cssi/SciSciGPT-SciSciNet huggingface dataset:
Hydrogen exchange as a probe of the dynamic structure of DNA: I. General acid-base catalysis☆

Abstract In this paper it is shown that positively-charged proton transfer agents can catalyze the exchange-out from native DNA of the hydrogens involved in internucleotide hydrogen-bonding. The negatively-charged catalysts tested did not increase the rate of exchange. The effectiveness of hydronium ion catalysis is decreased by increasing concentrations of sodium ion, while that of hydroxide ion is increased. The measured rates of proton transfer in the presence of various catalysts can be quantitatively accounted for in terms of a Bronsted-type relationship involving the pK′A values of both the catalyst and the titratible sites of DNA, plus a superimposed electrostatic effect of the DNA phosphates which decreases the effectiveness of negatively-charged catalysts and facilitates catalysis by positively-charged species. The two types of chemically distinct DNA proton exchange sites (amino and imino groups), do not participate independently in exchange, since the addition of catalysts affects all kinetic classes of hydrogens equally. These results support the hypothesis (Printz & von Hippel, 1968) that exchange of the interchain hydrogens of DNA proceeds via a local, transiently-open (non-hydrogen bonded) conformational state which is maintained (“propped” open) by the presence of two (at acid pH) or no (at alkaline pH) hydrogens at the locus of the NH … N internucleotide hydrogen bond. The over-all rate of the exchange process appears to depend on the product of the equilibrium constant for the formation of open (propped) sites, and the rate constant for the initial transfer of protons to and from the open DNA sites exposed in this process.
Write for Your Life: Developing Digital Literacies and Writing Pedagogy in Teacher Education

The need for the effective development of digital literacies pervades every aspect of instruction in contemporary classrooms. As a result, teacher candidates must be equipped to draw upon a variety of literacies in order to tap into the complex social worlds of their future pupils. The Write for Your Life Project was designed to strengthen teacher candidates’ skills in both traditional and digital writing literacies through the use of social networks, blogging, texting, online modules and other social media. The project, to a large degree, was structured according to Calkins’ (1994) Writing Workshop Approach. This process encourages teacher candidates to write daily, devise writing minilessons, use peer conferencing, and publish final pieces. This article describes the Write for Your Life Project that was piloted in two courses with 45 teacher candidates, shares findings from the implementation process, and makes recommendations for more effectively integrating writing and technology across the content areas in teacher education courses.
Reactions on Carbon-14

In inhomogeneous nudeosynthesis, a series of neutron captures is thought to lead to the production of 14C. We have studied the branching at 14C and have deduced the importance of the 14C(d, n)15N reaction which may be the dominant channel for the production of heavier elements.
Who Needs an Evidence Code?: The New York Court of Appeals' Radical Reevaluation of Hearsay

New York remains one of a handful of states without an evidence code. The law of evidence in New York has not, however, remained dormant. In the vital field of hearsay evidence jurisprudence, the New York Court of Appeals in the past decade has dramatically reshaped the admissibility landscape through common law development, leading to an unprecedented increase in the admission of out-of-court statements. Proponents of codification of the evidentiary rules in New York view it as the best way to achieve much-needed reform in the area, while opponents believe that codification inappropriately involves legislatures and politics in evidence law and will vest the trial judge with too much discretion, resulting in increased admissibility.This Article shows that the Court of Appeals has altered the face of hearsay in New York State both by creating new exceptions and expanding existing ones, leading to in a pronounced trend toward greater admissibility. The consequence is a transformation in the types of evidence that jurors are permitted to hear and the ways in which trials are conducted. Part I examines the expansion of existing hearsay exceptions, focusing on excited utterances and statements made by witnesses who are unavailable due to the defendant's misconduct. Part II analyzes the recently adopted present sense impression exception, and the newly recognized due process catchall for reliable evidence that does not fit within any presently recognized exception. Part III evaluates the increased reliance on judicial interpretations of out-of-court statements as “nonhearsay.” Finally, Part IV analyzes the unintended, but predictable, consequences of the relaxation of evidentiary standards and attendant greater admissibility and their implications for the codification debate.
Vasoactive Peptides and Substrates and Their Relation to Protein Handling by the Kidney

The properties of anephrotensin, a polypeptide liberated by acid incubation of serum, are reviewed. Experiments with antirenin rule out the possibility that renin is the enzyme that liberates anephrotensin. Serum anephrotensinogen increases after bilateral nephrectomy or after several weeks of treatment with desoxycorticosterone (DCA). There are perallel changes under these conditions in the amounts of anephrotensinogen and angiotensinogen in the serum, suggesting that a common substrate may be involved. The increase in substrate is in accord with the possibility that DCA treatment results in some deficiency in the handling of proteins by the kidney. There is an increase in urine vasoactive peptides and total proteins in DCA-treated rats. These increases are probably related to deficiency in tubular reabsorption. The increase in the albumin/globulin ratio of the urine proteins under these circumstances supports this idea. The changes described above are not necessarily related to the onset of hypertension...
Single nucleotide polymorphisms and breast cancer: not yet a success story

Numerous studies have examined low penetrance susceptibility polymorphisms in candidate genes, with some reporting significant findings. However, for the most part these associations could not be replicated in subsequent studies, suggesting that the original observations were due to chance. The failure to identify meaningful common genetic variation in relation to breast cancer should give us pause for thought and make us reconsider our current research strategies. The most recent directions of pooling samples to increase statistical power and pursuing whole genome screens may overcome some obstacles while also creating new challenges. Future studies should perhaps also consider alternative designs such as using surrogate (preferably continuous) markers of breast cancer, focusing on high-risk populations, and defining pathologically distinct outcomes.
The alternate forms of the positive and negative mood scales: Reliability, validity, and equivalence in referred samples

The reliability (internal consistency and alternate form) of the trait version of the Positive and Negative Mood Scales in referred samples was found to be high, and the concurrent and discriminate validity was found to be moderate. As expected, means of the Positive Mood Scales were significantly higher in nonreferred samples and means of the Negative Mood Scales were significantly higher in referred samples. The alternate forms for each scale were equivalent. The Positive and Negative Mood Scales seem to be ready for use in research.
A Hubble Space Telescope Search for Lyman Continuum Emission from Galaxies at 1.1 < z < 1.4

If enough of their Lyman-limit continuum escapes, star-forming galaxies could be significant contributors to the cosmic background of ionizing photons. To investigate this possibility, we obtained the first deep imaging in the far-ultraviolet of 11 bright blue galaxies at intermediate redshift (1.1 < z < 1.4) with the Space Telescope Imaging Spectrograph Far-Ultraviolet Multianode Microchannel Array detector on the Hubble Space Telescope. No Lyman continuum emission was detected. Sensitive, model-independent, upper limits of typically less than 10-19 ergs cm-2 s-1 A-1 were obtained for the ionizing flux escaping from these normal galaxies. This corresponds to lower limits on the observed ratio of 1500-700 A flux of 150 up to 1000. On the basis of a wide range of stellar synthesis models, this suggests that less than 6%, down to less than 1%, of the available ionizing flux emitted by hot stars is escaping these galaxies. The magnitude of this spectral break at the Lyman limit confirms that the basic premise of "Lyman break" searches for galaxies at high redshift can also be applied at intermediate redshifts. This implies that the integrated contribution of galaxies to the UV cosmic background at z ~ 1.2 is less than 15% and may be less than 2%.
The effects on priming of word frequency, number of repetitions, and delay depend on the magnitude of priming.

Conflicting findings with respect to the effects of experimental manipulations on priming have been reported in previous studies. It is argued that, in many priming tasks, large amounts of task-relevant information are available from various sources, and that, therefore, the information available from a specific study episode will have only a small impact on overall performance level. Under such circumstances, high levels of baseline performance and small priming effects will be observed. The experiments reported here investigated the hypothesis that a high baseline performance in informationprocessing tasks that are used to measure priming may constrain priming effects. In a series of wordnaming experiments, perceptual difficulty and, therefore, baseline performance was manipulated. Under easy conditions, priming effects were relatively small and were not affected by word frequency, spaced repetition, or delay. Under more difficult conditions, priming effects were larger, and significant effects of all of the above-mentioned experimental manipulations were observed. Under conditions that produced the largest priming effects, a significant relationship between priming and explicit-memory performance could be observed. In the last experiment, it was shown that the characteristics of the retrieval task can substantially affect the magnitude of priming. It is argued that priming effects should be considered to reflect interactions between memory traces and the information-processing components of the priming task.
On the number of unlabeled vertices in edge-friendly labelings of graphs

Let G be a graph with vertex set V(G) and edge set E(G), and f be a 0-1 labeling of E(G) so that the absolute difference in the number of edges labeled 1 and 0 is no more than one. Call such a labeling fedge-friendly. We say an edge-friendly labeling induces a partial vertex labeling if vertices which are incident to more edges labeled 1 than 0, are labeled 1, and vertices which are incident to more edges labeled 0 than 1, are labeled 0. Vertices that are incident to an equal number of edges of both labels we call unlabeled. Call a procedure on a labeled graph a label switching algorithm if it consists of pairwise switches of labels. Given an edge-friendly labeling of K"n, we show a label switching algorithm producing an edge-friendly relabeling of K"n such that all the vertices are labeled. We call such a labeling opinionated.
Liquid chromatographic separation of metals by on-column chelation with 4-(2-pyridylazo) resorcinol

A method for the separation of trace levels of Zn(II), Fe(II), Ni(II) and Co(II) by on-column formation of their complexes with 4-(2-pyridylazo)resorcinol and subsequent separation of the complexes by reversed-phase liquid chromatography is described. Either acidic or buffered mobile phases can be used. For the separation using acidic mobile phases the role of the mobile-phase pH, concentration of PAR, and type of stationary phase is described. For buffered (slightly acidic) mobile phases it is shown that the complexing ability of the buffer can be used to influence the separation. Data on the use of this system for quantitative analysis are included.
Evaluation of a closed-chamber method for estimating methane emissions from aquatic plants

Closed-flow chambers are commonly used to measure CH 4 emissions from aquatic plants. We monitored environmental and plant physiological responses to closed chambers during measurements of CH 4 emission from Typha latifolia (cattails) to evaluate potential errors in emission estimates. In 1990, two wetlands were studied: one in NE Kansas and one in central New York. Leaves and stems of Typha enclosed in gas-impermeable, collapsible bags were exposed to rapid increases in chamber air temperature and, thus, tissue temperatures (up to 9 °C above ambient) as well as rapid reductions in both CO 2 partial pressure due to photosynthesis and the leaf-to-air water vapor pressure deficit due to transpiration. These rapid (< 5 min) environmental changes within chambers are known to affect stomatal aperture through which CH 4 exits Typha leaves. Indeed, stomatal conductance ( g ) increased up to 42% compared to control leaves after 19 min of enclosure in chambers, and chamber effects on interactions between irradiance and g were detected. The duration of enclosure also critically affected the CH 4 gradient within chambers. Estimated CH 4 emission from leaves in chambers sampled after 19 min (3 nmol m -2 s -1 ) was 10-fold lower than estimates based on 30-s sampling periods (30 nmol m -2 s -1 ) due to reduction in the leaf-to-air concentration gradient for CH 4 . Since closed chambers (1) induce alterations in g, (2) may result in rapid environmental changes, and (3) lead to almost instantaneous reductions in the leaf-to-air concentration gradient for CH 4 diffusion, we suggest that only very short enclosure times should be used when measuring CH 4 emission from plants. DOI: 10.1034/j.1600-0889.1992.00006.x
Linear programming, recurrent associative memories, and feed-forward neural networks

Abstract Many optimization procedures presume the availability of an initial approximation in the neighborhood of a local or global optimum. Unfortunately, finding a set of good starting conditions is itself a nontrivial proposition. Our previous papers [1,2] describe procedures that use simple and recurrent associative memories to identify approximately solutions to closely related linear programs. In this paper, we compare the performance of a recurrent associative memory to that of a feed-forward neural network trained with the same data. The neural network's performance is much less promising than that of the associative memory. Modest infeasibilities exist in the estimated solutions provided by the associative memory, but the basic variables defining the optimal solutions to the linear programs are readily apparent.
Managing Scientists: Leadership Strategies in Scientific Research. Alice M. Sapienza. New York: Wiley-Liss, 2004, 260 pp., $39.95, softcover. ISBN 0-471-22614-9.

Nearly everyone has experienced the penalty of skilled incompetence when a gifted scientist is thrust into a leadership position primarily because of his or her technical know-how, but without consideration of that person’s ability to manage the human side of research and development. Without the requisite “soft skills”, even the most brilliant, well-intentioned leader will adversely affect group morale and productivity, including those of the leader. Analogous to the technical credentials demanded by our profession, leadership should be treated as a discipline that calls for training, mentoring, and experience. This book is a revision …
Near real‐time GPS sensing of atmospheric water vapor

We describe sensing of atmospheric column water vapor in near real-time using the Global Positioning System (GPS). We use predicted GPS orbits for automated computation of vertical column water vapor within 30 minutes of GPS data collection. Based on a 4 month comparison, near real-time GPS column water vapor agrees with radiosondes and radiometers within 2 mm rms. Our near real-time column water vapor data are posted hourly at www.unavco.ucar.edu. They are available for assimilation in numerical weather models and for other applications.
Searching the protein structure database for ligand-binding site similarities using CPASS v.2

A recent analysis of protein sequences deposited in the NCBI RefSeq database indicates that ~8.5 million protein sequences are encoded in prokaryotic and eukaryotic genomes, where ~30% are explicitly annotated as "hypothetical" or "uncharacterized" protein. Our C omparison of P rotein A ctive-S ite S tructures (CPASS v.2) database and software compares the sequence and structural characteristics of experimentally determined ligand binding sites to infer a functional relationship in the absence of global sequence or structure similarity. CPASS is an important component of our F unctional A nnotation S creening T echnology by NMR (FAST-NMR) protocol and has been successfully applied to aid the annotation of a number of proteins of unknown function. We report a major upgrade to our CPASS software and database that significantly improves its broad utility. CPASS v.2 is designed with a layered architecture to increase flexibility and portability that also enables job distribution over the Open Science Grid (OSG) to increase speed. Similarly, the CPASS interface was enhanced to provide more user flexibility in submitting a CPASS query. CPASS v.2 now allows for both automatic and manual definition of ligand-binding sites and permits pair-wise, one versus all, one versus list, or list versus list comparisons. Solvent accessible surface area, ligand root-mean square difference, and Cβ distances have been incorporated into the CPASS similarity function to improve the quality of the results. The CPASS database has also been updated. CPASS v.2 is more than an order of magnitude faster than the original implementation, and allows for multiple simultaneous job submissions. Similarly, the CPASS database of ligand-defined binding sites has increased in size by ~ 38%, dramatically increasing the likelihood of a positive search result. The modification to the CPASS similarity function is effective in reducing CPASS similarity scores for false positives by ~30%, while leaving true positives unaffected. Importantly, receiver operating characteristics (ROC) curves demonstrate the high correlation between CPASS similarity scores and an accurate functional assignment. As indicated by distribution curves, scores ≥ 30% infer a functional similarity. Software URL: http://cpass.unl.edu .
Role of Reactive Oxygen Species in Bradykinin-Induced Mitogen-Activated Protein Kinase and c-fos Induction in Vascular Cells

Bradykinin stimulates proliferation of aortic vascular smooth muscle cells (VSMCs). We investigated the action of bradykinin on the phosphorylation state of the mitogen-activated protein kinases p42(mapk) and p44(mapk) in VSMCs and tested the hypothesis that reactive oxygen species (ROS) might be involved in the signal transduction pathway linking bradykinin activation of nuclear transcription factors to the phosphorylation of p42(mapk) and p44(mapk). Bradykinin (10(-8) mol/L) rapidly increased (4- to 5-fold) the phosphorylation of p42(mapk) and p44(mapk) in VSMCs. Preincubation of VSMCs with either N-acetyl-L-cysteine and/or alpha-lipoic acid significantly decreased bradykinin-induced cytosolic and nuclear phosphorylation of p42(mapk) and p44(mapk). In addition, the induction c-fos mRNA levels by bradykinin was completely abolished by N-acetyl-L-cysteine and alpha-lipoic acid. Using the cell-permeable fluorescent dye dichlorofluorescein diacetate, we determined that bradykinin (10(-8) mol/L) rapidly increased the generation of ROS in VSMCs. The NADPH oxidase inhibitor diphenylene iodonium (DPI) blocked bradykinin-induced c-fos mRNA expression and p42(mapk) and p44(mapk) activation, implicating NADPH oxidase as the source for the generation of ROS. These findings demonstrate that the phosphorylation of cytosolic and nuclear p42(mapk) and p44(mapk) and the expression of c-fos mRNA in VSMCs in response to bradykinin are mediated via the generation of ROS and implicate ROS as important mediators in the signal transduction pathway through which bradykinin promotes VSMC proliferation in states of vascular injury.
Learning to see: the moral opportunity of art.

In one sense, seeing comes naturally. We enter the world equipped with eyes and the other components of the human visual apparatus, and we begin looking at things from the very moment of our birth. In other respects, however, seeing is something we must learn to do. For example, the images that focus on our retinas are upside down and backwards, and some neural “rewiring” is required for us to see things in their proper orientation. More broadly speaking, the eye needs training. Though the visual equipment of a first-year medical student and a seasoned radiologist are essentially the same, the student is able to glean far less diagnostic information from a chest radiograph. We can quickly train such a student to detect findings, such as pneumothorax, but a fully equipped visual diagnostician requires the ability to discern subtleties of line and texture, to correlate visual stimuli with clinical context, and to distinguish extraneous from essential information. Yet patients are more than diagnoses. They are also human beings, and being a good physician entails recognizing, responding to, and caring for patients in human, as well as purely biological terms [1]. It is relatively straightforward to teach a medical student to recognize a pneumothorax. But how to see and respond with compassion to a patient’s humanity is not so easy [2]. Fortunately, extraordinary resources for educating the eye lie at our fingertips. They represent some of the most beautiful products of the human hand, and their creators are household names. Such resources are all the more remarkable precisely because they have been so infrequently recognized and exploited [3]. They have been available to physicians for decades, and most of the best of them have been around for more than a century, yet they are completely absent from the curricula of most medical schools, residencies, and continuing education programs. As far as many of us are concerned, such resources might not even exist. We are referring to the paintings of some of the greatest artists who ever lived. In the western tradition, we have in mind the works of such artists as Michelangelo, Da Vinci, Rembrandt, and Van Gogh. Such works are not merely decorative, the equivalent of “eye candy.” Quite the
High resolution rainfall mapping in the Dallas-Fort Worth urban demonstration network

Flooding is one of the most catastrophic disasters in the world. Radar rainfall estimation for flash flood forecasting in small, urban catchments is an important accomplishment of CASA. A K dp (specific differential propagation phase) based rainfall algorithm was developed using the K dp values of X-band radars. The performance of this rainfall algorithm is evaluated for all major rainfall events using a gauge network in the center of CASA IP1 test bed for a 5- year period. The cross comparison with gauge estimates shows great improvement compared to the current state-of-the-art. Since the beginning of 2012, CASA has been involved in developing the first urban weather demonstration network in Dallas-Fort Worth (DFW) area. This paper will summarize the performance of the radar rainfall product in the IP1 network. In addition, the implementation of CASA QPE (quantitative precipitation estimation) system in DFW Urban Demonstration Network will also be presented.
Psychosocial Adjustment of Adolescents and Young Adults with Intellectual Disabilities.

Issues with adolescents with intellectual disabilities have received little attention in the research literature. This study compared adolescents with and without intellectual disabilities on several indices of psychosocial adjustment. The participants were selected from a large longitudinal database and comparisons were made at three points in time. Analyses indicated that adolescents with intellectual disabilities report mild to moderate depression over time when compared with their typically developing peers, they express more family connectedness, but differ little on measures of self-concept. In later adolescence, typically developing adolescents appear to have a significant increase in optimism that is not experienced by the adolescents with intellectual disabilities. Implications of the findings are discussed as well directions for further investigation.
Noncovalent occupancy of the retinal-binding pocket of opsin diminishes bleaching adaptation of retinal cones

Abstract Bright light bleaches visual pigment and leads to a persistent desensitization of isolated rod and cone photoreceptors called bleaching adaptation. Bleaching adaptation results from the combined effects of pigment depletion and adaptational modulation of certain cellular reactions in the visual transduction cascade. Here, we present evidence that in solitary cone photoreceptors isolated from the salamander retina, the latter effect is due to the presence of free opsin in the outer segment. Also, we demonstrate that this “opsin adaptation” can be reversed by treating the cells with synthetic retinoids similar to 11-cis retinal but having polyene chains too short to form protonated Schiff base attachments to opsin.
Physiological arousal, exposure to a relatively lengthy aggressive film, and aggressive behavior ☆

Abstract Male college students viewed either a 15-minute aggressive television program excerpt or a neutral one. Half of the students in each group were then angered or treated in a neutral fashion by a confederate. Each subject was allowed to retaliate by delivering electric shocks to the confederate as an evaluation of a problem solution he supposedly had completed. Heart rate was measured (a) before exposure to the television program, (b) after exposure to the program, (c) immediately before delivering the shock, and (d) immediately after shock delivery. Angered men who had seen the aggressive film were most aggressive toward the confederate and exhibited the lowest average pulse rates both before and after shock delivery. The findings are discussed in terms of their implication for arousal vs disinhibition conceptualizations of aggressive behaviors following exposure to television violence.
Communication apprehension and self-perceived communication competence in adolescents who stutter

The purpose of this study was to examine the communication apprehension and self-perceived communication competence of 39 adolescents who stutter and 39 adolescents who do not stutter using two standardized communication measures. Significantly higher levels of communication apprehension and poorer scores on self-perceived communication competence were found in adolescents who stutter when compared with adolescents who do not stutter. Subscore test data revealed that adolescents who stutter had significantly greater fears about speaking in Group Discussions and Interpersonal Conversations than they had about Public Speaking and talking during Meetings, when compared with students who do not stutter. They also had significantly poorer perceptions about their own communication competence on the Talking to Strangers subscore test when compared with students who do not stutter. A significant positive relationship among stuttering severity, communication apprehension, and self-perceived communication competence total scores was found. Students who stutter severely had greater fears about speaking in group discussions and interpersonal conversations. Implications for stuttering therapy and the need for specifically addressing communication apprehension in treatment sessions are discussed. Educational objectives: (1) The reader will learn about communication apprehension and fear in people who stutter and be able to describe different types of responses to these fears. (2) The reader will be able to learn about commercially available instruments for testing communication apprehension and compare differences between adolescents who stutter and who do not stutter. (3) The reader will be able to describe and explain the relationship between communication apprehension and stuttering and determine its impact on stuttering and resulting treatment decisions.
Correction of laser tracking data for the effects of horizontal refractivity gradients.

Pulsed laser ranging systems are being used to measure accurately the distance from the earth to retroreflector equipped satellites. At the lower elevation angles horizontal refractivity gradients can introduce centimeter level errors into the range measurements. A correction formula which compensates for the gradient effects is developed and evaluated using typical meteorological data obtained from weather stations located near Washington, D.C.
Kinetics of Solvolyses of Various N-Alkyl-N-nitrosoureas in Neutral and Alkaline Solutions

The N- alkyl- N -nitrosoureas possess antitumor activity but readily decompose at the pH of biological fluids with half-lives about 20 minutes at pH 7 and 37.5°. The effect of substituents, R, on the kinetics of solvolysis of synthesized R─N─(NO)─CO─NH 2 was determined in the phosphate buffer region, pH 6–7.8, as a basis for the proper design of biologically effective compounds. Spectrophotometric techniques were used over a range of several temperatures. The solvolytic rates were first order in substrate and hydroxyl ions and the log k -pH profile was linear with a slope of + 1.0. No solvent or general acid-base catalysis was observed, and salt effects were negligible. No significant differences in reactivities, entropies, or heats of activation were observed for R = methyl, ethyl, and butyl. The 2-methylpropyl was slightly more reactive. When R = allyl, phenethyl, and benzyl, a significant increase in reactivities was observed. The unsaturated substituents favored hydroxyl ion attack as expected. However, the cyclohexyl compound also had high reactivity to hydroxyl ion attack.
A Computerized 3-D Plotting Program

A conceptually simple computer plotting program has been developed that provides an efficient method of plotting a projection of a three-dimensional surface with remarkable clarity, even if the surface comprises a large amount of detail. The method consists of plotting successive parallel cuts of the surface, each displaced to establish the desired projection. Only that portion of the cut that lies above the previous cuts is then plotted. The plotting sometimes requires several hours, depending on the speed of the computer and on the complexity of the function, but the cost need not be excessive since a relatively small computer can be used. A few of the functions that have been plotted are discussed in some detail.© (1967) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Reversal of the Inhibition of TSH Secretion Due to Acute Stress

Chronic stress of minor intensity prevents the usual inhibition of TSH secretion induced by an acute stressing procedure. Chronic administration of reserpine reverses the usual inhibition of TSH secretion induced by acute stress, which is now followed by an elevation of plasma TSH concentration. Chronic stress leads to increased resting levels of plasma TSH. The studies reported here were conducted on rats with direct measurements of plasma TSH levels by bio-assay. (Endocrinology 80: 953, 1967)
Reconstruction of comminuted posterior wall fractures using the buttress technique: a review of 32 fractures.

Fractures of the posterior wall are the most common of the acetabular fractures. The aim of this study was to assess the medium-term results of reconstruction of comminuted posterior wall fractures of the acetabulum by using the buttress technique. This is a retrospective review conducted at a level 1 trauma centre. Thirty-two patients (25 men, 7 women, mean age 41 years, range 14–80 years) with comminuted posterior wall fracture of the acetabulum underwent reconstruction of the posterior wall during the period of July 1998 to February 2004. The average follow-up was 43 months (range 24–70 months). Clinical evaluation was based on modified Merle d’Aubigne and Postel scoring. Radiographic evaluation was according to criteria developed by Matta. The postoperative reduction was graded as anatomical in 28 patients (88%) and imperfect in 4 patients (12%). The clinical outcome was excellent in 11 (34% ), very good in 9 (28%), good in 4 (12%), fair in 3 (9%) and poor in 5 (15%). Radiological grading at the final follow-up was excellent 12 (37%), good 11 (34%), fair 4 (12%) and poor 5 (15%). Reconstruction of comminuted posterior wall acetabular fractures by buttress technique can be expected to produce good results. It can provide a stable fixation of the posterior wall amenable to early range of motion and weight bearing.
Total cross section of the 3 H ( p , n ) 3 He reaction from threshold to 4.5 MeV

We report new measurements of the total cross section for the {sup 3}H(p,n){sup 3}He reaction from threshold (E{sub p}=1.02 MeV) to E{sub p}=4.5 MeV. The experiment utilized specially prepared Ti-{sup 3}H targets, and neutrons were detected using a 4{pi} detector. A weak resonant structure due to an excited state in {sup 4}He is observed which was not seen in previous cross section measurements. A new expression for the {sup 3}He(n,p){sup 3}H thermonuclear reaction rate for temperatures below 10 GK is presented which will allow for more accurate calculations of the yields of light elements produced by big-bang nucleosynthesis. {copyright} {ital 1999} {ital The American Physical Society}
Effect of Hypothermia on Intracellular Ca2+in Rabbit Renal Tubules Suspended in UW-Gluconate Preservation Solution

Abstract Altered cellular calcium (Ca) homeostasis may be important in mediating hypothermic injury in preserved kidneys. In this study the effect of hypothermic (5°C) storage on ionized intracellular Ca concentration ([Ca]i) in rabbit tubules was examined using Indo-1. Tubules were stored up to 250 min in UW-gluconate solution containing either 0.0, 0.5, 1.5, or 5.0 mMCa (yielding about 3.6, 62, 371, and 1,010 μMionized solution Ca (Ca2+) at 5°C, respectively). [Ca]iincreased to about 1,600 nMwithin 1 min after suspension in UW solution followed by a decrease in [Ca]iduring the subsequent 60 min in all groups, suggesting mitochondrial Ca sequestration. Thereafter, [Ca]ieither 1) increased in tubules incubated with 1.5 and 5.0 mMCa to levels greater than 2,500 nM;2) decreased to about 800 nMin tubules incubated with 0.5 mMCa and then remained stable; or 3) continued to decrease in tubules incubated with 0.0 mMadded Ca to reach an apparent steady-state concentration of about 175 nMafter 180 min of incubation. The early spike in [Ca]iwas unaffected by adding EGTA (solution Ca2+= 50 nM). Ryanodine eliminated the [Ca]ispike, indicating that cooling in UW-gluconate solution caused release of endoplasmic reticulum Ca. This study shows that [Ca]iinitially increases after exposure to UW-gluconate solution and appears to be transiently buffered through intracellular, probably mitochondrial, sequestration. Saturation of cellular buffer mechanisms resulted in a sustained dependence of [Ca]ion extracellular Ca2+. These results support the hypothesis that the effect of Ca on kidney viability is related to solution-induced alterations in [Ca]i.
Nanoscale Subsurface Imaging via Resonant Difference-Frequency Atomic Force Ultrasonic Microscopy

A novel scanning probe microscope methodology has been developed that employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by the fundamental resonance frequency of the cantilever, engages the sample top surface. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave in the region defined by the cantilever tip-sample surface interaction force generates difference-frequency oscillations at the cantilever fundamental resonance. The resonance-enhanced difference-frequency signals are used to create images of embedded nanoscale features.
Unique Temperature-Sensitive Defect in Vaccinia Virus Morphogenesis Maps to a Single Nucleotide Substitution in the A30L Gene

Marker rescue experiments demonstrated that the genetic lesion of a previously isolated vaccinia virus temperature-sensitive mutant which forms multilayered envelope structures with lucent interiors and foci of viroplasm with dense centers mapped to the A30L open reading frame. A single base change, resulting in a nonconservative Ser-to-Phe substitution at residue 17, was associated with degradation of the A30L protein at elevated temperatures.
SU-E-T-482: Development and Systematic Testing of Dose Analysis Engine for Research and Clinical Applications Using API Interface of Varian Eclipse Treatment Planning System

Purpose: To validate standalone software that provides dose analysis capabilities of a treatment planning system. The intended use of this software is in research and in clinical applications where commercial solutions are not yet available. Methods: We used Application Programmer Interface (API) of the Eclipse Treatment Planning System (Varian,Inc), to extract dosimetric information from treatment plans. We used dose volume histogram (DVH) object to extract standard dose volume histogram data. We used two API functions to construct 3D representation of anatomy (a bitmap) and compute dose values at all voxels that belong to a structure. We wrote a C++ package which achieves the same reconstruction based on stored contour data and a dose volume. For this work we compared structure volumes and simple dose statistics on dose buffers (minimum, mean, maximum and standard deviation). We used data from 6 Head and Neck patients and examined a total of 102 structures. Results: The API based reconstruction of 3D anatomy systematically overestimates structure volumes when compared to volumes reported by the API DVH module. The discrepancy is largest for small structures, and can exceed 20%. Volume estimates obtained by the C++ package show better agreement with the DVH module if partial volume corrections are applied to surface voxels. Among four dosimetric variables, largest discrepancies are observed for the minimum dose. While we observe better than 2% agreement in most cases, we find outliers with discrepancies reaching over 20%, even when we compare the two API based methods. Conclusion: We find that good validation of a standalone dose analysis package requires testing on a large series of structures obtained from multiple patients. Disagreements between two API based methods show that vendor algorithms have hidden features which may affect dosimetric analysis.
Miniature variable optical delay using silicon micromachined scanning mirrors

Summary form only given.Optical coherence tomography (OCT) is a cross-sectional optical technique for high-resolution clinical imaging of microstructure in biological systems. OCT performs spatially localized imaging by combining coherent signal acquisition and joint time frequency analysis of wide-band near IR radiation in a white light interferometer. The technique requires a rapid (/spl sim/1-2 kHz) scanning optical delay (RSOD) in order to construct images at 4-8 Hz. Quasi-real time OCT imaging with a delay line of /spl sim/3 mm/sup 2/ has been demonstrated using scanners based on technology originally developed for femtosecond optical pulse diagnostics. We report the development of compact RSOD scanners that use, for the first time, silicon micromachined scanning mirrors. Use of a micromirror allows for high speed and low mechanical vibration. We investigate the design trades-off of a RSOD optimized for the stringent requirements of OCT, namely, large optical bandwidth and long linearly scanned delay range.
Observations of Comet 9P/Tempel 1 with the Keck 1 HIRES instrument during Deep Impact

Abstract We report high-spectral resolution observations of Comet 9P/Tempel 1 before, during and after the impact on 4 July 2005 UT of the Deep Impact spacecraft with the comet. These observations were obtained with the HIRES instrument on Keck 1. We observed brightening of both the dust and gas, but at different rates. We report the behavior of OH, NH, CN, C 3 , CH, NH 2 and C 2 gas. From our observations, we determined a CN outflow velocity of at least 0.51 km s −1 . The dust color did not change substantially. To date, we see no new species in our spectra, nor do we see any evidence of prompt emission. From our observations, the interior material released by the impact looks the same as the material released from the surface by ambient cometary activity. However, further processing of the data may uncover subtle differences in the material that is released as well as the time evolution of this material.
GABA antagonists enhance dopamine turnover in the rat retina in vivo

Abstract Previous results provided evidence for an inhibitory GABAergic influence on the dopamine neurons of the rat retina, without proving that endogenous GABA physiologically regulates the activity of these cells. We injected picrotoxinin intraocularly to dark-adapted rats and measured retinal dopamine turnover. Dopamine was analyzed radioenzymatically, and the decline in dopamine after α-methyl-p-tyrosine was used as an index of dopamine turnover. Picrotoxinin significantly stimulated dopamine turnover (P ⪡ 0.05). In similar experiments with light-exposed rats picrotoxinin slightly enhanced dopamine turnover beyond that produced by light alone. Intraocular bicuculline methiodide produced similar results in dark-adapted and also in light-exposed rats. These data suggest that endogenous GABA tonically inhibits the activity of the retinal dopamine neurons in the dark and that there may be some remaining GABA tone on these cells in the light-exposed rat. Atropine pretreatment did not affect the picrotoxinin-induced activation of retinal dopamine turnover which negates the involvement of a cholinergic interneuron.
Ca2+ capacity and uptake rate in skinned fibers of myodystrophic muscle

Parameters related to the capacity and the rate of uptake of calcium ions by the sarcoplasmic reticulum were measured in skinned extensor digitorum longus fibers of control and myodystrophic mice. Single fibers were isolated and skinned in a relaxing solution and mounted on a force transducer and apparatus for changing the bathing solution (T = 25 degrees C). To test the capacity of the sarcoplasmic reticulum, fibers were placed in a solution for maximal loading and then moved to a test solution in which the major anion in the relaxing solution, gluconate, was replaced by chloride. In the resulting contractures, the means of the forces produced by 10 control and myodystrophic fibers were not significantly different. The conclusion is that the capacities of sarcoplasmic reticulum for calcium in control and myodystrophic fibers are equivalent. To test the rate of loading of sarcoplasmic reticulum, 11 control and myodystrophic fibers were depleted of calcium with caffeine and EGTA. Then they were placed in a solution with pCa = 5.5, and the delay before a contracture began was recorded. The delay was the time required for the sarcoplasmic reticulum to load calcium and attain a threshold for calcium-induced calcium release. The mean delay for the control fibers was significantly less than the mean delay in myodystrophic for the control fibers was significantly less than the mean delay in myodystrophic fibers. The disparity of loading times probably reflected a difference in the activities of the calcium pumps or a difference in the number of pump sites; 5 microM valinomycin did not significantly alter the loading times of either type or fiber.
Cavity-enhanced direct band electroluminescence near 1550 nm from germanium microdisk resonator diode on silicon

We electrically and optically characterize a germanium resonator diode on silicon fabricated by integrating a germanium light emitting diode with a microdisk cavity. Diode current-voltage characteristics show a low ideality factor and a high on/off ratio. The optical transmission of the resonator features whispering gallery modes with quality factors of a few hundred. Direct band gap electroluminescence under continuous current injection shows a clear enhancement of emission by the cavity. At this stage, the pumping level is not high enough to cause linewidth narrowing and invert the material. A higher n-type activated doping of germanium is necessary to achieve lasing.
Goal-Setting and Task Persistence

Goal-setting as an effective technique for improving performance has been determined but its value in increasing persistence at practicing a task when unlimited practice time and alternative activi...
Impact of Sinter Process and Metal Coverage on Transistor Mismatching and Parameter Variations in Analog CMOS Technology

In this paper, we report detailed studies on the impacts of sinter process and metal coverage on CMOS transistor matching and parameter variability in an analog CMOS technology. Transistor matching and parameter variations with different metal slotting sizes processed at different sinter temperatures have also been studied. It has been found that both metal plating and sinter temperature play critical roles in transistor matching and parameter variation. Metal plating degrades VT and current matching (VT offset ~30 mV, DeltaI/I~18% at moderate inversion and DeltaI/I~3% at strong inversion) significantly at low sinter temperature. Metal slotting array of size 15umX15um with 5um separation over the transistor array has been demonstrated to be very effective in reducing the systematic mismatching. The transistor mismatching improves at higher sinter temperature. Calculated current variations agree well with experimental results.
Quantum control of spins and photons in diamond

We will discuss our recent work on developing new approaches for quantum control of single spins and single photons in diamond. Novel applications of these techniques to realization of quantum repeaters and nanoscale magnetic sensing will be described.
Recovery of Lactose from Aqueous Solutions: Precipitation with Manganese (II) Chloride and Sodium Hydroxide

Abstract Addition of sodium hydroxide to solutions containing lactose and manganese (II) chloride precipitated insoluble manganese hydroxide and lactose as a complex or adduct. Maximum lactose precipitation occurred at molar ratios sodium hydroxide to manganese chloride 2.0 and manganese chloride to lactose 4.0 with 55% yield. Apparent oxidation of manganese(II) did not affect the amount of lactose precipitated. Analysis by response surface methodology confirmed the location of the maximum but was unable to elucidate the precise nature of the relationship between variables. The amount of complex and lactose precipitated may be a function of the relative insolubility of the metal hydroxide and the solubility of the adduct.