cssi/SciSciGPT-SciSciNet huggingface dataset:
Hierarchical Factoring in a Standardized Achievement Battery

This study was concerned with the factorial validity of the Iowa Tests of Basic Skills (ITBS). Previous research identified a strong general factor for this battery, which was taken as evidence of redundancy among the subtests. Hierarchical factor analysis was done with a subset of the standardization data to explore the presence of second-order group factors. The results supported the construct validity of the Language and Mathematics subscales, though a degree of factorial complexity was found in both. Verbal and Visual Information group factors were also identified. Extension of the ITBS general and group factors to subtests of the Cognitive Abilities Test supported the interpretations made of the various group factors. MAJOR achievement test batteries are generally designed to indicate specific strengths and weaknesses in a student’s educational development. Consistent with this purpose, norms and reliability coefficients are reported for subtest and subscale scores. Much recent interest has focused on the degree to which the individual subtest scores are factorially distinct; that is, on the extent to which these subtests have discriminant validity. A number of researchers (e.g., Merrifield and Hummel-Rossi, 1976; Klein, 1981) have argued that there is a high degree of redundancy among the subtests of achievement batteries. In each of these studies, a principal factors analysis was performed on the matrix of subtest intercorrelations for a particular achievement battery. The eigenvalues derived in this analysis were compared to the largest communality estimate for the subtests. In each study, the presence of a second eigenvalue that was smaller than the largest
Multiple mechanisms are responsible for altered expression of gap junction genes during oncogenesis in rat liver

Although several abnormalities in gap junction (GJ) structure and/or function have been described in neoplasms, the molecular mechanisms responsible for many of the alterations remain unknown. The identification of a family of GJ proteins, termed connexins, prompted this study of connexin32 (Cx32), connexin26 (Cx26) and connexin43 (Cx43) expression during rat hepatocarcinogenesis. Using antibody, cDNA and cRNA probes, we investigated connexin mRNA and protein expression in preneoplastic and neoplastic rat livers. In normal liver, Cx32 is expressed in hepatocytes throughout the hepatic acinus, Cx26 is restricted to periportal hepatocytes, and Cx43 is expressed by mesothelial cells forming Glisson's capsule. Most preneoplastic altered hepatic foci generated by diethylnitrosamine (DEN) initiation and either phenobarbital (PB) or 2,3,7,8-dichlorodibenzo-p-dioxin (TCDD) promotion exhibited decreased Cx32 or increased Cx26 staining. Foci from either protocol failed to display Cx43 immunoreactivity. In the majority of PB-promoted foci, Cx32 immunoreactivity decreased independently of changes in mRNA abundance. Continuous thymidine labeling, following cessation of PB promotion, showed that downregulation of Cx32 staining is reversible in foci that are promoter-dependent for growth, but irreversible in lesions that are promoter-independent for growth. Hepatic neoplasms from rats initiated with DEN and promoted with PB or TCDD also displayed modified connexin expression. While all 24 neoplasms studied were deficient in normal punctate Cx32 and Cx26 staining, altered cellular localization of these proteins was apparent in some tumors. Immunoblotting of crude tissue extracts revealed that neoplasms with disordered Cx32 staining showed immunoreactive bands with altered electrophoretic mobility. These observations show that hepatomas may downregulate Cx32 expression through changes in the primary structure of Cx32 or by post-translational modifications. Northern blotting of total tumor mRNAs failed to demonstrate consistent changes in the abundance of Cx32, Cx26 or Cx43 transcripts. Some tumors expressed steady-state transcripts without observable immunoreactivity, indicating that some hepatomas downregulate connexin immunoreactivity independently of mRNA abundance. Increased levels of Cx43 mRNA and protein were found in several neoplasms, but immunostaining was always localized to nonparenchymal cells. Areas of bile duct proliferation and cholangiomas displayed Cx43 staining, whereas, cholangiocarcinomas were deficient in immunoreactivity. These findings show that alterations in the expression of connexins, by either downregulation or differential induction, represent common modifications during hepatocarcinogenesis. Although our results imply that connexins represent useful markers for the boundary between tumor promotion and progression, preneoplastic and neoplastic rat hepatocytes fail to use a common mechanism to modify connexin expression.
Event servers for crisis management

Organizations need to respond rapidly to threats and opportunities in the extended environment Examples of threats are terrorism, chemical spills, intrusion into networks, and delayed arrivals of components Opportunities include arbitrage and control of distributed systems such as the electrical power grid and logistics networks The increasing prevalence of sensors such as RFID (radio frequency ID) and Web sites that offer measured information, coupled with information in databases and applications allows organizations to sense critical conditions in the extended environment A response to a critical condition is to send an alert to appropriate people or send a message that initiates an application A critical condition is a predicate on the history of global states of a system An event server is a software component with sensors, responders, and computational elements Computations are incremental in the sense that computations incorporate each new event in an online algorithm as opposed to repeatedly computing predicates over the entire history This talk discusses the problem space, proposes an abstract mathematical model of the problem, suggests approaches to solutions, describes an implementation, and relates this work to research in data stream management systems and rules engines.
Using Clinical Case Studies to Teach Biochemistry in a Doctoral Program: A Descriptive Paper

Introduction: Biochemistry has traditionally been taught through lectures and rote memorization paying little attention to nurturing key problem solving skills. The literature on clinical case studies utilized in health education indicates that case studies facilitate and promote active learning, help clinical problem solving and encourage the development of critical thinking skills. Methods: This paper describes a method of using clinical case studies to deepen and solidify the students understanding of biochemical facts and concepts as related to clinical medicine. Discussion: Clinical case studies can be a helpful adjunct for teaching the content of human biochemistry that complements the traditional approach of lecture, textbook and laboratory. The learning issues presented to the students required them to reformulate biochemical concepts in their own words, integrate diverse principles and decide what information was important and what was superfluous. Limitations include a small subset of students riding the coat tails of their more ambitious peers, and biochemistry professors not having the confidence to take the students through a clinical case study because they may feel like they do not have sufficient “clinical expertise”. Conclusion: Clinical case studies are a valuable addition to the traditional methods of lecture, textbook reading and laboratory for teaching biochemistry. More importantly clinical case studies help remind students that what they are learning has relevance in the real world, and may help motivate students to pay more attention to the numerous facts faced in biochemistry.
(0,G/I) codes are a subclass of MTR codes

Maximum transition run (MTR) codes are defined that enable quasicatastrophic error propagation to be avoided in Viterbi detectors matched to partial response channels with spectral nulls both at DC and at the Nyquist frequency. It is shown that the new class of MTR codes includes (0, G/I) codes as a subclass.
c-fms mRNA is Regulated Posttranscriptionally by 1,25(OH)2D3 in HL-60 Cells

Macrophage colony-stimulating factor (MCSF) is required for normal osteoclast and macrophage development. The receptor for MCSF (c-fms) is expressed on the pluripotent precursor and mature osteoclasts and macrophages. We have previously shown in myelomonocytic HL-60 cells that phorbol myristate acetate (PMA) upregulates c-fms mRNA expression. This induction of c-fms is inhibited by 1,25(OH)2D3. The major regulatory control of c-fms mRNA levels by PMA has been identified as posttranscriptional. However, a role of transcript elongation in controlling levels of c-fms mRNA has also been suggested. To better understand the 1,25(OH)2D3 regulation of c-fms mRNA expression we studied nuclear run on, mRNA stability, and transcript elongation in HL-60 cells treated with 10 ng/ml phorbol myristate acetate, 10 nM 1,25(OH)2D3 alone or combined. We demonstrated by nuclear run on that c-fms was constitutively transcribed in 1,25(OH)2D3 as well as control and PMA-treated cells. Transcript elongation was evaluated by RT-PCR for exon 2 or exon 3. Both exons were minimally expressed in control and 1,25(OH)2D3-treated cells, and increased in PMA-treated cells; this increased expression was inhibited by the addition of 1,25(OH)2D3. These results fail to show differential transcript elongation. Measurement of mRNA stability demonstrated decreased mRNA half-life to 5 hours in cells treated with PMA and 1,25(OH)2D3 compared with a half-life of 8 hours in cells treated with PMA alone. Our findings demonstrate that c-fms is regulated by 1,25(OH)2D3 at the posttranscriptional level by changes in mRNA stability. This gives the cell the ability to respond to local signals with rapid changes in c-fms levels altering the ability of the cell to respond to MCSF.
Absolute redox potential of liquid water: a first-principles theory

A first-principles molecular dynamics method is proposed to calculate the absolute redox potentials of liquid water. The key of the method is the evaluation of the difference between the vacuum level and the average electrostatic potential inside liquid water, which employs an average over both space and time. By avoiding the explicit use of the Kohn–Sham levels, such as the position of the valence band maximum, as the reference energy for the excited electrons, we are able to calculate water redox potentials accurately using a semi-local density functional and an entropic contribution estimated from experimental data.
Convenient labelling technique for mass spectrometry: acid catalyzed deuterium and oxygen-18 exchange via gas-liquid chromatography

Tandem column gas-liquid chromatography labeling technique for mass spectrometry, noting ketones exchange and data on deutrium and oxygen compounds
Darwin would be proud: Bioturbation, dynamic denudation, and the power of theory in science

Charles Darwin's worm book influenced many early researchers who, following his lead, demonstrated how soil biota mechanically generate new strata and soil horizons, as well as blur or destroy them. Such early observations on biomechanical processes failed to find visibility in our models of landscape evolution for several reasons, chief of which are (1) except for ichnology, an Earth sciences tradition of adopting frameworks where biomechanical processes are absent and (2) a lapse of over 100 years after Darwin before a genetic language backed by supporting theory appeared that could showcase the importance of such processes. Examples of influential Earth science frameworks in which biomechanical processes are absent are the V.V. Dokuchaev–USDA–H. Jenny soil formational (five factors) paradigm, W.M. Davis' geographical cycle, the W. Penck–L.C. King–R.V. Ruhe backwasting-pedimentation concept, the stratigraphic Law of Superposition, and other traditional approaches to archaeology, geomorphology, and pedology. Examples of recent genetic language that serve to ameliorate the problem are soil thickness concepts, biomantle, bioturbation, faunalturbation, floralturbation, and pedoturbation. Examples of recent supporting theory that incorporate biomechanical processes are soil evolution, biomantle evolution, dynamic pedogenesis, and the dynamic denudation framework advocated here. Dynamic denudation is a unified synthesis that elevates bioturbation to parity levels with other major archaeogenic, geomorphogenic, and pedogenic processes. The general framework and its principal elements are summarized and simulated by diagrams and augmented by photographs taken in disparate parts of the world. The model has useful explanatory and predictive value in archaeology, geomorphology, pedology, and other surficial process research. © 2002 John Wiley & Sons, Inc.
Microarrayed recombinant allergens for diagnostic testing

The development of protein microarray–based immunoassays and the availability of recombinant allergens have, to a significant extent, emerged together over the past decade. Their long-anticipated wider application to allergy diagnosis has recently begun to accelerate. This review discusses some of the strengths and weaknesses of molecularly defined allergy testing and the microarray platform. Several recent applications of microarray assays to allergy testing are also summarized. Promising findings, particularly in the context of food and latex allergy, point to the potential for greater resolution between clinical reactivity and asymptomatic sensitization with this platform.
Life Cycle of the Screw-Worm Reared in Outdoor Cages Near Veracruz City, Mexico

The life cycle of the screw-worm ( Cochliomyia hominivorax (Coquerel)) native to the coastal plain of Veracruz State, Mexico, differed from that reported for Texas and Florida strains only in the longer time between copulation and first oviposition. However, this delayed oviposition may have been caused by the cold windy weather that occurred during the winter of the test. Sizes of eggs and pupae were within the ranges previously reported. Weights of larvae were slightly less than those of a similar strain reared at Mission, Texas, but this difference may be the result of an error in the way samples were collected for the Mexican study.
Cellular telephone communication between hospitals and ambulances

Cellular telephones provide a new means of wireless telephone communication. In an experimental design study comparing the clarity of receiving and transmitting communications with cellular telephones versus conventional emergency medical radio/microwave equipment, cellular telephones proved to be superior in all aspects of clarity and ease. Cellular telephones have numerous cost and equipment advantages over radio equipment and should replace conventional radio/microwave equipment for emergency medical communication in areas where reliable cellular telephone networks are available. This will improve an important facet of prehospital emergency care.
On the relationship between divorce and rheumatoid arthritis.

The hypothesis of suppressed hostility as a factor in rheumatoid arthritis is supported by the finding that rheumatoid arthritics are more liable to divorce, but put up with an unsatisfactory marriage longer than those who are free of the disease. This is more striking for males than for females. Le hypothese de supprimite hostilitate como factor in arthritis rheumatoide es supportate per le constatation que patientes de arthritis rheumatoide ha un augmentate incidentia de divorcios sed indura un dissatisfacente maritage plus longemente que subjectos sin ille morbo. Iste relation es plus marcate in masculos que in femininas.
Higher-Order Homogenization of Initial/Boundary-Value Problem

Higher-order homogenization of an initial/boundary-value problem with oscillatory coefficients in one dimension is studied. Validity range and limitations of the theory are established. We show that the higher terms are necessary to account for wave dispersion but introduce secular terms that grow unbounded in time. Numerical procedures requiring superconvergent recovery of higher-order derivatives are described.
Quantum logic between remote quantum registers

We consider two approaches to dark-spin-mediated quantum computing in hybrid solid-state spin architectures. First, we review the notion of eigenmode-mediated unpolarized spin-chain state transfer and extend the analysis to various experimentally relevant imperfections: quenched disorder, dynamical decoherence, and uncompensated long-range coupling. In finite-length chains, the interplay between disorder-induced localization and decoherence yields a natural optimal channel fidelity, which we calculate. Long-range dipolar couplings induce a finite intrinsic lifetime for the mediating eigenmode; extensive numerical simulations of dipolar chains of lengths up to L=12 show remarkably high fidelity despite these decay processes. We further briefly consider the extension of the protocol to bosonic systems of coupled oscillators. Second, we introduce a quantum mirror based architecture for universal quantum computing that exploits all of the dark spins in the system as potential qubits. While this dramatically increases the number of qubits available, the composite operations required to manipulate dark-spin qubits significantly raise the error threshold for robust operation. Finally, we demonstrate that eigenmode-mediated state transfer can enable robust long-range logic between spatially separated nitrogen-vacancy registers in diamond; disorder-averaged numerics confirm that high-fidelity gates are achievable even in the presence of moderate disorder.
CO2 Retention in High-Alkali Borate Glasses

A study of the high-alkali region of glass formation in the system Na2O +B2O3 reveals that retention of CO2 from carbonate starting materials can become a serious preparative problem at the high-alkali extreme. Results presented for glasses prepared using both Na2O and Na2CO3 show that residual CO2 can lead to major differences in physical properties which in this work are represented by the viscosity-related glass transition temperature.
Early viral functions of in (ts)-1501 temperature-sensitive SV40 mutant.

TEMPERATURE-SENSITIVE (ts) virus mutants have been useful in defining virus–host interactions in SV40 productive and transforming infections. We have isolated an SV40 ts mutant, in(ts)-1501, by extracellular mutagenesis, using ultraviolet radiation of wild type (WT) SV401. The mutant, which has properties different from previously described SV40 ts mutants2,3, is activated from its integrated state in nonpermissive transformed cells at temperatures above 39 °C and is capable of productive infection in permissive cells at elevated (conditional) temperatures1. Many properties of the 1501 mutant are analogous to the early ts cI mutants of bacteriophages in which a heat-inactivated protein cannot maintain the stable integration of the prophage in the bacterial chromosome at elevated temperatures4–8. This analogy suggested that maintenance of SV40 DNA integration in transformed cells requires an early viral function, that is, before the inception of viral DNA replication. Therefore we have investigated the effect of the in gene mutation on two other early virus functions—stimulation of host-cell DNA synthesis and tumour (T)-antigen synthesis.
The cloud imaging and particle size experiment on the aeronomy of ice in the mesosphere mission: Cloud morphology for the northern 2007 season

Abstract The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 4:26:03 EDT on April 25, 2007, becoming the first satellite mission dedicated to the study of noctilucent clouds (NLCs), also known as polar mesospheric clouds (PMC) when viewed from space. We present the first results from one of the three instruments on board the satellite, the Cloud Imaging and Particle Size (CIPS) instrument. CIPS has produced detailed morphology of the Northern 2007 PMC and Southern 2007/2008 seasons with 5 km horizontal spatial resolution. CIPS, with its very large angular field of view, images cloud structures at multiple scattering angles within a narrow spectral bandpass centered at 265 nm. Spatial coverage is 100% above about 70° latitude, where camera views overlap from orbit to orbit, and terminates at about 82°. Spatial coverage decreases to about 50% at the lowest latitudes where data are collected (35°). Cloud structures have for the first time been mapped out over nearly the entire summertime polar region. These structures include ‘ice rings’, spatially small but bright clouds, and large regions (‘ice-free regions’) in the heart of the cloud season essentially devoid of ice particles. The ice rings bear a close resemblance to tropospheric convective outflow events, suggesting a point source of mesospheric convection. These rings (often circular arcs) are most likely Type IV NLC (‘whirls’ in the standard World Meteorological Organization (WMO) nomenclature).
Do solute-solute interactions affect activation-limited reactions? A Brownian dynamics study

Abstract In this study we use Brownian dynamics (BD) to investigate a model activated reaction. We simulate varying activation energy using the probability of reaction on collision. We find that, as the reaction probability decreases (activation energy increases), local structural effects are seen more strongly at ever higher density. In the limit of very low values of the reaction probability, local structural effects on reactivity are seen over the entire density range studied. This provides clear evidence that the degree to which activation energy affects a chemical reaction correlates directly with the extent to which solute-solute correlations may influence that reaction.
Single-unit responses of serotonergic dorsal raphe neurons to specific motor challenges in freely moving cats

Serotonin has been hypothesized to play an important role in the central control of motor function. Consistent with this hypothesis, virtually all serotonergic neurons within the medullary nuclei raphe obscurus and raphe pallidus in cats are activated in response to specific motor challenges. To determine whether the response profile of serotonergic neurons in the midbrain is similar to that observed in the medulla, the single-unit activity of serotonergic dorsal raphe nucleus cells was studied during three specific motor activities: treadmill-induced locomotion, hypercarbia-induced ventilatory response and spontaneous feeding. In contrast to the results obtained for medullary raphe cells, none of the serotonergic dorsal raphe cells studied (n=26) demonstrated increased firing during treadmill-induced locomotion. A subset of serotonergic dorsal raphe cells (8/36) responded to the hypercarbic ventilatory challenge with increased firing rates that were directly related to the fraction of inspired carbon dioxide, and a non-overlapping subset of cells (6/31) was activated during feeding. All feeding-on cells demonstrated a rapid activation and de-activation coincident with feeding onset and offset, respectively. Although the proportions of serotonergic cells activated by hypercarbia or feeding in the dorsal raphe nucleus were similar to those found in the medullary raphe, there were several major distinctions in the response characteristics for the two cell groups. In contrast to the medullary serotonergic neurons, only a minority of dorsal raphe nucleus serotonergic neurons responded to a motor challenge. Overall, the above results suggest very different roles for the midbrain and medullary serotonergic neurons in response to motor activities.
What's so Hard About Bronchoscopic Surgery?

This study identified aspects of bronchoscopic surgery that are the most physically and mentally demanding in order to focus future technological improvements in areas that are likely to result in the greatest gains in procedure success rate. Seventeen bronchoscopic surgeries were observed and the three participating physicians and their assisting respiratory therapists filled out questionnaires to identify areas of particular challenge. The results indicate that the greatest difficulty in performing pre-biopsy navigation is physical demand. Needle and forceps biopsies are the most difficult tasks of the procedure, where brush biopsies are the least difficult, forceps the next, and needle biopsies the most difficult. The greatest demand for all biopsies was mental. Physicians would benefit from technological developments that aided biopsy location and execution.
Hypertriglyceridemia: risks and perspectives.

Abstract The evidence linking hypertriglyceridemia and coronary artery disease (CAD) is reviewed. A positive correlation between plasma triglyceride level and CAD incidence has been demonstrated in most prospective studies on univariate analysis. However, the significance is weakened on multivariate analysis, in particular when level of highdensity lipoprotein (HDL) cholesterol is taken into account, perhaps because of the close metabolic interrelation between the triglyceride-rich lipoproteins and HDL particles. Recent analyses of clinical data have shown that the combination of elevations of low-density lipoprotein cholesterol and triglyceride and low levels of HDL cholesterol confers particularly high risk for CAD. The U.S. National Institutes of Health Consensus Development Conference on Triglyceride, High Density Lipoprotein, and Coronary Heart Disease in February 1992 made recommendations to integrate more fully HDL cholesterol and triglyceride levels into the assessment and treatment of dyslipidemia and CAD risk. Treatment of hypertriglyceridemia should focus on diet and weight control, exercise, and smoking cessation, as well as control of other major risk factors for CAD, notably hypercholesterolemia and hypertension.
How to Reform the Credit-Rating Process to Support a Sustainable Revival of Private-Label Securitization ¤

US product-liability laws unwisely treat credit-rating organizations (CROs) as if they produce opinions rather than empirically-based economic research. In principle, trained professionals gather time-varying information ("financial news") and analyze it statistically to reduce it to a single dimension, allegedly for the benefit of investors, which, in turn, enables issuers to finance themselves at lower cost. In practice, the issuer-pays business model currently used for funding the production and distribution of ratings information creates an incentive to favor high-volume issuers by over-rating private-label securitizations. While the Dodd–Frank Act intensifies SEC oversight of CRO activity, the SEC has a history of being captured by regulatory clients. We argue that the fundamental solution is to create accountability in the ratings process so that private label securitizations can play a constructive role in the provision of credit and we go on to offer some conjectures about how this could be done.
Fully aromatic thermotropic liquid crystalline polyesters of 3,4′‐dihydroxybenzophenone

A series of fully aromatic, thermotropic polyesters, derived from 3,4′-dihydroxybenzophenone and various aromatic dicarboxylic acids, was prepared by the high-temperature solution polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic dicarboxylic acids used in this study were 2,6-naphthalenedicarboxylic acid, 4,4′-bibenzoic acid, and terephthalic acid. The two homopolymers of 3,4′-DHB with either 2,6-NDA or 4,4′-BBA formed nematic LC phases at 285°C and 255°C and also exhibited isotropization transitions (Ti) at 317°C and 339°C, respectively. The copolymer of 3,4′-DHB with 50% TA and 50% 2,6-NDA also formed a nematic LC phase and had a broader range of LC phase than that of its respective homopolymers. Two other copolymers of 3,4′-DHB, both containing 50% 4,4′-BBA, also formed nematic LC phases at low Tf values. All of the thermotropic polyesters had high thermal stabilities. © 1994 John Wiley & Sons, Inc.
EFFECTS OF SLEEPING POSITION ON CLINICAL VARIABLES IN HEALTHY PRETERM INFANTS. † 1124

To evaluate effects of prone (P) versus supine (S) sleeping position in healthy preterm infants, 20 infants [mean birth weight 1661 ± 435g and mean gestational age 31 ± 2 wks] in the Intermediate Care Nursery at Packard Children's Hospital at Stanford between August 1994 and July 1995 were randomized at 33 weeks post-conceptional age (PCA) to either P (n=13) or S(n=7) sleeping position until discharge. Clinical data regarding weight, apnea, bradycardia [heart rate (HR) < 100], desaturations (oxygen saturation < 95%), and feeding were collected from the nursing records.
Scientific Drilling at Sulphur Springs, Valles Caldera, New Mexico: Core Hole VC 2A

A scientific core hole has been drilled into the western ring fracture zone of the Valles Caldera, N.Mex. Hole VC-2A, the second scientific core hole in the caldera, was cored through a faulted and brecciated sequence of intracaldera tuffs and volcaniclastic rocks to a depth of 528 m at Sulphur Springs. As of November 1, 1986, the unequilibrated bottom hole temperature was 212°C. The rocks that have been penetrated are intensely altered and contain molybdenite mineralization (MnC>2) that is less than or equal to 1.1 m.y. in age. The active hydrothermal system at Sulphur Springs consists of a thin (5-m) acid condensation zone overlying vapor- and water-dominated zones. The latter two zones are apparently separated by a region of tightly sealed rock.
Synthesis of potent and selective serotonin 5-HT1B receptor ligands

A series of serotonin 5-HT1B ligands were synthesized and evaluated for their potency and selectivity against other 5-HT receptor subtypes. Many of these new compounds displayed high affinity and selectivity for the 5-HT1B receptor and compound 6c was found to have the in vitro binding profile necessary for development as a PET radioligand.
Conformational mapping of the N‐terminal peptide of HIV‐1 gp41 in lipid detergent and aqueous environments using 13C‐enhanced Fourier transform infrared spectroscopy

The N-terminal domain of HIV-1 glycoprotein 41,000 (gp41) participates in viral fusion processes. Here, we use physical and computational methodologies to examine the secondary structure of a peptide based on the N terminus (FP; residues 1–23) in aqueous and detergent environments. 12C-Fourier transform infrared (FTIR) spectroscopy indicated greater α-helix for FP in lipid-detergent sodium dodecyl sulfate (SDS) and aqueous phosphate-buffered saline (PBS) than in only PBS. 12C-FTIR spectra also showed disordered FP conformations in these two environments, along with substantial β-structure for FP alone in PBS. In experiments that map conformations to specific residues, isotope-enhanced FTIR spectroscopy was performed using FP peptides labeled with 13C-carbonyl. 13C-FTIR results on FP in SDS at low peptide loading indicated α-helix (residues 5 to 16) and disordered conformations (residues 1–4). Because earlier 13C-FTIR analysis of FP in lipid bilayers demonstrated α-helix for residues 1–16 at low peptide loading, the FP structure in SDS micelles only approximates that found for FP with membranes. Molecular dynamics simulations of FP in an explicit SDS micelle indicate that the fraying of the first three to four residues may be due to the FP helix moving to one end of the micelle. In PBS alone, however, electron microscopy of FP showed large fibrils, while 13C-FTIR spectra demonstrated antiparallel β-sheet for FP (residues 1–12), analogous to that reported for amyloid peptides. Because FP and amyloid peptides each exhibit plaque formation, α-helix to β-sheet interconversion, and membrane fusion activity, amyloid and N-terminal gp41 peptides may belong to the same superfamily of proteins.
Monoethylglycinexylidide and lidocaine determination in porcine microsomal preparations.

Abstract A simple, accurate, and sensitive HPLC analysis of monoethylglycinexylidide (MEGX) and lidocaine in porcine microsome samples is described. Lidocaine and MEGX were measured by direct injection after the addition of the internal standard. Chromatography was performed on a μBondapak C 18 column using an isocratic mobile phase of 0.03 M potassium dihydrogen phosphate:acetonitrile (87:13), pH 5.9. UV absorbance was measured at 205 nm. The procedure produced linear curves for the concentration range 50–1000 ng/mL with a limit of detection of 10 ng/mL. Recoveries for both compounds were greater than 90%. This assay produced accurate and repeatable results.
Clinical effects of a controlled trial of methylphenidate on adolescents with attention deficit disorder.

Abstract Forty-eight attention deficit disorder patients, 12 to 18 years old and without previous stimulant therapy, received a double-blind trial of methylphenidate and placebo for 3 weeks each. Stimulant treatment produced mild side effects and weight reduction, Methylphenidate significantly reduced teachers' and parents' ratings of hyperactivity, inattention, and oppositionality. In addition, patients rated themselves as clinically improved and reported elevated subjective mood during stimulant therapy. Treatment benefits were comparable for patients with and without concurrent conduct or oppositional disorder as well as those with and without past or present depressive disorders. These results support the continued effectiveness of stimulant therapy for attention deficit disorder in adolescence. However, the magnitude of clinical effectiveness reported was smaller than previously found in younger patients. J. Am. Acad. Child Adolesc. Psychiatry, 1990, 29, 5:702–709.
Measurement of neuropeptides in crustacean hemolymph via MALDI mass spectrometry

Neuropeptides are often released into circulatory fluid (hemolymph) to act as circulating hormones and regulate many physiological processes. However, the detection of these low-level peptide hormones in circulation is often complicated by high salt interference and rapid degradation of proteins and peptides in crude hemolymph extracts. In this study, we systematically evaluated three different neuropeptide extraction protocols and developed a simple and effective hemolymph preparation method suitable for MALDI MS profiling of neuropeptides by combining acid-induced abundant protein precipitation/depletion, ultrafiltration, and C18 micro-column desalting. In hemolymph samples collected from the crab Cancer borealis, several secreted neuropeptides have been detected, including members from at least five neuropeptide families, such as RFamide, allatostatin, orcokinin, tachykinin-related peptide (TRP), and crustacean cardioactive peptide (CCAP). Furthermore, two TRPs were detected in the hemolymph collected from food-deprived animals, suggesting the potential role of these neuropeptides in feeding regulation. In addition, a novel peptide with a Lys-Phe-amide C-terminus was identified and de novo sequenced directly from the Cancer borealis hemolymph sample. To better characterize the hemolymph peptidome, we also identified several abundant peptide signals in C. borealis hemolymph that were assigned to protein degradation products. Collectively, our study describes a simple and effective sample preparation method for neuropeptide analysis directly from crude crustacean hemolymph. Numerous endogenous neuropeptides were detected, including both known ones and new peptides whose functions remain to be characterized.
Thermal properties of 2-Oleodipalmitin and 2-Elaidodipalmitin and some of their mixtures

The polymorphism of 2-oleodipalmitin (POP), 2-elaidodipalmitin (PEP), and five of their mixtures was investigated by differential scanning calorimetry (DSC). The heat of fusion (ΔHf), heat of crystallization (ΔHc), and heat of transition (ΔHt) were determined. Rapid conversion to higher polymorphs, partial melting during conversion, and the overlapping of polymorphic forms precluded accurate determination of some caloric values. Four of five previously identified polymorphs of POP and all four polymorphs of PEP were identified by DSC. Five POP: PEP mixtures containing 8, 16, 25, 50, and 75% PEP, respectively, were examined. The presence of PEP in POP increased the stability of the lower POP polymorphs and, in concentrations as low as 8%, also increased the conversion rate of the higher POP polymorphs. In these heating curves, POP forms 5, 4, and 3, and a higher melting fraction that consisted of higher polymorphs of POP, polymorphs of PEP, and probably mixed crystals were evident. The ΔHf values for the tempered mixtures are lower, and the ΔHc values for the mixtures are higher than the calculated values. Heating and cooling curves and calorimetric data tables for POP, PEP, and their five mixtures are included.
A Simple Interferometric Method for Workshop Testing of Optics

A simple step-by-step method is given for deriving the shapes of wavefronts from data obtained with a wavefront shearing interferometer. No mathematics, other than arithmetic, is used. The result is the accurate deviation of the wavefront from a reference sphere that coincides with it at three chosen reference points. The method is intended primarily for the use of opticians in optical workshops, but is also quite practical for the final testing of optics for performance rating. A method is given by which an optician can evaluate an optical surface by comparing the interferogram produced by it and a known prism interferometer, with a drawing of the desired interferogram. This procedure is analogous to using test plates for visual inspection of optical surfaces.
A single peripheral injection of basic fibroblast growth factor (bFGF) stimulates granule cell production and increases cerebellar growth in newborn rats.

The control of neuronal number is critical for coordinating innervation and target organ requirements. Although basic fibroblast growth factor (bFGF) is known to regulate neuron number in the developing embryonic cortex, its potential role during postnatal brain development remains undefined. To address this issue, the cerebellum, a site of postnatal neurogenesis, was used. Previously, we found that a single peripheral injection of bFGF in newborn rats elicited mitosis of neuronal precursors in the external germinal layer (EGL) 8 h after administration. We now define the sustained effects of bFGF treatment on postnatal granule cell production and cerebellar growth. Seventy-two h after a single injection of bFGF (20 ng/g) in newborn rats, the fraction of BrdU-labeled cells in the EGL increased by 46% without altering apoptotic cell number, consistent with enhanced precursor proliferation. Moreover, bFGF increased mitotically labeled cells by 100% and total cell density by 33% in the internal granular layer (IGL), the final destination of the EGL precursors. Because cerebellar volume also increased by 22%, bFGF-induced proliferation enhanced generation of total IGL neurons and increased cerebellar growth. These morphometric measures were corroborated independently by using DNA quantitation: cerebellar DNA content increased 16% after bFGF injection, consistent with increased neuron number. Furthermore, using DNA quantitation as an index, increased total cerebellar cell number elicited by bFGF injection persisted beyond the neurogenetic period, until P35. We conclude that a single postnatal injection of bFGF increases granule neuron number and enhances cerebellar growth following mitotic stimulation. © 2001 John Wiley & Sons, Inc. J Neurobiol 46: 220–229, 2001
“An Honest Sense of the Place”: Reconsidering John Szarkowski's The Face of Minnesota

AbstractJohn Szarkowski was a photographer for nearly two decades before accepting his influential curatorial post at the Museum of Modern Art in New York in 1962. He published two books of his photographs in the 1950s, The Idea of Louis Sullivan (1956), and The Face of Minnesota (1958). Szarkowski's second book became a best seller in the months after its publication, but has received little critical attention in recent discussions of his photographic oeuvre. An examination of early correspondence, publishing records, and Szarkowski's own writings provides a framework for reconsidering the significance of The Face of Minnesota, placing it within a period of innovation in the expanding field of photographically illustrated books. The book is analyzed in terms of its roles as both celebration of the state and platform for the author's personal expression. The book's legacy is considered in terms of its reception since 1958.
π-Arene/Cation Structure and Bonding. Solvation versus Ligand Binding in Iron(III) Tetraphenylporphyrin Complexes of Benzene, Toluene, p-Xylene, and [60]Fullerene

Benzene, toluene, p-xylene, and [60]fullerene are shown to be weak ligands to a hard metal such as iron(III) in Fe(TPP)+ cation (TPP = tetraphenylporphyrinate). X-ray crystal structures of [Fe(TPP)(C6H6)][CB11H6Br6] · 3.5C6H6 (1), [Fe(TPP)(C7H8)][CB11H6Cl6] · 2C7H8 (2), [Fe(TPP)(C8H10)][Ag(CB11H6Br6)2] · arene (3), and [Fe(TPP)(C60)][F20-BPh4] · 2.5dichlorobenzene (4) show distinctively short Fe · · · C contacts, in the range 2.65-2.95 A, which distinguish ligation from π-π cocrystallized solvation. Dihedral angles between the arene and metalloporphyrin planes are also diagnostic of ligand versus solvate roles. The essential features of the arene coordination can be faithfully reproduced using density functional theory. In contrast to alkali metal cation/π-arene interactions, a component of the covalent bonding can be recognized. In a broader context, this study suggests that solvents such as benzene should always be viewed as potential ligands in the presence of coordinatively unsaturated cations. The common use in supramolecular chemistry of the term 'noncovalent' to describe entities with metal-ligand bonds is viewed as misleading.
Effect of vitamin E on arachidonic acid peroxidation and its binding to Chinese hamster V79 cell DNA.

Abstract Following 24 h incubation in standard culture medium (containing 2 μM of arachidonic acid, AA), and 10 and 20 μM supplemented AA, approx. 55, 40 and 33%, respectively, of the fatty acid was incorporated into Chinese hamster V79 cell lipids. The AA content of cell increased 5 to 7-fold with the 10 and 20 μM supplementations of AA and, there was a correspondingly marked decrease in the proportion of AA incorporated into phospholipids (94 vs. 50 and 32%), whereas an increased percentage of AA was recovered in triacylglycerols (1 vs. 30 and 50%) and free fatty acids (1 vs. 3 and 8%). AA at 12 and 22 μM induced a 50 and 80% increase, respectively, in cellular content of thiobarbituric acid reactive substances (TBARS), an indication of increased peroxidation of cell lipids. This formation of TBARS was inhibited by vitamin E but not by indomethacin or SKF-525. Binding of [3H]AA-derived counts to DNA increased in parallel to the levels of cellular lipid peroxidation. Vitamin E added to the culture medium at 10−4 was readily taken up by the cells within 48 h and significantly reduced both lipid peroxidation and binding of AA-derived counts to DNA, without affecting AA uptake. Cell vitamin E content was significantly reduced following 24 h incubation in the presence of 10 and 20 μM supplemented AA. This study indicates that products of lipid peroxidation can bind to DNA in cultured cells, and points to a potential cyto- and geno-toxic risk posed by increased cellular AA content relative to anti-oxidant defenses.
Ar(2) excimer emission from a pulsed-discharge-excited pulsed supersonic gas jet.

We report what is to our knowledge the first observation of argon excimer fluorescence between 115 and 140 nm in a pulsed supersonically cooled gas jet after pulsed-discharge excitation. The emission is observed tor measured pressures at the supersonic orifice greater than 3 atm.
Rubbing Salt into Wounds: Hypertonic Saline to Assist with Volume Removal in Heart Failure

Traditionally accepted management strategies for patients with heart failure include sodium and fluid restriction, neurohormonal blockade, and the use of loop diuretics to achieve and maintain euvolemia. Despite continued advances in medical and device therapy, fluid management remains a significant problem in patients with the cardiorenal syndrome (manifested as diuretic resistance and worsening renal function with more aggressive attempts at volume removal). This article examines the counterintuitive use of hypertonic saline as a potential therapy to facilitate diuresis in patients with decompensated heart failure and diuretic resistance. Low-volume hypertonic saline administration offsets counterproductive neurohormonal upregulation, transiently improves hemodynamics, and promotes renal sodium excretion with accompanied net water loss and preservation of renal function. This “new” therapeutic tool should be explored further as an adjunct to current medical therapies in the management of patients with refractory volume overload.
Lead isotope systematics and the evolution of the core, mantle, crust and atmosphere

Abstract A new analysis of the isotope systematics of sulphide common leads can be made on the basis of examining the deriations of the data from a simple single-stage evolution. Δt , the age discrepancy between the single-stage lead model age and the geologic age, increases systematically from 3.8 Ga to the present. This trend appears to reflect an increase in the μ of the primitive mantle due to incorporation of a large portion of the earth's lead into the core, early in the earth's evolution. Leads associated with shale-hosted lead-zinc deposits show a rapid increase in Δt beginning at 2.5 to 2.0 Ga. This deviation of shale-hosted leads from the general trend is interpreted as a response to concentration of uranium in organic-rich shales subsequent to the evolution of an oxidizing atmosphere. Comparison of common leads in alkali feldspars with the volcanogenic sulphide data suggests that they have a similar evolution of Δt with time. Numerical simulations reveal that even substantial increases in real μ over the last 2.0 Ga are not reflected in significant increases in the single-stage model μs.
Initial Stages in the Propagation of Cosmic Rays Produced by Solar Flares

The propagation of solar cosmic rays produced in the February 23, 1956 flare has been studied from the time they leave the flare region to the time when the terrestrial cosmic-ray intensity reaches a maximum value. Within this interval there are observed not only strong anisotropies in the incident radiation, but also relatively large differences in time (\ensuremath{\le}9 minutes) between the commencements of the intensity increases in different parts of the world. This distribution of time delays is superposed upon the transit-time delay which all particles experience between production and detection.