cssi/SciSciGPT-SciSciNet huggingface dataset:
Use of radioisotope techniques in the clinical evaluation of patients with megaloblastic anemia

Because virtually all cases of vitamin B 12 deficiency seen in this country are due to malabsorption, the availability of radioactive vitamin B 12 for direct measurement of absorption of this essential nutrient has proved to be of great clinical value. These tests are useful not only in demonstrating vitamin B 12 malabsorption but also often in defining the pathophysiological mechanism responsible for this abnormality. The urinary excretion test of Schilling remains the most useful test for vitamin B 12 absorption. Minor precautions and modifications in technique make the test results more reliable and easier to interpret. The 8-hr plasma test for vitamin B 12 absorption can no longer be considered acceptable. Some patients with vitamin B 12 malabsorption have results in the normal range when studied by this method. Serum vitamin B 12 assays utilizing radioactive vitamin B 12 and the isotope dilution principle are now widely used and are useful screening tests. Low normal or borderline results observed in patients with clinical evidence suggestive of vitamin B 12 deficiency should be interpreted with caution or confirmed by radioactive vitamin B 12 absorption studies. Radioactive vitamin B 12 can also be used for rapid, reliable assay of gastric intrinsic factor, antibody to intrinsic factor and unsaturated vitamin B 12 serum binding capacity. Methods using radioactive folate compounds for similar in vivo and in vitro studies are not yet applicable for routine use in nuclear medicine laboratories.
Hatchability of chicken embryos under simulated high altitude conditions.

Abstract High altitude decreases the hatchability of chicken eggs and has some cellular and physiologic effects on young and adult chickens. Francis et al. (1967) observed that the hatchability of eggs from the same strain decreased 10 percent at a 305 m. increase in altitude, 20 percent at a 610 m. increase. These authors also reviewed the earlier literature of altitude effects on hatchability. A significant reduction in hatchability was also reported by Stephens and Ploog (1967), working at a natural altitude of 3,200 m. in Peru. However, Fraps (1945) did not record any significant reduction in the ability of the embryo to hatch until the pressure was reduced to 12.5 mm. of Hg (27,000 m.) for a period of 12 hours per day. Evidently, short term exposure to high altitude is tolerated well. Some physiologic changes in the bloodstream of chick embryos incubated at a 5,490 m. simulated altitude was…
Calculation of resonances in the H+H2 reaction using the faddeev–AGS method

The H+H2 reactive collision is described quantum mechanically in terms of valence–bond electronic states and the Faddeev–AGS equations for three-body collisions. The permutational symmetry of identical nuclei is considered within the present approach, which appears to avoid some of the difficulties associated with the use of electronically adiabatic states. A procedure based on the eigenvalue analysis of the K-matrix is used to locate resonances. Calculations probing the energy region of the lowest resonance in the H3 system revealed one with an energy in good agreement with previous work.
Histone modifications proposed to regulate sexual differentiation of brain and behavior

Expression of sexually dimorphic behaviors critical for reproduction depends on the organizational actions of steroid hormones on the developing brain. We offer the new hypothesis that transcriptional activities in brain regions executing these sexually dimorphic behaviors are modulated by estrogen-induced modifications of histone proteins. Specifically, in preoptic nerve cells responsible for facilitating male sexual behavior in rodents, gene expression is fostered by increased histone acetylation and reduced methylation (Me), and, that the opposite set of histone modifications will be found in females. Conversely, in ventromedial hypothalamic neurons that are responsible for coordinating female sexual behavior, transcriptional activities in genetic females are fostered by increased histone acetylation and reduced Me, and, further, that the opposite set of histone modifications will be found in males. Thus, these epigenetic events will guarantee that effects of sex hormone exposure during the neonatal critical period will be translated into lasting sex differences in adult reproductive behaviors.
Health insurance coverage and cost barriers to needed medical care among U.S. adult cancer survivors age <65 years

BACKGROUND The health insurance and cost barriers to care among cancer survivors age <65 years were examined. METHODS Using the 1998 and 2000 National Health Interview Survey, survivors ages 18 to 64 years (n = 1718) were compared with similarly aged adults without cancer (n = 50,276) to examine health insurance and reported delayed/missed needed medical care within the previous year because of cost. Findings were initially adjusted for age, sex, race, and ethnicity, and further adjusted for employment, income, health status, marital status, and region. RESULTS Before adjustment, survivors were less likely to be uninsured (12.4% vs. 18.0%) and more likely to have public insurance (11.2% vs. 6.2%). After initial adjustment, survivors were as likely to lack insurance, less likely to have private insurance, and more likely to have public insurance. After further adjusting, differences in being uninsured were found to be small, differences in having private insurance were eliminated, and differences in having public insurance were reduced. Survivors most likely to lack insurance were younger, female, African-American, or lower income. Survivors, particularly uninsured or publicly insured survivors, were more likely to delay/miss care because of cost. Overall, 20.9% of survivors, including 68% of uninsured survivors, reported delaying/missing needed care. CONCLUSIONS Health insurance coverage among cancer survivors age <65 years appears to be comparable to that of adults of similar age, sex, race, and ethnicity, but survivors may more likely be publicly insured. Differences are attributable in part to employment, income, and health status, factors potentially influenced by cancer. Unmet medical care needs because of cost were common among survivors, particularly uninsured survivors. Cancer 2006. © 2006 American Cancer Society.
Physical Attributes of Pulse Jet Mixer Operation

Vessels mixed using pulse jet mixers that produce a periodic, rather than steady, flow present challenges with respect to modeling slurry mixing. A PJM is a cylindrical tank within the mixed tank that has a conical bottom with an orifice through which process fluid cyclically enters and is expelled forcefully by pressurizing the air space above the liquid in the PJM. Between pulses, some of the solids settle from the slurry, which nominally is a failure in mixing, but during the pulses (if operated to attain bottom clearing conditions), all of the solids are resuspended and made available for processing or transfer. Overall, mixing is successful if the solids are processed and removed from the vessel as needed when averaged over repeated PJM cycles. This paper describes the physics of pulse jet mixing process based on physical observation during experiments and analysis of experimental concentration profile data obtained during the mixing cycle.Copyright © 2013 by ASME
Quality assessment of clinical practice guidelines

Fundamentally, evidence-based medicine (EBM) represents an effort to improve the quality of information about benefits of healthcare services and their related effectiveness [1]. One of the most im...
Large Putative PEST-like Sequence Motif at the Carboxyl Tail of Human Calcium Receptor Directs Lysosomal Degradation and Regulates Cell Surface Receptor Level

A deletion between amino acid residues Ser895 and Val1075 in the carboxyl terminus of the human calcium receptor (hCaR), which causes autosomal dominant hypocalcemia, showed enhanced signaling activity and increased cell surface expression in HEK293 cells (Lienhardt, A., Garabedian, M. G., Bai, M., Sinding, C., Zhang, Z., Lagarde, J. P., Boulesteix, J., Rigaud, M., Brown, E. M., and Kottler, M. L. (2000) J. Clin. Endocrinol. Metab. 85, 1695–1702). To identify the underlying mechanism(s) for these increases, we investigated the effects of carboxyl tail truncation and deletion in hCaR mutants using a combination of biochemical and cell imaging approaches to define motifs that participate in regulating cell surface numbers of this G protein-coupled receptor. Our data indicate a rapid constitutive receptor internalization of the cell surface hCaR, accumulating in early (Rab7 positive) and late endosomal (LAMP1 positive) sorting compartments, before targeting to lysosomes for degradation. Recycling of hCaR back to the cell surface was also evident. Truncation and deletion mapping defined a 51-amino acid sequence between residues 920 and 970 that is required for targeting to lysosomes and degradation but not for internalization or recycling of the receptor. No singular sequence motif was identified, instead the required sequence elements seem to distribute throughout this entire interval. This interval includes a high proportion of acidic and hydroxylated amino acid residues, suggesting a similarity to PEST-like degradation motif (PESTfind score of +10) and several glutamine repeats. The results define a novel large PEST-like sequence that participates in the sorting of internalized hCaR routed to the lysosomal/degradation pathway that regulates cell surface receptor numbers.
Effect of primary amines on interferon action

Abstract Dansyl cadaverine, added to human fibroblasts before and during a 1-hr incubation with human interferon (IFN), inhibited the induction of the antiviral state. The inhibitory effect of dansyl cadaverine was rapidly reversible and could not be attributed to either direct inactivation of IFN or to its reduced binding to cells. Of two other amines tested, ammonium chloride caused a small decrease in IFN action, while methylamine was without effect. The transglutaminase inhibitor bacitracin did not significantly reduce IFN action. The effects of methylamine and dansyl cadaverine on lysosomal pH were measured using fluorescein-dextran as a pH indicator. While the increase in lysosomal pH produced by methylamine was large and rapid in onset (1.7 pH units by 10 min), that produced by dansyl cadaverine was smaller and slower in onset (0.5 pH unit by 60 min). Thus, the inhibitory effects of dansyl cadaverine could not be attributed to an alteration in lysosomal pH. Our data show that dansyl cadaverine inhibits IFN action at a step distal to cell surface binding and suggest a role for IFN internalization or receptor recycling.
Iodine nutrition in the Chernobyl area before and after the nuclear accident

Abstract Reports from 1950 to 1960 suggest that goiter was frequent in the Chernobyl area and vigorous efforts were undertaken to distribute iodine supplements. There resulted enthusiastic reports stating that endemic goiter was no longer a problem. During the 1970s, the distribution of iodized salt became undependable and by 1980, goiter incidence was reported to have increased. Four to ten years after the Chernobyl nuclear accident, severe iodine deficiency was unusual but goiter by ultrasound measurement was found in more than 35% of the children. Unusual thyroid cancer appeared and its prevalence continues to increase.
THE ECONOMICS OF SOCIAL SECURITY POLICY

Books reviewed in this articles: Henry J. Aaron, Economic Effects of Social Security Peter J. Ferrara, Social Security; Adverting the Crisis Carolyn L. Weaver, The Crisis in Social Security; Economic and Political Origins
Credibly assessing reading and writing abilities for both elementary student and program assessment

Abstract The authors explored the credibility of using informal reading inventories and writing samples for 138 students (K–4) to evaluate the effectiveness of a summer literacy program. Running Records (a measure of a child's reading level) and teacher experience during daily reading instruction were used to estimate the reliability of the more formal Developmental Reading Assessment scores. Training of scorers was used to increase the reliability of writing scores; a second scoring was used to estimate the reliability of the scores. The results suggested that with minimal modifications to administration and scoring procedures, scores from both reading inventories and writing samples can be a dependable source of data for teachers, administrators, and policy makers. This result is significant because it suggests that formative literacy assessments can be reliably used instead of standardized multiple-choice tests to make more credible summative decisions without taking time away from instruction, and can truly match curriculum, instruction, and assessment.
Photorefractive studies of normal and handicapped infants and children.

Abstract We have photorefracted 360 infants and children of ages 2 months to 5 years from and around Tompkins County, New York, who were free of any obvious ocular pathology. From these studies we have established 95% confidence limits for largest cylinder, largest sphere, and spherical and cylindrical differences between eyes as a function of age. Using this normal data we have begun to photorefract handicapped children from special childrens' centers in and around Tompkins County. Our preliminary data indicate a higher prevalance (> 4 ×) of refractive anomalies in handicapped children, as compared to normal children, even when allowance for ocular pathology is made.
Hormone Replacement Therapy and Obstructive Airway Diseases

Controversy exists as to the role of female reproductive hormones in asthma and COPD and, specifically, the effect of hormone replacement therapy (HRT) on these disorders. The differential incidence of asthma over the menstrual life cycle suggests an effect of female reproductive hormones on asthma; less data are available for COPD. Estrogen and progesterone have protean effects at the cellular level, consistent with potentially harmful and beneficial effects in lung disease. Large epidemiologic studies show an increased risk of development of asthma with the use of HRT but no consistent effects on COPD. Clinical and epidemiologic studies of exacerbations are limited, but suggest either a harmful effect or no effect of HRT on exacerbations of asthma and COPD. HRT appears to increase the risk of development of asthma but is not associated with the loss of lung function characteristic of COPD. Because the development of asthma is rare in postmenopausal women, the absolute increase in risk among women without asthma is modest. Physicians may wish to avoid HRT therapy in patients with difficult to control asthma and COPD. Clinical decisions to start or continue HRT among women without asthma or COPD should be based on the effects of HRT on more common diseases such as cardiovascular disease, breast cancer and osteoporosis, non-vertebral fractures and colon cancer.
The reliability of electrolyte measurements in plasma

The difference between serum and plasma electrolyte measurements and the effects of delay, cooling and addition of sodium heparin on plasma electrolyte measurements were observed. Delay of more than 30 min from sampling to analysis renders plasma potassium measurements unreliable. All other factors assessed produced no changes in plasma electrolyte measurements. Arterial blood gas laboratories can, therefore, reliably provide rapid or serial measurements of plasma sodium and potassium provided the analysis is performed within 30 min of obtaining an appropriate arterial blood sample.
Histology-Specific MicroRNA Alterations in Melanoma

We examined the microRNA signature that distinguishes the most common melanoma histological subtypes, superficial spreading melanoma (SSM) and nodular melanoma (NM). We also investigated the mechanisms underlying the differential expression of histology-specific microRNAs. MicroRNA array performed on a training cohort of 82 primary melanoma tumors (26 SSM, 56 NM), and nine congenital nevi (CN) revealed 134 microRNAs differentially expressed between SSM and NM (P<0.05). Out of 134 microRNAs, 126 remained significant after controlling for thickness and 31 were expressed at a lower level in SSM compared with both NM and CN. For seven microRNAs (let-7g, miR-15a, miR-16, miR-138, miR-181a, miR-191, and miR-933), the downregulation was associated with selective genomic loss in SSM cell lines and primary tumors, but not in NM cell lines and primary tumors. The lower expression level of six out of seven microRNAs in SSM compared with NM was confirmed by real-time PCR on a subset of cases in the training cohort and validated in an independent cohort of 97 melanoma cases (38 SSM, 59 NM). Our data support a molecular classification in which SSM and NM are two molecularly distinct phenotypes. Therapeutic strategies that take into account subtype-specific alterations might improve the outcome of melanoma patients.
Algorithms for reducing the bandwidth and profile of a sparse matrix

Abstract This paper presents a new technique for reducing the bandwidth and profile of a symmetric and sparse matrix. A graph representation of the matrix is decomposed into a group of isolated sets by general level structures. These are exploited to construct a maximal-depth partitioned structure, each level of which has as equal width as possible. Then, the vertices of the partitioned structure are numbered consecutively. The presented method is more complicated than the well-known GPS algorithm, but it can provide a more reliable procedure to reduce the bandwidth. The bandwidth reduced by the presented method is smaller than or equal to the one reduced by the GPS. Examples are included to illustrate in detail the presented algorithms.
Traitement chirurgical des tumeurs envahissant l'aorte et les structures artérielles majeures

Rationnelle Cette etude etudie la gestion chirurgicale des tumeurs naissant de ou impliquant l'aorte et les structures arterielles majeures. Methodes Une etude monocentrique retrospective a ete conduite chez les patients subissant une resection arterielle pour des tumeurs impliquant l'aorte ou les structures arterielles majeures entre janvier 1992 et mai 2009 dans un centre de soin tertiaire. Les patients avec des tumeurs touchant des arteres sans rendre necessaire la resection et celles impliquant seulement des structures veineuses ont ete exclus. Les patients ont ete analyses en groupes par localisation anatomique : aorte, carotide, iliaque externe/commune, iliaques interne, femoral superficielle et divers. Resultats Soixante patients ont ete identifies et inclus dans l'etude. Les arteres iliaques ont ete le plus souvent resequees, et la pathologie sarcomateuse etait la plus commune (37 patients, 62%). Douze patients ont eu une resection aortique, avec huit (67%) ayant eu une reconstruction prothetique, un un patch prothetique (8%), et deux (17%) une suture directe. Aucun des 17 patients ayant eu une resection iliaque interne n'a eu de reconstruction, tandis que la majorite de patients de tous autres groupes a eu une reconstruction. La mortalite a trente jours (MTJ) etait de 0% dans tous les groupes, excepte le groupe aortique (2/12, 17% MTJ), et le groupe artere iliaque interne (1/17, 6% MTJ). La perte de sang prevue variait considerablement et n'etait pas sensiblement differente entre les groupes de vaisseaux ( p = 0,280). De facon generale, 44 des 60 patients (de 73%) avaient des marges negatives. Quatorze patients (23%) ont necessite une reintervention, la plupart pour infection ou dehiscence de la plaie operatoire. Le suivi moyen etait de 20,25 mois (extremes : 0,5-122,0 mois, ecart-type : 23 mois). Quarante patients ont ete suivis pendant plus d'un an. Ainsi, avec un suivi median global de 12,25 mois, la survie globale etait de 60% avec une survie saine de 40%. Conclusions La resection des tumeurs impliquant l'aorte et les structures arterielles principales fournit une option raisonnable pour le traitement, mais la morbidite peri-operatoire est significative. Chez des patients selectionnes, cette intervention agressive devrait etre consideree.
A model for the flow of solid particles in gases

Abstract The flow of solid particles in air streams involves a great deal of variables and complex phenomena, difficult to analyse. In practice the flow quantities in gas-solid flows are predicted by the use of empirical correlations of data or semi-empirical methods. The predictive power of these methods varies substantially between different systems. This paper presents an analytical approach to the subject of gas-solid flows, based on a turbulent model. The mixture is modeled as a variable density fluid flowing in a duct; the equations for the Reynolds stress incorporate the variation of velocity and density together, and yield the velocity profile of the flow and average quantities of interest such as the mass flux, the friction factor, the average density and average areas occupied by each phase. The predicted values for the friction factor are compared with known correlations emanating from experimental data. It is found that there is a very good agreement between the predicted values and the experimental correlations.
Carnitine content of skeletal muscle from diabetic and insulin-treated diabetic rats.

Abstract Diabetes was induced in two groups of male rats by an intraperitoneal injection of streptozotocin. One group of diabetic animals was maintained on insulin for a 1-week period while the other group was untreated. The free fatty acid content of both the soleus and diaphragm from diabetic animals was elevated. Free carnitine, long-chain carnitine, and total carnitine levels were increased in the soleus of the streptozotocin-injected animals and the concentrations of free carnitine and the long-chain derivative were elevated in the diaphragm from these rats. The amounts of carnitine and carnitine esters in tissue from the insulin-treated animals were comparable to those measured in control rat muscle.
Adjuvant Radiation for Rectal Cancer: Do We Measure Up to the Standard of Care? An Epidemiologic Analysis of Trends Over 25 Years in the United States

In the United States, adjuvant radiation therapy is currently recommended for most patients with rectal cancer. We conducted this population-based study to evaluate the rate of radiation therapy and the factors affecting its delivery. We used the Surveillance Epidemiology and End Results database to assess treatment of patients with nonmetastatic rectal cancer diagnosed over a 25-year period (1976 through 2000). We evaluated the rate of radiation therapy use and its timing (preoperative vs. postoperative) and the influence of factors such as tumor stage and grade; patient gender and race; and geographic location. In this 25-year period, 45,627 patients met our selection criteria. The rate of radiation therapy use increased dramatically over time: from 17 percent of advanced-stage patients in 1976 to 65 percent in 2000 (P < 0.0001). Until 1996, the increase was due almost entirely to postoperative radiation therapy. Since 1996, the rate of preoperative radiation therapy use has increased (P < 0.0001) and the rate of postoperative radiation therapy use has begun to decline. We found, after controlling for the year of diagnosis, that female patients, African Americans, older patients, and patients with low-grade lesions were less likely to undergo radiation therapy (P < 0.0001). Geographic location was also an important predictor of radiation therapy use. The use of radiation therapy for patients with rectal cancer has dramatically increased over the 25-year period studied, with a recent shift to the use of preoperative radiation therapy; however, in 2000, over 30 percent of patients with advanced-stage nonmetastatic rectal cancer did not undergo radiation therapy. Given the variation in radiation therapy use that we found to be due to demographic factors, access to adjuvant radiation therapy can be improved.
Improved methods for reducing calcium and magnesium concentrations in tissue culture medium: application to studies of lymphoblast proliferation in vitro.

We have compared several methods for reducing calcium and magnesium concentrations in tissue culture medium, with the objective of producing selective deficiency effects on the growth of mouse (L5178Y) and human (P1R) lymphoblasts. In experiments in which calcium- and magnesium-“free” McCoy’s medium was supplemented with 15% horse or fetal calf serum, enough calcium and magnesium was provided by serum to support normal lymphoblast growth rate. Either dialysis or chelating-resin treatment of horse or fetal calf serum reduced calcium and magnesium contents approximately 100-fold. Use of dialyzed sera resulted in reduced growth rate, although in most cases the reduction in growth could be attributed to other effects of dialysis on serum, inasmuch as growth in those experiments was not restored to normal by the addition of calcium and magnesium to the medium.
Elevated blood Hg at recommended seafood consumption rates in adult seafood consumers.

Abstract Mercury (Hg) exposure from seafood continues to be a public health concern due to health effects from elevated exposure, increasing worldwide seafood consumption, and continued Hg inputs into the environment. Elevated Hg exposure can occur in populations with specialized diets of sport-caught freshwater fish. However, we need a better understanding of Hg exposure from seafood, the most common exposure source, and from specific seafood types. We examined Hg exposure in avid seafood consumers, and the seafood items and consumption frequency that confer the largest Hg exposure. Adult, avid seafood consumers, in Long Island, NY, USA, with blood total Hg concentrations predicted to exceed the USEPA reference concentration that is considered safe (5.8 μg L−1), were eligible for the study; 75% of self-reported avid seafood consumers were eligible to participate. We measured blood total Hg concentrations and seafood consumption in 285 participants. We examined relationships between Hg and seafood consumption using multiple linear regression. Seafood consumption rate for our population (14.4 kg yr−1) was >2 times that estimated for the U.S. (6.8 kg yr−1), and lower than the worldwide estimate (18.4 kg yr−1). Mean blood Hg concentration was 4.4 times the national average, and 42% of participants had Hg concentrations exceeding 5.8 μg L−1. Elevated Hg exposures occurred at all seafood consumption frequencies, including the recommended frequency of 2 meals per week. Blood Hg concentrations were positively associated with weekly tuna steak or sushi intake (β = 6.30 change in blood Hg, μg L−1) and monthly (β = 2.54) or weekly (β = 9.47) swordfish, shark or marlin intake. Our findings show that seafood consumers in this population have elevated Hg exposures even at relatively low seafood consumption rates that are at or below current dietary recommendations. Further study should examine health risks and benefits of avid seafood consumption, and consider modifying guidelines to include recommendations for specific seafood types.
Stress and maternal adaptation in first-time mothers more than 35 years old

This prospective longitudinal study assessed relationships among variables of the early transition to parenthood and maternal stress and adaptation 1 year after delivery in primiparas older than 35 years. Life change scores at 1 month were associated with greater stress at 1 year. Positive self-evaluations of parenting early in the transition to parenthood were associated with greater confidence and support in mothering at 1 year. Compared with normative data, stress scores of study participants were found to be high. The importance of addressing early perceptions of parenting with older first-time mothers was supported.
Intravenous compared with oral busulfan as preparation for allogeneic hematopoietic progenitor cell transplantation for AML and MDS

BU and CY is a common conditioning regimen for allogeneic hematopoietic progenitor cell transplantation (HPCT). I.v. BU is increasingly used in place of the oral formulation for conditioning. We compared the outcomes of 135 consecutively treated AML and myelodysplastic syndrome patients who underwent allogeneic HPCT at our institution with BUCY2 using oral (n=93) or i.v. (n=42) BU, without dose adjustment. The i.v. BU patients had a lower incidence of any severity of oral mucositis (3 versus 55%, P=0.002) and severe mucositis (3 versus 24%, P=0.005). Other post transplant outcomes were comparable between the groups. In all 26 i.v. BU and 33 oral BU patients are alive; however, the median follow-up was significantly longer for the oral BU group. One- and two-year non-relapse mortality for the i.v. BU patients was 21% for both, and for the oral BU group was 23% and 29%, respectively. One- and two-year relapse mortality for the i.v. BU patients was 21% for both, and for the oral BU group was 24% and 29%, respectively. Substituting i.v. for oral BU reduces variability in drug exposure and potentially improves toxicity as suggested by our finding of significantly less oral mucositis and decreased severity with i.v. BU.
Simultaneous gas evolution detection—dynamic reflectance spectroscopy: a new simultaneous thermal technique

Abstract A DRS—GED system in which the diffuse reflectance and the gas-evolution detection curves of the same sample are recorded simultaneously is described. The new system was used to study the dehydration of CuSO 4 ·5H 2 O and the deaquation and anation of [Co(NH 3 ) 5 H 2 O]Cl 3 .
An ion gating mechanism of gastric H,K-ATPase based on molecular dynamics simulations.

Gastric H,K-ATPase is an electroneutral transmembrane pump that moves protons from the cytoplasm of the parietal cell into the gastric lumen in exchange for potassium ions. The mechanism of transport against the established electrochemical gradients includes intermediate conformations in which the transferred ions are trapped (occluded) within the membrane domain of the pump. The pump cycle involves switching between the E1 and E2P states. Molecular dynamics simulations on homology models of the E2P and E1 states were performed to investigate the mechanism of K+ movement in this enzyme. We performed separate E2P simulations with one K+ in the luminal channel, one K+ ion in the occlusion site, two K+ ions in the occlusion site, and targeted molecular dynamics from E2P to E1 with two K+ ions in the occlusion site. The models were inserted into a lipid bilayer system and were stable over the time course of the simulations, and K+ ions in the channel moved to a consistent location near the center of the membrane domain, thus defining the occlusion site. The backbone carbonyl oxygen from residues 337 through 342 on the nonhelical turn of M4, as well as side-chain oxygen from E343, E795, and E820, participated in the ion occlusion. A single water molecule was stably bound between the two K+ ions in the occlusion site, providing an additional ligand and partial shielding the positive charges from one another. Targeted molecular dynamics was used to transform the protein from the E2P to the E1 state (two K+ ions to the cytoplasm). This simulation identified the separation of the water column in the entry channel as the likely gating mechanism on the luminal side. A hydrated exit channel also formed on the cytoplasmic side of the occlusion site during this simulation. Hence, water molecules became available to hydrate the ions. The movement of the M1M2 transmembrane segments, and the displacement of residues Q159, E160, Q110, and T152 during the conformational change, as well as the motions of E343 and L346, acted as the cytoplasmic-side gate.
Globally optimal lung tumor co-segmentation of 4D CT and PET images

Four-dimensional CT scans provides valuable motion information of patient throughout different respiratory phases. PET, on the other hand, provides functional information about tumor, which differentiate tumor from normal tissue effectively. However, manually contouring structures of interest on 4D CT is prohibitively tedious due to the large amount of data. In this paper, we propose an automatic method to segment lung tumor simultaneously for 4D CT scans in all phases and PET scan. The problem is modeled as an optimization problem based on Markov Random Fields (MRF) which involves region, boundary terms and a regularization term between PET and CT scans. The problem is solved optimally by computing a single max flow in a properly constructed graph. As far as the authors know, this is the first work in simultaneously segmenting tumor in 4D CT while incorporating PET information. Experiments on 3 lung cancer patients are conducted. The average Dice coefficient is improved from 0.680 to 0.791 compared to segmenting tumor volume in 4D CT phase by phase without incorporating PET information. The proposed method is efficient in terms of running time since the method only requires computing a max flow for which efficient algorithm exists. The memory consumption is linearly scalable with respect to number of 4D CT phases, which enables our method to handle multiple 4D CT phases with reasonable memory consumption.
Syntheses and properties of H-1,2,3-triazoles

About twenty new H-1,2,3-triazoles (T) were readily synthesized by nucleophilic attack of sodium azide on activated acetylenes in dimethylformamide. Typical activating groups were COR, COOR, O2NC6H4 PO(OC2H5, COT, and (C6H5)3P+. Propynyl 4-triazolyl ketone or phenylethynyl 4-triazolyl ketone may be converted to acylic adducts (triazolylketoenamines), biheteroaromatic systems (isoxazolytriazoles, pyrazolytriazoles), as well as to ditriazolyl ketones. Certain T properties were examined in detail. The apparent pK′s for our group of ca 30 triazoles were in the range 4·95−9·45 in ethanol-water (v/v 1/1) at 25°. The Hammett correlation for five 4-aryl-T was log Ka = 0·89σ− −9·21 and for seven 4-aryl-5-carbethoxy-T was log Ka = 1·45σ−6·95. The UV spectra of T are similar to those of other heteroaromatic and phenyl compounds: interesting analogies between triazolyl and phenyl, e.g., ”ortho“ crowding effects, appear to be indicated in the spectra of compounds related to biphenyl, stilhene and benzophenone. With regard to structure assignment on the basis of spectra, characteristic features of UV and IR spectra of the H-1,2,3-triazoles are discussed.
Relationships among litterfall, fine-root growth, and soil respiration for five tropical tree species

Although significant advances have been made in understanding terrestrial carbon cycling, there is still a large uncertainty about the variability of carbon (C) fluxes at local scales. Using a carb...
Interpersonal Dynamics Within Adolescent Friendships: Dyadic Mutuality, Deviant Talk, and Patterns of Antisocial Behavior

Interpersonal dynamics within friendships were observed in a sample of 120 (60 male, 60 female) ethnically diverse 16- and 17-year-old adolescents characterized as persistently antisocial, adolescent-onset, and normative. Dyadic mutuality and deviant talk were coded from videotaped friendship interactions. Persistently antisocial adolescents demonstrated lower levels of dyadic mutuality compared with adolescent-onset and normative adolescents. Persistently antisocial and adolescent-onset adolescents spent more time in deviant talk than did normative adolescents. Across groups, girls were rated as more mutual and coded less in deviant talk than boys. Furthermore, friendship dyads who engaged in high levels of deviant talk and were mutual in their interactions reported the highest rates of antisocial behavior.
Pseudo beam's-eye-view as applied to beam orientation selection in intensity-modulated radiation therapy

Abstract Purpose: To introduce the concept of pseudo beam’s-eye–view (pBEV), to establish a framework for computer-assisted beam orientation selection in intensity-modulated radiation therapy (IMRT), and to evaluate the utility of the proposed technique. Methods and Materials: To facilitate the selection of beam orientations for IMRT treatment planning, a scoring of beam direction was introduced. The score function was based on the maximum target dose deliverable by the beam without exceeding the tolerance doses of the critical structures. For the score function calculation, the beam portal at given gantry and couch angles was divided into a grid of beamlets. Each beamlet crossing the target was assigned the maximum intensity that could be used without exceeding the dose tolerances of the organs at risk (OARs) and normal tissue. Thereafter, a score was assigned to the beam according to the target dose delivered. The beams for the treatment were selected among those with the highest scores. In a sense, this technique is similar to the beam’s-eye–view approach used in conventional radiation therapy, except that the evaluation by a human is replaced by a score function, and beam modulation is taken into account. Results: The pBEV technique was tested on two clinical cases: a paraspinal treatment and a nasopharyngeal cancer with both coplanar and noncoplanar beam configurations. The plans generated under the guidance of pBEV for the paraspinal treatment offered superior target dose uniformity and reduced OAR doses. For the nasopharyngeal cancer case, it was also found that the pBEV-selected coplanar and noncoplanar beams significantly improved the target coverage without compromising the sparing of the OARs. Conclusions: The pBEV technique developed in this work provides a comprehensive tool for beam orientation selection in IMRT. It is especially valuable for complicated cases, where the target is surrounded by several sensitive structures and where it is difficult to select a set of good beam orientations. The pBEV technique has considerable potential for simplifying the IMRT treatment planning process and for maximizing the technical capacity of IMRT.
Circulating Chlamydia pneumoniae DNA and advanced coronary artery disease

Abstract Background Chlamydia pneumoniae ( C. pneumoniae ) has been linked to atherosclerosis. Detection of this pathogen in peripheral blood cells may be valuable in the diagnosis of disease state. This study aimed to evaluate the prevalence of circulating C. pneumoniae DNA and its relationship with severity and extent of coronary artery disease (CAD). Methods Blood samples from 269 patients undergoing coronary angiography were collected. The presence of circulating C. pneumoniae DNA was determined by real-time PCR assay. Data regarding coronary risk factors and severity and extent of CAD were collected. Severity and extent of CAD was defined by the number of major epicardial coronary arteries with >50% stenosis and by the Duke jeopardy score. Results Sixteen of 269 specimens (5.9%) from the study cohort were positive for C. pneumoniae DNA. Thirteen specimens among 149 samples from patients with multi-vessel disease (8.7%) were positive for C. pneumoniae DNA compared with 3 of 120 (2.5%) among patients without multi-vessel CAD. The prevalence of circulating C. pneumoniae DNA was significantly associated with multi-vessel disease. The odds ratio was 5.1 ( P =0.02) after adjustment for conventional risk factors. Conclusions Presence of circulating C. pneumoniae DNA is associated with advanced CAD, suggesting C. pneumoniae infection as a contributing factor to progression of coronary atherosclerosis.
Real-time large-deformation substructuring

This paper shows a method to extend 3D nonlinear elasticity model reduction to open-loop multi-level reduced deformable structures. Given a volumetric mesh, we decompose the mesh into several subdomains, build a reduced deformable model for each domain, and connect the domains using inertia coupling. This makes model reduction deformable simulations much more versatile: localized deformations can be supported without prohibitive computational costs, parts can be re-used and precomputation times shortened. Our method does not use constraints, and can handle large domain rigid body motion in addition to large deformations, due to our derivation of the gradient and Hessian of the rotation matrix in polar decomposition. We show real-time examples with multi-level domain hierarchies and hundreds of reduced degrees of freedom.
α-Helical Structural Elements within the Voltage-Sensing Domains of a K+ Channel

Voltage-gated K+ channels are tetramers with each subunit containing six (S1–S6) putative membrane spanning segments. The fifth through sixth transmembrane segments (S5–S6) from each of four subunits assemble to form a central pore domain. A growing body of evidence suggests that the first four segments (S1–S4) comprise a domain-like voltage-sensing structure. While the topology of this region is reasonably well defined, the secondary and tertiary structures of these transmembrane segments are not. To explore the secondary structure of the voltage-sensing domains, we used alanine-scanning mutagenesis through the region encompassing the first four transmembrane segments in the drk1 voltage-gated K+ channel. We examined the mutation-induced perturbation in gating free energy for periodicity characteristic of α-helices. Our results are consistent with at least portions of S1, S2, S3, and S4 adopting α-helical secondary structure. In addition, both the S1–S2 and S3–S4 linkers exhibited substantial helical character. The distribution of gating perturbations for S1 and S2 suggest that these two helices interact primarily with two environments. In contrast, the distribution of perturbations for S3 and S4 were more complex, suggesting that the latter two helices make more extensive protein contacts, possibly interfacing directly with the shell of the pore domain.
Global left ventricular remodeling with the Acorn Cardiac Support Device: hemodynamic and angiographic findings in dogs with heart failure

Preventing progressive left ventricular (LV) remodeling is paramount in the treatment of heart failure. In recent years, several surgical approaches have been implemented with the objective of improving LV function through amelioration of progressive LV remodeling. These included surgical reduction of LV size, the so-called Batista procedure, dynamic cardiomyoplasty and mitral valve repair to limit or eliminate functional mitral regurgitation. While the Batista procedure and dynamic cardiomyoplasty have for all practical purposes been abandoned, the lessons learned from these procedures gave rise to a new generation of devices aimed at preventing progressive LV dilation and restoring LV shape by passive mechanical containment of the failing LV. One such device is the Acorn Cardiac Support Device (CSD) or the CorCap. Studies in dogs with intracoronary microembolization-induced moderate and advanced heart failure have shown that long-term monotherapy with the CSD not only prevents progressive LV dilation but, in effect, partially reverses this phenotype. These studies have also shown that the CSD restores, albeit in part, progressive LV chamber sphericity and attenuates functional mitral regurgitation. These benefits were accompanied by improvement in global LV function along with improvements of remodeling at the cellular level. The findings were largely responsible for initiating safety and feasibility clinical trials with the CSD and ultimately, the initiation of the Acorn efficacy trial that was completed in 2004. This review will focus on studies conducted in dogs with heart failure and, specifically on hemodynamic, angiographic and echocardiographic results from these studies that provided support for the CSD as a successful technology targeting "reverse LV remodeling" for the treatment of heart failure.
Acute stroke trials: Reasons for patient withdrawal

Knowing why patients fail to complete a clinical trial should help in planning such trials and in estimating their costs. We analyzed reasons why subjects failed to complete two similar acute stroke trials of calcium-channel antagonists. The trials were double-blind, placebo-controlled, and lasted 2 and 3 weeks, respectively. We enrolled 43 patients in the first trial and 37% were withdrawn; 30 patients were enrolled in the second trial and 47% were withdrawn. Reasons for withdrawal were similar in the two trials. When data from the two trials were combined, reasons for withdrawal were errors in administering medication (11%), use of a proscribed drug (7%), early death (7%), a disqualifying illness discovered after enrollment (8%), withdrawal of consent (4%), and enrollment beyond the time limit (<1%). Presence of stroke risk factors, age, sex, and even stroke severity did not significantly increase withdrawal frequency. Since most patients were lost early in the trial, its length did not contribute substantially to premature withdrawal.
The Psychology of Future-Oriented Thinking: From Achievement to Proactive Coping, Adaptation, and Aging

Contributions to this special issue examine multiple aspects of how people think about and prepare for desired and undesired future outcomes, including the processes that link thoughts about one's present situation to possible future outcomes and those that promote the balanced pursuit of long-term vs. short-term goals. They also identify new distinctions among widely studied future-oriented thoughts and feelings (e.g., optimism versus hope). Several contributions examine proactive efforts to prevent adverse effects or reduce their impact in such challenging contexts as being discriminated against, aging and becoming disabled, preparing for potential disasters, or coping with terrorist attacks. Two final contributions examine the implications of temporal factors for advance decision-making in medicine and business. This introductory article highlights the central issues addressed by the contributions and discusses ways in which studying future-oriented thoughts, feelings, and behavior in the contexts of stress and lifespan development may extend our understanding of future-oriented phenomena beyond the achievement domain.
Suppression of chaotic dynamics and localization of two-dimensional electrons by a weak magnetic field

We study a two-dimensional motion of a charged particle in a weak random potential and a perpendicular magnetic field. The correlation length of the potential is assumed to be much larger than the de Broglie wavelength. Under such conditions, the motion on not too large length scales is described by classical equations of motion. We show that the phase-space averaged diffusion coefficient is given by the Drude-Lorentz formula only at magnetic fields $B$ smaller than certain value ${B}_{c}.$ At larger fields, the chaotic motion is suppressed and the diffusion coefficient becomes exponentially small. In addition, we calculate the quantum-mechanical localization length as a function of $B$ at the minima of ${\ensuremath{\sigma}}_{\mathrm{xx}}.$ At $Bl{B}_{c}$ it is exponentially large but decreases with increasing $B$. At $Bg{B}_{c},$ this decrease becomes very rapid and the localization length ceases to be exponentially large at a field ${B}_{*},$ which is only slightly larger than ${B}_{c}.$ Implications for the crossover from the Shubnikov--de Haas oscillations to the quantum Hall effect are discussed.