cssi/SciSciGPT-SciSciNet huggingface dataset:
The Glymphatic System: A Beginner’s Guide

The glymphatic system is a recently discovered macroscopic waste clearance system that utilizes a unique system of perivascular tunnels, formed by astroglial cells, to promote efficient elimination of soluble proteins and metabolites from the central nervous system. Besides waste elimination, the glymphatic system also facilitates brain-wide distribution of several compounds, including glucose, lipids, amino acids, growth factors, and neuromodulators. Intriguingly, the glymphatic system function mainly during sleep and is largely disengaged during wakefulness. The biological need for sleep across all species may therefore reflect that the brain must enter a state of activity that enables elimination of potentially neurotoxic waste products, including β-amyloid. Since the concept of the glymphatic system is relatively new, we will here review its basic structural elements, organization, regulation, and functions. We will also discuss recent studies indicating that glymphatic function is suppressed in various diseases and that failure of glymphatic function in turn might contribute to pathology in neurodegenerative disorders, traumatic brain injury and stroke.
Self-Generated Memory Cues: Effective Tools for Learning, Training, and Remembering:

People generate a variety of memory cues, such as mnemonic devices and to-do lists, to support memory for difficult information. Self-generated memory cues make difficult information understandable...
Paul Baran, Network Theory, and the Past, Present, and Future of Internet

Paul Baran’s seminal 1964 article “On Distributed Communications Networks” that first proposed packet switching also advanced an underappreciated vision of network architecture: a lattice-like, distributed network, in which each node of the Internet would be homogeneous and equal in status to all other nodes. Scholars who have subsequently embraced the concept of a lattice-like network approach have largely overlooked the extent to which it is both inconsistent with network theory (associated with the work of Duncan Watts and Albert-Laszlo Barabasi), which emphasizes the importance of short cuts and hubs in enabling networks to scale, and the actual way, the Internet initially deployed, which relied on a three-tiered, hierarchical architecture that was actually what Baran called a decentralized network. However, empirical studies reveal that the Internet’s architecture is changing: it is in the process of becoming flatter and less hierarchical, as large content providers build extensive wide area networks and undersea cables to connect directly to last-mile networks. This change is making the network more centralized rather than becoming more distributed. As a result, this article suggests that the standard reference model that places backbones at the center of the architecture should be replaced with a radically different vision: a stack of centralized star networks, each centered on one of the leading content providers.
Mapping the kinetochore MAP functions required for stabilizing microtubule attachments to chromosomes during metaphase

In mitosis, faithful chromosome segregation is orchestrated by the dynamic interactions between the spindle microtubules (MTs) emanating from the opposite poles and the kinetochores of the chromosomes. However, the precise mechanism that coordinates the coupling of the kinetochore components to dynamic MTs has been a long-standing question. Microtubule-associated proteins (MAPs) regulate MT nucleation and dynamics, MT-mediated transport and MT cross-linking in cells. During mitosis, MAPs play an essential role not only in determining spindle length, position, and orientation but also in facilitating robust kinetochore-microtubule (kMT) attachments by linking the kinetochores to spindle MTs efficiently. The stability of MTs imparted by the MAPs is critical to ensure accurate chromosome segregation. This review primarily focuses on the specific function of nonmotor kinetochore MAPs, their recruitment to kinetochores and their MT-binding properties. We also attempt to synthesize and strengthen our understanding of how these MAPs work in coordination with the kinetochore-bound Ndc80 complex (the key component at the MT-binding interface in metaphase and anaphase) to establish stable kMT attachments and control accurate chromosome segregation during mitosis.
RIP1, RIP3, and MLKL Contribute to Cell Death Caused by Clostridium perfringens Enterotoxin.

ABSTRACT Clostridium perfringens type F strains cause gastrointestinal disease when they produce a pore-forming toxin named C. perfringens enterotoxin (CPE). In human enterocyte-like Caco-2 cells, low CPE concentrations cause caspase-3-dependent apoptosis, while high CPE concentrations cause necrosis. Since necrosis or apoptosis sometimes involves receptor-interacting serine/threonine-protein kinase-1 or 3 (RIP1 or RIP3), this study examined whether those kinases are important for CPE-induced apoptosis or necrosis. Highly specific RIP1 or RIP3 inhibitors reduced both CPE-induced apoptosis and necrosis in Caco-2 cells. Those findings suggested that the form of necrosis induced by treating Caco-2 cells with high CPE concentrations involves necroptosis, which was confirmed when high, but not low, CPE concentrations were shown to induce oligomerization of mixed-lineage kinase domain-like pseudokinase (MLKL), a key late step in necroptosis. Furthermore, an MLKL oligomerization inhibitor reduced cell death caused by high, but not low, CPE concentrations. Supporting RIP1 and RIP3 involvement in CPE-induced necroptosis, inhibitors of those kinases also reduced MLKL oligomerization during treatment with high CPE concentrations. Calpain inhibitors similarly blocked MLKL oligomerization induced by high CPE concentrations, implicating calpain activation as a key intermediate in initiating CPE-induced necroptosis. In two other CPE-sensitive cell lines, i.e., Vero cells and human enterocyte-like T84 cells, low CPE concentrations also caused primarily apoptosis/late apoptosis, while high CPE concentrations mainly induced necroptosis. Collectively, these results establish that high, but not low, CPE concentrations cause necroptosis and suggest that RIP1, RIP3, MLKL, or calpain inhibitors can be explored as potential therapeutics against CPE effects in vivo. IMPORTANCEC. perfringens type F strains are a common cause of food poisoning and antibiotic-associated diarrhea. Type F strain virulence requires production of C. perfringens enterotoxin (CPE). In Caco-2 cells, high CPE concentrations cause necrosis while low enterotoxin concentrations induce apoptosis. The current study determined that receptor-interacting serine/threonine-protein kinases 1 and 3 are involved in both CPE-induced apoptosis and necrosis in Caco-2 cells, while mixed-lineage kinase domain-like pseudokinase (MLKL) oligomerization is involved in CPE-induced necrosis, thereby indicating that this form of CPE-induced cell death involves necroptosis. High CPE concentrations also caused necroptosis in T84 and Vero cells. Calpain activation was identified as a key intermediate for CPE-induced necroptosis. These results suggest inhibitors of RIP1, RIP3, MLKL oligomerization, or calpain are useful therapeutics against CPE-mediated diseases.
Rapidly training African giant pouched rats (Cricetomys ansorgei) with multiple targets for scent detection.

Abstract Since 1997, APOPO, a non-profit organization based in Tanzania, has deployed African giant pouched rats (Cricetomys ansorgei) to detect landmines in post-conflict areas. More recent research suggests the pouched rats can also be trained to detect tuberculosis in human sputum samples. Despite proven success on both tasks, the potential impact of each rat is limited by the required training time and constraint to a single target odor. The aim of this project was to establish a technique to rapidly train pouched rats to detect multiple odor targets. Eight pouched rats were trained to detect five unrelated target odors in Experiment 1. In addition to training duration, we measured maintenance of all odor targets. In Experiment 2, we examined response persistence under conditions of extinction. Experiment 3 investigated whether refresher sessions before tests would maintain detection accuracy. The animals mastered all odor targets in significantly fewer sessions than APOPO’s operational rats require to master a single target odor. Importantly, rats demonstrated strong discrimination between targets and non-targets despite the potential for interference and forgetting, suggesting pouched rats can be trained to detect at least five targets simultaneously. These results have the potential to increase the impact of each detection rat by both decreasing training time and expanding operational versatility, e.g., a single rat could be trained to detect multiple diseases.
8.13 – Zyvox

This case history chronicles the discovery of Zyvox (linezolid), the first marketed oxazolidinone antibiotic, and a member of the first completely new class of antibiotics to be approved in over 35 years. Zyvox is marketed by Pfizer for the treatment of susceptible and multidrug-resistant Gram-positive infections. The review focuses most intensively on the development of the structure–activity relationships and the structure–toxicity relationships that led to linezolid as well as eperezolid, the first oxazolidinone clinical candidate from this program. In addition, successful strategies that the research team employed to facilitate the discovery timeline for this important new antibiotic are detailed. Specific aspects presented include: a description of the medical need for new antibiotics created by multidrug resistance; a historical perspective of linezolid relative to other antibiotics; details of the mechanism of action of this new class of antibiotics; the development of an enantioselective oxazolidinone synthesis; key attributes of eperezolid and linezolid; and approved clinical indications.
Hippocampal Neuron Functional Phenotype Influences the Stability of Its Neural Code

ABSTRACT Trajectory-dependent splitter neurons in the hippocampus encode information about a rodent’s prior trajectory during performance of a continuous alternation task. As such, they provide valuable information for supporting memory-guided behavior. Here, we employed single-photon calcium imaging in freely moving mice to investigate the emergence and fate of trajectory-dependent activity through learning and mastery of a continuous spatial alternation task. We found that the quality of trajectory-dependent information in hippocampal neurons correlated with task performance. We thus hypothesized that, due to their utility, splitter neurons would exhibit greater stability than would traditional place cells. We found that splitter neurons were more likely to remain active and retained more consistent spatial information across multiple days than did place cells. Furthermore, we found that both splitter neurons and place cells emerged rapidly and maintained stable trajectory-dependent/spatial activity thereafter. Our results suggest that a neuron’s functional coding properties influence its long-term stability.
Commercial Real Estate Market with Two-sided Random Search: Theory and Implications

In this paper, we set up a two-sided random search model to study the trading behaviour between buyers and sellers in the commercial real estate market. Our model shows that the interaction between...
“Say What You Really Believe”: Freedom Schools, Youth Empowerment, and Black Power in 1960s Milwaukee

BackgroundThe historical literature on the civil rights movement has tended to underemphasize the movement's educational activities, while literature on the civil rights and Black Power movements h...
Remote versus early corticosteroid wean outcomes in heart transplant recipients in the contemporary era

Purpose The risks and benefits of remote corticosteroid weaning in heart transplant recipients more than 2 years post-transplant are unknown. We compared outcomes in patients undergoing early and remote steroid weaning after heart transplantation. Methods We performed a retrospective study (range 09, 1991-04, 2017). Primary outcomes included short-term and long-term mortality, allograft dysfunction, and burden of rejection. Secondary outcomes included impact on hemoglobin A1c, lipid panel, bone scan T-score, and body mass index. Results 63 patients underwent corticosteroid weaning between 2012 and 2017. Outcomes of patients weaned early (n = 34; median time from transplant = 1.1 years) were compared with those weaned late (n = 29; median time from transplant = 4.4 years). 52 (82.5%) patients were successfully weaned off corticosteroids. No statistically significant difference in outcomes was found between the early and late weaning groups (p = .20). There were no differences in allograft function (p-value = .16), incidence of rejection (p = .46), or mortality (p = .15). Improvement in metabolic profile was seen in both groups but was not statistically significant. Conclusions In heart transplant recipients, remote vs early weaning of corticosteroids is not associated with significant differences in graft function or the incidence of rejection after 1-year follow-up. Moreover, there were no significant differences in survival up to 3 years between the two groups.
An Economic Analysis of the Impact of Changes in the EC's Milk Quota

Worried by rapidly increasing milk and beef policy costs, but constrained by political considerations, the European Community (EC) Council of Agriculture ministers introduced a milk quota regime effective April 1984. The extent to which a quota regime reduces economic efficiency and influences world trade depends upon how it is implemented. The method of implementation is also a major determinant of the policy's effect on world trade. Regulations favorable to production in grass-based dairy regions will, other things being equal, reduce world cereal demand. Regulations favorable to butterfat production may distort world, animal, and vegetable fat markets.
Update on Novel Hormonal and Nonhormonal Male Contraceptive Development.

Background The advent of new methods of male contraception would increase contraceptive options for men and women and advance male contraceptive agency. Pharmaceutical R&D for male contraception has been dormant since the 1990s. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) has supported a contraceptive development program since 1969 and supports most ongoing hormonal male contraceptive development. Nonhormonal methods are in earlier stages of development. Content Several hormonal male contraceptive agents have entered clinical trials. Novel single agent products being evaluated include dimethandrolone undecanoate, 11β-methyl-nortestosterone dodecylcarbonate, and 7α-methyl-19-nortestosterone. A contraceptive efficacy trial of Nestorone®/testosterone gel is underway. Potential nonhormonal methods are at preclinical stages of development. Many nonhormonal male contraceptive targets that affect sperm production, sperm function, or sperm transport have been identified. Summary NICHD supports development of reversible male contraceptive agents. Other organizations such as the World Health Organization, the Population Council, and the Male Contraception Initiative are pursuing male contraceptive development, but industry involvement remains limited.
Robustness and performance of radiomic features in diagnosing cystic renal masses.

We study the inter-reader variability in manual delineation of cystic renal masses (CRMs) presented in computerized tomography (CT) images and its effect on the classification performance of a machine learning algorithm in distinguishing benign from potentially malignant CRMs. In addition, we assessed whether the inclusion of higher-order robust radiomic features improves the classification performance over the use of first-order features. 230 CRMs were independently delineated by two radiologists. Through a combination of random fluctuations, dilation, and erosion operations over the original region of interests (ROIs), we generated four additional sets of synthetic ROIs to capture the inter-reader variability realistically, as confirmed by dice coefficient measurements and visual assessment. We then identified the robust features based on the intra-class coefficient (ICC > 0.85) across these datasets. We applied a tenfold stratified cross-validation (CV) to train and test the performance of the random forest model for the classification of CRMs into benign and potentially malignant. The mean area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value were 0.87, 0.82, 0.90, 0.85, and 0.93, respectively. With the usage of first-order features alone, the corresponding values were nearly identical. AUC ranged for the robust and uncorrelated features from 0.83 ± 0.09 to 0.93 ± 0.04 and for the first-order features from 0.84 ± 0.09 to 0.91 ± 0.04. Our study indicates that the first-order features alone are sufficient for the classification of CRMs, and that inclusion of higher-order features does not necessarily improve performance.
Guanadrel

Synopsis: Guanadrel1 sulphate is an orally active peripheral sympathetic inhibitor (adrenergic neuron-blocking drug). In comparative studies, guanadrel was comparable in efficacy with guanethidine or methyldopa in mild to moderately severe hypertension, although generally it caused fewer central nervous system side effects than methyldopa and less orthostatic dizziness and diarrhoea than guanethidine. However, its efficacy in patients whose blood pressure remains inadequately controlled by other drugs (except diuretics alone) has yet to be adequately demonstrated. Guanadrel has a rapid onset of action and a half-life of about 10 hours, thus dose titration can be achieved more rapidly than with guanethidine, and twice daily administration is appropriate. Generally, guanadrel has been well tolerated, withdrawal of treatment due to adverse effects seldom being necessary. Thus, guanadrel appears to be a suitable alternative to methyldopa for the treatment of mild to moderately severe hypertension not controlled adequately by diuretics alone.
Interest Factors in Equipment Economics

The interest factor to be included in equipment economic studies has not been properly explained in the past. A method, Market Value Maximization, is outlined for the correct calculation of the interest rate to be used in economic analyses. Example calculations are demonstrated and the applicability to the construction contractor situation is discussed.
Curiouser and Curiouser: The Practice of Nonfiction Today

When I was first invited to speak at this conference on nonfiction, I imagined myself safely sandwiched between such luminaries as Pico Iyer, Lauren Slater, Bob Shacochis, David Shields and other distinguished participants. Then I discovered that I was slated to give the keynote address?a horrifying prospect. The term "keynote speaker" connotes someone who will make large generalizations that sum up the field and boost the morale of the troops. Political conventions usually turn to a rising star in the party, someone with charisma and glamour, a Barack Obama, not an old skeptic like me. But I will do my best to lift your spirits. Lord knows, nonfiction may be in need of morale-boosting. Consider the very name of this thing we practice, a genre defined by what it is not. Like the Uncola, the Anti-Christ, or anti-matter. In the last twenty years some attempt has been made to cloak our selves with dignity by adding the word "creative" before nonfiction; but this is tantamount to saying ugood poetry." No one sets out to write "uncreative nonfiction." I myself prefer the more traditional sounding term "literary nonfiction," though I have to admit that "literary" is also a bit of gratuitous self-praise. Our boastful inse curity mirrors, in a way, the larger literary world's condescending attitude toward our area of endeavor. Every year the cash prizes for the Whiting and Rona Jaffe fellowships, the Lannans and the MacArthurs, are announced: a healthy list of fiction writers and poets, and one or two nonfiction writers, if that. When was the last time a Nobel Prize was given to a nonfiction writer? Personal essay collections, even by such established masters as Edward Hoagland, Nancy Mairs and Joseph Epstein, are relegated to The New York Times "Books In Brief" column, as though the whole genre were a dodge to get around writing a real book. Those of us who teach or study creative writing in university set tings know that, in the beginning, God created Fiction and Poetry, and saw that it was good; and then some whiners started demand
Hassan Fathy Revisited

Abstract This article investigates an important, yet unexplored aspect of Hassan Fathy's work, namely his 1957–1961 collaboration with the prolific international firm, Doxiadis Associates. Focusing on Fathy's proposals for mass housing in Iraq and Pakistan, the article examines how the Egyptian architect recast his famous 1945 project of New Gourna in a new perspective, to calibrate his social and formal sensibilities according to Doxiadis's scientific and developmentalist ethos. The goal is to demonstrate that Fathy's thought was complexly intertwined with larger mid-twentieth century architectural debates on culture and modernity, and as such, it transcended any essentialist discourses of identity that often appropriated his notion of vernacular architecture.
Factors Associated with Operative Treatment of De Quervain Tendinopathy

Background: Geographic and doctor-to-doctor variations in care are a focus of quality and safety efforts in medicine. This study addresses factors associated with variation in the rate of operative treatment of de Quervain tendinopathy. Methods: We used a database including all patient encounters at 2 large medical centers, to study the experience of 10 hand surgeons and 1 physiatrist working in a hand surgery office in the treatment of 2,513 patients with de Quervain tendinopathy over a 12-year period. Survival analysis using the Kaplan-Meier method was used to compare surgery rates and time to surgery. Cox multivariable regression analysis was applied to identify factors associated with operative treatment. Results: One hundred ninety nine (7.9%) patients had surgery. The odds of operative treatment were 1.7 times greater after corticosteroid injection and varied more than 10-fold among providers. There was substantial variation in the overall rate of surgery by provider. Corticosteroid injection delayed surgery slightly, but was associated with a higher rate of surgery. Conclusion: Providers have substantial influence on treatment of de Quervain tendinopathy. The use of decision aids and other methods that help involve the patient in decision-making merit investigation as interventions to help reduce doctor-to-doctor variation.
Embedding Civic Engagement in Undergraduate Research

This paper initiates a discussion about the feasibility of using civic engagement projects to motivate students to learn research practices through immediate application in a community setting. Liberal arts colleges celebrate both civic engagement and undergraduate research as "high impact practices" on student learning. Our contribution to this discussion is to identify the challenges faculty face in creating academic year classes that contribute to such initiatives, and to delineate the trade-offs in adopting experiential-learning based courses. In this paper, we collect opinions from survey and in-depth interviews with 33 students in two St. Olaf college courses in the 2011-2012 academic year: Immigration & Citizenship and Analyzing Politics. To supplement our analysis, we also draw upon course evaluations completed by former students and community partners who participated in all three iterations of the first class, which was taught at St. Olaf College from 2008-2012. Broadly, the undergraduate research projects address immigration and citizenship in Rice County, Minnesota. Research projects involve a combination of individual and team efforts by students. End products from the research include policy reports, analysis of qualitative interviews about community priorities, and novel graphic narratives that re-map or “re-present” how civic engagement transpires in Rice County. Given course participants’ experiences, we examine the extent to which undergraduate research projects with a civic engagement component promote student learning about research design techniques through social observations and graphic narratives; understand the broader significance of their research efforts in communities; and uncover challenges in implementing social inquiry theories into practice. We link our discussion to both the broader context of liberal arts college priorities and the pedagogical literature.
Predictors of Depressive Symptomatology Among Lower Social Class Caregivers of Persons with Chronic Mental Illness

This study examined the predictors of depressive symptomatology among caregivers of persons with chronic mental illness. Data were collected through in-person interviews with family caregivers of 103 adults with chronic mental illness who were served by mental health case management agencies. The results indicated that insufficiency of overall social support was the most powerful predictor of caregiver depressive symptomatology. In addition, caregiver burden had a significant unique contribution to caregiver depressive symptomatology, with higher levels of burden associated with greater levels of caregiver depressive symptomatology. Higher levels of client behavioral problems and insufficient support from family members and mental health professionals related to the caregiving role were associated with higher levels of caregiver depressive symptomatology through their associations with caregiver burden. Caregiver race was not significantly related to caregiver burden or to caregiver depressive symptomatology after controlling for other variables. Over two-fifth of White caregivers and over one-quarter of Black caregivers were at risk for clinical depression. Implications for practice and research are discussed.
Classification of Multivector Theories and the Modification of the Postulates of Physics

We propose a graded classification of the entire field of multivector physics, including all alternative points of view. The (often tacit) postulates of different types of formulations are contrasted, summarizing their consequences. Specifically, spin-gauge formulations of gravitation and GUT which assume standard column spinors will require unnecessarily large matrix algebras. An extreme generalization is introduced, where wavefunctions are assumed to be multivectors, in which multiple generations of particle families naturally appear without increasing the size of the algebra. Further, this allows for two-sided (bilateral) operators, which can accomodate in excess of 10 times more gauge fields without increasing the algebraic representation. As this generalization encompasses all the essential features of the other categories, it is proposed to be the best path to new physics.
Superoxide Dismutase AN ENZYMIC FUNCTION FOR ERYTHROCUPREIN (HEMOCUPREIN)

An enzyme which catalyzes the dismutation of superoxide radicals (O2·- + O2·- + 2H+ → O2 + H2O2) has been purified by a simple procedure from bovine erythrocytes. This enzyme, called superoxide dismutase, contains 2 eq of copper per mole of enzyme. The copper may be reversibly removed, and it is required for activity. Superoxide dismutase has been shown to be identical with the previously described copper-containing erythrocuprein (human) and hemocuprein (bovine). Stable solutions of the superoxide radical were generated by the electrolytic reduction of O2 in an aprotic solvent, dimethylformamide. Slow infusion of such solutions into buffered aqueous media permitted the demonstration that O2·- can reduce ferricytochrome c and tetranitromethane, and that superoxide dismutase, by competing for the superoxide radicals, can markedly inhibit these reactions. Superoxide dismutase was used to show that the oxidation of epinephrine to adrenochrome by milk xanthine oxidase is mediated by the superoxide radical. An assay of several tissues indicates that superoxide dismutase is widely distributed within mammalian organisms.
Participatory action research in corrections: The HITEC 2 program.

Abstract Background HITEC 2 (Health Improvement through Employee Control 2) is the follow-up to HITEC, a participatory action research (PAR) program that integrates health and work conditions interventions designed by the workforce. HITEC 2 compares intervention programs between two correctional sites, one using a pure workforce level design team and the other using a more structured and time delineated labor-management kaizen effectiveness team. Methods HITEC 2 utilizes a seven step participatory Intervention Design and Analysis Scorecard (IDEAS) for planning interventions. Consistent with PAR, process and intervention efficacy measures are developed and administered through workforce representation. Results Participation levels, robustness of participatory structures and sophistication of interventions have increased at each measured interval. Health comparisons between 2008 and 2013 showed increased hypertension, static weight maintenance, and increased ‘readiness to change’. Conclusions The PAR approaches are robust and sustained. Their long-term effectiveness in this population is not yet clear.
THE QUENCHING OF TYROSINE AND TRYPTOPHAN FLUORESCENCE BY H2O AND D2O

— The quantum yields and lifetimes of the fluorescence of tyrosine and tryptophan were determined in D2O-H2O and glycerol-H2O solvent mixtures of varying composition from 10 vol.% to 100% H2O at 15°C. Forboth amino acids the ratio of the quantum yields in D2O and H2O (i.e., qD/qH) was smaller than the ratio of the corresponding lifetimes (D/H). For tyrosine the ratio of the quantum yields in glycerol and H2O (qG/qH) was also smaller than the corresponding G/H ratio, but for tryptophan qG/gHG/H. The proximity of the q vs. plots for tyrosine in the two solvent mixtures indicates that at 15°C neither D2O nor glycerol, in the pure state or when diluted with H2O, quench tyrosine significantly. However, H2O quenches tyrosine by a dynamic process, which increases both the radiative and the nonradiative rate constant. The quenching action is attributed to a tyrosine-H2O exciplex, whose formation is independent of bulk viscosity and dielectric constant. Unlike tyrosine, tryptophan is quenched weakly by D2O by a static process at 15°C (i.e., involving no change in), but H2O quenches tryptophan much more efficiently by a dynamic process, which involves the nonradiative rate constant, but not the radiative constant. These results are explained on the basis of electrostatic complexation of the ammonium group to the carbon atom adjacent to the ring nitrogen with a lifetime which is longer thanin D2O but shorter thanin H2O, with solvent reorientation possibly also being an important factor in the quenching. This explanation is consistent with the fact that concentrated (8 M) urea increases q andof aqueous tryptophan ˜ 15–20%, while guanidine hydrochloride (6.4 M) has the opposite effect, i.e., it decreases q and t of tryptophan ˜ 15–20%, and with the fact that neither 8 M urea nor 6.4 M guanidine hydrochloride affects any fluorescence parameter of tyrosine at all.
A comparison of levels of genetic polymorphism and self-compatibility in geographically restricted and widespread plant congeners

Evolutionary theory predicts low levels of genetic polymorphism and high levels of self-compatibility in plant species with small ranges and few individuals. To test these predictions, I compared published data on electrophoretically detectable genetic variation and breeding systems for geographically restricted and widespread congeners in eleven genera. The restricted species exhibit significantly fewer polymorphic loci and alleles per polymorphic locus than do their widespread congeners. Although some rare species are genetically impoverished, others are nearly as polymorphic as their widespread congeners. The restricted species and their widespread congeners do not differ consistently with respect to breeding systems.
Diffusion of Sr, Ba and Na in obsidian

Tracer diffusion coefficients have been determined for Sr, Ba and Na in a natural obsidian at temperatures between 650 and 950°C. The results are D(Sr) = 0.055 exp(−42.7 × 103/RT), D(Ba) = 0.038 exp(−45.1 × 103/RT) and D(Na) = 0.044 exp(−22.9 × 103/RT). The equation forD(Na) is based on data by SIPPEL (1963), CARRON (1968) and present results, all of which fit a single straight line on the Arrhenius plot, D = D0 exp(−ERT). Because the diffusivities depend strongly on ionic charge in addition to ionic radius, simple relationships, such as the Stokes-Einstein equation, which relate diffusivity and viscosity are not applicable to cation diffusion in natural silicate melts. Our results are, however, in approximate agreement with Winchell's compensation law (WINCHELL, 1969, High Temp. Sci. 1, 200–215), which is an empirical straight-line relation between log D0 and E. We apply our results to estimate the effect of diffusion control on the trace element distribution in crystals growing from a granitic melt. If crystal and melt are stationary (diffusive transport only), observable zoning will be produced in the crystal when the ratio of linear growth rate to the diffusion coefficient ranges between 10° and 104. If diffusion control is effective in a boundary layer only, the concentration in the crystal will deviate from the equilibrium value whenever the product of linear growth rate and boundary layer thickness exceeds a value of about 102− Application of the Sr diffusion data to partially molten, granitic rocks (migmatites) yields an equilibration range on the order of tens of centimeters, for a wide range of initial conditions. Sampling of migmatites for the purpose of measuring the whole rock RbSr age of the partial-melting event should therefore be done on a similarly small scale.
Superconducting Dy(IrxRh1−x)4B4 system

Abstract The boundaries between the paramagnetic, superconducting and magnetically-ordered phases in the pseudoternary system Dy(Ir x Rh 1−x ) 4 B 4 have been established down to 1.2 K. Comparisons between the present system and other pseudoternary systems M(Ir x Rh 1−x ) 4 B 4 show that the depression of the superconducting transition temperature (ΔT c ), relative to the nonmagnetic Lu compounds, can be described qualitatively by the de Gennes factor (g−1) 2 J(J+1). The nature of the magnetic order for the Rh-rich compounds was investigated by means of low field measurements and seems to be different from simple ferromagnetism.
Laparoscopic-assisted nephrectomy with inferior vena cava tumor thrombectomy: preliminary results.

Abstract Objectives To evaluate the feasibility and outcome of laparoscopic-assisted radical nephrectomy and inferior vena cava (IVC) tumor thrombectomy in patients with renal cell carcinoma and level I IVC tumor thrombus. Methods The clinical, operative, and pathologic data were retrospectively obtained from patients undergoing the above-mentioned procedure for renal tumors involving the IVC. This approach involved laparoscopic dissection of the kidney and renal vasculature/IVC. After renal artery ligation, an 8 to 12-cm incision was made from the tip of the 11th rib extending anteriorly toward the midline. Through this incision, a Satinsky vascular clamp was placed on the IVC in such a way as to include all the caval thrombus. The tumor thrombus was removed en bloc with the kidney and the cavotomy repaired with a running suture. Results Four obese patients underwent transperitoneal laparoscopic-assisted right nephrectomy with inferior vena cava (IVC) thrombectomy. The mean tumor size was 9 cm (range 6 to 13), with the thrombus extending 2 cm into the IVC in all cases. Patients had a mean body mass index of 32.8 (range 30.5 to 37.2) and a mean American Society of Anesthesiologists score of 2.8 (range 2 to 3). The mean operative time was 248 minutes (range 225 to 274). The mean estimated blood loss was 517 mL (range 250 to 900). No intraoperative or postoperative complications occurred. The mean hospital stay was 6.2 days (range 4 to 11, median 5). Conclusions Laparoscopic-assisted nephrectomy and IVC thrombectomy is a difficult but feasible procedure. This approach allows a smaller incision than a typical open approach. Additional studies are needed to examine the advantages of this approach over a pure open approach.
Swirling flows of viscoelastic fluids

Abstract Few problems in Newtonian fluid mechanics can match the attention which has been given to the study of the flow of a Newtonian fluid between two parallel plates rotating about a common axis. Most of these analyses are based on the similarity transformation of Karman to study axi-symmetric solutions. Recently, Parter and Rajagopal have proved the existence of solutions which do not possess axi-symmetry. Here, we shall discuss the analogous problems which arise within the context of viscoelastic fluids. We shall also discuss in detail the flow of viscoelastic fluids between infinite parallel plates rotating about non-coincident axes. When the angular speeds of both the plates are the same, the flow reduces to that in an orthogonal rheometer. We shall discuss such flows in some detail. Finally, we shall discuss the case when the two angular speeds are not the same.
A Bayesian model for efficient visual search and recognition.

Abstract Humans employ interacting bottom-up and top-down processes to significantly speed up search and recognition of particular targets. We describe a new model of attention guidance for efficient and scalable first-stage search and recognition with many objects (117,174 images of 1147 objects were tested, and 40 satellite images). Performance for recognition is on par or better than SIFT and HMAX, while being, respectively, 1500 and 279 times faster. The model is also used for top-down guided search, finding a desired object in a 5 × 5 search array within four attempts, and improving performance for finding houses in satellite images.
Framing for Learning: Lessons in Successful Technology Implementation

The decision to adopt a new technology in the health care setting is merely the first step in an implementation journey. While some new technologies are readily embraced by those who must use them, most are met with some resistance. In some cases, members of diverse groups—including administrators, clinicians, and technicians—must work together for a new technology to effectively take hold, becoming incorporated into routine practice in an organization. This article reports on a qualitative study of hospitals adopting a new technology for minimally invasive cardiac surgery that uncovered substantial differences in both approach and implementation success. Four case studies are presented to illustrate distinct, tacit frames held by the leaders of each implementation project and how these influenced the team learning process and, in turn, implementation success.
Angular Distributions of Deuterons from ( p , d ) Reactions in Light Nuclei. I. Nitrogen

Deuterons have been observed from the reaction ${\mathrm{N}}^{14}(p, d){\mathrm{N}}^{13}$, produced by 18.7-Mev protons. The deuterons were distinguished from proton background by a thin NaI crystal in a scintillation counter with the crystal thickness equal to the deuteron range. The angular distribution of deuterons to the ${\mathrm{N}}^{13}$ ground state was fitted by a curve calculated from Butler's theory for an angular momentum transfer ${l}_{n}=1$. This shows that the ground states of ${\mathrm{N}}^{13}$ and ${\mathrm{N}}^{14}$ have opposite parity and is consistent with the assignment of 1 + to the ${\mathrm{N}}^{14}$ ground state. The reduced width for the ground state transition is in qualitative agreement with that calculated using an independent-particle shell model with some indication that the ${\mathrm{N}}^{14}$ ground state is largely a $D$ state. The transition ${\mathrm{N}}^{14}(p, d){\mathrm{N}}^{13*}$ to the first excited state of ${\mathrm{N}}^{13}$ was not observed. The experimental upper limits on its cross section give upper limits of a few percent probability for admixtures of the configurations ${p}^{8}{s}^{2}$ and ${p}^{8}\mathrm{sd}$ in the ${\mathrm{N}}^{14}$ ground state. Application to the lifetime of ${\mathrm{C}}^{14}$ is discussed.
The Roles of Personal Investment and Reasoning Competence in Career-Relevant Everyday Problem Solving

To examine developmental differences in practical problem-solving, 51 late adolescents and 52 young adults were presented measures of everyday problem-solving that were either self-relevant or self-neutral. Results indicated: (a) a developmental shift in everyday problem-solving strategies, such that adolescents rated higher than adults those strategies that involved reconsideration of the problem situations and adapting to the conditions of the problems. By contrast, young adults rated higher more goal-defensive strategies than adolescents; (b) reasoning competence was more strongly related to ratings of self-relevant problems than to ratings of self-neutral problems, but only for the adolescents, providing some support for a relation between reasoning competence and everyday problem-solving; and (c) relevance effects on strategy ratings were clearly evidenced as both age groups rated planning for the future and shaping the present environment to correspond to their current goals higher for self-relevant than for neutral problems. These findings are discussed in terms of the possible roles of domain specificity, personal investment, age, and reasoning competence in adolescent and adult everyday problem-solving.
The Madistor-A Magnetically Controlled Semiconductor Plasma Device

The madistor is a new active device which makes use of the effects of a magnetic field on an injection plasma in a semiconductor. The formation of an injection plasma has been observed in p-type InSb at temperatures below 100°K as donor traps become saturated by electrons injected through a forward biased n+p junction. In an appropriately designed n+pp+ diode, the saturation of traps and the subsequent increase in electron lifetime bring about an abrupt decrease of base resistance, and a negative resistance region is observed in the current-voltage characteristic. Because of the high mobility of electrons in InSb (5×105 cm2/vsec) the plasma can be appreciably deflected and deformed by transverse magnetic fields of the order of 10 gauss. The possibility of controlling the position of a plasma inside a solid by means of a magnetic field can be utilized in a number of different types of madistors in which the input circuit is isolated from the output. The operation at 77°K of four types of InSb madistors has been studied. The first makes use of a specially designed n+ pp+ diode mounted in the air gap of a small ferromagnetic-core electromagnet. A small change in the electromagnet winding current produces a magnetic field at the diode and causes a larger change in diode current. Typically an increase in mmf of 200-ma turns produces an additional magnetic field intensity of 5 gauss which decreases the diode current by 10 ma.
Differential Effects of Microsomal Enzyme Inducers on in Vitro Thyroxine (T4) and Triiodothyronine (T3) Glucuronidation

Microsomal enzyme inducers that increase UDP-glucuronosyltransferase (UDP-GT) activity are suspected to affect the thyroid gland by increasing the glucuronidation of T(4), which reduces serum thyroxine (T(4)). In response to reduced serum T(4), serum thyroid-stimulating hormone (TSH) increases. However, not all microsomal enzyme inducers that reduce serum T(4) produce an increase in serum TSH. We have shown that serum TSH is increased the most in rats treated with the microsomal enzyme inducers phenobarbital (PB) or pregnenolone-16alpha-carbonitrile (PCN), whereas TSH is affected less in rats treated with 3-methylcholanthrene (3MC) and Aroclor 1254 (PCB). It is unclear why serum TSH is differentially affected by various microsomal enzyme inducers. We propose that the glucuronidation of T(3) might be the reason serum TSH is increased by some microsomal enzyme inducers but not by others. Male Sprague-Dawley rats were fed either a basal diet or a diet containing PB (at 300, 600, 1200, or 2400 ppm), PCN (at 200, 400, 800, or 1600 ppm), 3MC (at 50, 100, 200, or 400 ppm), or PCB (at 25, 50, 100, or 200 ppm) for 7 days; and T(4) and T(3) UDP-GT activities were then determined. T(4) UDP-GT activity was increased in rats treated with PB (120%), PCN (250 to 400%), 3MC (400 to 600%), or PCB (300 to 430%). In contrast, T(3) UDP-GT activity was increased in rats treated with PB (90%) or PCN (120 to 200%), whereas 3MC and PCB treatments did not have an appreciable effect. In conclusion, differential effects on T(3) glucuronosyltransferase activity were found in rats treated with microsomal enzyme inducers.
Reduced Thermic Effect of Feeding in Obesity: Role of Norepinephrine

Several studies have suggested that obese subjects have a reduced thermic effect of feeding when compared to normal weight controls. The present study was undertaken to further define this apparent abnormality, and evaluate the role of norepinephrine in the thermic response to food. A test formula meal of 800 calories (85% carbohydrate, 15% protein) was taken by 7 control and 6 moderately obese subjects whose obesity was adult in onset. The rise in resting oxygen consumption following the test meal was greater in the control than in the obese group (p less than 0.01), and there was a significant inverse correlation between the relative degree of obesity and this response to feeding (r = -0.59, p less than 0.05). Norepinephrine concentrations were greater in the obese than in the control group both before (p less than 0.05) and after (p less than 0.05) feeding. No correlations were found between the plasma norepinephrine concentrations and the rise in oxygen consumption after feeding. Four of the 6 obese subjects were restudied after weight reduction. The reduced-obese group showed a trend toward normalization of basal measurements and responses to feeding. It is concluded that the reduced thermic response to feeding seen in the obese subjects studied cannot be directly accounted for by diminished sympathetic nervous system activity as reflected by plasma levels of norepinephrine.
Toward an understanding of the factors influencing anhydrate-to-hydrate transformation kinetics in aqueous environments

Approximately one-third of all drugs can form hydrates, and therefore an in-depth understanding of the factors affecting anhydrate-to-hydrate transformation kinetics in a variety of environments is of interest. In this work, real-time analytical methods, in the form of Raman spectroscopy and optical microscopy, were used to establish representative transformation profiles and growth kinetics for hydrate formation of several drug substances. By comparing and contrasting the behavior of these different hydrates in terms of their specific properties such as solubility, dissolution rate, and growth rate of hydrate phase, and the influence of external factors such as seeding and agitation conditions, an increased understanding of hydrate formation has been achieved. The overall transformation rate from anhydrous to hydrate form was found to be not only a function of compound-specific properties, but was also strongly affected by surface properties and external factors such as the presence of seeds and the degr...