cssi/SciSciGPT-SciSciNet huggingface dataset:
Will Cutting the Payroll Tax Increase Jobs? (Empirical Evidence from the EU VAT)

Red Ink Rising, the Peterson–Pew Commission on Budget Reform’s report presents the country with a fiscal/employment dilemma – Congress must act immediately to stem the federal debt, but it must move carefully lest it harm employment in the fragile economy. In short, we must act fast and slow – we must decrease the debt and increase employment. This is a difficult task. The Peterson-Pew dilemma (notably its jobs-creation aspect) was taken to heart by both of the reform commissions that issued reports soon thereafter (National Commission on Fiscal Responsibility and Reform, The Moment of Truth and The Debt Reduction Task Force (Domenici/Rivlin), Restoring America’s Future). The dilemma also appears to be have played a role in President Obama’s compromise with the Republican leadership in the Tax Relief, Unemployment Insurance Reauthorization, and Jobs Creation Act of 2010 (P.L. 111-312) – particularly the 2% payroll tax cut enacted at section 601. The Congressional Budget Office (CBO) places the payroll tax at the intersection of the policies that Peterson-Pew examines. Empirical evidence from the EU suggests that P.L. 111-312 got it right (as between general reductions in the employees’ and employers’ payroll taxes). The evidence gathered in a two-year policy experiment conducted in nine EU Member States also suggests that the CBO estimates of employment gains from employers’ payroll tax cuts cannot be supported (if they are targeted generally). In addition, EU macro-economic simulations based on these findings also suggest that the best way to use payroll tax incentives to increase employment is to use them to directly reduce the cost of labor. This can be accomplished either (1) under mechanisms used in the HIRE Act or (2) by targeting specific categories of workers (the unemployed) for an employees’ payroll tax cut that would be tethered to (used in conjunction with) an employers’ tax incentive to significantly reduce the cost of labor. This paper endeavors to bring EU analysis into the US payroll tax debate. Five options are considered: •(1) Employers’ payroll tax holiday. •(2) Employees’ payroll tax holiday. •(3) Targeted employers’ payroll tax holiday. •(4) Targeted employees’ payroll tax holiday. •(5) Tethering an employers’ payroll tax holiday to a targeted employees’ payroll tax holiday.
The maintenance and reestablishment of self-tolerance: T cell receptor (TCR) peptide-specific regulatory T cells

While we know that mature peripheral T cells are generally unresponsive to dominant determinants on self-antigens, the mechanism inducing this self tolerance is still unclear. Clonal deletion of self-reactive T cells during the thymic selection process has been described as one of the major mechanisms for inducing central tolerance (Kappler et al., 1987; von Boehmer, 1990). The presence of autoaggressive cells in healthy individuals as well as the demonstration of physiological presentation of self-antigens in vivo, suggest involvement of other mechanisms in maintenance of peripheral tolerance, for example anergy or suppressive regulation (Schwartz, 1990; Kumar and Sercarz, 1991). It has also been hypothesized that a deficiency of regulatory T cells may lead to autoimmunity (Sakaguchi and Sakaguchi, 1990; Powrie and Mason, 1990). Many studies suggest that potentially pathogenic autoimmune cells are not tolerized at the outset, but rather become activated normally and then controlled by regulatory T cells. Thus the equilibrium between autoreactive and regulatory T cells may determine the expression of autoimmunity.
COPBLAM: Infusion Chemotherapy for Large Cell Lymphoma

Early in 1977, a new combination chemotherapy program was initiated at the New York Hospital-Cornell Medical Center for large cell lymphoma (LCL). This program, known as COPBLAM: {cyclophosphamide, Oncovin, (vincristine), prednisone, bleomycin, Adriamycin, Matulane (procarbazine)} was an intensive multidrug regimen designed to maximize tumor cell kill1. Unique to this treatment for LCL was the incorporation of then novel concepts and features which were as follows: 1) Dosage escalation provisions for two major drug components (cyclo-phosphamide, Adriamycin) appropriate to patient tolerance, thereby allowing fullest implementation of these agents. Protocols in the past had provided dosage reduction schedules when treatment proved too intense, but few had ever contained provisions for increasing treatment intensity, notwithstanding the steep dose-response relationship of these drugs2. 2) Treatment cycles of 21 days, in contrast to the customary monthly schedules used in the past. Toxicity from both cyclophosphamide and Adriamycin is usually ameliorated in this interval, and shorter cycles provided for further intensification of treatment2. 3) The use of six drugs rather than the customary four or five, all putatively non-cross-resistant with differing mechanisms of action. Procarbazine was added to the standard BACOP (bleomycin, Adriamycin, cyclophosphamide, Oncovin, prednisone) combination because of its ability to cross the blood brain barrier. Its previous incorporation in the COP (cyclophosphamide, Oncovin, prednisone) regimen to form the C-MOPP (cyclophosphamide, Oncovin, procarbazine, prednisone) program greatly augmented the cure rate3. 4) The fuller use of nonmyelosuppressive agents, particularly vin-cristine, prednisone and bleomycin, of which the latter was given at day 14, allowing further tumor treatment in the face of nadir blood counts.
Patterns in complex hydraulic fractures observed by true-triaxial experiments and implications for proppant placement and stimulated reservoir volumes

Rocks are host to complex fracture networks that are difficult to locate in situ, and yet characterization of these fractures is crucial to predicting the effects of hydraulic stimulation. We analyze three-dimensional hydraulic fracture patterns among varied laboratory experiments to identify recurring geometries. Building on the constitutive tensile and shear fracture modes, we observe examples of offset fracture branching, traversing fracture coalescence, and smooth fracture reorientation as relatively simple structures within complex fracture networks. The evolution of fracture branching, also referred to as stranding, is revealed to be a fundamentally three-dimensional process, in which continued propagation can result in traversing fracture coalescence. Fracture branching, therefore, can create an illusion of unconnected, staggered, and offset hydraulic fracture growth when viewed from a single cross section; meanwhile, these fractures are likely connected through a common fracture surface elsewhere. The fractures are also investigated at a smaller scale, where similar fracture patterns are observed. In the field, these complex patterns are likely to hinder proppant settling, reduce open fracture permeability, create larger fracture surface areas, and lead to increased stimulated reservoir volumes. A balance of stimulation methods to prevent this complexity in some areas and exploit it in others could be key to improving recovery from oil and gas resources, improving geothermal energy efficiency, and optimizing disposal of waste water or CO2 via injection wells. Representation of these complex structures is needed for accurate modeling predictions for reservoir management.
Evaluation of weed control in acetyl coA carboxylase-resistant rice with mixtures of quizalofop and auxinic herbicides

Rice with enhanced tolerance to herbicides that inhibit acetyl coA carboxylase (ACCase) allows POST application of quizalofop, an ACCase-inhibiting herbicide. Two concurrent field studies were conducted in 2017 and 2018 near Stoneville, MS, to evaluate control of grass (Grass Study) and broadleaf (Broadleaf Study) weeds with sequential applications of quizalofop alone and in mixtures with auxinic herbicides applied in the first or second application. Sequential treatments of quizalofop were applied at 119 g ai ha−1 alone and in mixtures with labeled rates of auxinic herbicides to rice at the two- to three-leaf (EPOST) or four-leaf to one-tiller (LPOST) growth stages. In the Grass Study, no differences in rice injury or control of volunteer rice (‘CL151’ and ‘Rex’) were detected 14 and 28 d after last application (DA-LPOST). Barnyardgrass control at 14 and 28 DA-LPOST with quizalofop applied alone or with auxinic herbicides EPOST was ≥93% for all auxinic herbicide treatments except penoxsulam plus triclopyr. Barnyardgrass control was ≥96% with quizalofop applied alone and with auxinic herbicides LPOST. In the Broadleaf Study, quizalofop plus florpyrauxifen-benzyl controlled more Palmer amaranth 14 DA-LPOST than other mixtures with auxinic herbicides, and control with this treatment was greater EPOST compared with LPOST. Hemp sesbania control 14 DA-LPOST was ≤90% with quizalofop plus quinclorac LPOST, orthosulfamuron plus quinclorac LPOST, and triclopyr EPOST or LPOST. All mixtures except quinclorac and orthosulfamuron plus quinclorac LPOST controlled ivyleaf morningglory ≥91% 14 DA-LPOST. Florpyrauxifen-benzyl or triclopyr were required for volunteer soybean control >63% 14 DA-LPOST. To optimize barnyardgrass control and rice yield, penoxsulam plus triclopyr and orthosulfamuron plus quinclorac should not be mixed with quizalofop. Quizalofop mixtures with auxinic herbicides are safe and effective for controlling barnyardgrass, volunteer rice, and broadleaf weeds in ACCase-resistant rice, and the choice of herbicide mixture could be adjusted based on weed spectrum in the treated field.
Access to a regular medical provider among head and neck cancer survivors

Background Patients with head and neck cancer (HNC) are at risk for limited healthcare access. Methods Individuals reporting a history of cancer were identified from the Medical Expenditure Panel Survey, an annual assessment of the nation's health. Access to care variables were compared between "HNC" and "other cancer" using multivariable methods and stratified by age 65. Results From 1998 to 2015, 420 patients with HNC and 14 468 with other cancers completed the survey. Among patients with HNC, 10.4% (95% confidence interval [CI] 5.0-15.9) lacked a regular provider, compared to 6.1% (95% CI 5.5-6.6) of other cancer survivors. Ten percent of HNC survivors lacked a regular provider and 14.6% report barriers to needed care. For those 65 years and older, HNC was associated with lacking a regular provider (adjusted odds ratio 2.58, 95% CI 1.15-5.80). Conclusion HNC was associated with lack of a regular care provider after age 65, which may result in substandard survivorship care.
The “War on Drugs”

In the Preface to Part One of this work, I discussed some of the methodological issues one confronts in arguing that a certain decision-procedure for morally justified criminalization is superior to a competing procedure. An important difficulty, in arguing that Filtering is superior to Balancing, concerns the selection of actions which might be prohibited, or criminal statutes (extant or proposed) as the basis for comparison. If one selects statutes about which there is little controversy, it is unlikely that the virtues and vices of the two procedures will become evident. Indeed, it might well be the case that yielding a certain result—about murder, rape, assault, etc.—is an adequacy condition on any decision-procedure for criminalization. Alternatively, if one selects statutes about which there is great controversy, it is unlikely that the virtues and vices of the two procedures will become evident; they are likely to remain enmeshed in the controversies that swirl around the action or statute under discussion. I have sought to evade these companion difficulties by selecting for discussion two different sorts of issues. First, I have investigated some statutes that, although controversial, are not (too) emotionally charged: seat belt laws, motorcycle helmet laws, and laws prohibiting bestiality. Second, I have investigated some specialized issues in the philosophy of the criminal law: the “Voluntariness Tribunal,” “garrison situations,” “Community Self- Paternalism,” etc.
Multivariate holomorphic Hermite polynomials

We introduce holomorphic Hermite polynomials in n complex variables that generalize the Hermite polynomials in n real variables introduced by Hermite in the late 19th century. We discuss cases in which these polynomials are orthogonal and construct a reproducing kernel Hilbert space related to one such orthogonal family. We also introduce a multivariate analog of the Ito polynomials. We show how these multivariate polynomials generalize the univariate complex Hermite and Ito polynomials. Generating functions, orthogonality relations, Rodrigues formulas, recurrence and linearization relations, and operator formulas are also derived for these multivariate holomorphic Hermite and Ito polynomials. A Kibble–Slepian formula and a Mehler-type formula for the multivariate Ito polynomials are established.
Natural language markers of social phenotype in girls with autism.

Background Girls with autism spectrum condition (ASC) are chronically underdiagnosed compared to boys, which may be due to poorly understood sex differences in a variety of domains, including social interest and motivation. In this study, we use natural language processing to identify objective markers of social phenotype that are easily obtained from a brief conversation with a nonexpert. Methods 87 school-aged children and adolescents with ASC (17 girls, 33 boys) or typical development (TD; 15 girls, 22 boys) were matched on age (mean = 11.35 years), IQ estimates (mean = 107), and - for ASC participants - level of social impairment. Participants engaged in an informal 5-min 'get to know you' conversation with a nonexpert conversation partner. To measure attention to social groups, we analyzed first-person plural pronoun variants (e.g., 'we' and 'us') and third-person plural pronoun variants (e.g., 'they' and 'them'). Results Consistent with prior research suggesting greater social motivation in autistic girls, autistic girls talked more about social groups than did ASC boys. Compared to TD girls, autistic girls demonstrated atypically heightened discussion of groups they were not a part of ('they', 'them'), indicating potential awareness of social exclusion. Pronoun use predicted individual differences in the social phenotypes of autistic girls. Conclusions Relatively heightened but atypical social group focus is evident in autistic girls during spontaneous conversation, which contrasts with patterns observed in autistic boys and TD girls. Quantifying subtle linguistic differences in verbally fluent autistic girls is an important step toward improved identification and support for this understudied sector of the autism spectrum.
Firm Size Influence on Construction Safety Culture and Construction Safety Climate

AbstractSmaller construction firms represent the majority of US construction firms. The safety record of smaller construction firms indicates a lower safety performance and higher incident rates th...
SU-E-T-259: Development of a Primary Standard for LDR Brachytherapy

Purpose: The National Research Council initiated a program in 2012 to develop a primary standard to calibrate I-125 and Pd-103 sources used for LDR brachytherapy and disseminate this through calibration services to Canadian users. This will simplify procedures as Canadian cancer centres currently have to ship instruments to the US. Methods: The standard is based on a commercial version of the wide-angle free air chamber (WAFAC) pioneered by NIST. Significant enhancements were implemented to improve signal-to-noise and measurement reproducibility and eliminate electric field effects. Validation of this ionization chamber was then carried out in a low-energy X -ray beam (∼ 31 keV) where the dose rate had been previously established using the existing NRC primary standard free-air chamber. As a final component of this initial testing, measurements were made with a set of I-125 seeds (with air kerma strength traceable to NIST). Results: Excellent agreement of the two NRC free-air chambers was obtained within the combined standard uncertainty of 0.5 %. However, it was found that the WAFAC response is very sensitive to the beam geometry (distance from the source, diameter of the beam-defining aperture, etc) and Monte Carlo calculations, carried out to evaluate these geometry corrections, have confirmed the experimental results. The results for the seed measurements indicated a precision of better than 1 % is achievable for a reasonable acquisition time and the air kerma strength agreed with the manufacturer (NIST-traceable) value within 2 %. Conclusion: The prototype primary standard for LDR brachytherapy has met accuracy target of 3 % for the determination of air kerma strength. Work is ongoing to refine operation of the device and develop the calibration protocol for clinical users, with an anticipated launch of a calibration service in late 2015.
Fluctuation in population dynamics

A dynamics for a large population of randomly mating individuals is formulated as a Markov process on a large product space which involves a pairwise interaction between components. Each individual in the population possesses a character (the state of individual). An individual undergoes Markovian change of its character during its life time. Two individuals may make random mating after which they die, leaving two children with new characters. Each individual is a unique member of a lineage at each time. We are interested in the number of lineages which, comprise individuals possessing the character xi at time ti for i = 1,…,m, where xl,…,xm and tl,…,tm are given in advance. If the initial distribution is i.i.d. and the size n of the population is very large, the proportion of this number to n is approximately computed by means of a joint distribution of a nonlinear Markov process (for a single individual in a infinite population). We shall study the law of the error in this approximation and establish a limit theorem about it.
Work in progress - along the spectrum of inquiry: a project-based approach to the first year experience

We present a pedagogical approach that pushes students toward a space in which they pose and solve authentic questions. Such an approach does help students develop a conceptual framework, but more importantly engages them in developing key competencies, and gives students ownership of their learning. The approach has connections to design learning research emphasizing the importance of both generative and deep reasoning questioning in the learning process
Respiratory-gated PET/CT versus delayed images for the quantitative evaluation of lower pulmonary and hepatic lesions.

Purpose Respiratory motion degrades fluorodeoxyglucose positron emission tomography (FDG PET) images of the lower chest and upper abdomen, as the blur introduced by breathing motion increases the apparent size of the moving tumour lesions and decreases their apparent uptake, reducing the sensitivity of PET in detection of small lesions. We assessed the role of delayed and respiratory-gated PET acquisition in the quantitative evaluation of lung and liver lesions. Methods A retrospective analysis of 64 lesions was performed. After initial non-gated whole-body PET/CT, respiratory gating was performed with 15 min in list mode. Non-gated delayed images were obtained by summing all list mode data. SUVmax adjusted for lean body mass (SULmax) was measured in the initial whole-body scan, the delayed non-gated scans and the individual gated bins for each lesion. The axial z-position of SULmax for each lesion in five respiratory-gated bins was determined. The mean SUL of the non-pathological liver parenchyma was also recorded for each patient. Results Tumour lesion SULmax increased by an average of 34% in the delayed non-gated scan as compared with the whole-body initial scan and further by an additional 17.2% in respiratory-gated images. The maximum lesion displacement was 6.2 ± 5.0 mm. Conclusion Delayed imaging alone substantially increases the magnitude of the SUL of liver and lung lesions as compared with standard whole-body images and may allow for a more accurate definition of the lesion's volume and localisation and improve tracer quantitation in malignant lesions in the lungs or upper abdomen. While respiratory gating provides more optimal imaging with greatest increase in SULmax, the benefit is small, and delayed imaging appears sufficient in most cases.
The Service Layer

The OpenCard Framework service layer shields the application programmer from smart card details. This layer abstracts the smart card and on-card applications. Figure 10.1 shows the general structure of this layer.
Analyzing student assimilation of Japanese phonological transformation rules

The authors describe a method for statistically analyzing a student's proficiency at reading one of the distinct orthographies of Japanese, known as katakana. They provide a brief introduction to how a student model is constructed by analyzing a student's responses. A method is then presented for statistically analyzing a student model assuming that all of the phonological rules that would be required to completely transform these katakana into English contributed equally to the student's failure to understand. With this assumption, the student model becomes a binomial distribution for which the Bayes theorem is used to estimate the student's current knowledge state. A variety of techniques for assessing prior information is then proposed. The correlation between the probability of comprehension and the phonetic properties of transformation rules is addressed. It is shown that combining the binomial model with these factors allows the tutorial system to more accurately estimate a student's knowledge state and thus provide more efficient instruction. >
Complications of peritonsillar abscess due to Fusobacterium necrophorum.

Even though anaerobic bacteria have been causally related to peritonsillar abscesses and secondary complications, 1-3 such infections have been diagnosed infrequently. Reported here is a patient with a peritonsillar abscess, complicated by cellulitis and lung abscesses. An anaerobic organism, Fusobacterium necrophorum, , was identified as the etiological agent. CASE REPORT A 14-year-old black boy was in good health until three weeks prior to admission when he developed a sore throat, dysphasia, fever, and chills. His physician diagnosed viral pharyngitis; a throat culture was not obtained and no antimicrobial therapy was prescribed. During the following 12 days, because the patient had developed a nonproductive cough and experienced a 4.52-kg weight loss, he was brought to the Pediatric Emergency Clinic, Grady Memorial Hospital.
Propagation time delay spread measurements at 915 MHz in a large train yard

Time delay spread and path loss measurements were performed in a large, active train yard to support development of intra-yard wireless communication systems, such as those intended to communicate with individual railcars and for track-to-terminal communications. Propagation measurements focused on three sites within the train yard: a close-in site, a parallel-track site, and a cross-track site. The maximum RMS delay spread was 1161 ns across cross-track measurements. Parallel-track measurements yielded a maximum RMS delay spread of 732 ns, while close-in measurements showed a maximum RMS delay spread of 281 ns. Upper bound path loss exponents were found to be 2.7 and 3.4 for the parallel- and cross-track sites, respectively.
Suppressor T Cell Mechanisms in Contact Sensitivity II. Afferent Blockade by Alloinduced Suppressor T Cells

We investigated the mechanism(s) by which MHC-restricted suppressor T cells (Ts) induced by i.v. injection of allogeneic DNP-modified lymphoid cells (alloinduced Ts) suppress the DNFB contact sensitivity response. It was shown that alloinduced Ts acted only during the early phases (afferent limb) of sensitization. They were incapable of suppressing previously sensitized recipients or of inhibiting the expression of DNFB-immune LN cells when co-transferred into normal recipients. The target of alloinduced Ts seems to be cell proliferation, i.e., inhibition of antigen-induced cell proliferation (DNA synthesis) in Ts recipient mice. The failure of recipients of alloinduced Ts to generate DNFB-immune LN cells capable of transferring contact sensitivity to normal recipients also suggests that these Ts act by preventing the development of an expanded clone of mature immune T cells. The suppressive effects of alloinduced Ts also were inhibited by prior in vitro treatment with anti-TNP serum. The data are discussed in terms of current models of suppression, and are compared to mechanisms of suppression in other contact sensitivity models.
The marginal efficiency effects of taxes and subsidies in the presence of externalities: A computational general equilibrium approach

Abstract Using 1983 data, we develop a 19-sector computational general equilibrium model, incorporating producer-producer externalities and producer-consumer externalities. Simulation results indicate that when additional government expenditure is financed by Pigouvian taxes, the marginal cost of public funds is substantially below one. Labor, sales, and output taxes also affect the output of the polluting industries, and thus have indirect Pigouvian effects which tend to reduce the associated marginal costs of public funds. Pigouvian taxes are usually more efficient than Pigouvian subsidies, since the tax revenue can be used to reduce other taxes.
Philosophy of Science, with Special Consideration Given to Behaviorism as the Philosophy of the Science of Behavior

The philosophy of science is the branch of philosophy that critically examines the foundations, assumptions, methods, products, and implications of the activity called science. The present sketch reviews the historical development of the philosophy of science, representative individuals in the field, and topics of longstanding interest. The sketch is intended to prepare readers for subsequent discussions on behaviorism, cognitive psychology, and the meaning of mental terms.
Examples of Scaffolding and Chunking in Online and Blended Learning Environments

Scaffolding and chunking are instructional strategies designed to support the relationship of new information to prior knowledge in manageable sizes for the learner’s working memory. This paper defines scaffolding and chunking instructional strategies as they relate to information processing, describes how to determine and when to use scaffolding and chunking, and provides examples of when scaffolding and chunking have been used effectively in online and blended learning environments.Scaffolding is based within Vygotsky’s Social Development Theory that proposes that learning occurs through participation in socially or culturally embedded experiences. A competent instructor presents information that activates the learner’s zone of proximal development just above the learner’s current skills level. Online and blended materials can include interactive strategies to help the learner elaborate on their prior knowledge. The interactive bridges are built within the educational materials or provided through interactions with other learners or the instructor.Chunking is the process of taking individual units of information and grouping them into larger units. Working memory functions optimally with no more than five to nine pieces of information. By chunking information in larger blocks, the information becomes easier to move from working memory to permanent memory, be linked to prior knowledge, and be recalled at a later time.The placement and use of instructional strategies is based upon where the learner demonstrates difficulty in relating the materials to prior knowledge or has difficulty recalling the information. Hierarchical analysis of the instructional materials, learner analysis, and evaluation of learner performance are techniques used to place the instructional strategies most effectively and efficiently for a proper balance of support and challenge to motivate the learner.
A bottleneck aware routing metric for wireless mesh networks

Routing metrics are critical for selecting a path with maximum throughput in wireless multi-radio multi-hop mesh networks. Due to the unique characteristics of wireless mesh networks, such as various wireless losses, data transmission rates and transmission channels, the traditional minimum hop count metric does not perform well. To address this diversity, we propose a new routing metric called Bottleneck Aware Transmission Delay (BATD). For EACH channel on a path, the BATD metric accumulates the total transmission time on the links within the same carrier sense range, and assigns a weight to the path based on the transmission delay of the channel that yields the maximal sum. The path with the least weight is preferred. As a consequence, BATD not only takes into account the diverse channel distribution when there are multiple non-overlapping channels within one path, but also considers that links on different channels can transmit data packets simultaneously.This study extensively evaluates the effectiveness of the BATD routing metric along with other popular metrics via ns-2 simulations. The experiments are performed on a controlled chain topology as well as on a randomly generated topology. The results show that the novel BATD metric outperforms other routing metrics, especially for scenarios when more than two radios are configured within each node. It achieves up to 35% throughput improvement over the current known metrics.
The role of extracellular material in chick neurulation. II. Surface morphology of neuroepithelial cells during neural fold fusion

Changes in cell surface morphology of the neuroepithelium during fusion of neural folds in the chick were studied. As the folds were about to meet, a thick extracellular coat material (ECM) appeared between the two leading edges. Cell membranes forming the fusion area were relatively smooth and heavily coated with ECM. By contrast, the apical surface of most cells lining the wall of the neural tube was folded with much less ECM. During the contact of neural folds, ECM was displaced from the space between the two leading edges, leaving a thin, closely adherent "typical" cell surface coat. Trypsin and concanavalin A inhibited proper alignment and fusion of apposing neural folds by modifying the surface of developing neuroepithelium. Results of this study support a hypothesis that ECM may serve temporarily as an adhesive to bind together the leading edges of neural folds until establishment of more intimate contacts (junctional complexes).
NMR-Based Characterization of Phenothiazines as a RNA Binding Scaffold†

Phenothiazines were identified by virtual screening as promising ligands for HIV-1 TAR RNA and A-site ribosomal RNA, and binding in each case was verified experimentally. Consequently, since phenothiazines generally possess high bioavailability and low toxicity, we used several NMR techniques to explore the binding characteristics of acetopromazine with a total of five different RNA constructs: four as potential drug targets plus one control RNA construct. Acetopromazine was able to bind to various internal bulges and terminal loops containing both purines and pyrimidines, but no binding could be detected with double-stranded RNA or tetraloops. Dissociation constants determined via NMR varied from 0.27 to >3 mM. Analysis of differential saturation transfer difference (STD) NMR effects of acetopromazine suggests that the phenothiazine moiety has the closest contact to the binding sites of TAR and A-site RNA while the flexible N,N-dimethylpropylamino side chain contributes less to binding. NMR studies on A-site ribosomal RNA binding by six commercially available phenothiazines, while too few to establish a true structure-activity relationship, revealed a distinct dependence on aromatic ring and side chain substituents. Substituted phenothiazines have low molecular weight, are not highly charged, and have an inherent affinity for irregular tertiary RNA folds, suggesting that they can serve as a novel scaffold for constructing RNA-binding ligands.
Optical-absorption bands in the 1–3 eV range in n -type SiC polytypes

Measured optical-absorption bands in the 1--3 eV range in fairly heavily doped n-type SiC polytypes 3C, 6H, 4H, 8H, and 15R are shown to arise from optical transitions between the lowest conduction band, which is to some extent perturbed by impurity effects, to higher conduction bands. The energies of the transitions are in good agreement with the differences between unperturbed low-lying energy bands calculated using the full-potential linear muffin-tin orbital method in the local-density approximation. The polarization dependence is explained by selection rules deriving from the symmetry of the bands involved. This indicates that the states involved in the transitions must to a good extent retain the symmetry characters of the unperturbed bands. On the other hand, the calculated absorption peaks from a pure band-to-band model are much narrower, and slightly lower in energy than the experimental ones. Calculations of the density of states over a restricted range of $\mathbf{k}$ space for the final states indicate that a partial breakdown of periodicity and hence the $\ensuremath{\Delta}\mathbf{k}=0$ selection rule can account for a major part of the broadening. This explanation is consistent with the degenerate carrier concentration, associated with the overlap of the impurity band tail with the bottom of the conduction band. In 6H-SiC, one feature in the absorption spectrum appears nevertheless to be associated with a more purely band-to-band-like transition. It is a sharp one-dimensional van Hove singularity in the joint density of states at the M point associated with the camel's-back structure of the lowest conduction band. At a lower carrier concentration, this feature is not present, and the transitions appear to have a more localized impurity-to-band character.
Early Pathogenesis of Transmucosal Feline Immunodeficiency Virus Infection

To identify the early target cells and tissues in transmucosal feline immunodeficiency virus (FIV) infection, cats were exposed to a clade C FIV isolate via the oral-nasal or vaginal mucosa and multiple tissues were examined by virus isolation coculture (VI), DNA PCR, catalyzed tyramide signal-amplified in situ hybridization (TSA-ISH), and immunohistochemistry between days 1 and 12 postinoculation (p.i.). FIV RNA was detected in tonsil and oral or vaginal mucosa as early as 1 day p.i. by TSA-ISH and in retropharyngeal, tracheobronchial, or external iliac lymph nodes and sometimes in spleen or blood mononuclear cells by day 2, indicating that regional and distant spread of virus-infected cells occurred rapidly after mucosal exposure. By day 8, viral RNA, DNA, and culturable virus were uniformly detected in regional and distant tissues, connoting systemic infection. TSA-ISH proved more sensitive than DNA PCR in detecting early FIV-infected cells. In mucosal tissues, the earliest demonstrable FIV-bearing cells were either within or subjacent to the mucosal epithelium or were in germinal centers of regional lymph nodes. The FIV(+) cells were of either of two morphological types, large stellate or small round. Those FIV RNA(+) cells which could be colabeled for a phenotype marker, were labeled for either dendritic-cell-associated protein p55 or T-lymphocyte receptor antigen CD3. These studies indicate that FIV crosses mucous membranes within hours after exposure and rapidly traffics via dendritic and T cells to systemic lymphoid tissues, a pathway similar to that thought to occur in the initial phase of infection by the human and simian immunodeficiency viruses.
Picosecond dynamics of the spin-lattice relaxation in La 0.7 Ca 0.2 MnO 3 : Magnetic-field dependence

We have employed ultrafast optical pump-probe measurements at 1.5 eV to study the picosecond dynamics of the magnetic-field-induced metal-insulator (MI) transition in ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ thin films in fields up to 7 T. We show that field induced modification of the photoinduced dynamic spectral weight transfer (DSWT) is related to changes in the magnetic entropy. The magnetic-field-induced increase of the ferromagnetic-paramagnetic transition temperature is evident in the spin-lattice relaxation time and amplitude scaling of the DSWT.
The loss of Nf1 transiently promotes self-renewal but not tumorigenesis by neural crest stem cells

Neurofibromatosis is caused by the loss of neurofibromin (Nf1), leading to peripheral nervous system (PNS) tumors, including neurofibromas and malignant peripheral nerve sheath tumors (MPNSTs). A long-standing question has been whether these tumors arise from neural crest stem cells (NCSCs) or differentiated glia. Germline or conditional Nf1 deficiency caused a transient increase in NCSC frequency and self-renewal in most regions of the fetal PNS. However, Nf1-deficient NCSCs did not persist postnatally in regions of the PNS that developed tumors and could not form tumors upon transplantation into adult nerves. Adult P0a-Cre+Nf1(fl/-) mice developed neurofibromas, and Nf1(+/-)Ink4a/Arf(-/-) and Nf1/p53(+/-) mice developed MPNSTs, but NCSCs did not persist postnatally in affected locations in these mice. Tumors appeared to arise from differentiated glia, not NCSCs.
Behavioral properties of GBR 12909, GBR 13069 and GBR 13098: Specific inhibitors of dopamine uptake

Two aryl 1,4-dialkylpiperazines (GBR 12909 and GBR 13098) and one aryl 1,4-diakenylpiperazine (GBR 13069) were very potent inhibitors of [3H]dopamine uptake in vitro in tissue slices obtained from rat neostriatum (IC50 values between 40 and 51 nM). Each compound was considerably weaker as an inhibitor of [3H]norepinephrine uptake in tissue slices obtained from rat occipital cortex (IC50 values between 560 and 2600 nM). These compounds thus are relatively specific inhibitors of [3H]dopamine uptake in vitro. The three compounds caused ipsilateral circling in rats with unilateral lesions of the nigrostriatal pathway as well as increased locomotor activity in naive mice, both of which could be greatly attenuated by pretreatment of the rodents with the dopamine receptor antagonist haloperidol. It thus follows that the compounds have dopaminergic activity in vivo. Ex vivo experiments with GBR 13069 (drug administration in vivo, uptake in vitro) suggested that these compounds may have the same relative specificity as dopamine uptake blockers in vivo. These compounds should prove to be useful pharmacological agents.
Competency-Based Student Self-Assessment on a Surgery Rotation

Background. Although self-assessment is an essential component of self-directed adult learning, few data exist regarding the ability of medical students to perform this important task. Therefore, the purpose of this study was to evaluate the ability of medical students to perform self-assessment during a third-year surgery clerkship. Methods. Sixty-eight (34 male, 34 female) third-year medical students assessed their progress at the midpoint of an 8-week surgery clerkship using an 11-item, competency-based evaluation. Students compared perceptions of their performance with a faculty member's assessment using the identical evaluation form. Results. Male students tended to overestimate their midclerkship performance compared with faculty formative and summative evaluations (3.31 ± 0.03 vs 3.23 ± 0.03 and 3.28 ± 0.03) although this did not reach statistical significance. Female students significantly underestimated their midclerkship performance compared with faculty formative and summative evaluations (3.06 ± 0.03 vs 3.40 ± 0.03 and 3.45 ± 0.03, P < 0.05 vs faculty evaluations). Preclerkship academic performance (first- and second-year grade point averages and NBME Part 1 scores) was not predictive of student self-assessment. Finally, women statistically outperformed men on the surgery clerkship (86.6% ± 0.75 vs 83.2% ± 1.20, P < 0.05 vs male students). Conclusions. Female students tend to underestimate their midclerkship performance compared with male students on a surgery rotation. Despite lower self-assessment, female students actually outperform male students. Women may underreport their capabilities when compared with men as a result of gender differences in socialization. These gender differences in self-assessment may be important to recognize when faculty provide feedback to students.
Oxalate synthesis from [14C1]glycollate and [14C1]glycoxylate in the hepatectomized rat

Hepatectomy significantly altered the metabolism of [1-14C]glyoxylate and [1-14C]glycollate in the rat. The production of 14CO2 was reduced by 47% and 77-86%, respectively, indicating the involvement of the liver in the oxidation of both substrates. Unidentified intermediates, assumed to be primarily glycine, serine and ethanolamine, were also reduced by over 50%, as would be expected from the removal of the aminotransferase enzymes through the hepatectomy. The biosynthesis of [14C]oxalate from [1-14C]glycollate was reduced by more than 80% in the hepatectomized rat. This suggests that this oxidation is primarily catalyzed by the liver enzymes, glycolic acid oxidase and glycolic acid dehydrogenase, in the intact rat. The limited formation of [14C]oxalate from [14C1]glycollate observed in the hepatectomized rat is probably catalyzed by lactate dehydrogenase or extrahepatic glycolic acid oxidase. Hepatectomy did not significantly alter the rate of formation of [14C]oxalate from [14C1]glyoxylate. However, since saturating concentrations of glyoxylate could not be used because of the toxicity of this substrate, the involvement of glycollic acid oxidase in this oxidation reaction in the intact rat can not be ruled out. In the hepatectomized rat, lactate dehydrogenase appears to be the enzyme making the major contribution, although other as yet not identified enzymes may be contributing. The increased deposition of oxalate in the tissues, oxalosis, may result from the shift in oxalate synthesis from the liver to the extrahepatic tissues.
Repeated low level formaldehyde exposure produces enhanced fear conditioning to odor in male, but not female, rats

Multiple chemical sensitivity (MCS) is an ill-defined disorder in humans attributed to exposure to volatile organic compounds. This study draws on apparent parallels between individuals with posttraumatic stress disorder (PTSD) and panic disorder and a subset of those reporting MCS, using a conditioned fear task in rats. Male and female Sprague-Dawley rats were given repeated exposure to 2 ppm formaldehyde (Form) (1 h/day x 5 days/week x 4 week) or air, and after 2-3 weeks, rats were trained on the conditioned fear task. One half of Air and Form rats were given odor (orange oil, the conditioned stimulus, CS) paired with footshock (PRD) and the other half was given the same stimuli in an unpaired manner (UNP). After 24 h, rats were placed into the same context without the CS or footshock. Male and female PRD groups demonstrated contextual freezing 5-15% of the time, while the UNP groups showed freezing 30-50% of the time, with no effect of Air or Form pretreatment. For the next 5 days, rats were placed into a novel context and tested for freezing in the absence or presence of the CS. In male rats, Form pretreatment produced a significantly greater freezing response in both UNP and PRD groups in the presence of the CS, with no differences in freezing in the absence of the CS. In female rats, no significant differences between Form pretreated rats and Air controls were observed in either the PRD or UNP groups. The increase in conditioned fear responding to the CS after Form exposure in males suggests that repeated low-level Form may act as a stressor to produce sensitized responding within olfactory/limbic pathways, and may help explain the panic-like responses observed in a subset of individuals reporting MCS. Furthermore, the male/female differences suggest a gonadal hormonal contribution to this behavior.
Water permeability of nanoporous graphene at realistic pressures for reverse osmosis desalination

Nanoporous graphene (NPG) shows tremendous promise as an ultra-permeable membrane for water desalination thanks to its atomic thickness and precise sieving properties. However, a significant gap exists in the literature between the ideal conditions assumed for NPG desalination and the physical environment inherent to reverse osmosis (RO) systems. In particular, the water permeability of NPG has been calculated previously based on very high pressures (1000–2000 bars). Does NPG maintain its ultrahigh water permeability under real-world RO pressures (<100 bars)? Here, we answer this question by drawing results from molecular dynamics simulations. Our results indicate that NPG maintains its ultrahigh permeability even at low pressures, allowing a permeate water flux of 6.0 l/h-bar per pore, or equivalently 1041 ± 20 l/m2-h-bar assuming a nanopore density of 1.7 × 1013 cm−2.
Testosterone and 17Β-estradiol have opposite effects on podocyte apoptosis that precedes glomerulosclerosis in female estrogen receptor knockout mice

Podocyte damage and apoptosis are thought to be important if not essential in the development of glomerulosclerosis. Female estrogen receptor knockout mice develop glomerulosclerosis at 9 months of age due to excessive ovarian testosterone production and secretion. Here, we studied the pathogenesis of glomerulosclerosis in this mouse model to determine whether testosterone and/or 17β-estradiol directly affect the function and survival of podocytes. Glomerulosclerosis in these mice was associated with the expression of desmin and the loss of nephrin, markers of podocyte damage and apoptosis. Ovariectomy preserved the function and survival of podocytes by eliminating the source of endogenous testosterone production. In contrast, testosterone supplementation induced podocyte apoptosis in ovariectomized wild-type mice. Importantly, podocytes express functional androgen and estrogen receptors, which, upon stimulation by their respective ligands, have opposing effects. Testosterone induced podocyte apoptosis in vitro by androgen receptor activation, but independent of the TGF-β1 signaling pathway. Pretreatment with 17β-estradiol prevented testosterone-induced podocyte apoptosis, an estrogen receptor-dependent effect mediated by activation of the ERK signaling pathway, and protected podocytes from TGF-β1- or TNF-α-induced apoptosis. Thus, podocytes are target cells for testosterone and 17β-estradiol. These hormones modulate podocyte damage and apoptosis.