cssi/SciSciGPT-SciSciNet huggingface dataset:
Molecular Mechanisms of the Voltage-Dependent Potentiation of KCNH Potassium Channels

EAG-like (ELK, Kv12) voltage-gated potassium channels in the KCNH channel family are primarily and abundantly expressed in the brain. Deletion of the ELK gene leads to hyperexcitability of hippocampal neurons, epilepsy and altered cognitive functions. One structural feature of KCNH channels important for channel function is an interaction between the N-terminal EAG domain and the C-terminal cyclic nucleotide-binding homology domain (CNBHD). Here we studied an orthologous zebrafish ELK channel (zELK) using patch-clamp recording and patch-clamp fluorometry (PCF). We noticed that a depolarizing prepulse potentiated the zELK channels in both the current amplitude and the voltage sensitivity. We named this phenomenon voltage-dependent potentiation (VDP) and found it developed and recovered within hundreds of milliseconds. Using direct application of diC8-PI(4,5)P2 and specific hydrolysis of PI(4,5)P2 by rapamycin-recruitable lipid 5-phosphatase, we demonstrated that, PI(4,5)P2 inhibits zELK channels, and its depletion suppresses the VDP. In addition, the VDP can be manipulated by multiple structural perturbations including removing, mutating or replacing the intracellular N-terminal EAG domain as well as the C-terminal CNBHD. Further, combining transition metal ion FRET and incorporation of a fluorescent noncanonical amino acid L-Anap, we measured the distances between positions in the EAG domain and CNBHD during voltage-dependent channel activation and deactivation. We found there was an apparent change in the distance between the EAG domain and CNBHD with kinetics that match the on- and off-rates of VDP. This change in the distance between the N- and C-terminal regions was abolished when PI(4,5)P2 was hydrolyzed, and the simultaneous VDP was eliminated. Collectively, we propose that the activation of zELK channels involves a rearrangement of the direct interaction between the N- and C-terminal regions, which transitions the channel to a potentiated state.
Protein molecular modeling shows residue T599 is critical to wild-type function of POLG and description of a novel variant associated with the SANDO phenotype

Sensory ataxic neuropathy with dysarthria and ophthalmoparesis (SANDO) is a rare phenotype resulting from pathogenic variants of mitochondrial DNA polymerase gamma (POLG). We modeled a novel POLG variant, T599P, that causes the SANDO phenotype and another variant at the same residue, p.T599E, to observe their effect on protein function and confirm the pathogenicity of T599P. Through neoteric molecular modeling techniques, we show that changes at the T599 residue position introduce extra rigidity into the surrounding helix-loop-helix, which places steric pressure on nearby nucleotides. We also provide a clinical description of the T599P variant, which was found in a 42-year-old female proband. The proband presented a 1-year history of progressive gait instability, dysarthria and foot numbness. Her neurologic examination revealed ataxic dysarthria, restricted eye movements, head and palatal tremors, reduced lower limb reflexes, distal multimodal sensory loss and a wide, unsteady ataxic gait. Electromyography studies indicated a sensory neuropathy. Whole-exome sequencing was pursued after tests for infectious, inflammatory and paraneoplastic causes were negative.
Pulse Oximetry and Arterial Oxygen Saturation during Cardiopulmonary Exercise Testing.

ABSTRACTIntroduction/PurposePeripheral capillary oxygen saturation (SpO2) is used as surrogate for arterial blood oxygen saturation. We studied the degree of discrepancy between SpO2 and arterial oxygen (SaO2) and identified parameters that may explain this difference.MethodsWe included patients who
Psychotic Disorders in Late Life

The term “psychosis” has changed over time and become more specific. The earlier Diagnostic and Statistical Manuals of Mental Disorders (DSM-I and DSM-II) (American Psychiatric Association, 1952, 1968) made a distinction between “psychotic” and “nonpsychotic” organic brain syndromes based mainly upon severity. That terminology was abandoned in the initial version of DSM-III (American Psychiatric Association, 1980) and has not been restored. Thus, some patients we would now diagnose as having dementia would have been diagnosed as having a “psychotic” condition if the dementia was severe. It is interesting to note the further progression of this redescriptive process in DSM-IV (American Psychiatric Association, 1994). Here, the term dementia is not abandoned, but is characterized as a cognitive disorder. This definition takes us even further from the concept of psychosis as it is generally understood, implying severe disorganization of the personality. The term psychosis in current usage is now mainly restricted to schizophrenia and bipolar disorder. The DSM-IV does not specifically characterize bipolar disorder as psychotic and limits that term to schizophrenic, schizoaffective, and delusional disorders. This chapter adopts that convention, but we will briefly consider psychotic features, notably delusions and hallucinations, that are frequently associated with some forms of dementia. We will deal largely with schizophrenia. A detailed presentation of late-onset psychotic conditions and schizophrenia in old age is contained in a volume by Miller and Cohen (1987) to which the reader is referred for more detailed information than can be presented here. It is noted that while schizophrenia may be a life-shortening disease, many schizophrenic patients live relatively long lives and may continue to suffer from symptoms of the disorder throughout those lives.
Thoughts about Sexual Difficulties and Related Anxiety Among a Predominantly Female Sample of Adolescents

AbstractThis qualitative data analysis examined adolescents’ thoughts and feelings about difficulties that can emerge during sexual experiences. The sample consisted of 53 sexually experienced, ethnically diverse, predominantly female, nonpregnant adolescents participating in a web-based sexual health intervention. As part of a message board discussion, adolescents described anxiety-enhancing attitudes and beliefs (e.g., men should be skilled sexually, women should express satisfaction even if they do not feel it). Several adolescents advocated for condom use despite potential difficulties when attempting to use them. Health professionals should equip adolescents with skills to communicate with partners about sexual difficulties and cope with related anxiety.
ICedge : When Edge Computing Meets Information-Centric Networking

In today’s era of explosion of Internet of Things (IoT) and end-user devices and their data volume emanating at the network’s edge, the network should be more in-tune with meeting the needs of these demanding edge computing applications. To this end, we design and prototype Information-Centric edge ( ICedge ), a general-purpose networking framework that streamlines service invocation and improves the reuse of redundant computation at the edge. ICedge runs on top of named-data networking, a realization of the information-centric networking vision, and handles the “low-level” network communication on behalf of applications. ICedge features a fully distributed design that: 1) enables users to get seamlessly on-boarded onto an edge network; 2) delivers application invoked tasks to edge nodes for execution in a timely manner; and 3) offers naming abstractions and network-based mechanisms to enable (partial or full) reuse of the results of already executed tasks among users, which we call “compute reuse,” resulting in lower task completion times and efficient use of edge computing resources. Our simulation and testbed deployment results demonstrate that ICedge can achieve up to $50\times $ lower task completion times leveraging its network-based compute reuse mechanism compared to cases, where reuse is not available.
Introduction: Water Supply and Management

Access to a safe water supply is a human right. Fresh water sustains human life and is vital for human health. Water availability depends upon the amount of water physically available, and whether it is safe for human consumption. Some of the arid regions of the world lack adequate safe drinking water.
Abstract A79: Myeloid-lymphatic endothelial progenitors significantly contribute to lymph node metastasis in clinical breast cancer

Introduction: Lymph node (LN) metastasis, a key prognostic factor for poor survival of breast cancer (BC) patients, directly depends on lymphangiogenesis, i.e., formation of new lymphatic vessels. Using orthotopic BC models, we previously showed that lymphangiogenesis is strongly promoted by tumor-mobilized myeloid-derived lymphatic endothelial cell (LEC) progenitors (M-LECP) and that M-LECP density correlates with lymphatic metastasis. The goal of this study was to examine the density and a prometastatic role of M-LECP in clinical human BC. Methods: Circulating CD14+ cells from BC patients (N=25) and healthy donors (N=24) were analyzed for expression of lymphatic-specific markers. Specimens from BC patients (N=104) along with normal mammary tissues (N=6) were co-stained with antibodies against myeloid and lymphatic markers including CD68, CD14, CD18 as well as LYVE1, podoplanin, and VEGFR-3. Sections were also double stained to identify LYVE1+ cells expressing lymphoid, M2-type macrophage, immunosuppressive, and stem cell markers. Densities of tumor CD68+ macrophages, LYVE1+ vessels, and CD68+/LYVE1+ double-stained M-LECP were quantified and correlated with node status and other parameters. Prometastatic potential of experimentally produced mouse M-LECP was determined by injecting in vitro differentiated myeloid-lymphatic cells into mice bearing syngeneic EMT6 breast tumors. Results: 92% of BC patients had monocytes expressing at least one lymphatic marker compared to 2% of healthy donors. More than 70% of breast tumors contained M-LECP with density ranging from 2 to 50 cells per high-power field. Tumor-recruited M-LECP expressed specific markers of myeloid but not lymphoid lineages as well as M2-type, immunosuppressive and stem cell markers. Tumors with high density (>20 cells/field) of M-LECP were significantly more likely to belong to aggressive subgroups (HER2+ and TNBC) and present with lymph node metastasis (P-value Conclusion: These data show for the first time that human breast tumors recruit significant amounts of immature myeloid cells with immunosuppressive and lymphatic-promoting properties. Such cells are largely absent in normal breast tissues. Statistical analyses indicate that M-LECP can significantly contribute to formation of new lymphatic vessels and promote metastasis. Citation Format: Lisa Volk-Draper, Radhika Patel, Nihit Bhattarai, Jie Yang, Sophia Ran. Myeloid-lymphatic endothelial progenitors significantly contribute to lymph node metastasis in clinical breast cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A79.
Fear, Trust and Hip Hop Nationalism

In an ideal universe we should define collective political excellence as a balancing of group self determination and political compromise. This paper is an inquiry into the development of political excellence of Blacks following the civil rights era. The study focuses on the development of two “virtues” essential to political excellence – fear and trust. These virtues have historically been essential to the development of identity and politics within the African Diaspora. Hip hop nationalism develops out of the struggle of Black youth of the 1960’s and afterwards attempting to understand the politics, conflict and compromise of two distinct Black political understandings the Civil Rights Movement and the Black Nationalist Movement. These two movements, their values and principles were personified for these emerging generations in two men – Malcolm X and Martin Luther King Jr. two martyrs with seemingly divergent messages which following generations have attempted to amalgamate into political excellence. I refer to this political excellence which is now two generations strong as hip hop nationalism. This new form of nationalism struggles with its attempt to balance self determination and compromise on the cultural level through its pursuit of nationalism and its attempt to gain mainstream acceptance especially in the economic realm. Its consequent fear and trust development in those areas will be analyzed in this paper.
An Assessment of Experiential E-Commerce Apparel Websites and Psychological Personality Traits among Females

The purpose of the study is to assess if there will be a difference in attitudes toward websites with varying degrees of interactivity and if the Five Factor Model (FFM) personality traits influence this relationship. Five experiential websites were designed where a picture of each was included in an online survey developed to measure purchase intention on the website, intention to revisit, attitude ands shopping value towards the website, and the personality of the participant. The findings suggest there is a significant difference in the perceptions of the websites and personality traits do exert influence on online experiential retail preferences. Online female shoppers that score higher on agreeableness, conscientiousness, and openness prefer highly interactive websites compared to those who score higher on extroversion and neuroticism.
A Multicenter Telemedicine Handoff Pilot to Improve the Transition of Care from NICU to PCPs and Families

Background: Medically complex infants are discharged from the Neonatal Intensive Care Unit (NICU) with complicated, multifaceted care needs that must transition from the NICU home, to their family and their primary care providers (PCPs). Critical to such management is the accurate and prompt transmission of important and relevant clinical information from the NICU team to the PCP. Currently, such communication happens largely by the discharge summary and occasionally via telephone calls. Despite these efforts, nuances of care may be lost in communication. Completing these handoffs by telemedicine could be …
B 2 -Coupon: Efficient and Non-intrusive Mobile Coupon Distribution using Dual Bloom Filter

In this paper, we propose B2-Coupon, an efficient mobile electronic coupon (mobile coupon or coupon in short) distribution system on mobile phones using the Dual Bloom Filter. The Dual Bloom Filter, consisted of the Interest Bloom Filter and the Forwarder Bloom Filter, achieve targeted forwarding and fair reward distributions among coupon forwarders. Particularly, the Interest Bloom Filter narrows down the target receivers (i.e. potential coupon users or forwarders) by user interest matching check, and the Forwarder Bloom Filter records all the coupon forwarder IDs in a space-efficient way. We use Bluetooth Low Energy (BLE) beacons to enable non-intrusive coupon transmission without manual connection setup. We conduct both large-scale simulation-based and implementation-based evaluations on our system. The simulation results show that our system realizes fast coupon propagation and fair reward distributions. The implementation is based on Android phones, such as Google and Samsung phones. The implementation results indicate that our system is capable of real-world deployment. We conclude that B2-Coupon can effectively facilitate efficient and non-intrusive coupon distribution among mobile users.
Is cultivating reciprocal learning the gold standard for high impact pedagogies

High Impact-Practices (HIPs) have been found to improve student engagement and retention, increase civic engagement, and enhance learning outcomes. Research on HIPs shows that combining multiple HI...
Do adolescents always take more risks than adults? A within-subjects developmental study of context effects on decision making and processing

Adolescents take more risks than adults in the real world, but laboratory experiments do not consistently demonstrate this pattern. In the current study, we examine the possibility that age differences in decision making vary as a function of the nature of the task (e.g., how information about risk is learned) and contextual features of choices (e.g., the relative favorability of choice outcomes), due to age differences in psychological constructs and physiological processes related to choice (e.g., weighting of rare probabilities, sensitivity to expected value, sampling, pupil dilation). Adolescents and adults made the same 24 choices between risky and safe options twice: once based on descriptions of each option, and once based on experience gained from sampling the options repeatedly. We systematically varied contextual features of options, facilitating a fine-grained analysis of age differences in response to these features. Eye-tracking and experience-sampling measures allowed tests of age differences in predecisional processes. Results in adolescent and adult participants were similar in several respects, including mean risk-taking rates and eye-gaze patterns. However, adolescents' and adults' choice behavior and process measures varied as a function of decision context. Surprisingly, age differences were most pronounced in description, with only marginal differences in experience. Results suggest that probability weighting, expected-value sensitivity, experience sampling and pupil dilation patterns may change with age. Overall, results are consistent with the notion that adolescents are more prone than adults to take risks when faced with unlikely but costly negative outcomes, and broadly point to complex interactions between multiple psychological constructs that develop across adolescence.
Middle ear disease requiring myringotomy in the first two years after tracheotomy in the pediatric population

Abstract Objectives Risk factors for middle ear disease necessitating myringotomy with tympanostomy tube placement after a tracheostomy have not been thoroughly explored. This study investigates the incidence and risk factors for ear tube placement in pediatric patients with a tracheostomy. Methods Pediatric patients under age 18 who underwent tracheotomy between 2002 and 2010 at two institutions were identified. Patients were excluded if they had undergone myringotomy prior to, or at the same time as, the tracheotomy, or did not have at least two years of follow-up clinic visits. The presence of other comorbidities was recorded. Descriptive statistics and logistic regression models were used to assess the impact of clinical characteristics on outcomes. Results A total of 214 patients met inclusion criteria. Median patient age at time of tracheotomy was 6 months (IQR 2–17), median patient age at time of myringotomy with tubes was 12 months (IQR8-17), and median time between tracheotomy and myringotomy with tube placement was 8 months (IQR 5–11). Sixty-seven (31%) patients required myringotomy with tympanostomy tube placement within the first two years after tracheotomy. Fifty-eight (87%) patients who underwent myringotomy with tympanostomy tubes were younger than 2 years at the time of the procedure. Logistical regression found younger age at time of tracheotomy to be a risk factor (OR: 0.71, 95% CI: 0.5–0.9, p Conclusion This study reports a high incidence of myringotomy with tubes in children with tracheostomy relative to the general pediatric population. Many comorbid conditions that often accompany the need for tracheotomy place these patients at a higher risk for ear disease requiring surgical intervention. Risk factors for operative middle ear disease in this population included age at time of tracheostomy, craniofacial abnormalities, and presence of a G-tube.
Comparative analysis of model-free and model-based HVAC control for residential demand response

In this paper, we present a comparative analysis of model-free reinforcement learning (RL) and model predictive control (MPC) approaches for intelligent control of heating, ventilation, and air-conditioning (HVAC). Deep-Q-network (DQN) is used as a candidate for model-free RL algorithm. The two control strategies were developed for residential demand-response (DR) HVAC system. We considered MPC as our golden standard to compare DQN's performance. The question we tried to answer through this work was, What % of MPC's performance can be achieved by model-free RL approach for intelligent HVAC control?. Based on our test result, RL achieved an average of ≈ 62% daily cost saving of MPC. Considering the pure optimization and model-based nature of MPC methods, the RL showed very promising performance. We believe that the interpretations derived from this comparative analysis provide useful insights to choose from various DR approaches and further enhance the performance of the RL-based methods for building energy managements.
Deconstructing intent to reconstruct morality

Mental state representations are a crucial input to human moral judgment. This fact is often summarized by saying that we restrict moral condemnation to ‘intentional’ harms. This simple description is the beginning of a theory, however, not the end of one. There is rich internal structure to the folk concept of intentional action, which comprises a series of causal relations between mental states, actions and states of affairs in the world. Moral judgment shows nuanced patterns of sensitivity to all three of these elements: mental states (like beliefs and desires), the actions that a person performs, and the consequences of those actions. Deconstructing intentional action into its elemental fragments will enable future theories to reconstruct our understanding of moral judgment.
Preventative lipid-based nutrient supplements (LNS) and young child feeding practices: findings from qualitative research in Haiti

To prevent undernutrition in an urban slum in Haiti a lipid-based nutrient supplement (LNS) was introduced through a randomized control trial. Food supplementation for young child nutrition has a long history in Haiti but there is little empirical information regarding the effects of supplementation on young child feeding practices. One of the concerns raised by supplementation is that it may disrupt other positive feeding practices such as breastfeeding and use of other complementary foods with negative consequences for child nutrition. We conducted 29 in-depth interviews with mother-baby pairs from the three comparison groups: control 3-month LNS supplementation and 6-month LNS supplementation. Findings from those in the LNS groups indicated high acceptance and satisfaction with LNS and perceptions that it positively affects child health and development. LNS was integrated into and enhanced ongoing complementary feeding practices. The effects of LNS use on duration and perceived quantity of breastfeeding were variable but generally breastfeeding was maintained during and after the intervention. Interviews generated insights into beliefs regarding infant and young child feeding practices such as introduction and use of complementary foods and breastfeeding duration exclusivity and cessation. Implications for the use of LNS in public health nutrition programmes are discussed.
Take an Active Approach to Getting Interviews

In your job search, you don't want to passively wait around for the ad to show up or the headhunter to call. You want to actively find people in a position to hire you within your target organizations and then go for it; write e-mails and follow up with phone calls to get meetings with these people. In other words, don't just drift around in the ocean hoping the currents will take you to an island of your dreams. Find that island and actively swim to it!
Value chain approaches to development

Purpose – The purpose of this paper is to look at the ever-popular, “value-chain approach” for linking smallholder farmers to high value export markets. Conventional wisdom says that value chains undertaken for development purposes redistribute risk and provide benefits and services to participants that are otherwise difficult or impossible to obtain. The authors take a farmer-centric approach and ask farmers participating in these higher value chains if they perceive greater, or different risks and compare results to their conventional counterparts. The authors also ask what benefits they associate with participation and if they believe they believe those benefits are exclusive to value chain participation. Design/methodology/approach – The authors collect data from growers in three different cocoa value chains in Ashanti, Ghana. These chains include one focussed on certified production practices (Rainforest Alliance), one that focussed on high-value product characteristics (Fine Flavor) and a convention...
Using Invariants for Phylogenetic Tree Construction

Phylogenetic invariants are certain polynomials in the joint probability distribution of a Markov model on a phylogenetic tree. Such polynomials are of theoretical interest in the field of algebraic statistics and they are also of practical interest-they can be used to construct phylogenetic trees. This paper is a self-contained introduction to the algebraic, statistical, and computational challenges involved in the practical use of phylogenetic invariants. We survey the relevant literature and provide some partial answers and many open problems.
Inhibition of protein synthesis in Krebs 2 ascites cells and cell-free systems by phenylalanine and its effect on leucine and lysine in the amino acid pool

1. The inhibition of incorporation of 14C-labelled amino acids into protein of whole cells by phenylalanine has been reproduced in a cell-free system. In both cases only the l-isomer was inhibitory. 2. The effect of phenylalanine on incorporation of [14C]leucine and [14C]lysine into protein was different in both whole cells and cell-free systems. 3. In whole cells inhibition of incorporation of leucine at 2·5μg./ml. was very rapid, but when the concentration was increased to 100μg./ml. the inhibition was not apparent for about 1hr. The kinetics of inhibition of lysine was the same at both these concentrations and was similar to that found with leucine at 100μg./ml. 4. Neither a lower specific radioactivity of the two amino acids in the pool nor a decrease in their pool size could be consistently related with inhibition of protein synthesis. 5. In the cell-free system l-phenylalanine inhibited the incorporation of leucine but not of lysine. 6. Charging of transfer RNA by leucine was markedly decreased in the presence of phenylalanine, whereas charging of transfer RNA by lysine was not.
Spontaneous Recovery in Idiopathic Unilateral Diaphragmatic Paralysis

Idiopathic unilateral diaphragmatic paralysis is a rare condition that typically causes minimal symptoms, especially during exercise. Several reports indicated progressive improvement or even complete recovery to normal function of diaphragmatic paralysis that complicated various thoracic and extrathoracic conditions. In this case we describe a 57-year-old male with spontaneous recovery of idiopathic right hemidiaphragm paralysis and review reported cases of reversible diaphragmatic dysfunction.
Uncertainties experienced by family members when one parent is dying

Purpose: This research examined uncertainty as a salient theme for families in which a parent was dying while receiving hospice care. Methods: Interviews were conducted with 61 participants from 26 families in the parent study to explore the strategies used by adolescents with a parent in a hospice. Second interviews were conducted with 15 original participants after the death of their parent. Conventional content analysis was used to analyse data. Results: Uncertainty was a prevalent and salient theme in the participants' stories revealing patterns about the causes, barriers, effects and strategies used to manage uncertainty. Conclusion: Uncertainties associated with the end of life can be problematic for some people, requiring attention by health professionals.
Plasma Jet for Flight Control

The need for high-speed flight-control devices has surged with recent interest in hypersonic flight. Plasma-based devices offer actuation times that are orders of magnitude smaller than conventional mechanical actuators. The plasma jet, which uses energy deposition to generate a high-speed jet, is evaluated for flight control. The jet is created by pulsing a cavity with energy deposition. The gas expands through a converging nozzle, inducing a jet flow. This research focuses on characterizing the forces generated by a single pulse of the plasma jet, assuming energy is deposited uniformly throughout the cavity and the jet exits to quiescent flow. A one-dimensional analytical model is developed to predict the force and impulse generated by the jet as well as the temporal evolution of the pressure, density, and temperature in the cavity. A relation between the dimensionless energy deposition and the dimensionless impulse is developed and verifiedwith computational results. It is shown that the dimensionless impulse generated by the jet is essentially independent of the dimensionless geometric parameters of the cavity. Additionally, a simplified analysis shows that the force from an array of plasma jets is sufficient to replace a conventional aerodynamic flap.
Morphology controlled high performance supercapacitor behaviour of the Ni–Co binary hydroxide system

The morphology evolution of the Ni–Co binary hydroxides was studied varying from nanosheets, to nanoplate–nanospheres, to nanorods and to a nanoparticle geometry by simply controlling the Co:Ni ratio in the initial reactant. High capacitances of 1030 F g−1 and 804 F g−1 can be achieved in the 1-D nanorod morphology at mass loading of 1 mg cm−2 and 2.8 mg cm−2 at a current density of 3 A g−1, respectively. To demonstrate its practical application, the binary hydroxide electrode was coupled with chemically-reduced graphene (CG) forming an asymmetric supercapacitor in order to improve the potential window and thus energy density. The asymmetric supercapacitor delivers a high energy density of 26.3 Wh kg−1 at the power density of 320 W kg−1. The approach of controlling morphology and crystallinity of the binary system for optimizing supercapacitive performance may be applied developing other promising multiply metal hydroxide/oxide systems for supercapacitor applications.
Structural effects in the action of antibiotics on the ion permeability of lipid bilayers. II. Kinetics of tyrocidine B

1. 1. The kinetics of tyrocidine B action on phospholipid and phospholipid-cholesterol bilayer shows autocatalytic behavior described by an hyperbolic tangent function 12 [1 + Tanh k1+ (t−t0)] characterized by two constants: a rate k1+ and a latency parameter μ = exp[−k1+t0]. 2. 2. These constants are studied as functions of transmembrane potential and concentration differences, as well as the usual kinetic parameters. 3. 3. The results are summarized in a reaction scheme for which a minimal interpretation is that tyrocidine acts through bimolecular transmembrane structures, the formation of which is autocatalytic and rate limiting. 4. 4. Prior to this a fast adsorption process is required which has a low (< 1 · 10−9 M) half-saturation constant. If it is assumed that the latter is ion dependent, being much smaller for K+ than for Na+, then anomalous results found previously for Na+-K+ bionic potential as function of antibiotic concentration are explained. 5. 5. There is also a fast bimolecular reaction, which may take place in the aqueous phase. Conductance development requires that its product reacts with the transmembrane structures above, to give a “carrier complex”. 6. 6. These results are markedly dependent on the polarity of lipid used, indicating that both mechanisms under (3) and (5) above are influenced by the charge profile of the bilayer. The latter can be changed by adsorption of Ca2+ on the one hand or acidic glycolipid (ganglioside) on the other, added to the aqueous phase. 7. 7. The dimers, referred to under (3) and (5) above, may be interpreted as non-polar and polar associations respectively. 8. 8. In all the above respects tyrocidine occupies a position intermediate between simple carriers and highly associative pore forming antibiotics.
Nature of the many-particle potential in the monatomic liquid state: Energetics, kinetics, and stability

Molecular-dynamics calculations have been used to explore and characterize the many-particle potential underlying the motion of particles in the monatomic liquid state. The potential used accurately represents metallic sodium at the density of the liquid at melt. It is found that the potential surface is composed of a large number of stable nearly harmonic valleys, and that these can be classified as random, symmetric, or crystalline. The random valleys cover by far the major portion of configuration space; they are macroscopically uniform, i.e., they all have the same structural potential and vibrational spectrum; and they all have microscopically irregular anharmonicity. The symmetric valleys lie at potential energies below the random valleys, but above the bcc crystalline valley. The symmetric valleys are not macroscopically uniform, but show scatter in their structural potentials and their eigenvalue spectra, and the symmetric valleys also have microscopically irregular anharmonicity. The equilibrium states of our system, from zero temperature up to and including the liquid states, fall into three groups, random, symmetric, and crystalline, according to which class of potential valley is mainly visited in the system motion. The random states are well separated from the symmetric and crystalline states, on the graph of mean potential energy versus temperature. The random states lie on a single line over the entire temperature range, and they include the liquid states, demonstrating that the random valleys dominate the statistical mechanics of the liquid. The present results provide detailed confirmation of the liquid-dynamics Hamiltonian previously used in equilibrium and nonequilibrium calculations. Further, the liquid-dynamics prediction of near equality of the log moment of the vibrational spectra, for the liquid and crystal at the same density, is verified here for the example of sodium.
Synthesis and thiol-responsive degradation of polylactide-based block copolymers having disulfide junctions using ATRP and ROP

A new method to synthesize a variety of well-con- trolled polylactide (PLA)-based block copolymers having disul- fide linkages at block junctions (PLA-ss-PATRPs) was investigated. The method uses a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) that initiates the synthesis of a new disulfide-labeled double-head initiator having both terminal OH and Br groups (HO-ss-iBuBr). The amount of tin catalyst and polymerization time significantly influenced the control of ROP initiated with HO-ss-iBuBr. A series of ATRP of various methacrylates as well as acrylate and styrene in the presence of the resulting PLA-ss- iBuBr macroinitiators proceeded in a living manner. These well-controlled PLA-ss-PATRPs were further characterized for thermal properties using differential scanning calorimetry and thiol-responsive degradation upon the cleavage of disulfide linkages. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 000: 000-000, 2012
Appearance of newly synthesized protein in myelin of young rats.

— Seventeen-day-old rats were injected intracranially with [3H]leucine, then sacrificed between 1 and 24 h. Myelin was prepared from the brains on discontinuous sucrose gradients and the proteins were separated by discontinuous gel electrophoresis in buffers containing sodium dodecyl sulphate. Proteins were stained with acid Fast Green and the distribution was quantitated by densitometry. The gels were then sliced and the radioactivity in each slice was determined. Between 1 and 24 h, the radioactivity in proteolipid protein increased from 18% to 37% of the total radioactivity in the proteins of isolated myelin. During this same period, the per cent distribution of radioactivity in basic and Wolfgram proteins remained constant while that in the remaining high molecular weight proteins decreased. Similar results were also obtained with [3H]glycine as a precursor. The relative specific activity of all of the myelin proteins increased between 1 and 6 h, then remained constant between 6 and 24 h. At 1 h, proteolipid protein reached only 25% of its maximal (6 h) relative specific radioactivity, while the other two proteins reached 50% of maximum. These results indicate a lag in the appearance of labelled amino acids in proteolipid protein relative to the other myelin proteins.
Calculations predict that carbon tunneling allows the degenerate cope rearrangement of semibullvalene to occur rapidly at cryogenic temperatures.

Calculations on the role of tunneling in the degenerate Cope rearrangements of semibullvalene (1) and barbaralane (3) predict that, at temperatures below 40 K, tunneling from the lowest vibrational level should make the temperature-independent rate constants k = 1.43 × 10−3 s−1 and k = 7.28 × 10−9 s−1, respectively. An experiment, using semibullvalene-2(4)-d1, is proposed to test the prediction of rapid tunneling by 1 at cryogenic temperatures.
The importance of wear and corrosion on the fretting fatigue behavior of two aluminum alloys

Research in the Quality and Integrity Design Engineering Center of the University of Utah was conducted to determine the relative importance of wear and corrosion (oxidation) failure mechanisms on the fretting fatigue behavior of 8090-T7 and 7075-T7351 aluminum alloy specimens. Specimens were tested either in laboratory air or in the vacuum chamber of a scanning electron microscope (SEM). The fretting fatigue process in the SEM vacuum was assumed to be relatively more wear and less corrosion dependent than the process in air. Under the test conditions it was found that the wear mechanism dominates for the 8090 alloy, but that the corrosion mechanism appears to dominate for the 7075 alloy.
Feather growth influences blood mercury level of young songbirds

Dynamics of mercury in feathers and blood of free-living songbirds is poorly understood. Nestling eastern bluebirds (Sialia sialis) living along the mercury-contaminated South River (Virginia, USA) had blood mercury levels an order of magnitude lower than their parents (nestling: 0.09 +/- 0.06 mg/kg [mean +/- standard deviation], n = 156; adult: 1.21 +/- 0.57 mg/kg, n = 86). To test whether this low blood mercury was the result of mercury sequestration in rapidly growing feathers, we repeatedly sampled free-living juveniles throughout the period of feather growth and molt. Mean blood mercury concentrations increased to 0.52 +/- 0.36 mg/kg (n = 44) after the completion of feather growth. Some individuals had reached adult blood mercury levels within three months of leaving the nest, but levels dropped to 0.20 +/- 0.09 mg/kg (n = 11) once the autumn molt had begun. Most studies of mercury contamination in juvenile birds have focused on recently hatched young with thousands of rapidly growing feathers. However, the highest risk period for mercury intoxication in young birds may be during the vulnerable period after fledging, when feathers no longer serve as a buffer against dietary mercury. We found that nestling blood mercury levels were not indicative of the extent of contamination because a large portion of the ingested mercury ended up in feathers. The present study demonstrates unequivocally that in songbirds blood mercury level is influenced strongly by the growth and molt of feathers.
Ac Susceptibility Measurements on Transition Metal Superconductors Containing Rare Earth and Ferromagnetic Metal Solutes

The question of simultaneous ferromagnetism and superconductivity in Gd/ sub x/Th/sub 1/-/sub x/Ru/sub 2/ is studied, as is the appare nt enhancement of superconductivity caused by the dissolution of small amounts of Fe or Ru in Ti. (T.F.H.)
What limits production of unusual monoenoic fatty acids in transgenic plants

Unusual monounsaturated fatty acids are major constituents (greater than 80%) in seeds of Coriandrum sativum L. (coriander) and Thunbergia alata Bojer, as well as in glandular trichomes (greater than 80% derived products) of Pelargonium x hortorum (geranium). These diverged fatty acid structures are produced via distinct plastidial acyl-acyl carrier protein (ACP) desaturases. When expressed in Arabidopsis thaliana (L.) Heynh. under strong seed-specific promoters the unusual acyl-ACP desaturases resulted in accumulation of unusual monoene fatty acids at 1-15% of seed fatty acid mass. In this study, we have examined several factors that potentially limit higher production of unusual monoenes in transgenic oilseeds. (i) Immunoblots indicated that the introduced desaturases were expressed at levels equivalent to or higher than the endogenous delta9 18:0-ACP desaturase. However, the level of unusual fatty acid produced in transgenic plants was not correlated with the level of desaturase expression. (ii) The unusual desaturases were expressed in several backgrounds, including antisense 18:0-ACP desaturase plants, in fab1 mutants, and co-expressed with specialized ACP or ferredoxin isoforms. None of these experiments led to high production of expected products. (iii) No evidence was found for degradation of the unusual fatty acids during seed development. (iv) Petroselinic acid added to developing seeds was incorporated into triacylglycerol as readily as oleic acid, suggesting no major barriers to its metabolism by enzymes of glycerolipid assembly. (v) In vitro and in situ assay of acyl-ACP desaturases revealed a large discrepancy of activity when comparing unusual acyl-ACP desaturases with the endogenous delta9 18:0-ACP desaturase. The combined results, coupled with the sensitivity of acyl-ACP desaturase activity to centrifugation and low salt or detergent suggests low production of unusual monoenes in transgenic plants may be due to the lack of, or incorrect assemble of, a necessary multi-component enzyme association.
Temperature-dependent thermodynamic contributions to the relative tautomeric stabilities of nucleic acid bases

Abstract Temperature-dependent components of the enthalpy and entropy contributions ot the Δ G Gibbs free tautomerization energies of DNA bases and their derivatives are computed within the rigid rotor—harmonic oscillator—ideal gas approximation using the data (rotational constants, harmonic frequencies) from the SCF/3-21 G calculations. For the tautomers existing in comparable concentrations, these contributions were found to be important parts of the Δ G energies, and they should be calculated for the proper comparison of the calculated and experimental tautomeric stabilities of the bases.
Metabolism and mechanisms of action of bendamustine: Rationales for combination therapies

Bendamustine hydrochloride is the active ingredient of Ribomustin (Ribosepharm GmbH, Munich, Germany). It was first synthesized in 1963 in the German Democratic Republic. Bendamustine is chemically related to the alkylating agent chlorambucil, with the benzene ring in the chlorambucil molecule replaced by a 1-methyl-benzimidazole moiety. The mechanisms of action of bendamustine have been under investigation since the early 1960s, and its first use was as a treatment for multiple myeloma in 1969. Bendamustine has three active moieties: an alkylating group, in common with the nitrogen mustard family; a benzimidazole ring, which may act as a purine analog; and a butyric acid side-chain. Bendamustine undergoes extensive first-pass metabolism. However, unmetabolized bendamustine accounts for about 45% of the total drug recovered in urine. The main transformation product is a cytotoxic hydroxy metabolite (beta-hydroxybendamustine). Bendamustine was originally synthesized with the intention of producing an antineoplastic agent with low toxicity and both alkylating and antimetabolic properties. However, it has been shown that, at least at high concentrations, it acts primarily as an alkylating agent. Based on the multiple actions and cell cycle effects of this agent, mechanism-based combination strategies have been suggested. The rationales behind bendamustine combination regimens and the importance of the sequence of administration of different drugs are explored.
Surface effects during fretting fatigue of Ti-6Al-4V

Abstract An investigation is described of surface effects which occur during fretting fatigue of Ti-6Al-4V alloy. A one stage test procedure was used whereby fretting and fatigue occur simultaneously. Friction forces and contact resistances were measured during testing. Results were found to fall into two classifications : low contact stress where fatigue failure initiates away from the fretting area, and higher contact stress where fretting cracks initiate at the edge of the fretting area and propagate to failure. With the low contact stress, slip occurs and wear particles become entrapped between the fretting surfaces, whereas with the higher contact stresses, no slip occurs and wear particles are not observed. Fatigue reduction with the high stress is attributed to localized fatigue due to the fretting stresses. The absence of fatigue failure at the fretting area with the low contact stress is attributed to stress reduction by entrapped particles and removal of fatigued material by fretting wear.
Direct measurement of electron channeling in a crystal using scanning transmission electron microscopy

Self-focusing of an atomic-scale high-energy electron wave packet by channeling along a zone axis in crystalline silicon is directly measured by scanning transmission electron microscopy using thin epitaxial SrTiO${}_{3}$(100) islands grown on Si(100) as test objects. As the electron probe propagates down a silicon atom column, it is progressively focused onto the column, resulting in a fourfold increase in the scattered signal at the channeling maximum. This results in an enhancement of the visibility of the SrTiO${}_{3}$ islands, which is lost if the sample is flipped upside down and the channeling occurs only after the probe scatters off the SrTiO${}_{3}$ layer. The evolution of the probe wave function calculated by the multislice method accurately predicts the trends in the channeling signal on an absolute thickness scale. We find that while electron channeling enhances the visibility of on-column atoms, it suppresses the contribution from off-column atoms. It can therefore be used as a filter to selectively image the atoms that are most aligned with the atomic columns of the substrate. By using this technique, coherent islands can be distinguished from relaxed islands. For SrTiO${}_{3}$ films formed in a topotactic reaction on Si(100), we show that only $\ensuremath{\sim}$55$%$ of the SrTiO${}_{3}$ is aligned with the Si atom columns. The fraction of coherent SrTiO${}_{3}$ islands on Si(100) can be increased by choosing growth conditions away from equilibrium.
Conservative difference equations

Abstract A general, difference equation approximation is described for differential systems which are conservative. The difference equations conserve exactly the same invariants as do the differential systems, and hence, can be characterized as computer physics. Motivation for the formulas is developed by consideration of motion under the force of gravity. The methodology is applied to a new, dynamical model of the chemical bond.