstrates the importance of incorporating human curated knowledge in the process of generating word embeddings.
Formation of N-Nitrosodimethylamine in Direct-Fire Dried Malt12

The principal objective of this work was to investigate the formation and establish the identity of amine precursors for N-nitrosodimethylamine (NDMA) in direct-fire dried malt. NDMA levels in malt...
Bicuspid Valve-Related Aortic Disease : Flow Assessment with Conventional Phase-Contrast MRI

Rationale and Objectives Abnormal blood flow with bicuspid aortic valve (BAV) has been characterized with four-dimensional flow magnetic resonance imaging (MRI), but this approach is time consuming and requires technical expertise. We assess the relationship between different leaflets fusion patterns with BAV, eccentric systolic flow, and dilation patterns of the ascending aorta using two-dimensional (2D) phase-contrast (PC) MRI. Materials and Methods Fifty-nine patients with BAV who underwent cardiac MRI were identified; 47 had right–left (RL) aortic leaflet fusion and 12 had right-noncoronary (RN) fusion. Flow displacement was calculated, and patients with abnormal displacement (>0.1) were classified as either rightward or leftward. Patterns of aortopathy were determined (0–3), and correlation between leaflet fusion, flow direction, aortopathy type, and other clinical parameters was performed with Pearson correlation, the Fisher exact test and chi-square analysis. Results Normal systolic flow was seen in 24% of cases and was significantly correlated with normal aortas ( P = .011). Abnormal flow displacement with RL fusion was strongly associated with rightward deviation (36 of 37 cases), whereas RN fusion skewed leftward (seven of eight cases; P P Conclusions Conventional PC MRI can identify abnormal systolic flow and differences in jet orientation with BAV. RL leaflet fusion is associated with rightward flow deviation and type 2 aortopathy, whereas RN fusion is linked to leftward deviation and type 3 aortopathy. The presence and direction of eccentric flow jets may help risk stratify these patients for valve-related aortic disease.
A Genetic Approach to Investigating Membrane Lipid Structure and Photosynthetic Function

Chloroplast membranes have a unique lipid composition, and its importance for normal photosynthetic function has been emphasized by biochemical and biophysical studies. In the last ten years, a new and rewarding way to approach this structure-function relationship has been through the investigation of a series of Arabidopsis mutants with specific alterations in lipid composition. The majority of lipid mutations that have been characterized have little or no impact on the growth and photosynthesis of plants grown at 22 °C and 150 μmol quanta m−2s−1. In general, reduced membrane unsaturation in a mutant line is often (though not always) associated with a slight increase in thermostability of photosynthesis. Conversely, growth and photosynthesis of these mutant plants is often adversely affected at low temperatures. By contrast, two particular mutations, dgd1 and fab2, have shown wide-ranging effects on growth and photosynthesis at all temperatures.
Connecting archival collections: the social networks and archival context project

This paper describes the Social Networks and Archival Context project, built on a database of merged Encoded Archival Context - Corporate Bodies, Persons, and Families (EAC-CPF) records derived from Encoded Archival Description (EAD) records held by the Library of Congress, the California Digital Library, the Northwest Digital Archives, and Virginia Heritage, combined with information from name authority files from the Library of Congress (Library of Congress Name Authority File), OCLC Research (The Virtual International Authority File), and the Getty Vocabulary Program (Union List of Artist Names). The database merges information from each instance of an individual name found in the EAD resources, along with variant names, biographical notes and their topical descriptions. The SNAC prototype interface makes this information searchable and browseable while retaining links to the various data sources.
Complex systems for a complex issue: race in health research.

While agent-based modeling and complex systems approaches are fledgling methodologies in health research, they are well suited to characterizing the myriad influences of race on health.
Tate’s Thesis and Applications

It is well known that much information on rational primes is encoded in the Riemann zeta function ζ(s), which is defined by the absolutely convergent series for complex numbers s such that Re(s)>1.
Economic Models of Knowledge Networks

“Knowledge Networks” is a concept invented and used by contemporary Swedish economists. It appears that international competition has led Swedish industry to focus increasingly on high technology that is perceived as knowledge intensive. To utilize knowledge inputs, close connections are sought between industry and research institutions.
Is 5 just what comes after 4

The fifth generation of mobile phone technology — 5G — promises higher data rates and more reliable communication than previous generations, leading to a variety of novel applications. But to make this a reality, developments in a range of technologies will be required.
Neuropeptide cocaine- and amphetamine-regulated transcript usage in Parkinson's disease

Abstract Neuropeptide cocaine- and amphetamine-regulated transcript (CART) is a hypothalamus- and midbrain-enriched neurotransmitter with an antioxidant property. Parkinson's disease (PD) is an age-associated progressive neurodegenerative disease that affects nearly 10 million people worldwide. To date, there is no effective treatment that halts its progression. Increasing evidence indicates that mitochondria and oxidative stress play an important role in the development of PD. Hence, mitochondria-targeted approaches or agents may have therapeutic promise for treatment of the disease. Interestingly, CART can be found in mitochondria and is considered a key antioxidant hormone. Administration of CART has been found to ameliorate dopaminergic neuronal loss and improve motor functions in animal models of PD. In this article, we summarize recent progress in studies investigating the relationship among CART, dopamine, and sex difference in the pathophysiology of PD.
The role of dentist supply, need for care and long-term continuity in Health Resources and Services Administration-funded health centres in the United States.

Author(s): Pourat, Nadereh; Chen, Xiao; Lu, Connie; Zhou, Weihao; Hoang, Hank; Hair, Brionna; Bolton, Joshua; Sripipatana, Alek | Abstract: ObjectivesHealth Resources and Services Administration-funded health centres (HCs) are an important source of dental services for low-income and vulnerable patients in the United States. About 82% of HCs in 2018 had dental workforce, but it is unclear whether this workforce meets the oral health needs of HC patients. Thus, we first examined (a) whether dental workforce was associated with any dental visits vs none and (b) whether HC patients with any visits were more likely to have a visit at the HC vs elsewhere. We then examined (c) if need for oral health care and long-term continuity at the HC were associated with dental visits and visits at the HC.MethodsThis study used the 2014 Health Center Patient Survey, a nationally representative study of US HC patients, and the 2013 Uniform Data System, an administrative dataset of HC characteristics. We also used the 2013 Area Health Resource File to measure the contribution of local supply of dentists. We included working-age adult patients (nn=n5006) and used multilevel structural equation models with Poisson specification.ResultsLarger dental workforce at the HC was significantly associated with 1% higher likelihood (relative risk [RR]: 1.01, 1.00-1.02) of any visits and 10% higher likelihood of a visit at the HC among those with a visit (RR: 1.10, 1.06-1.14). Patient self-reported oral health need was positively associated with 157% higher likelihood of dental visits (RR: 2.57, 2.29-2.88), and 42% higher likelihood of dental visit at the HC vs elsewhere (RR: 1.42, 1.19-1.69). Long-term continuity with the HC was not significantly associated with likelihood of dental visits, but was associated with 26% higher likelihood of visits at the HC among those who had any visits (RR: 1.26, 1.02-1.56).DiscussionThe findings highlight the potential impact of increasing dental workforce at HCs to promote access; the high level of need for oral health care at HCs; and the increased effort required to promote access among newer patients who may be less familiar with the availability of oral health care at HCs. Together, these findings reinforce the importance of addressing barriers of use of oral health services among low-income and uninsured patients.
DEVELOPMENT OF A TRANSIT POLICY ANALYSIS TOOL FOR SMALL URBAN AREAS

model to the irregular pattern of a real city. Furth and Wilson have demonstrated one technique based on KuhnTucker optimality conditions and found that under inelastic demand conditions, the allocation of resources was quite insensitive to the specific set of parameters and objectives (5). The authors noted that an important limitation of the model used in their study was the assumption of independence among the routes.
A Dynamic Model of Endogenous Horizonal Mergers

I develop a dynamic model of mergers, where mergers, investment, entry, and exit are endogenous variables rationally chosen by firms to maximize expected future profits. This model differs from previous analyses in that it incorporates dynamics and endogenizes the merger process. The model generates reasonable predictions: allowing for mergers has the expected effect on entry, exit, investment, and surpluses; changes in tastes and technologies affect industry equilibrium in plausible ways. The results demonstrate that this type of analysis is feasible and can potentially be used as a tool for antitrust policy analysis.
PIP2-dependent coupling of voltage sensor and pore domains in Kv7.2

Phosphatidylinositol-4,5-bisphosphate (PIP2) is a signaling lipid which regulates voltage-gated Kv7/KCNQ potassium channels. Altered PIP2 sensitivity of neuronal Kv7.2 channel is involved in KCNQ2 epileptic encephalopathy. However, the molecular action of PIP2 on Kv7.2 gating remains largely elusive. Here, we use molecular dynamics simulations and electrophysiology to characterize PIP2 binding sites in a human Kv7.2 channel. In the closed state, PIP2 localizes to the periphery of the voltage-sensing domain (VSD). In the open state, PIP2 binds to 4 distinct interfaces formed by the cytoplasmic ends of the VSD, the gate, intracellular helices A and B and their linkers. PIP2 binding induces bilayer-interacting conformation of helices A and B and the correlated motion of the VSD and the pore domain, whereas charge-neutralizing mutations block this coupling and reduce PIP2 sensitivity of Kv7.2 channels by disrupting PIP2 binding. These findings reveal the allosteric role of PIP2 in Kv7.2 channel activation.
The role of NO and rho kinase in contractions to serotonin in diabetic mice

Contraction to serotonin (5HT) is increased and relaxation to acetylcholine (ACH) is reduced in arteries from leptin receptor diabetic mice (DB) mice compared to non-diabetics (ND). To determine th...
Rewriting, inference, and proof

Rewriting is a form of inference, and one that interacts in several ways with other forms of inference such as decision procedures and proof search. We discuss a range of issues at the intersection of rewriting and inference. How can other inference procedures be combined with rewriting? Can rewriting be used to describe inference procedures? What are some of the theoretical challenges and practical applications of combining rewriting and inference? How can rewriters, decision procedures, and their combination be certified? We discuss these problems in the context of our ongoing effort to use PVS as a metatheoretic framework to construct a proof kernel for justifying the claims of theorem provers, rewriters, model checkers, and satisfiability solvers.
Shearography for Non-Destructive Evaluation with Applications to Bat Mask Tile Adhesive Bonding and Specular Surface Honeycomb Panels

In this report we examine the applicability of shearography techniques for nondestructive inspection and evaluation in two unique application areas. In the first application, shearography is used to evaluate the quality of adhesive bonds holding lead tiles to the BAT gamma ray mask for the NASA Swift program. By exciting the mask with a vibration, the more poorly bonded tiles can be distinguished by their greater displacement response, which is readily identifiable in the shearography image. A quantitative analysis is presented that compares the shearography results with a destructive pull test measuring the force at bond failure. Generally speaking, the results show good agreement. Further investigation would be useful to optimize certain test parameters such as vibration frequency and amplitude. The second application is to evaluate the bonding between the skin and core of a honeycomb structure with a specular (mirror-like) surface. In standard shearography techniques, the object under test must have a diffuse surface to generate the speckle patterns in laser light, which are then sheared. A novel configuration using the specular surface as a mirror to image speckles from a diffuser is presented, opening up the use of shearography to a new class of objects that could not have been examined with the traditional approach. This new technique readily identifies large scale bond failures in the panel, demonstrating the validity of this approach. For the particular panel examined here, some scaling issues should be examined further to resolve the measurement scale down to the very small size of the core cells. In addition, further development should be undertaken to determine the general applicability of the new approach and to establish a firm quantitative foundation.
Analysis of the ZnTe:Cu Contact on CdS/CdTe Solar Cells

We report on the recent use of cathodoluminescence (CL) to probe the depth-dependent changes in radiative recombination that occur in CdTe devices during ZnTe:Cu contacting procedures. These types of CL measurements may be useful to assist in linking impurity diffusion (e.g., Cu) from the contact with depth-dependent variation in electrical activation within the CdTe layer. Variable-energy CL suggests that diffusion from the ZnTe:Cu contact interface may assist in reducing effects of shallow donors in the CdTe bulk, and yield higher acceptor levels in the region near the contact. CL analysis near abrupt metal discontinuities provides estimates of diffusion lengths for carriers associated with both excitonic and donor-to-acceptor pair recombination. Finally, CL measurements at increasing excitation levels (i.e., increasing electron-beam current) provides estimates of the defect state density, as well as providing evidence that discrete multiple defect bands may exist in CdTe prior to contacting.
Experimental Investigation of 3-D MHD Flows at High Hartmann Number and Interaction Parameter

Experimental investigations of 3-D MHD flows in uniform thin conducting wall ducts of circular and square cross section, conducted at Argonne National Laboratory’s ALEX facility, are reported. The three-dimensional nature of the flow arises from the spacial variation of the applied transverse magnetic field. Measurements were performed at several Hartmann numbers, M, and interaction parameters, N, with the peak value for M exceeding 6 x 103 and the peak value for N exceeding 105. Typical results and their comparison to numerical analysis reported in a companion paper are given, as is a brief description of the ALEX facility and the experimental methods employed. Ongoing activities and plans for future experiments are also discussed.
Beyond Fair Use

For centuries, the fair use doctrine has been the main - if not the exclusive - bastion of user rights. Originating in the English court of equity, the doctrine permitted users under appropriate circumstances to employ copyrighted content without consent from the rightsholder. In the current digital media environment, however, the uncertainty that shrouds fair use and the proliferation of technological protection measures undermine the doctrine and its role in copyright policy. Notably, the enactment of the Digital Millennium Copyright Act, which prohibits the circumvention of such measures even for fair use purposes, has diminished the ability of fair use to act as a counterweight to a copyright owner’s rights in the digital age. Recognizing the relatively precarious state of the fair use doctrine, many copyright scholars have rushed to resuscitate the doctrine, offering various ways to revamp fair use. As this Article makes clear, these proposals fall short of the mark. To address the shortcomings of the fair use doctrine in the digital age, this Article reconceives of the policy challenge and takes a fundamentally different tack. Rather than tinkering with the fair use doctrine, this Article proposes the creation of a system of new user privileges that would supplement fair use. Specifically, it crafts a framework of adaptive regulation that would cause copyright owners to dramatically increase the access and use opportunities granted to users. This framework would do so by requiring content owners and distributors to acknowledge user needs and even compete among themselves over the creation of new user liberties. Such an approach, this Article explains, is superior to rival suggestions and can best assure ongoing technological development and the preservation of user privileges in the digital age.
Reforming Access: Trends in Medicaid Enrollment for New Medicare Beneficiaries, 2008–2011

Objective To evaluate whether aligning the Part D low-income subsidy and Medicaid program enrollment pathways in 2010 increased Medicaid participation among new Medicare beneficiaries. Data Sources Medicare enrollment records for years 2007–2011. Study Design We used a multinomial logistic model with state fixed effects to examine the annual change in limited and full Medicaid enrollment among new Medicare beneficiaries for 2 years before and after the reforms (2008–2011). Data Extraction Methods We identified new Medicare beneficiaries in the years 2008–2011 and their participation in Medicaid based on Medicare enrollment records. Principal Findings The percentage of beneficiaries enrolling in limited Medicaid at the start of Medicare coverage increased in 2010 by 0.3 percentage points for individuals aging into Medicare and by 1.3 percentage points for those qualifying due to disability (p < .001). There was no significant difference in the size of enrollment increases between states with and without concurrent limited Medicaid eligibility expansions. Conclusions Our findings suggest that streamlining financial assistance programs may improve Medicare beneficiaries’ access to benefits.
An analysis of residual NaCl taste response after amiloride.

The identity of the residual taste response to NaCl after lingual application of the sodium transport blocker, amiloride, was studied by electrophysiological recordings from the rat chorda tympani nerve. Stimulation of the anterior tongue with salt solutions resulted in responses to halogenated sodium salts that were not eliminated by amiloride; approximately 30% of the halogenated sodium salt response remained after amiloride. In contrast, responses to nonhalogenated sodium salts were reduced to less than 4% of the original response after amiloride. To further learn of characteristics relating to the residual NaCl response, binary mixture and cross-adaptation experiments were accomplished. Responses to mixtures of sodium acetate or sodium bicarbonate with choline chloride were similar to responses elicited by equimolar concentrations of NaCl before and after amiloride. Moreover, NaCl and NaBr cross-adapted with choline chloride after, but not before, lingual application of amiloride. These experiments indicate that the residual response to halogenated sodium salts (e.g., NaCl) is related to the halogen itself, and from findings presented here, we propose one pathway for sodium taste transduction.
Radiative lifetime measurements of quantum nanostructures: transformation from 0D to 1D systems

Summary form only given. We present our recent experimental results in the shape dependence of CdSe quantum rod's radiative lifetime, which qualitatively verify the theoretical prediction of a crossing over between P/sub x,y/ and P/sub z/ levels. The preparation of colloidal CdSe quantum rods was described elsewhere. We show the transmission electron microscopy (TEM) images of two samples of the nanorods used.
What we talk about when we talk about nuclear actin

In the cytoplasm, actin filaments form crosslinked networks that enable eukaryotic cells to transport cargo, change shape, and move. Actin is also present in the nucleus but, in this compartment, its functions are more cryptic and controversial. If we distill the substantial literature on nuclear actin down to its essentials, we find four, recurring, and more-or-less independent, claims: (1) crosslinked networks of conventional actin filaments span the nucleus and help maintain its structure and organize its contents; (2) assembly or contraction of filaments regulates specific nuclear events; (3) actin monomers moonlight as subunits of chromatin remodeling complexes, independent of their ability to form filaments; and (4) modified actin monomers or oligomers, structurally distinct from canonical, cytoskeletal filaments, mediate nuclear events by unknown mechanisms. We discuss the evidence underlying these claims and as well as their strengths and weaknesses. Next, we describe our recent work, in which we built probes specific for nuclear actin and used them to describe the form and distribution of actin in somatic cell nuclei. Finally, we discuss how different forms of nuclear actin may play different roles in different cell types and physiological contexts.
Multidisciplinary approach to the management of dermatofibrosarcoma protuberans.

Background Dermatofibrosarcoma protuberans (DFSP) is the most common cutaneous sarcoma. Tentacle-like extensions of neoplastic cells create a high incidence of local recurrence and pose challenges to resection and reconstruction. Objective Here we present a multidisciplinary approach to the management of DFSP incorporating the expertise of a Mohs micrographic surgeon, surgical oncologist, dermatopathologist, and plastic surgeon. Methods This was a single-institution, retrospective review of a prospectively maintained database of 19 consecutive patients who underwent resection and reconstruction of a DFSP from 1998 to 2010. All patients underwent Mohs micrographic surgery for mapping of peripheral margins (stage I excision), followed by wide local excision for delineation of the deep margin (stage II excision). Procedures were performed in consultation with a dermatopathologist who confirmed tumor-free margins, and a plastic surgeon who performed immediate reconstruction after the wide local excision (stage II reconstruction). Results Nineteen patients were included in this study. The average number of Mohs stages required for clearance of peripheral margins was 2.7 ± 0.7. The mean time between stage I and II procedures was 16 ± 11 days. The average defect size after the stage II operation was 87.3 cm 2 (range, 9-300 cm 2 ). There were no cases of tumor recurrence. Mean follow-up time was 17 months (range, 1-53 months). Limitations This is a retrospective review of a single-institution experience. Conclusion A multidisciplinary approach to the management of DFSP optimizes both oncologic and reconstructive outcomes, minimizing the risk for local recurrence and limiting the functional and cosmetic morbidity associated with surgical resection.
Achromatizing the human eye: the problem of chromatic parallax.

Attempts to correct the chromatic difference of focus of the human eye will introduce unwanted chromatic parallax if the eye is misaligned with the optical axis of the achromatizing system. Using geometrical optics, we show that the amount of parallax is approximately proportional to the amount of misalignment of the eye, with the constant of proportionality equal to the eye’s chromatic difference of refractive error. This prediction was confirmed by the experimental determination of chromatic parallax for two commercially available achromatizing lenses. On the basis of these results, we calculated that anticipated improvements in the polychromatic modulation transfer function of the eye offered by achromatizing lenses will be canceled by ~0.4 mm of the misalignment between the lens and the eye. Our prediction that further misalignment would severely reduce image quality of the achromatized eye was verified by psychophysical measurements of contrast sensitivity.
First principles determination of the interatomic force-constant tensor of the fullerene molecule

Abstract We have determined the full force constant tensor (Hessian) of the fullerene molecule, C 60 from first principles. From our all-electron density functional code, the forces on all of the atoms are calculated for different displacements of a single atom. Using finite differences and the symmetry operations of the molecule, the full matrix is determined. Diagonalization of the dynamical matrix yields the vibrational modes, which are in excellent agreement with experiment. The range and nature of the force constant tensor will be presented.
Thoracoabdominal situs: a practical approach accompanied by a short history of descriptive terms.

Classification systems for thoracoabdominal situs have been the subject of numerous reports, yet confusion persists. This essay presents an abbreviated historical review of the currently used terms, briefly discusses some of the nomenclature controversies, and proposes a classification system that more closely adheres to the etymology of the descriptors, especially “heterotaxy.”
GABAergic amacrine cells in rat retina: Immunocytochemical identification and synaptic connectivity

GABAergic neurons have been identified in light and electron microscopic preparations of rat retina by an immunocytochemical localization of the GABA-synthesizing enzyme, glutamic acid decarboxylase (GAD). GAD-positive neuronal somata are found only in the inner and middle parts of the inner nuclear layer, and GAD-positive neuronal terminals are observed exclusively within the inner plexiform layer (IPL) and the outermost part of the ganglion cell layer. Dense aggregations of GAD-positive terminals alternate with less dense zones to form a lamination of the IPL. GAD-positive terminals contain pleomorphic synaptic vesicles and are the presynaptic elements of conventional synapses onto bipolar and amacrine cell processes, as well as onto the somata and dendrites of ganglion cells. In addition, GAD-positive terminals are postsynaptic to unstained bipolar terminals and are components of synaptic dyads where they occasionally appear to form reciprocal synapses with the bipolar terminals, and serial with unstained amacrine processes. Probable synaptic contacts between adjacent GAD-positive terminals also have been observed. Most of the synaptic input to GAD-positive terminals comes from bipolar cells, while the small remaining input mainly comes from other GAD-positive terminals. The synaptic output to GAD-positive terminals is greatest to bipolar cells, followed in decreasing order by GAD-negative amacrine cells, ganglion cells, and other GAD-positive cells. The total synaptic output of GAD-positive cells appears to be more than twice as great as the total input of these cells. The location of GAD-positive somata, the distribution of GAD-positive terminals, and the synaptic relationships formed by these terminals all indicate that amacrine cells are the only GABAergic neurons in rat retina. Our observations also indicate that not all amacrines are GABAergic and suggest that GABAergic neurons may be limited to a narrow field subclass of amacrine cell. The findings concerning the synaptic connections of GABAergic amacrines suggest that such cells are the first link in several divergent pathways from bipolar to ganglion cells and that they probably serve more than one function since they feed synaptic activity forward directly upon ganglion cells as well as back upon bipolar cells.
Physical Properties of the Lyα Forest in a Cold Dark Matter Cosmology

We discuss the origin and physical nature of the Lyα forest absorption systems as found in hydrodynamical simulations of the intergalactic medium (IGM) in a standard cold dark matter cosmology (Ω = 1, H0 = 50 km s-1 Mpc-1, σ8 = 0.7). The structures of the systems that give rise to the Lyα forest span a wide range in morphologies, depending on the density contrast. Highly overdense systems, ρ -->b/${u{{ρ}}{"7016}}$ --> -->b10, where ρb denotes baryon density, tend to be spheroidal and are located at the intersections of an interconnecting network of filaments of moderate overdensity, 1ρ -->b/${u{{ρ}}{"7016}}$ --> -->b5. The typical thickness of the filaments is 100 kpc, with a typical length of a few megaparsecs. At the cosmological average density, the characteristic morphology is cell-like with underdense regions separated by overdense, sheetlike partitions. The lowest density contours tend to enclose amorphous, isolated regions. We find that the principal structures of the IGM are in place by z = 5, with the evolution in the IGM absorption properties due primarily to the expansion of the universe and the changing intensity of the photoionizing background radiation field. The absorption properties of the forest clouds correlate strongly with those of the underlying physical systems from which they arise. The highest column density systems (log NH I 15) correspond to the highly overdense spheroidal structures, moderate column density systems (13 log NH I 14) correspond to the filaments, and the lowest density absorption systems originate from discrete fluctuations within underdense regions a few megaparsecs across, cosmic minivoids. Most of the intergalactic He II opacity arises from these underdense regions. Similar correlations are found for the cloud temperature and divergence of the peculiar velocity field. Within the uncertainties of the statistics of the derived Lyα forest properties, we are able to account for the distribution of optical depths in our synthesized spectra entirely by absorption due to discrete systems. We find that virtually all the baryons in the simulation fragment into structures that we can identify with discrete absorption lines, with at most 5% remaining in a smoothly distributed component (the Gunn-Peterson effect). We compare our results with the cloud ionization parameters inferred from Keck HIRES measurements of carbon and silicon in the Lyα forest. Combining with constraints imposed by measurements of the mean intergalactic H I opacity permits separate limits to be set on the mean cosmological baryon density, Ωb, and H I ionization rate, ΓH I. For the cosmological model investigated, we find 0.03 Ωb 0.08 and 0.3 ΓH I,-12 1 (ΓH I,-12 = ΓH I/10-12 s-1) at z = 3-3.5. Our results for the amount of intergalactic H I and He II absorption and for the ionization parameters of the clouds are consistent with a forest photoionized by a UV background dominated by QSO sources with an intrinsic spectral index of αQ ≈ 1.8-2.
Extrageniculostriate vision in the monkey III. Circle vs triangle and “red vs green” discrimination

Four monkeys were trained on 3 visual discriminations using a two-choice pulling-in technique with movable transilluminated stimuli, before and after histologically verified total bilateral removal of area 17, most of 18, and part of 19. Test 1 consisted of one small bright circle vs a large, dim circle closely matched for total luminous flux. Test 2 was a circle vs a triangle of equal brightness and approximately equal area and luminous flux. Test 3 contained a “red” circle vs a “green” circle of equal area. Preoperatively, all monkeys mastered the 3 tests. Postoperatively, test 1 was relearned by all animals with 6.7 fold increase in the mean error score. Test 2 was solved by all subjects to a criterion of 18 correct out of 20 responses, and by only 3 to a level of 90% correct in 200 trials after considerable training. Test 3 was mastered by all monkeys. Controls were carried out following each of the tests. The principal type involved the introduction of a fixed additional density to the right side stimulus box. After test 3, this manipulation was made in increasing steps to the point of complete occlusion of the stimulus on the right side. For test 2, variations in orientation, relative size and brightness were also part of the controls. The results of the original tests and controls confirmed and extended previous findings showing that monkeys without striate cortex can discriminate luminous flux-equated figures, that prior training on luminous flux differences is not a prerequisite, and that they can master a circle vs triangle, and “red vs green” type of visual discriminations.
Complotypes in individuals of African origin: frequencies and possible extended MHC haplotypes.

We analyzed the frequency distribution of 106 complotypes [four allele sets of the major histocompatibility complex (MHC) genes for the complement proteins factor B, C2, C4A, and C4B] from 32 Black families residing in Boston and Washington, DC. Twenty-five different complotypes were identified, among which there were four complotypes that had not been previously observed in our large database of complotypes compiled from family studies of Boston Caucasians and that are, presumably, unique to individuals of African origin. These four African-derived complotypes areFC(1,90)0, FC63, S1C2,17, andSC(3,2,90)0. The frequencies of two of these four unique Black complotypes,FC(1,90)0 andFC63, were increased significantly when compared to Caucasians (pcorr <0.00042, pcorr=0.00294, respectively). The complotypeFC(1,90)0 was in positive linkage disequilibrium withHLA-DR3 haplotypes containing theB locus antigens Bw42, Bw52, Bw53, and Bw58, whileFC63 was associated withHLA-Bw70,-DR5. These findings demonstrate the extensive polymorphism of complotypes in Blacks, and also suggest that it may be possible to define unique extended haplotypes of African origin.
Differential regulation of cardiac actomyosin S-1 MgATPase by protein kinase C isozyme-specific phosphorylation of specific sites in cardiac troponin I and its phosphorylation site mutants.

The significance of site-specific phosphorylation by protein kinase C (PKC) isozymes alpha and delta and protein kinase A (PKA) of troponin I (TnI) and its phosphorylation site mutants in the regulation of Ca(2+)-stimulated MgATPase activity of reconstituted actomyosin S-1 was investigated. The genetically defined TnI mutants used were T144A, S43A/S45A, S43A/S45A/T144A (in which the PKC phosphorylation sites Thr-144 and Ser-43/Ser-45 were respectively substituted by Ala) and N32 (in which the first 32 amino acids in the NH2-terminal sequence containing Ser-23/Ser-24 were deleted). Although the PKC isozymes displayed different substrate phosphorylation kinetics, PKC-alpha phosphorylated equally well TnI wild type and all mutants, whereas N32 was a much poorer substrate for PKC-delta. Furthermore, the two PKC isozymes exhibited discrete specificities in phosphorylating distinct sites in TnI and its mutants, either as individual subunits or as components of the reconstituted troponin complex. Unlike PKC-alpha, PKC-delta favorably phosphorylated the PKA-preferred site Ser-23/Ser-24 and hence, like PKA, reduced the Ca2+ sensitivity of the reconstituted actomyosin S-1 MgATPase. In contrast, PKC-alpha preferred to phosphorylate Ser-43/Ser-45 (common sites for all isozymes) and thus reduced the maximal Ca(2+)-stimulated activity of the MgATPase. In this respect, PKC-delta, by cross-phosphorylating the PKA sites, functioned as a hybrid of PKC-alpha and PKA. The site specificities and hence functional differences between PKC-alpha and -delta were most evident at low phosphorylation (1 mol of phosphate/mol) of TnI wild type and were magnified when S43A/S45A and N32 were used as substrates. The present study has demonstrated, for the first time, that distinct functional consequences could arise from the site-selective preferences of PKC-alpha and -delta for phosphorylating a single substrate in the myocardium, i.e., TnI.
A 512kb 8T SRAM Macro Operating Down to 0.57 V With an AC-Coupled Sense Amplifier and Embedded Data-Retention-Voltage Sensor in 45 nm SOI CMOS

There is a need for large embedded memory that operates over a wide range of supply voltage compatible with the limits of static CMOS logic that also minimizes standby power [1,2]. A 512kb 8T SRAM macro in 45nm SOI CMOS is developed as a building block for this application. It addresses the design challenges related to area efficiency and process variation with three contributions: 1) an AC coupled sense amplifier (ACSA) that operates at a power supply ultimately limited by the worst-case bit line on/off current ratio; 2) area efficient, regenerative driving of long data lines to permit bidirectional signaling on a single metal 4 wiring track on the memory cell column pitch; 3) a data retention voltage (DRV) sensor to determine the mismatch-limited minimum standby supply voltage without corrupting the contents of the memory.
Contemporary tourism: an international approach

Contemporary tourism: an international approach, by Chris Cooper and Michael Hall, Woodeaton, Oxford, Goodfellow Publishers, 2012, 364 pp., £65, €78, US$104 (hardback), £29.99, €36, US$48 (paperbac...
32-approximation algorithm for two variants of a 2-depot Hamiltonian path problem

We consider two variants of a 2-depot Hamiltonian path problem and show that they have an algorithm with an approximation ratio of 32 if the costs are symmetric and satisfy the triangle inequality. This improves the 2-approximation algorithm already available for the problem.