cssi/SciSciGPT-SciSciNet huggingface dataset:
Influence of saline solution absorption and compressive rate on the material properties of brain tissue.

Abstract Traumatic brain injuries (TBI) affect millions of people each year and can result in long-term difficulties in thinking or focusing. Due to the number of people affected by these injuries, significant research has been dedicated to determining the mechanical properties of the brain using postmortem tissue from animals harvested within 24 h. The postmortem brain tissue is often stored in a solution until a rheological experiment is ready to begin. However, the effect of storage duration on the mechanical behavior of brain tissue is not understood. In this paper, postmortem porcine brains were placed in normal saline solution (0.9% NaCl) and refrigerated between 30 min and 6.5 h to allow the brain to absorb the solution. Afterwards, samples from both soaked and freshly extracted brains were subjected to unconfined compression tests at compressive rates of 5, 50, and 500 mm/min. The fractional Zener viscoelastic model was applied to obtain the brain's mechanical properties. While the results did not show a significant relationship between absorption and the long-term stiffness ( E ∞ ), both the relaxation time ( τ 0 ) and fractional order (α) were statistically influenced by both the length of time in the solution and compressive rate. Further, the instantaneous stiffness ( E 0 ) was statistically influenced by the length of time in solution, though not the compressive rate.
Comparing Performance of Comorbidity Indices in Predicting Functional Status, Health-Related Quality of Life, and Total Health Care Use in Older Adults With Back Pain.

Study Design Secondary analysis of prospective cohort study. Background Common comorbidity indices were developed to predict mortality and may not be optimal for functional outcomes. Objective Dete...
Sources of Information and Beliefs About the Health Effects of Marijuana

Marijuana is currently legal for recreational use in 10 states and Washington DC while a total of 34 states have implemented varying degrees of medical marijuana. The commercialization of marijuana has been accompanied by a proliferation of false claims regarding the therapeutic potential of marijuana, which are popularized by several different information sources. To date, no study has examined where US adults get their information regarding marijuana. To determine the sources of information associated with believing unsupported claims about marijuana. Probability-based online survey 16,820 adults, with a response rate of about 55% (N = 9003) Most influential sources of information about marijuana and belief of statements consistent with misinformation, for example, smoking marijuana has preventative health benefits, secondhand marijuana smoke or use during pregnancy is completely or somewhat safe, and marijuana is not at all addictive. There were 9003 respondents (response rate 55%). Forty-three percent believed unsupported claims about marijuana. The most influential sources of information were health professionals, traditional media, friends/relatives, and social media/internet. Individuals reporting social media or the Internet (1.46 CI [1.30, 1.64]), the marijuana industry (e.g., advertisements, dispensaries) (2.88 CI [2.15, 3.88]), and friends or relatives (1.41 CI[1.26, 1.58]) as the most influential source of information about marijuana were more likely to believe any statement consistent with misinformation about marijuana in comparison with those who reported other sources as most influential. Individuals reporting the most significant source of information regarding marijuana was from social media or the Internet, the marijuana industry, or friends or relatives were more likely to believe unsupported claims about marijuana. Public health campaigns to counter the misinformation about marijuana to the public are needed.
Intertwined order in a frustrated four-leg t -J cylinder

We report a density-matrix renormalization group study of the $t\text{\ensuremath{-}}J$ model with nearest $({t}_{1}$ and ${J}_{1})$ and next-nearest $({t}_{2}$ and ${J}_{2})$ interactions on a four-leg cylinder with concentration $\ensuremath{\delta}=1/8$ of doped holes. We observe an astonishingly complex interplay between uniform $d$-wave superconductivity (SC) and strong spin and charge-density wave ordering tendencies (SDW and CDW). Depending on parameters, the CDWs can be commensurate with period 4 or 8. By comparing the charge ordering vectors with $2{k}_{F}$, we rule out Fermi surface nesting-induced density wave order in our model. Magnetic frustration (i.e., ${J}_{2}/{J}_{1}\ensuremath{\sim}1/2)$ significantly quenches SDW correlations with little effect on the CDW. Typically, the SC order is strongly modulated at the CDW ordering vector and exhibits $d$-wave symmetry around the cylinder. There is no evidence of a near-degenerate tendency to pair-density wave (PDW) ordering, charge $4e$ SC, or orbital current order.
Facile healing of cracks in organic-inorganic halide perovskite thin films

Abstract Organic–inorganic halide perovskite (OIHP) thin films at the heart of the burgeoning thin-film perovskite solar cells (PSCs) technology possess poor mechanical properties, which is likely to limit the long-term reliability of PSCs as they are poised for commercialization. In an effort to address this issue, here we demonstrate that through-thickness cracks induced by bending-tension in thin films of the two prototypical OIHPs, methylammonium lead triiodide (MAPbI3) and formamidinium lead triiodide (FAPbI3), can be healed easily. This is through the application of either a moderate compressive stress (bending-compression) at room temperature or a simple heat-treatment at modest temperatures. The crack-healing process is found to be time-dependent, which indicates that facile mass-transport in OIHPs plays a key role in this phenomenon. An explanation for this phenomenon is provided, one based on the fundamentals of brittle fracture. This discovery has broad implications for the prevention and/or restoration of the overall performance, environmental stability, and mechanical reliability of PSCs, and other devices.
Acute Kidney Injury after CAR-T Cell Therapy: Low Incidence and Rapid Recovery

ABSTRACT Chimeric antigen receptor (CAR) T cell therapy using engineered cytotoxic T cells has shown promising responses in various hematologic malignancies. Cytokine release syndrome (CRS) and immune effector cell-associated neurologic syndrome (ICANS) are recognized toxicities of CAR-T, whereas kidney injury remains less well recognized. The objective of the present study was to identify the incidence of acute kidney injury (AKI) after CAR-T cell therapy, potential risk factors, and recovery of kidney function. We performed a retrospective review of 46 adult patients with non-Hodgkin lymphoma treated with CAR-T therapy between February 2018 and February 2019 at our institution. Serum creatinine values before CAR-T therapy through day 100 were used to assess AKI, as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria: grade 1, 1.5- to
Insta-echoes: Selective exposure and selective avoidance on Instagram

Abstract Many studies have examined the degree to which social media facilitate echo chambers that keep users from diverse political perspectives (Bakshy, Messing, & Adamic, 2015; Parmelee & Bichard, 2012; Zhu, Skoric, & Shen, 2017). The present study expands the debate regarding selective exposure and selective avoidance to political Instagram use. A survey of politically active Instagram users measured how often users expose themselves to opinion-reinforcing political leaders and the extent to which users avoid opinion-challenging leaders. The findings indicate a high level of selective avoidance behavior on Instagram, especially by users who are conservative, Republican, very ideological, and female.
Order-Constrained ROC Regression With Application to Facial Recognition

The receiver operating characteristic (ROC) curve is widely used to assess discriminative accuracy of two groups based on a continuous score. In a variety of applications, the distributions of such...
On foundation of statistical inference by C R Rao relating to information inequality

This is the birth centenary year of the living legend and giant in the world of statistics, Prof. Calyampudi Radhakrishna (C R) Rao. This article is a partial reflection of Dr. Rao’s contributions to statistical theory and methodology, including unbiased estimation, variance reduction by sufficiency, efficiency of estimation, information geometry, as well as the application of matrix theory in linear statistical inference. His contributions are so massive, it will be impossible to review all of them. This article will comprise mostly his major discovery, which is Cramer–Rao lower bound and related applications and extensions.
Use of Medications for Alcohol Use Disorder in the US: Results From the 2019 National Survey on Drug Use and Health

This cross-sectional study investigates the prevalence of guideline-directed use of medications for treating alcohol use disorder and its association with outcomes.
CHANGES OF BAETE’S ACCREDITATION MANUAL FOR BACHELOR’S DEGREE PROGRAMS IN ENGINEERING IN BANGLADESH

Accreditation has recognized itself worldwide as the key appliance for quality assurance in engineering education, Beginning with the pioneering efforts of Accreditation Board for Engineering and Technology ABET [14], USA, and countries are approaching under the shade of the Washington Accord [7]. Accreditation includes a two-stage process, self-assessment and peer evaluation; the essential changes are highlighted. In the last two decades, an explosive growth in the number of institutions offering engineering programs has been detected. This unprecedented growth obviously led to several problems with regard to quality of engineering education. In order to ensure the quality of engineering education, the Institution of Engineers, Bangladesh (IEB) to formulate the criteria or standards, by which individual programs in any engineering institution can be evaluated [5]. Bangladesh has engaged a big leap forward in the area of engineering education by becoming a provisional member of the Washington Accord through the Board of Accreditation for Engineering and Technical Education (BAETE) [3]. As per the requirement the Institution of Engineers, Bangladesh (IEB) has revised the procedures and criteria of accreditation to bring it to international standards. The new procedures and criteria of accreditation came to effect from 1st January 2020. This paper presents the changed part of accreditation of the BAETE. Article visualizations:
The subjective life course framework: Integrating life course sociology with gerontological perspectives on subjective aging

Abstract The expansion of life expectancy has precipitated a cultural transformation of the life course – altering the perceived temporal contours of middle and later life. However, our understanding of these perceptions is limited by the absence of a framework within which to examine them. This paper builds on the life course perspective – which emphasizes the objective patterning of lives – by focusing on the subjective side of the life course. Drawing on theoretically, methodologically, and substantively diverse studies, this paper develops the concept of the subjective life course – a term we use to denote individuals’ perceptions of the life course, including its structure and timing and their advancing location in it. We outline two dimensions of the subjective life course – the target of the perception (i.e., generalized other versus self) and the temporal frame of reference (i.e., past, present, or future). Using the resulting framework as an organizational tool, we then discuss key constructs located at each intersection along these dimensions, providing examples, where possible, of empirical studies examining them. We close with a discussion of two broad directions for research: leveraging the framework to yield insight on the subjective life course and exploring links between objective and subjective dimensions of the life course.
The use of social media platforms to discuss and educate the public on allergic contact dermatitis.

BACKGROUND Social media platforms are increasingly used by patients to research and discuss medical problems. OBJECTIVE The aim of this study was to identify by whom, how frequently, and how allergic contact dermatitis (ACD) is discussed on social media sites. METHODS Search terms allergic contact dermatitis and contact dermatitis were queried across Twitter, Instagram, Reddit, Facebook, YouTube, and Google search metrics. The frequency, content, and creators of content were assessed. RESULTS ACD content was identified on all platforms and was made by patients, physicians, professional organizations, and companies. When comparing the volume of posts, more content was on Instagram than Twitter, particularly among patients. Patients support groups were identified on Facebook but not on Reddit. A formal analysis of YouTube videos found that the medical information presented in these videos was often of poor quality. CONCLUSIONS Patch testing physicians should be aware information on ACD exist across social media sites. While some content is generated by physicians, patients and industry groups also post and share material. Patch testing physicians should be aware that there is an opportunity to share ACD information, but they should also be aware our patients are posting and creating online support communities independent of us. This article is protected by copyright. All rights reserved.
Diagnosis of Granulomatous Disease and Vasculitis in Small Lung Biopsies

The most common causes of granulomas in small lung biopsies are sarcoidosis and infections. A variety of less common entities also enter the differential diagnosis, including some vasculitides. Necrotizing granulomas are most likely to be mycobacterial or fungal infections. Identification of organisms, aided by acid-fast and silver stains, is the key to a specific diagnosis, but organisms are often absent, mainly because of limited sampling in small biopsies. The most common cause of non-necrotizing granulomas is sarcoidosis, especially in transbronchial biopsies. This chapter discusses the histologic findings that favor or argue against sarcoidosis and provides guidance on communicating these findings in a pathology report. Hypersensitivity pneumonitis, hot tub lung, and talc granulomatosis also enter the differential diagnosis of non-necrotizing granulomas. The most common vasculitis encountered in small lung biopsies is granulomatosis with polyangiitis (Wegener’s granulomatosis). The pathognomonic combination of necrotizing granulomas and necrotizing vasculitis is seldom seen in a small biopsy, yet there are several clues that can help to suggest the diagnosis. Although sampling limitations inherent in small biopsies can cause difficulties in interpretation, occasional samples contain diagnostic findings, obviating the need for an invasive surgical procedure.
Hypohydration Does Not Alter Dynamic Balance in Type II Diabetics

Peripheral neuropathy is a common complaint of diabetes which could in turn cause balance impairments. Further, hypohydration is known to degrade orthostatic tolerance via reduced blood volume (hyp...
Inference Based on Complete Data

The primary focus of nonparametric Bayesian approach is to draw inference about the underlying distribution function which generates the data being analyzed. Thus the parameter of interest is the distribution function (or probability measure) itself and a prior is assigned to it. Various applications in which the Dirichlet process or its variants—the Dirichlet invariant process and mixture of Dirichlet processes are used as priors—are collected and presented in this chapter. They cover wide areas of interest such as estimation, confidence bands and tolerance regions, two-sample problems, and hypothesis testing. Applications with respect to other prior processes are presented in the next chapter while dealing with incomplete data and can be specialized to the present case easily. In estimation problems, the usual squared error or weighted squared error loss function is used. In view of the conjugacy property of the Dirichlet process, the strategy employed is to solve first the so-called no-sample problem and then update the parameter of the process for full sample size. The solutions obtained are mostly in closed form. An interesting fact highlighted is that when the total mass of the prior distribution goes to zero, the Bayesian estimators tend to reduce to the maximum likelihood estimators—a desirable feature to have.We begin with the problem of estimation of the distribution function, including sequential, empirical Bayes, and minimax estimation, and show that the estimators tend to be a linear combination of the prior guess and the sample distribution function. Confidence band and tolerance regions are presented next. It is noted that in the Bayesian context, the distribution function is treated as random and the bands are fixed determined in terms of the prior and posterior probabilities. Thereafter, estimators of functional of the distribution, such as the mean, median, variance, and quantiles, are derived. Other applications such as a regression problem, bioassay problem, and density estimation are also treated. Estimation of a bivariate distribution function, covariance, and concordance coefficient is obtained next. In two-sample problems we report estimation of the difference and distance between two distribution functions. Finally, decision theoretic procedures for testing the hypothesis regarding a distribution function and testing positive versus nonpositive dependence are also presented.
Flagellin is the major proinflammatory determinant of enteropathogenic Salmonella.

The gastroenteritis-causing pathogen Salmonella typhimurium induces profound transcriptional changes in intestinal epithelia resulting in the recruitment of neutrophils whose presence is the histopathologic hallmark of salmonellosis. Here we used cDNA microarray expression profiling to define the molecular determinants that mediate such changes in model intestinal epithelia. Enteropathogenic Salmonella induced a classical proinflammatory gene expression program similar to that activated by the canonical proinflammatory agonist TNF-α. Nonproinflammatory bacteria, both commensals ( Escherichia coli ) and systemic pathogens ( S. typhi ), did not activate this expression profile. While S. typhimurium strains lacking the SPI-1-encoded type III system were fully proinflammatory, strains lacking the genes for the flagellar structural component flagellin were nearly devoid of proinflammatory signaling. Lastly, the epithelial proinflammatory response could be largely recapitulated by basolateral addition of purified flagellin. Thus, S. typhimurium flagellin is the major molecular trigger by which this pathogen activates gut epithelial proinflammatory gene expression.
Finite-volume solution of the euler equations for steady three-dimensional transonic flow

A numerical finite-volume method is proposed for solving the Euler equations of a steady three-dimensional flow. The subsonic regions embedded in steady supersonic flow about aircraft are computed by introducing a time-dependent coordinate system that maps the fuselage and wing into one coordinate surface. The suitability of the method to a delta-winged aircraft is demonstrated, and its applicability to rectangular-winged aircraft and problems in internal transonic flow is pointed out.
The Structure and Competance of Family Units

The relative associations of family structure (intact, vs. one-parent, vs. step-parent family) and of family-system functioning with children's self-esteem and locus of control were examined, using mutivariate analysis. Children in two-parent families had significantly higher self-esteem than children from one-parent families, even when family income was controlled. However, family-system functioning was much more important in predicting self-esteem than was family structure. Implications for clinical and preventive social work practice are discussed.
Vibration Characterization and Control of Miniature Stirling-Cycle Cryocoolers for Space Application

A number of near-term precision space-science instruments have baselined the use of miniature long-life space Stirling-cycle cryocoolers. In support of these instruments, JPL is conducting an extensive cooler characterization test and analysis program focused at developing special sensitive performance measurement techniques and identifying means of improving cooler performance. This paper provides a summary overview of the vibration characteristics of split Stirling cryocoolers of the Oxford type and describes means being developed to achieve vibration levels consistent with the exacting requirements of sensitive infrared spectrometer instruments currently under development for NASA applications. A key emphasis of the paper is on exploring both active and passive means of reducing the residual upper harmonics of the drive frequency that remain with nulled back-to-back compressor and displacer units. Vibration supression results, measured with JPL’s unique 6-degree-of-freedom force dynamometer, are presented for the 80K Stirling cooler manufactured by British Aerospace.
Transient receptor potential vanilloid 2 is a mediator of left ventricular hypertrophy (862.5)

Background: Impaired calcium handling has been implicated in the development of left ventricular hypertrophy (LVH) and subsequent development of heart failure (HF). We have recently shown that the calcium channel Transient Receptor Potential Vanilloid 2 (TRPV2) is present in cardiomyocytes and regulates contractility on a beat to beat basis. This study was performed to elucidate if TRPV2 also modulates the development of LVH in a pressure overload mouse model via transverse aortic constriction (TAC). Methods: WT and TRPV2-/- mice were subjected to pressure overload via TAC and followed echocardiographically for 8 weeks. A subgroup of WT mice were treated with a nonspecific TRPV2 antagonist (tranilast) for the same amount of time. At the conclusion, the hearts were collected for molecular and histological analysis of hypertrophy. Results: There was significantly less hypertrophy in TRPV2-/- and in the WT mice treated with tranilast (n=5 and 2) in comparison to untreated WT mice (n=7) as noted via heart wei...
Fostering new relational experience: clinical process in couple psychotherapy.

One of the most critical goals for couple psychotherapy is to foster a new relational experience in the session where the couple feels safe enough to reveal more vulnerable emotions and to explore their defensive withdrawal, aggressive attacking, or blaming. The lived intimate experience in the session offers the couple an opportunity to gain integrative insight into their feelings, expectations, and behaviors that ultimately hinder intimacy. The clinical processes that are necessary include empathizing with the couple and facilitating safety within the session, looking for opportunities to explore emotions, ruptures, and unconscious motivations that maintain distance in the relationship, and creating a new relational experience in the session that has the potential to engender integrative insight. These clinical processes will be presented with empirical support. Experts from a session will be used to highlight how these processes influence the couple and promote increased intimacy. 1
Short-term retreat statistics of a slowly eroding coastal cliff

Abstract. The frequency, spatial distribution, and dimensions of coastal cliff retreats, a basic statistic underlying cliff top hazard assessment, are presented for 7.1 km of unprotected and slowly retreating coastal cliffs near Point Loma in San Diego, California, US. Using 8 airborne light detection and ranging (lidar) surveys collected over 5.5 years, 130 individual cliff edge failures (primarily rockfalls, block falls, and topples) were detected. Footprint areas varied from 3 to 268 m2, maximum landward retreats from 0.8 to 10 m, and alongshore lengths from 2 to 68 m. The failures with the largest landward retreats were also relatively long, and 13% of the slides accounted for 50% of the lost cliff area over the study period. On this short (5.5 years) time scale, "no change" was the most common observation (84% of the cliff edge). Probability distributions of non-zero cliff retreat during each time interval usually had a single peak between 1 and 2.5 m. Intervals with high mean retreat had elevated numbers of failure in all class sizes, and also contained the largest individual retreats. Small and medium slides tended to reoccur preferentially (relative to randomly) near previous small and medium slides, forming short-term hot spots, while large slides were less likely to reoccur near previous large slides. Cumulative distributions of landslide failure parameters (area, mean retreat, maximum retreat, and length) follow an inverse power-law for medium to large size events, similar to previously reported distributions of coastal and inland landsliding.
Extreme southwestern margin of late Quaternary glaciation in North America: Timing and controls

Well-preserved latero-frontal moraines in the eastern San Bernardino Mountains of southern California provide evidence for several glacial advances during the late Quaternary and mark the southwesternmost limit of glaciation in the Western Cordillera. Using geomorphology and 10Be cosmogenic radionuclide dating, a succession of moraines from three glaciated valleys is dated to 18–20 ka (Last Glacial Maximum), 15–16 ka (Heinrich Event 1), 12–13 ka (Younger Dryas Stade), and 5–9 ka (early-middle Holocene). These ages substantiate the view that glaciation throughout the American Cordilleras was synchronous during the late Quaternary. Furthermore, these data show that glacial advances in southern California occur when a significant decrease in summer temperature is coupled with an increase in moisture flux producing high winter snowfall. This allows for perennial snow accumulation that may, under appropriate conditions, persist to form glacial ice.
Positive feedback of G1 cyclins ensures coherent cell cycle entry

In budding yeast, Saccharomyces cerevisiae, the Start checkpoint integrates multiple internal and external signals into an all-or-none decision to enter the cell cycle. Here we show that Start behaves like a switch due to systems-level feedback in the regulatory network. In contrast to current models proposing a linear cascade of Start activation, transcriptional positive feedback of the G1 cyclins Cln1 and Cln2 induces the near-simultaneous expression of the ∼200-gene G1/S regulon. Nuclear Cln2 drives coherent regulon expression, whereas cytoplasmic Cln2 drives efficient budding. Cells with the CLN1 and CLN2 genes deleted frequently arrest as unbudded cells, incurring a large fluctuation-induced fitness penalty due to both the lack of cytoplasmic Cln2 and insufficient G1/S regulon expression. Thus, positive-feedback-amplified expression of Cln1 and Cln2 simultaneously drives robust budding and rapid, coherent regulon expression. A similar G1/S regulatory network in mammalian cells, comprised of non-orthologous genes, suggests either conservation of regulatory architecture or convergent evolution. The cell cycle couples growth and cell division to ensure the consistent size and shape of individual cells. This involves a vast array of genes and proteins, and requires sophisticated mechanisms to keep them acting in step. Two reports in this issue focus on different points in the cell cycle of the budding yeast Saccharomyces cerevisiae, and find that in each case, positive feedback keeps the process on the rails. Skotheim et al. studied the Start checkpoint in the G1 cell cycle phase, where cells irreversibly commit to cell division. Single-cell analysis reveals that Start is a positive feedback-dependent switch that coordinates the simultaneous transcription of a large group of cell cycle genes and the budding of a daughter cell. Holt et al. studied the onset of anaphase in mitosis, at which chromosome pairs separate abruptly and simultaneously. Cohesion between sister chromatids is dissolved by the enzyme separase, which is held in check by securin. A positive feedback loop regulating the ubiquitination and destruction of securin appears to make anaphase a switch-like event. In budding yeast, the Start checkpoint in the G1 cell cycle phase is a point after which cells are irreversibly committed to cell division. Previous work has identified a linear pathway that triggers the Start transition. In contrast, analyses of single cells reveal that Start represents a positive feedback-dependent sharp switch that coordinates the simultaneous transcription of a large group of cell cycle genes and the budding of a daughter cell.
Neurons in the paraventricular nucleus of the hypothalamus that project to the sexually dimorphic lower lumbar spinal cord concentrate 3H-estradiol in the male rat

The location and distribution of estradiol-concentrating neurons in the hypothalamus afferent to segments of lumbar spinal cord that contain the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) were determined by combining retrograde fluorescent tract tracing with steroid hormone autoradiography. Injections of Fluorogold were made into segments of L5-L6 of the spinal cord of adult male rats and 12 days later animals were castrated. One week following castration, males received injections of [3H]estradiol and were perfused. Their brains were then processed for steroid hormone autoradiography. Following exposure times of 11 to 12 months, autoradiograms were developed and the hypothalamus was analyzed for neurons that concentrate estradiol and project to the spinal cord. Numerous neurons in the hypothalamus projected to the spinal cord, specifically neurons in the paraventricular nucleus (PVN), the lateral hypothalamus and the dorsal area of the hypothalamus. Although many subnuclei of PVN, as well as lateral hypothalamus, contained Fluorogold labelled neurons and estradiol concentrating neurons, the majority of double labeled cells were found in the lateral parvocellular (LP) subnucleus of PVN. Approximately 30% of the neurons in the lp subnucleus that projected to spinal cord also concentrated estradiol. Up to one half of the estradiol-concentrating neurons in lp sent axons to the lower lumbar spinal cord. These results suggest that some of the effects of gonadal steroid hormones on SNB development, plasticity and function may in fact, be indirect, via steroid-sensitive afferents.
Rapid incorporation of the solubilized dihydropyridine receptor into phospholipid vesicles.

Abstract We describe the rapid incorporation of the CHAPS solubilized dihydropyridine receptor into phospholipid vesicles. A series of sucrose gradient sedimentation experiments demonstrate that the (+)-[ 3 H]PN200-110-labeled dihydropyridine receptor is associated with lipid vesicles following detergent removal by Extracti-gelchromatography. Solubilization of the receptor results in a loss of (+)-[ 3 H]PN200-110 binding affinity relative to that observed in native membranes; the high affinity binding of (+)-[ 3 H]PN200-110 can be restored upon reincorporation of the receptor into phospholipid vesicles. Similarly, the incorporation of the receptor restores its stability to incubation at 37°C relative to that of the detergent solubilized receptor, thereby mimicking the properties of the membrane bound form of the receptor. The dissociation rate of (+)-[ 3 H]PN200-110 from the reconstituted receptor is shown to be allosterically regulated by verapamil and diltiazem, indicating that the binding sites for these calcium antagonists have been inserted along with the dihydropyridine receptor into phospholipid vesicles. The results presented in this report, thus demonstrate the successful reconstitution of the dihydropyridine receptor into phospholipid vesicles by a variety of criteria. The reconstitution method described here is rapid and efficient, and should now facilitate structure-function studies of this receptor and its interrelationships with other regulatory components of the voltage-sensitive calcium channel system.
Mechanisms of Paroxysmal Supraventricular Tachycardia

Paroxysmal supraventricular tachycardia (PSVT) is a common arrhythmia in patients with and without organic heart disease. It has generally been believed to reflect either reentrant mechanisms or rapid firing of ectopic foci. Recent clinical and experimental observations have suggested that most PSVT appears to reflect reentrance. 1-6 In man, the occurrence of reentrance has been demonstrated in the sinus node, 7-9 atrium, 9 atrioventricular node, 1-6 and possibly the His bundle. 10 Longitudinal dissociation of a conducting structure (for example, the atrioventricular node) allows reentry to occur 11-14 (Fig 1, left). With dissociation into two pathways, a premature impulse encounters refractoriness (unidirectional block) in one pathway and conducts slowly in the other pathway. The previously blocked pathway recovers for retrograde conduction during the period of slow conduction. If the two pathways are connected by a final common pathway, the impulse can reenter the previously blocked pathway and return to the chamber of origin. While conducting retrograde,
A Semiautomated Instrument for Measuring Total and Radiolabeled Carbon Dioxide Evolution from Soil

The design and operation of a semiautomated instrument for measuring total and radiolabeled CO₂ evolution from soil is described. In the recirculation mode, headspace gases are recirculated in a closed loop through an infrared (IR) detector. After a steady state is achieved, the concentration of total CO₂ is read and recorded. In the flush mode, compressed air is used to flush CO₂ from the headspace into test tubes containing trapping solution. Radiolabeled carbon dioxide is quantified by counting aliquots of trapping solution in a liquid scintillation counter. The variability associated with the IR detector is 3.6% (coefficient of variation). The trapping efficiency is 100% (±2.0%). The variability associated with two different methods of pesticide application to soil was also investigated. With the slurry method, aliquots of air-dried soil were added to a pesticide solution [carbofuran(2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate)] with thorough mixing. With the spray method, the carbofuran solution was applied as an aerosol to soil that had been previously wetted. There was little difference in the variability of total CO₂ production between the two methods. The variability associated with ¹⁴CO₂ evolution from soil (carbofuran hydrolysis), however, was greater with sprayed soil than with slurred soil, suggesting that the slurry method resulted in a more homogenous distribution of pesticide throughout the soil. The low analytical variability associated with measurements of total CO₂ and ¹⁴CO₂ production, as well as the large number of samples that can be accommodated (up to 94 flasks or intact soil cores) make this instrument ideal for the execution of the large screening studies needed to obtain reliable estimates of the spatial variability of rates of pesticide degradation. Contribution from the USDA-ARS.
The organization of microtubules within rat odontoblast processes revealed by perfusion fixation with glutaraldehyde.

Abstract Perfusion fixation of adult rat molar teeth via the ascending aorta with 1 per cent glutaraldehyde in Tyrode's solution produced well preserved odontoblast processes deep within fully mineralized dentine. The processes contained dense granules, mitochondria, an occasional multivesicular body, and a well developed network of microfilaments and microtubules. The microtubules were approximately 27 nm wide and several microns long. Bundles of microtubules coursed parallel to the cell membrane for the whole length of the odontoblast process. Structures interpreted as side arms or cross-bridges were observed between adjacent microtubules and filaments. The possible function of microtubules in odontoblast process elongation, structural support and saltatory transport of granules is discussed. The most distal parts of the dentinal tubules were either empty or occluded by collagen and amorphous material. It is suggested that dentinal tubules are not completely occupied by odontoblast processes but that a normal recession of the processes occur with or without a deposition of occluding substances.
Distribution and pharmacology of intravenous 99mTc-labeled multilamellar liposomes in rats and mice

Abstract The use of liposomes for the delivery of macrophage activators offers a new approach for the selective targeting of antitumor therapy. We have investigated the distribution, retention, and pharmacology of multilamellar liposomes (phosphatidylserine (PS): phosphatidylcholine (PC) 3:7) on i.v. injection in normal rats. Sprague-Dawley rats were injected with doses varying from 300 to 1000 mg/kg of 99m Tc-liposomes. The organ distribution of doses ranging from 300 to 500 mg/kg showed 45% mean uptake by liver, 25% by spleen, and 4% by lung. At higher doses of 800–1000 mg/kg, uptake in the lung increased significantly to 9 ± 3%. Whole body retention at 24 h after i.v. injection in Hale Stoner mice was 70%. The blood disappearance curve was biphasic and compared with the free isotope, a decrease was observed in the initial a phase t12 while the terminal phase t12 increased by 100%. These data suggest that encapsulation prolongs the initial distribution to the peripheral compartments and that higher doses may increase uptake by organs other than the liver.
Infant Motion: Detection (M:D) Ratios for Chromatically Defined and Luminance-defined Moving Stimuli

In order to assess the relative contributions of chromatic vs luminance information to motion processing in infants, we employed a motion:detection (M:D) paradigm. Stimuli consisted of 27 deg by 40 deg, 0.25 c/deg sinusoidal gratings moving at 22 deg/sec (5.6 Hz), and were either chromatically defined or luminance-defined. Contrast thresholds for direction-of-motion (M) were obtained using a directional eye movement technique. Contrast thresholds for detection (D) were obtained using forced-choice preferential looking. M:D threshold ratios were obtained for individual infant subjects, and results were compared to those of adults. As expected, adult M:D threshold ratios were near 1:1 for luminance-defined stimuli, but greater than 1:1 for chromatically defined stimuli. This suggests that, for adults, luminance-defined, but not chromatically defined, stimuli are detected by mechanisms labeled for direction of motion. By contrast, infant M:D ratios for chromatically and luminance-defined stimuli were approximately equal and close to 1:1, suggesting that, for infants, luminance- as well as chromatically defined stimuli are detected by mechanisms that are labeled for direction of motion. Copyright © 1996 Elsevier Science Ltd.
Dimensional analysis of activity and elimination in a genetically heterogeneous group of mice (Mus musculus)

Abstract Eighty mice of a 4-way cross derived from the C 57 BL Crgl , C 3 H Crgl , A Crgl and DBA 2 Crgl inbred strains were tested for activity and elimination in five different apparatuses. Factor and cluster analyses of the scores obtained suggest that five factors can account for the observed intercorrelations between measures. The factors are tentatively identified as (I) ambulatory activity, (II) territory marking, (III) wall seeking, (IV) defaecation, and (V) behaviour relating to barriers.
School trips: Are they worth the effort?

During my 40 years of teaching biology in secondary schools, I have led or taken part in more than 150 school trips. Most were biological but a few have involved other subjects, including geography...
Vitamin A and the sulfate-activating enzymes.

Summary 1. The sulfate-activating enzyme ATP-sulfurylase (ATP:sulfate adenylyl-transferase, EC 2.7.7.4) has been determined in vitamin A-deficient rat-liver supernatant fraction by (a) molybdolysis of ATP, (b) pyrophosphorolysis of adenosine 5′-phosphosulfate, (c) incorporation of 35S-labeled sulfate into 3′-phosphoadenosine 5′-phosphosulfate, and found to be depressed, compared to enzyme from normal animals. Some kinetic data on these reactions are presented. 2. Both liver and colon particulate fractions had ATP-sulfurylase activities, thus possessing part of the machinery for mucopolysaccharide synthesis. 3. An acidic lipid-soluble factor extracted from the ATP-sulfurylase of normal rat-liver supernatant could be used to restore the enzyme activity from deficient animals to almost normal levels, while vitamin A or vitamin A acid did not activate the deficient enzyme. 4. The lipid factor was radioactive when obtained from animals given [14C]-vitamin A or [14C]vitamin A acid and some radioactivity remained with, enzymatic activity throughout several purification steps of the enzyme. 5. Increasing concentrations of the lipid factor, when added to the deficient enzyme, caused an increased rate of sulfurylase reaction to a saturation level. 6. Both for release of the lipid factor from the normal enzyme, and for acceptance of the factor by the deficient enzyme, the preparation had to be treated with acid (pH 5.5). 7. It is suggested that a compound which appears to be an acidic metabolite of vitamin A and vitamin A acid is attached to, and can activate the enzyme ATP-sulfurylase.
Dynamical effects on the photo-detachment spectra of Li4−

Abstract It is shown that the observed sharp peaks in the photodetachment spectra of Li 4 − can be understood by including the effect of cluster dynamics. Theoretical electronic structure studies show that Li 4 − is marked by doublet rhombus and quartet distorted tetrahedral isomers. By including dynamical effects within a classical picture, it is shown that the observed spectrum can be explained in terms of transitions from rhombus ground state to the singlet neutral configurations. A vibrational analysis is used to identify the modes leading to the observed peaks. Our studies underscore the importance of dynamical effects on the photodetachment spectra.
Improved performance of an electrically initiated HF laser

Some methods for improving the efficiency of electrically initiated HF lasers are discussed. Measurement of the laser pulse shape produced by 30-ns discharges in SF 6 :C 2 H 6 at several mixtures and pressures is reported. These pulse shapes are compared to the laser and current pulses produced by a two-stage Marx bank that gives laser pulses of 1.4 J with 3.1-percent electrical efficiency from an active volume of 0.331. A second bank is described, which gives pulses up to 3.5 J with 1.8-percent efficiency, with a peak power of 35 MW.
A Simple CPM Time-Cost Tradeoff Algorithm

This article describes an algorithm for efficiently shortening the duration of a project when the expected project duration exceeds a predetermined limit. The problem consists of determining which activities to expedite and by what amount. The objective is to minimize the cost of the project. This algorithm is considerably less complex than the analytic methods currently available. Because of its inherent simplicity, the algorithm is ideally suited for hand computation and also is suitable for computer solution. Solutions derived by the algorithm were compared with linear programming results. These comparisons revealed that the algorithm solutions are either a equally good or b nearly the same as the solutions obtained by more complex analytic methods which require a computer. With this method the CPM time-cost tradeoff problem is solved without access to a computer, thereby making this planning tool available to managers who otherwise would find implementation impractical.
Boundary conditions and boundary layers for a multi-dimensional relaxation model

Abstract In this paper we study the linearized relaxation model of Katsoulakis and Tzavaras in a half-space with arbitrary space dimension n ⩾1. Our main interest is to establish the asymptotic equivalence of the relaxation system and its corresponding multi-dimensional equilibrium conservation law. We identify and rigorously justify a necessary and sufficient condition (which we refer to as stiff Kreiss condition, or SKC in short) on the boundary condition to guarantee the uniform stability of the initial–boundary value problem of the relaxation system independent of the relaxation rate. The asymptotic convergence and the corresponding boundary layer behavior are studied by Fourier–Laplace transform and a detailed asymptotic analysis. The SKC is shown to be more restrictive than the classical uniform Kreiss condition for all n ⩾1.
Mechanism and Significance of Cell Type-Dependent Neutralization of Flaviviruses

The production of neutralizing antibodies (NAbs) is a correlate of protection for many human vaccines, including currently licensed vaccines against flaviviruses. NAbs are typically measured using a plaque reduction neutralization test (PRNT). Despite its extensive use, parameters that impact the performance of the PRNT have not been investigated from a mechanistic perspective. The results of a recent phase IIb clinical trial of a tetravalent dengue virus (DENV) vaccine suggest that NAbs, as measured using a PRNT performed with Vero cells, do not correlate with protection. This surprising finding highlights the importance of understanding how well the PRNT captures the complexity of the NAb response to DENV. In this study, we demonstrated that the structural heterogeneity of flaviviruses arising from inefficient virion maturation impacts the results of neutralization assays in a cell type-dependent manner. Neutralization titers of several monoclonal antibodies were significantly reduced when assayed on Vero cells compared to Raji cells expressing DC-SIGNR. This pattern can be explained by differences in the efficiency with which partially mature flaviviruses attach to each cell type, rather than a differential capacity of antibody to block infection. Vero cells are poorly permissive to the fraction of virions that are most sensitive to neutralization. Analysis of sera from recipients of live-attenuated monovalent DENV vaccine candidates revealed a strong correlation between the sensitivity of serum antibodies to the maturation state of DENV and cell type-dependent patterns of neutralization. Cross-reactive patterns of neutralization may be underrepresented by the “gold-standard” PRNT that employs Vero cells. IMPORTANCE Cell type-dependent patterns of neutralization describe a differential capacity of antibodies to inhibit virus infection when assayed on multiple cellular substrates. In this study, we established a link between antibodies that neutralize infection in a cell type-dependent fashion and those sensitive to the maturation state of the flavivirus virion. We demonstrated that cell type-dependent neutralization reflects a differential capacity to measure neutralization of viruses that are incompletely mature. Partially mature virions that most efficiently bind maturation state-sensitive antibodies are poorly represented by assays typically used in support of flavivirus vaccine development. The selection of cellular substrate for neutralization assays may significantly impact evaluation of the neutralization potency of the polyclonal response. These data suggest that current assays do not adequately capture the full complexity of the neutralizing antibody response and may hinder the identification of correlates of protection following flavivirus vaccination.