cssi/SciSciGPT-SciSciNet huggingface dataset:
Single-molecule fluorescence methods for the analysis of RNA folding and ribonucleoprotein assembly.

Publisher Summary In addition to its role as an information carrier in gene expression, RNA is now recognized to carry out a broad range of biological functions, and novel activities continue to emerge on a regular basis. RNA molecules can act as catalysts in reversible phosphodiester-cleavage reactions, mediate splicing of premessenger RNA, silence specific genes, and act as molecular switches to sense metabolites and regulate the translation of genes into proteins, to name just a few important examples. Perhaps the most impressive (and unexpected) function of RNA is the ability to catalyze peptide bond formation on the ribosome. Similar to proteins, RNAs are synthesized as linear polymers that must fold into compact three-dimensional structures to attain their biological activity. However, there are fundamental differences between these two types of macromolecular folding processes. While small RNAs, including many ribozymes, can fold autonomously, most large RNA molecules require one or more protein chaperones for efficient and correct folding. Proteins can prevent misfolding of large RNAs and/or accelerate the escape from kinetic traps. Additionally, proteins may guide proper folding by manipulating the structure of the RNA chain. Chemical cross-linking can capture RNA folding intermediates, but the technique provides only limited structural information. Fluorescence spectroscopy can provide both structural and dynamic information and is emerging as a powerful tool for studies of RNA folding and RNP assembly processes. Fluorescence measurements can be performed in solution under physiologically relevant conditions, without restrictions arising from the size of the molecules under study. Moreover, the method provides dynamic information spanning a wide range of time scales, from picoseconds to minutes.
A Critique of the ‘AD 1300 Event’, with Particular Reference to Palau

In several recent publications, scholars have postulated that a widespread climatic change, termed the 'AD 1300 event,' caused massive social disruption in the Pacific Basin, including resource depletion, increased conflict and cannibalism, the establishment of fortified settlements, changing settlement (coastal to inland) patterns, and an end to ocean voyaging. Although the role of the environment in influencing social behaviour is certainly an avenue of research that should be explored, this environmentally deterministic model is not supported by empirical findings. Palau, used as one of the examples to support the model, is considered here to show that there is in fact a great deal of archaeological and palaeoenvironmental evidence suggesting the inverse of the proposed model.
Mapping the termini and intron of the spliced immediate-early transcript of equine herpesvirus 1.

Abstract Equine herpesvirus 1 (EHV-1) has been shown to synthesize a 6.0-kilobase (kb) species of immediate-early (IE) mRNA in productively infected cells. This IE gene region maps within the outer portion (map units 0.79 to 0.83 and 0.96 to 1.00) of the two inverted repeat segments of the short genomic region, and elucidation of its DNA sequence has revealed multiple potential open reading frames (ORFs), including a major ORF of 4,461 nucleotides (F. J. Grundy, R. P. Baumann, and D. J. O'Callaghan, Virology 172:223-236, 1989). Analyses of IE polypeptides synthesized in EHV-1-infected cells (in vivo) and in vitro translation of hybrid-selected IE mRNA indicated that multiple species of IE proteins are encoded by this IE mRNA species. To address the nature of the 6.0-kb IE RNA species, Northern (RNA) blot hybridization, S1 nuclease mapping, and primer extension analyses have been employed. These data revealed that no major introns were detected within the body of the IE transcript. However, the IE mRNA was shown to be spliced at the 5' terminus, such that a 372-base intron containing two small ORFs (19 and 51 amino acids) was removed from the leader region of the transcript. This splicing event reduced the leader region from 625 to 253 bases. S1 and primer extension analyses of the 5' terminus of this transcript revealed that the transcription initiation site is located 24 to 26 bases downstream of the consensus TATAAA motif. The 3' transcription termination site was mapped by S1 nuclease analysis to approximately 10 to 20 bases downstream of the polyadenylation signal, AATAAA. The distance from the stop codon of the major ORF to the polyadenylation site is approximately 300 bases. Results from S1 nuclease experiments indicated that splicing does not occur at the 3' terminus. These studies indicated that the EHV-1 6.0-kb IE mRNA is spliced at the 5' terminus and that alternative splicing of this transcript may function in regulating translation of the IE mRNA species.
Left-sided pancreatectomy: a multicenter comparison of laparoscopic and open approaches.

OBJECTIVES To compare perioperative outcomes of laparoscopic left-sided pancreatectomy (LLP) with traditional open left-sided pancreatectomy (OLP) in a multicenter experience. SUMMARY AND BACKGROUND DATA LLP is being performed more commonly with limited data comparing results with outcomes from OLP. METHODS Data from 8 centers were combined for all cases performed between 2002-2006. OLP and LLP cohorts were matched by age, American Society of Anesthesiologists, resected pancreas length, tumor size, and diagnosis. Multivariate analysis was performed using binary logistic regression. RESULTS Six hundred sixty-seven LPs were performed, with 159 (24%) attempted laparoscopically. Indications were solid lesion in 307 (46%), cystic in 295 (44%), and pancreatitis in 65 (10%) cases. Positive margins occurred in 51 (8%) cases, 335 (50%) had complications, and significant leaks occurred in 108 (16%). Conversion to OLP occurred in 20 (13%) of the LLPs. In the matched comparison, 200 OLPs were compared with 142 LLPs. There were no differences in positive margin rates (8% vs. 7%, P = 0.8), operative times (216 vs. 230 minutes, P = 0.3), or leak rates (18% vs. 11%, P = 0.1). LLP patients had lower average blood loss (357 vs. 588 mL, P < 0.01), fewer complications (40% vs. 57%, P < 0.01), and shorter hospital stays (5.9 vs. 9.0 days, P < 0.01). By MVA, LLP was an independent factor for shorter hospital stay (P < 0.01, odds ratio 0.33, 95% confidence interval 0.19-0.56). CONCLUSIONS In selected patients, LLP is associated with less morbidity and shorter LOS than OLP. Pancreatic fistula rates are similar for OLP and LLP. LLP is appropriate for selected patients with left-sided pancreatic pathology.
Alternative polyadenylation generates three low-pI α-amylase mRNAs with differential expression in barley

Specific low-pI α-amylase genes from barley (Hordeum vulgare L.) produced alternative mRNAs with a 17-base 3′ extension (extension 1) or a 17-base extension beyond this (extension 2). The extended mRNAs do not arise from splicing of downstream sequences, and not all low-pI genes contain the extended sequences. All three mRNAs occur in aleurones and shoots, while extension 2 is missing from scutella. Also, the unextended mRNAs predominate in total mRNA, but the extended mRNAs predominate in membrane-bound polysomes. The extended sequences do not occur in previously characterized α-amylases, but 16 of 18 bases, mainly in extension 1, are identical with a sequence in the 3′-UTR of PAPI, a putative inhibitor of α-amylase. These observations suggest that the extended sequences could play a functional role in α-amylase expression.
Determination of the fragmentation mechanisms of organophosphorus ions by H2O and D2O atmospheric-pressure ionization tandem mass spectrometry II—dialkyl alkylphosphonate ions†

Diethyl methylphosphonate (DEMP), diisopropyl methylpbosphonate (DIMP), diethyl isopropylphosphonate (DEIP) and diethyl ethylphosphonate (DEEP) were characterized by H2O and D2O atmospheric pressure ionization tandem mass Spectrometry (API-MS/MS). Collision-induced dissociation (CID)/fragmentation pathways included alkyl ions by direct cleavage, alkyl radical and water loss processes and McLafferty and McLafferty-type rearrangements by six- and five-membered ring transition states, respectively. D2O API proved particularly useful in that certain decomposition pathways (i.e. water and methanol neutral losses) had a statistical distribution as to the loss of an acid deuteron and proton(s). This phenomenon was manifested by two pairs of ions in the D2O API daughter-ion mass spectrum for each phosphonate compound (e.g. both m/z 79/80 and 65/66 for DEMP and DIMP). The observed ion intensity ratios for these pairs of ions served as guides in the determination of their predicted ion relative abundance ratios and CID decomposition pathways. Water neutral losses as opposed to ether and alcohol neutral losses were favored for most of the protonated organophosphonate molecular ion decomposition schemes.
Hearing Loss in Former Prisoners of War of the Japanese

OBJECTIVE To describe the prevalence, degree, and types of hearing loss present in a group of older American veterans who had been prisoners of war of the Japanese. DESIGN A descriptive study. SETTING A Veterans Affairs university hospital. PARTICIPANTS Seventy-five male veterans, mean age 68 (+/− 3.6) years. INTERVENTIONS Hearing aids were prescribed for eight veterans. MEASUREMENTS Subjects were examined, and pure tone air and bone conduction, speech reception threshold, and speech discrimination were determined. Results were compared with age- and sex-matched controls from the largest recent American population study of hearing loss. RESULTS 95% of subjects had been imprisoned longer than 33 months. Starvation conditions (100%), head trauma (85%), and trauma-related loss of consciousness (23%) were commonly reported. A total of 73% complained of hearing loss, and 29% (22/75) dated its onset to captivity. Most of those with the worst losses in hearing and speech discrimination were found in this subgroup. When the entire group was compared with published age- and sex-matched controls from the Framingham Study, no significant differences were found. CONCLUSIONS We advocate screening examinations and long-term follow-up of populations with similar histories of starvation, head trauma, and torture.
Selection of treatment among Latina and non-Latina white women with ductal carcinoma in situ

Abstract Background: The growing rates of ductal carcinoma in situ (DCIS) and evidence that Latinas may underuse breast-conserving surgery (BCS) compared with white women highlight the need to better understand how treatment decisions are made in this understudied group. To help address this gap, this study compared surgery and radiation treatment decision making among white and Spanish-speaking and English-speaking Latina women with DCIS recruited from eight population-based cancer registries from 35 California counties. Methods: Women aged ≥18 who self-identified as Latina or non-Latina white diagnosed with DCIS between 2002 and 2005 were selected from eight California Cancer Registry (CCR) regions and surveyed about their DCIS treatment decision making by telephone approximately 24 months after diagnosis. Survey data were merged with CCR hospital-based records to obtain tumor and treatment data. Results: Mean age was 57 years. Multivariate analysis indicated no differences by ethnicity or language in t...
Two methods for the preparation of 2-cyclohexenones from resin-bound 1,3-cyclohexanedione

The addition of organolithium or Grignard reagents to vinylogous ester resin 1 followed by mild hydrolysis of product resins 2 provides 3-alkyl-2-cyclohexenones in high purity (>95%). Alternatively, conversion of 1 to vinyl triflate resin 4 followed by palladium-mediated couplings with aryl boronic acids and hydrolysis furnishes 3-aryl-2-cyclohexenones in lower yield, but exceptional purity.
External-beam radiation therapy for improved dialysis access patency: Feasibility and early safety

Rectenwald, J. E., Pretus, H. A., Seeger, J. M., Huber, T. S., Mendenhall, N. P., Zlotecki, R. A., Palta, J. R., Li, Z. F., Hook, S. Y., Sarac, T. P., Welborn, M. B., Klingman, N. V., Abouhamze, Z. S. and Ozaki, C. K. External-Beam Radiation Therapy for Improved Dialysis Access Patency: Feasibility and Early Safety. Radiat. Res. 156, 53-60 (2001).Prosthetic dialysis access grafts fail secondary to neointimal hyperplasia at the venous anastomosis. We hypothesized that postoperative single-fraction external-beam radiation therapy to the venous anastomosis of hemodialysis grafts can be used safely in an effort to improve access patency. Dogs (n = 8) underwent placement of expanded polytetrafluoroethylene grafts from the right carotid artery to the left jugular vein. Five dogs received single-fraction external-beam photon irradiation (8 Gy) to the venous anastomosis after surgery. Controls were not irradiated. Shunt angiograms were completed 3 and 6 months postoperatively. Anastomoses, mid-graft, and the surrounding tissues were analyzed. Immunohistochemistry for smooth muscle cell alpha-actin, proliferating cellular nuclear antigen (PCNA), and apoptosis was performed. Incisions healed well, though all animals developed wound seromas. One control suffered graft thrombosis 4 months postoperatively. Angiography/histology confirmed severe neointimal hyperplasia at the venous anastomosis. The remaining seven dogs developed similar amounts of neointimal hyperplasia. PCNA studies showed no accelerated fibroproliferative response at irradiated anastomoses compared to controls. Skin incisions and soft tissues over irradiated anastomoses revealed no radiation-induced changes or increase in apoptosis. Thus we conclude that postoperative single-fraction external-beam irradiation of the venous anastomosis of a prosthetic arteriovenous graft that mimics the situation in humans is feasible and safe with regard to early wound healing.
The central origin of efferent pathways in the carotid sinus nerve of the cat

The application of horseradish peroxidase to the central cut end of the carotid sinus nerve of the cat produced retrograde labeling of neurons in the ipsilateral medulla in the region of the nucleus ambiguus at anterior-posterior coordinates -8 to -10.5. These data coupled with previous electrophysiological observations suggest that the nucleus ambiguus may be the origin of an efferent inhibitory pathway to the carotid body.
Effects of equal and unequal reinforcer duration during functional analysis.

In the functional analysis described by Iwata, Dorsey, Slifer, Bauman, and Richman (1982/1994), reinforcer duration varied across conditions (e.g., brief attention vs. 30 s of escape); this may result in unequal exposure to the establishing operations for aberrant behavior. In this study, we compared the effects of unequal and equal reinforcer duration during a functional analysis. The results showed that reinforcer duration affects the rate of aberrant behavior and may potentially alter functional analysis interpretation.
Do dietary intakes affect search for nutrient information on food labels

Nutrition labels on food packages are designed to promote and protect public health by providing nutrition information so that consumers can make informed dietary choices. High levels of total fat, saturated fat and cholesterol in diets are linked to increased blood cholesterol levels and a greater risk of heart disease. Therefore, an understanding of consumer use of total fat, saturated fat, and cholesterol information on food labels has important implications for public health and nutrition education. This study explores the association between dietary intakes of these three nutrients and psychological or demographic factors and the search for total fat, saturated fat, and cholesterol information on food labels. Psychology literature suggests a negative association between intakes of these nutrients and probability of search for their information on food labels. Health behavior theories also suggest perceived benefits and costs of using labels and perceived capability of using labels are associated with the search behavior. We estimate the relationship between label information search and its predictors using logistic regressions. Our samples came from the 1994-1996 Continuing Survey of Food Intakes by Individuals and Diet and Health Knowledge Survey conducted by the United States Department of Agriculture. Results suggest that search for total fat, saturated fat, and cholesterol information on food labels is less likely among individuals who consume more of the three nutrients, respectively. The search is also related to perceived benefits and costs of using the label, perceived capability of using the label, knowledge of nutrition and fats, perceived efficacy of diets in reducing the risk of illnesses, perceived importance of nutrition in food shopping, perceived importance of a healthy diet, and awareness of linkage between excessive consumption of the nutrients and health problems. These findings suggest encouraging search of food label information among consumers with unhealthy dietary habits would need innovative approaches. Yet, nutrition education can be instrumental in encouraging this search by stimulating motivation and providing technical help.
Prediction and filtering for random parameter systems

This work generalizes the Wiener-Kolmogorov theory of optimum linear filtering and prediction of stationary random inputs. It is assumed here that signal and noise have passed through a random device before being available for filtering and prediction. A random device is a unit whose behavior depends on an unknown parameter for which an a priori probability distribution is given. A number of engineering applications are cited. Two of these are worked out in some detail to illustrate the optimization procedure.
Some considerations of radiation in magnetohydrodynamic Couette flow

In der Abhandlung wird der Einfluss magnetischer Felder auf den Energietransport in inkompressibler Couette-Stromung zwischen zwei sich relativ zueinander bewegenden ebenen Platten untersucht. Das aussere Magnetfeld wirkt senkrecht zur Stromungsrichtung und senkrecht zur Oberflache der Platten. Die beiden isothermen Platten emittieren und reflektieren diffus Warmestrahlung. Das Stromungsmedium ist isotrop und kann Warme absorbieren und emittieren. Die nicht lineare Integro-Differential-Energiegleichung ist naherungweise gelost. Die numerischen Ergebnisse zeigen den Einfluss der Hartmannschen Zahl und anderer dimensionsloser Kenngrossen auf die Temperaturverteilung und die Warmeubertragung.
Beliefs About Poverty and Opportunity Among Mexican Immigrant Farm Workers1

This study examined attributions for poverty and beliefs about upward mobility among 124 Mexican immigrant farm workers. The effects of gender and length of United States residency were also analyzed. Despite living in poverty and perceiving racism as a significant problem, respondents expected upward mobility for themselves and their children. Consistent with previous research on low-income and ethnic minority attributions (Bullock, 1999; Hunt, 1996; Kluegel & Smith, 1986), structural explanations for poverty were favored over individualistic causes, however, considerable support for individualistic causes was also expressed. Gender and length of residency were not predictive of immigrants’ beliefs about poverty. Implications for future research are discussed.
The Jailing of America’s Homeless: Evaluating the Rabble Management Thesis:

The authors of this article test hypotheses derived from Irwin’s rabble management thesis. The analysis uses data from 47,592 interviews conducted with jailed adults in 30 U.S. cities as part of the Arrestee Drug Abuse Monitoring program. Clearly, homeless persons are overrepresented among those arrested and booked into local jails. Bivariate analysis support a fundamental assertion of the rabble management thesis: Homeless are jailed not because of their dangerousness but rather their offensiveness. Homeless arrestees are distinct from their domiciled counterparts in terms of sociodemographic characteristics, previous experiences with alcohol and drug treatment, mental health, criminal justice systems, and alcohol and drug use histories. In addition, homeless are less likely than domiciled arrestees to be jailed for felonies and violent crimes but more likely to be charged with maintenance and property crimes. Logistic regression models confirm these differences, even after other factors are controlled. ...
Metallothionein-null mice are highly susceptible to the hematotoxic and immunotoxic effects of chronic CdCl2 exposure.

Cadmium (Cd) is an environmental pollutant. Chronic exposure of humans to Cd results in various maladies, including anemia and altered immune function. Metallothionein (MT) has been proposed to play an important role in Cd detoxication. Thus, we hypothesized that intracellular MT protects against Cd-induced hematotoxicity and immunotoxicity. Control and MT-I/II knock-out (MT-null) mice were given s.c. injections of CdCl2 over a wide range of doses, 6 times/week for up to 10 weeks. Cd-induced anemia was evident after 5 weeks of exposure and progressed with time. MT-null mice were about 10 times more susceptible to Cd-induced anemia, as evidenced by decreased erythrocytes (25%), hemoglobin concentration (30%), and hematocrit (35%) after 10 weeks of Cd injections. Cd produced dose- and time-dependent increases in neutrophils (7x), along with a marked elevation of serum IL-1 beta (6x) and TNF-alpha (20x) levels. MT-null mice were more susceptible than controls to Cd-induced alterations in peripheral leukocytes and cytokine levels. Chronic exposure to Cd also produced dose- and time-dependent splenomegaly (5x), with loss of lymphoid structure, inflammation, hyperplasia, appearance of giant cells, and fibrosis. Thymus weights were decreased by Cd in a dose-dependent manner (60%). MT-null mice were also approximately 10 times more susceptible than controls to these lesions. In conclusion, the present study demonstrates that repeated injections of Cd produces hematotoxic and immunotoxic effects, and intracellular MT protects against these chronic Cd-induced effects.
The Aquilegia FRUITFULL‐like genes play key roles in leaf morphogenesis and inflorescence development

Summary The APETALA1/FRUITFULL (AP1/FUL) MADS box transcription factors are best known for the role of AP1 in Arabidopsis sepal and petal identity, the canonical A function of the ABC model of flower development. However, this gene lineage underwent multiple duplication events during angiosperm evolution, providing different taxa with unique gene complements. One such duplication correlates with the origin of the core eudicots, and produced the euAP1 and euFUL clades. Together, euAP1 and euFUL genes function in proper floral meristem identity and repression of axillary meristem growth. Independently, euAP1 genes function in floral meristem and sepal identity, whereas euFUL genes control phase transition, cauline leaf growth and fruit development. To investigate the impact of the core eudicot duplication on the functional diversification of this gene lineage, we studied the role of pre-duplication FUL-like genes in columbine (Aquilegia coerulea). Our results show that AqcFL1 genes are broadly expressed in vegetative and reproductive meristems, leaves and flowers. Virus-induced gene silencing of the loci results in plants with increased branching, shorter inflorescences with fewer flowers, and dramatic changes in leaf shape and complexity. However, aqcfl1 plants have normal flowers and fruits. Our results show that, in contrast to characterized AP1/FUL genes, the AqcFL1 loci are either genetically redundant or have been decoupled from the floral genetic program, and play a major role in leaf morphogenesis. We analyze the results in the context of the core eudicot duplication, and discuss the implications of our findings in terms of the genetic regulation of leaf morphogenesis in Aquilegia and other flowering plants.
Vector-Meson Production by Polarized Photons at 2.8, 4.7, and 9.3 GeV

We present results on vector-meson photoproduction via $\ensuremath{\gamma}p\ensuremath{\rightarrow}\mathrm{Vp}$ in the LBL-SLAC 82-in. hydrogen bubble chamber exposed to a linearly polarized photon beam at 2.8, 4.7, and 9.3 GeV. We find ${\ensuremath{\rho}}^{0}$ production to have the characteristics of a diffractive process, i.e., a cross section decreasing slowly with energy and a differential cross section with slope of \ensuremath{\sim} 6.5 ${\mathrm{GeV}}^{\ensuremath{-}2}$. Within errors the ${\ensuremath{\rho}}^{0}$ production amplitudes are entirely due to natural-parity exchange. $s$-channel helicity is conserved to a high degree in the $\ensuremath{\gamma}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}$ transition. We find evidence for small helicity-flip amplitudes for $\ensuremath{\pi}\ensuremath{\pi}$ pairs in the ${\ensuremath{\rho}}^{0}$ region. Photoproduction of $\ensuremath{\omega}$ mesons is separated into its natural- (${\ensuremath{\sigma}}^{N}$) and unnatural- (${\ensuremath{\sigma}}^{U}$) parity-exchange contributions. The ${E}_{\ensuremath{\gamma}}$ and $t$ dependence and the spin density matrix of the unnatural-parity-exchange contribution are consistent with a one-pion-exchange process. The natural-parity-exchange part has characteristics similar to ${\ensuremath{\rho}}^{0}$ production. At 9.3 GeV the ratio of $\ensuremath{\sigma}({\ensuremath{\rho}}^{0})$ to ${\ensuremath{\sigma}}^{N}(\ensuremath{\omega})$ is \ensuremath{\sim} 7. The slope of the $\ensuremath{\varphi}$ differential cross section is \ensuremath{\sim} 4.5 ${\mathrm{GeV}}^{\ensuremath{-}2}$, smaller than that of ${\ensuremath{\rho}}^{0}$ and $\ensuremath{\omega}$ production. Natural-parity exchange is the main contributor to $\ensuremath{\varphi}$ production. No evidence for higher-mass vector mesons is found in $\ensuremath{\pi}\ensuremath{\pi}$, $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\pi}$, or $K\overline{K}$ final states. The $s$ and $t$ dependences of Compton scattering as calculated from $\ensuremath{\rho}$, $\ensuremath{\omega}$, and $\ensuremath{\varphi}$ photoproduction using vector-meson dominance agree with experiment, but the predicted Compton cross section is too small by a factor of 2.
A Zero-Space algorithm for Negative Cost Cycle Detection in networks

This paper is concerned with the problem of checking whether a network with positive and negative costs on its arcs contains a negative cost cycle. The Negative Cost Cycle Detection (NCCD) problem is one of the more fundamental problems in network design and finds applications in a number of domains ranging from Network Optimization and Operations Research to Constraint Programming and System Verification. As per the literature, approaches to this problem have been either Relaxation-based or Contraction-based. We introduce a fundamentally new approach for negative cost cycle detection; our approach, which we term as the Stressing Algorithm, is based on exploiting the connections between the NCCD problem and the problem of checking whether a system of difference constraints is feasible. The Stressing Algorithm is an incremental, comparison-based procedure which is as efficient as the fastest known comparison-based algorithm for this problem. In particular, on a network with n vertices and m edges, the Stressing Algorithm takes O(m@?n) time to detect the presence of a negative cost cycle or to report that none exists. A very important feature of the Stressing Algorithm is that it uses zero extra space; this is in marked contrast to all known algorithms that require@W(n)extra space. It is well known that the NCCD problem is closely related to the Single Source Shortest Paths (SSSP) problem, i.e., the problem of determining the shortest path distances of all the vertices in a network, from a specified source; indeed most algorithms in the literature for the NCCD problem are modifications of approaches to the SSSP problem. At this juncture, it is not clear whether the Stressing Algorithm could be extended to solve the SSSP problem, even if O(n) extra space is available.
Using a model selection criterion to identify appropriate complexity in aquatic biogeochemical models.

Aquatic biogeochemical models are widely used as tools for understanding aquatic ecosystems and predicting their response to various stimuli (e.g., nutrient loading, toxic substances, climate change). Due to the complexity of these systems, such models are often elaborate and include a large number of estimated parameters. However, correspondingly large data sets are rarely available for calibration purposes, leading to models that may be overfit and possess reduced predictive capabilities. We apply, for the first time, information-theoretic model-selection techniques to a set of spatially explicit (1D) algal dynamics models of varying parameter dimension. We demonstrate that increases in complexity tend to produce a better model fit to calibration data, but beyond a certain degree of complexity the benefits of adding parameters are diminished (the risk of overfitting becomes greater). The particular approach taken here is computationally expensive, but several suggestions are made as to how multimodel methods may practically be extended to more sophisticated models.
Kupffer cells mediate increased anoxic hepatocellular killing from hyperosmolarity by an oxygen- and prostaglandin-independent mechanism.

The purpose of this study was to evaluate the roles of Kupffer cells, prostaglandin biosynthesis, and glycolytic metabolism in accelerated anoxic cell killing by hyperosmolar stress. Isolated rat livers were perfused with anoxic normosmolar Krebs–Heinseleit bicarbonate buffer (KHB) or anoxic hyperosmolar KHB (+40 mM NaCl). Hyperosmolar KHB accelerated LDH release during anoxia in livers from both fed and fasted rats by as much as 3.7-fold. GdCl3 pretreatment to inactivate Kupffer cells substantially delayed anoxic LDH release during normosmolar perfusions and blocked entirely the hyperosmolarity-induced acceleration of LDH release. Cyclooxygenase inhibition with indomethacin failed to alter LDH release during anoxia in hyperosmolar KHB. Neither GdCl3 nor hyperosmolarity changed glycolytic flux during hypoxia, and hyperosmolarity did not change basal oxygen uptake. We conclude that accelerated cell killing in hyperosmolar buffer is a Kupffer cell-dependent event that is independent of oxygen-requiring prostaglandin synthesis, changes of glycolytic flux, and activation of cellular ATP demand. Another as yet unidentified Kupffer cell product appears to mediate the effect of hyperosmolarity of anoxic hepatocellular injury.
Hydroxyurea retards the progression of G2 cells.

Abstract Continuous treatment of monolayer cultures of Chinese hamster ovary (CHO) cells with 1.0 mM HU reduced the rate at which G2 cells entered mitosis. Although all cells in G2+M at the start of treatment eventually entered mitosis, early G2 cells, which were exposed to HU the longest, entered mitosis 45 min later than untreated G2 cells. This perturbation of G2 progression should be considered when employing HU as a synchronizing agent in mammalian cell populations.
Low frequency vibrational stirring: A new method for rapidly mixing solutions and melts during growth

A new method for rapidly stirring liquids has been developed which may be useful in crystal growth applications. The method involves the introduction of orthogonally coupled low frequency vibrations to fluids contained in cylindrical crucibles. A mathematical model has been developed to describe the influence of this vibrational stirring method on fluid flow. The optimum sloshing frequencies calculated for a specific system geometry were very close to those observed experimentally. A systematic study of the fluid flow induced by the vibrational motion was carried out at room temperature using aqueous solutions containing glycerine. Preliminary experiments were carried out to study the effect of vibrational stirring on interface shape and position during the Bridgman growth of CsCdCl3, a model system.
Evaluation of INR Monitoring Frequency and Time in Therapeutic Range

Background:Although anticoagulant therapy has been used for more than 50 years, the optimal interval between international normalized ratio (INR) measurements in patients who demonstrate a stable dose response remains unsettled. Based on the results of observational studies, the American College of Chest Physicians currently recommends that patients receiving a stable dose of warfarin undergo INR testing at least once every 4 weeks.1Objective:To determine whether an increased frequency of INR monitoring impacts time in therapeutic range (TTR) among patients receiving maintenance warfarin therapy managed by an anticoagulation clinic.Methods:A total of 2,222 INR results belonging to more than 700 adults who were followed by the anticoagulation service at the University of Pittsburgh Medical Center and who were receiving maintenance warfarin therapy between April 1, 2006, and September 30, 2006, were retrospectively reviewed. INR measurements were categorized as having been determined fewer than 21 days or 2...
Preparation and Solid State Characterization of Isostructural Bifunctional 1,2,3,5-Dithiadiazolyls with Benzene, Bithiophene, and Piperazine Spacers

The preparation of the bis(1,2,3,5-dithiadiazolyl) radicals [S2N2C]−X−[CN2S2], where X is a heterocyclic bridging group (X = piperazine, thiophene, bithiophene) is described. Crystal structures of ...
Bound and resonant (110) surface electronic states for GaAs, GaP and GaSb

Abstract Dispersion curves E( k ) are predicted for the surface electronic bound states and resonances at the relaxed (110) surfaces of GaAs, GaP, and GaSb. GaAs and GaSb are predicted to have no surface states within the fundamental band gap, but GaP is predicted to have unoccupied surface states with energies extending below the conduction band edge, in agreement with experiment. The predicted dispersion curves are in good agreement with the angle-resolved photoemission measurements for GaAs. Using the analytic Green's function, effective-Hamiltonian technique, we are able to locate some new resonant structure.
Eddy-current modeling using neural networks

There is a considerably history of using Eddy Current measurements for inspecting metal surfaces. The interpretation of the results, however, has been somewhat subjective. The sensitivity of the Eddy Current measurement to changes in material thickness is easily demonstrated. However, the reconstruction of thickness from the measurements (with any degree of confidence) has remained elusive. Part of the issue is the additional sensitivity of Eddy Current measurements to Lift distance and local geometry. This project is a culmination of an feasibility study to see if neural networks could provide estimates of material thicknesses for thin materials (< 0.15 inches or 4 mm) for metals with low conductivity (approximately 0.7 x mega/Ohm cm). The study a neural network model, whose accuracy varies depending upon the conditions. It turns out that the conditions required for good accuracy are usually not the conditions one wants to take measurements. The model not only suggests why this problem has been unwieldy, but also suggests that most of the difficulties could be alleviated by using an independent source to measure the Lift distance.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
What is needed to reverse the trends in childhood obesity? A call to action

Background To address the complexity of issues surrounding childhood obesity, the Society of Behavioral Medicine identified childhood obesity as a special focus of its 2007 Annual Meeting.
Soil response to track and wheel tractor traffic

Abstract Experiments were conducted on a Eudora silt loam to determine the effect of tracked and wheeled tractor traffic on cone penetration resistance and soil bulk density at three different soil-water content levels. Treatment plots were ripped to a depth of 0.45 m and irrigated 5 days prior to the experiment. Significant differences in penetration resistance and bulk density were observed between the treatments within the plowing depth (0.30 m). After the tractor passes, the average penetration resistance recorded was about 7.5% higher and the soil bulk density was about 3% higher in the wheel treatment plots. However, at the soil-water content level close to Proctor optimum (15% w/w), no significant difference was observed in the average penetration resistance of the two treatments.
Long-term vocal recognition in the northern fur seal

The ability to recognize and remember individual identities for long periods of time has important implications for the evolution of animal social behaviour, particularly complex interactions such as cooperation or mate choice. Despite this importance, there is only a single example of long-term individual recognition in nature, the 8-month retention of neighbour's song among male hooded warblers, Wilsonia citrina, and there is none for a non-human mammal. Associations between individuals spanning years, which are especially prevalent in carnivores, primates and seabirds, and evidence of mate fidelity provide indirect support for the ability of long-term recognition. In many of these instances, however, individuals do not separate for extended periods, and thus long-term recognition, although often assumed, may be both unnecessary and nonexistent. Furthermore, site fidelity rather than individual recognition may explain many instances of mate fidelity. Here I show that mother-offspring pairs of a migratory otariid pinniped--the northern fur seal (Callorhinus ursinus)--not only have the ability to recognize each other's vocalizations during the course of a breeding season, but are also able to retain these memories for at least 4 years.
Interstitial deletion of 11q13 sequences in HeLa cells

Previous cytogenetic and molecular genetic studies have shown that the HeLa (cervical carcinoma) cell line D98/AH-2 contains two apparently normal copies of chromosome 11 and additional 11q13-25 material translocated onto a chromosome 3 marker. To determine the 11q13 breakpoint, we performed fluorescence in situ hybridization (FISH) using 18 different 11q13 specific BAC (bacterial artificial chromosome) and cosmid probes spanning a 5.6 Mb interval. Markers localized to the multiple endocrine neoplasia type 1 (MEN1) gene (menin) were also included in the analysis. The FISH study identified an interstitial deletion between markers D11S449 and GSTP1, an interval of 2.3 Mb, in the marker chromosome. This deletion did not include the MEN1 gene. Because point mutations and methylations can inactivate the MEN1 gene, single stranded conformational polymorphism (SSCP) and Northern and Western blot analyses were performed with MEN1 specific probes and antibody. SSCP did not reveal mutations of the MEN1 gene in HeLa or in seven other cervical cancer cell lines. Northern and Western blot studies revealed normal levels of expression of this gene in the cervical cancer cell lines as well as in HeLa cell derived tumorigenic hybrids. Because deletions of tumor suppressor genes often occur in cancer progression, we hypothesize that the inactivation of a tumor suppressor gene other than MEN1, localized to the 2.3 Mb interval on 11q13, might play a role in the abnormal growth behavior of HeLa cells in vitro or in vivo.
Treatment of cognitive deficits associated with schizophrenia: potential role of catechol-O-methyltransferase inhibitors.

In the last two decades, understanding of the dynamics of dopamine function in the prefrontal cortex and its role in prefrontal cortex physiology has opened up new avenues for therapeutic interventions in conditions in which prefrontal cortex function is compromised. Neuropsychological and imaging studies of prefrontal information processing have confirmed specific cognitive and neurophysiological abnormalities in individuals with schizophrenia. Because such findings are also observed in the healthy siblings of patients with schizophrenia, they may represent intermediate phenotypes related to schizophrenia susceptibility genes. Catechol-O-methyltransferase (COMT) represents an important candidate as a susceptibility gene for cognitive dysfunction in schizophrenia because of the unique role this enzyme plays in regulating prefrontal dopaminergic function. A functional COMT polymorphism (Vall58Met) predicts performance in tasks of prefrontal executive function and the neurophysiological response measured with electroencephalography and functional magnetic resonance imaging in tasks assessing working memory. In fact, individuals with the Val/Val genotype, which encodes for the high-activity enzyme resulting in lower dopamine concentrations in the prefrontal cortex, perform less well and are less efficient physiologically than Met/Met individuals. These findings raise the possibility of new pharmacological interventions for the treatment of prefrontal cortex dysfunction and of predicting outcome based on COMT genotype. One strategy consists of the use of CNS-penetrant COMT inhibitors such as tolcapone. A second strategy is to increase extracellular dopamine concentrations in the frontal cortex by blocking the noradrenaline (norepinephrine) reuptake system, a secondary mechanism responsible for the disposal of dopamine from synaptic clefts in the prefrontal cortex. A third possibility involves the use of modafinil, a drug with an unclear mechanism of action but with positive effects on working memory in rodents. The potential of these drugs to improve executive cognitive function by selectively increasing dopamine load in the frontal cortex but not in subcortical territories, and the possibility that response to them may be modified by a COMT polymorphism, provides a novel genotype-based targeted pharmacological approach without abuse potential for the treatment of cognitive disorder in schizophrenia and in other conditions involving prefrontal cortex dysfunction.
Association between ambient noise exposure, hearing acuity, and risk of acute occupational injury.

Objective This study aimed to examine the associations between acute workplace injury risk, ambient noise exposure, and hearing acuity, adjusting for reported hearing protection use. Methods In a cohort of 9220 aluminum manufacturing workers studied over six years (33 300 person-years, 13 323 person-jobs), multivariate mixed effects models were used to estimate relative risk (RR) of all injuries as well as serious injuries by noise exposure category and hearing threshold level (HTL) adjusting for recognized and potential confounders. Results Compared to noise <82 dBA, higher exposure was associated with elevated risk in a monotonic and statistically significant exposure–response pattern for all injuries and serious injuries with higher risk estimates observed for serious injuries [82–84.99 dBA: RR 1.26, 95% confidence interval (95% CI) 0.96–1.64; 85–87.99 dBA: RR 1.39, 95% CI 1.05–1.85; ≥88 dBA: RR 2.29, 95% CI 1.52–3.47]. Hearing loss was associated with increased risk for all injuries, but was not a significant predictor of risk for the subset of more serious injuries. Compared to those without hearing loss, workers with HTL ≥25 dB had 21% increased all injury risk (RR 1.21, 95% CI 1.09–1.33) while those with HTL 10–24.99 dB had 6% increased risk (RR 1.06, 95% CI 1.00–1.13). Reported hearing protection type did not predict injury risk. Conclusion Noise exposure levels as low as 85 dBA may increase workplace injury risk. HTL was associated with increased risk for all, but not the subset of serious, injuries. Additional study is needed both to confirm the observed associations and explore causal pathways.
Planovalgus foot deformity. Current status

Flatfoot may be classified as pathologic or physiologic. Pathologic flatfoot is often characterized by stiffness of the foot, causes disability, and requires treatment. Physiologic flatfoot is a normal variation; it causes no disability and tends to improve with time. Physiologic flatfoot is most common in individuals who are loose-jointed, are obese, or usually wore shoes during childhood. Treatment of children with physiologic flatfoot with orthoses or shoe modifications not only is ineffective but is uncomfortable and embarrassing for the child and is associated with lowered self-esteem in adult life.
A novel computational paradigm for creating a Triangular Irregular Network (TIN) from LiDAR data

Abstract The Triangular Irregular Network (TIN) model is an alternative to the grid-based representation of the terrain surface adopted in numerous digital mapping and geographic information systems. In TIN, irregularly spaced sample points model the terrain in such a way that more points represent the areas with rough terrain and there are fewer in smooth terrain. Despite its simplicity, creating a TIN model for an area involves (a) picking sample points, (b) connecting points into triangles, and (c) modeling the surface within each triangle. Most of the available algorithms for picking sample points use either a dense Digital Elevation Model (DEM) or a set of digitized contours as input. Now, the availability and popularity of Light Detection And Ranging (LiDAR) devices, which produce clouds of points, require the development of a new computational paradigm for picking sample points from the new data. This article presents a novel computational framework for picking sample points to create a TIN model from LiDAR data.
Complementary base pairing and the origin of substitution mutations

On the basis of chemical considerations and model building, the Watson–Crick concept of complementary base pairing is extended to a wider range of DNA pairs than A–T and G–C (including A–C, G–T, A–A, G–G and G–A) by invoking imino or enol tautomers (or protonated species) and syn isomers. The virtual absence of these additional base pairs from DNA is explained in terms of the low frequency with which these unfavoured forms occur and the two-step mechanism of DNA synthesis, whereby residues are first incorporated by the DNA polymerase and then checked. This base-pairing hypothesis is used to explain the origin, nature and level of spontaneous substitution mutations, their enhancement by base analogues, and the unique effects of certain mutator alleles.
Poetry in Engineering Education

An important element of integrating disciplines and enhancing creativity in Drexel University's engineering curriculum is an assignment which combines poetry and engineering. For this assignment, students choose an artifact, research it, create a one-page annotated visual explaining how it works, and then write an original poem about it. Although the poetry instruction, based on a transactional model, takes place in the Humanities classroom, student poems become a component of a concurrent engineering assignment and are read aloud in an engineering lecture, attended by humanities faculty, designated as the “Poetry Reading.” Short in length and having a distinct design on the page, poetry is a particularly suitable literary medium for engineering students to explore. Students relinquish stereotypes about engineers when they see their engineering professor endorse poetry. They also begin to broaden their educational and professional goals.