cssi/SciSciGPT-SciSciNet huggingface dataset:
Hydrophobic and Charged Residues in the Central Segment of the Measles Virus Hemagglutinin Stalk Mediate Transmission of the Fusion-Triggering Signal

ABSTRACT The pH-independent measles virus membrane fusion process begins when the attachment protein H binds to a receptor. Knowing that the central segment of the tetrameric H stalk transmits the signal to the fusion protein trimer, we investigated how. We document that exact conservation of most residues in the 92 through 99 segment is essential for function. In addition, hydrophobic and charged residues in the 104 through 125 segment, arranged with helical periodicity, are critical for F protein interactions and signal transmission.
Insect venom allergy: a prospective case study showing lack of correlation between immunologic reactivity and clinical sensitivity

Abstract This case report demonstrates the lack of correlation between clinical sensitivity to insect venoms and immunologic reactivity as indicated by the presence of venom-specific IgE. A 20-yr-old venom collector was monitored over a 3-yr period with measurements of venom-specific IgE (skin test and RAST) and venom-specific IgG. In the first year of venom collection, multiple stings were tolerated with no reaction. In the second season, she had an anaphylactic reaction after a yellow jacket sting. Subsequently, there was a rising titer of serum yellow jacket and bee venom-specific IgE and positive skin-test reactions. In the third season, yellow jacket, hornet, and bee venom skin tests remained positive and serum IgE antibody titers remained elevated. Stings from all three insects were tolerated with no reaction. Throughout the 3-yr course, serum venom-specific IgG remained low and unchanged. The factors other than IgE-modulating clinical anaphylaxis, perhaps responsible for this clinical and immunologic dichotomy, are unknown. These observations add a further complication to the choice of patients for venom immunotherapy.
Reliability of assessing trunk motor control using position and force tracking and stabilization tasks

System-based methods have been applied to assess trunk motor control in people with and without back pain, although the reliability of these methods has yet to be established. Therefore, the goal of this study was to quantify within- and between-day reliability using systems-based methods involving position and force tracking and stabilization tasks. Ten healthy subjects performed six tasks, involving tracking and stabilizing of trunk angular position in the sagittal plane, and trunk flexion and extension force. Tracking tasks involved following a one-dimensional, time-varying input signal displayed on a screen by changing trunk position (position tracking) or trunk force (force tracking). Stabilization tasks involved maintaining a constant trunk position (position stabilization) or constant trunk force (force stabilization) while a sagittal plane disturbance input was applied to the pelvis using a robotic platform. Time and frequency domain assessments of error (root mean square and H2 norm, respectively) were computed for each task on two separate days. Intra-class correlation coefficients (ICC) for error and coefficients of multiple correlations (CMC) for frequency response curves were used to quantify reliability of each task. Reliability for all tasks was excellent (between-day ICC≥0.8 and CMC>0.75, within-day CMC>0.85). Therefore, position and force control tasks used to assess trunk motor control can be deemed reliable.
Clement of Rome and Moralism

Clement of Rome has often been judged and found wanting by his Protestant interpreters. His letter is frequently presented as “a good illustration of the break between the New Testament faith and the Apostolic Fathers' lapse into moralism.” (And “moralism,” to put it mildly, is not always a pleasant word in Protestant theological circles.) Rudolf Knopf calls attention to the “rationalen Moralismus des Schreibens.” And Johannes Weiss says that “a strong moralism runs through all its expressions from the first page to the last.” When James Mackinnon gives us examples of Christian moralism in the sub-apostolic period, Clement is of course present in a prominent way, as indeed he is also significantly present when H. E. W. Turner mentions the “tradition of ‘sober moralism’ which was so notable a feature of late first-century and early second-century Christianity.” Moreover, A. C. McGiffert stands in the same tradition of interpretation when he says that for Clement “salvation is to be had only by obeying God and doing his will.” One could of course go on and on citing examples of this kind, but it seems unnecessary to do so, especially in view of the fact that a great many more illustrations are readily available in Thomas F. Torrance's The Doctrine of Grace in the Apostolic Fathers. Not only does Professor Torrance mention numerous scholars who stress the moralism of Clement, but also he himself comes to the conclusion that grace in I Clement appears to be an “enabling power granted to those who are worthy.” Clement “may use the language of election and justification, but the essentially Greek idea of the unqualified freedom of choice is a natural axiom in his thought, and entails a doctrine of ‘works,’ as Paul would have said.”
Subsurface damage in single-crystal sapphire

Subsurface damage (SSD) and material removal rates in the C, A, and M crystallographic faces of single-crystal sapphire have been examined. SSD is related to the peak-to-valley surface microroughness by SSD? 1.4 x PV.
Beta-neurotoxin reduces neurotransmitter storage in brain synapses.

β-neurotoxin, a component of Bungarus multicinctus venom, is known to cause neuromuscular blockade by first increasing the rate of spontaneous ACh release and then inhibiting the nerve impulse-induced release of ACh. We report that the toxin also affects the storage of several neurotransmitters in rat brain and it is active on synaptosomes and brain minces. Synaptosomes prepared from brain tissue that had been treated with β-toxin have a reduced ability to accumulate radioactive NE, GABA, serotonin and the ACh precursor, choline. The toxin also causes a release of previously accumulated NE and GABA from synaptosomes, suggesting that the storage process rather than the uptake transport process is affected. The toxin does not contain phospholipase A, phospholipase C, protease or hyaluronidase activity.
Top down and bottom up engineering of bone

The goal of this retrospective article is to place the body of my lab′s multiscale mechanobiology work in context of top-down and bottom-up engineering of bone. We have used biosystems engineering, computational modeling and novel experimental approaches to understand bone physiology, in health and disease, and across time (in utero, postnatal growth, maturity, aging and death, as well as evolution) and length scales (a single bone like a femur, m; a sample of bone tissue, mm–cm; a cell and its local environment, μm; down to the length scale of the cell's own skeleton, the cytoskeleton, nm). First we introduce the concept of flow in bone and the three calibers of porosity through which fluid flows. Then we describe, in the context of organ–tissue, tissue–cell and cell–molecule length scales, both multiscale computational models and experimental methods to predict flow in bone and to understand the flow of fluid as a means to deliver chemical and mechanical cues in bone. Addressing a number of studies in the context of multiple length and time scales, the importance of appropriate boundary conditions, site specific material parameters, permeability measures and even micro-nanoanatomically correct geometries are discussed in context of model predictions and their value for understanding multiscale mechanobiology of bone. Insights from these multiscale computational modeling and experimental methods are providing us with a means to predict, engineer and manufacture bone tissue in the laboratory and in the human body.
Reversible and Irreversible Inhibition of Thyroid Peroxidase-Catalyzed Iodination by Thioureylene Drugs*

The mechanism of reversible and irreversible inhibition of thyroid peroxidase (TPO)-catalyzed iodination by thioureylene drugs was investigated using a model incubation system. The major observations may be summarized as follows. 1) TPO is inactivated by 1-methyl-2-mercaptoimidazole and propylthiouracil even in the presence of a relatively high concentration of iodide. The extent of this inactivation depends on the ratio of iodide to drug. 2) Spectral changes observed on oxidation of the drugs with the peroxidase-iodide system were very similar to those observed when the drugs were oxidized nonenzymatically with I3-. These findings support the view that oxidized iodine is an intermediate in TPO-catalyzed oxidation of the drugs. 3) Under conditions where TPO is largely inactivated, inhibition of iodination is complete and irreversible. Drug metabolism, on the other hand, occurs to a limited extent. 4) Under conditions where TPO is only partially inactivated, inhibition of iodination is transient (reversibl...
X-ray structure of putative acyl-ACP desaturase DesA2 from Mycobacterium tuberculosis H37Rv

Genome sequencing showed that two proteins in Mycobacterium tuberculosis H37Rv contain the metal binding motif (D/E)X(2)HX(approximately 100)(D/E)X(2)H characteristic of the soluble diiron enzyme superfamily. These putative acyl-ACP desaturase genes desA1 and desA2 were cloned from genomic DNA and expressed in Escherichia coli BL21(DE3). DesA1 was found to be insoluble, but in contrast, DesA2 was a soluble protein amenable to biophysical characterization. Here, we report the 2.0 A resolution X-ray structure of DesA2 determined by multiple anomalous dispersion (MAD) phasing from a Se-met derivative and refinement against diffraction data obtained on the native protein. The X-ray structure shows that DesA2 is a homodimeric protein with a four-helix bundle core flanked by five additional helices that overlay with 192 structurally equivalent amino acids in the structure of stearoyl-ACP Delta9 desaturase from castor plant with an rms difference 1.42 A. In the DesA2 crystals, one metal (likely Mn from the crystallization buffer) was bound in high occupancy at the B-site of the conserved metal binding motif, while the A-site was not occupied by a metal ion. Instead, the amino group of Lys-76 occupied this position. The relationships between DesA2 and known diiron enzymes are discussed.
A Novel and Selective Photoisomerization of Allylic Benzoates

Ultraviolet irradiation of a series of polyunsaturated allylic benzoates results in highly selective E/Z interconversion of the allylic double bond.
Visualization of replication initiation and elongation in Drosophila.

Chorion gene amplification in the ovaries of Drosophila melanogaster is a powerful system for the study of metazoan DNA replication in vivo. Using a combination of high-resolution confocal and deconvolution microscopy and quantitative realtime PCR, we found that initiation and elongation occur during separate developmental stages, thus permitting analysis of these two phases of replication in vivo. Bromodeoxyuridine, origin recognition complex, and the elongation factors minichromosome maintenance proteins (MCM)2–7 and proliferating cell nuclear antigen were precisely localized, and the DNA copy number along the third chromosome chorion amplicon was quantified during multiple developmental stages. These studies revealed that initiation takes place during stages 10B and 11 of egg chamber development, whereas only elongation of existing replication forks occurs during egg chamber stages 12 and 13. The ability to distinguish initiation from elongation makes this an outstanding model to decipher the roles of various replication factors during metazoan DNA replication. We utilized this system to demonstrate that the pre–replication complex component, double-parked protein/cell division cycle 10–dependent transcript 1, is not only necessary for proper MCM2–7 localization, but, unexpectedly, is present during elongation.
Differential Induction of Gelatinase B (MMP-9) and Gelatinase A (MMP-2) in T Lymphocytes upon α4β1-Mediated Adhesion to VCAM-1 and the CS-1 Peptide of Fibronectin☆

Integrin alpha(4)beta(1) on the surface of T lymphocytes interacts with vascular cell adhesion molecule-1 (VCAM-1) and fibronectin during migration of lymphocytes from the blood to sites of inflammation. Migrating lymphocytes actively modify their environment through a number of mechanisms including proteolysis of the extracellular matrix by matrix metalloproteinases (MMP) synthesized by the cells. In this study, expression of MMP upon alpha(4)beta(1)-mediated adhesion of leukocytes to two major ligands, the IIICS-1 domain of fibronectin and VCAM-1, has been examined. Adhesion of T lymphoblastoid Jurkat cells to the CS-1 peptide induced expression of mRNA for two MMPs, gelatinase A (MMP-2) and gelatinase B (MMP-9). As evaluated by relative RT-PCR and Northern blot analyses, the level of mRNA was upregulated about 4- to 5-fold for both MMPs compared to control cells maintained in suspension. With time, both enzymes were detected in conditioned media and inside the cells, and their identities were verified by Western blotting and gelatin zymography. Adhesion of Jurkat cells to the second major alpha(4)beta(1) ligand, VCAM-1, upregulated mRNA for MMP-2 (3.5-fold) and failed to induce expression of mRNA for MMP-9. Accordingly, only MMP-2 protein was detected in conditioned media of cells adherent to VCAM-1. Occupancy of alpha(4)beta(1) on the surface of suspended cells with soluble CS-1 peptide or VCAM-1 did not upregulate synthesis and release of MMPs. A similar pattern of induction of MMPs after adhesion to CS-1 and VCAM-1 was observed in T lymphocytes isolated from human blood. These results demonstrate that adhesion of T lymphocytes through alpha(4)beta(1) to different ligands, which bind to similar or overlapping sites in the integrin, induces intracellular events leading to distinct patterns of MMPs biosynthesis.
SATCHMORE: SATCHMO with RElevancy

We introduce a relevancy detection algorithm to be used in conjunction with the SATCHMO prover. The version of SATCHMO considered here is essentially a bidirectional prover, utilizing Prolog (back chaining) on Horn clauses and forward chaining on non-Horn clauses. Our extension, SATCHMORE (SATCHMO with RElevancy), addresses the major weakness of SATCHMO: the uncontrolled use of forward chaining. By marking potentially relevant clause head literals, and then requiring that all the head literals be marked relevant (be “totally relevant”) before a clause is used for forward chaining, SATCHMORE is able to guide the use of these rules. Furthermore, the relevancy testing is performed without extending the proof search beyond what is done in SATCHMO. A simple implementation of the extended SATCHMO can be written in Prolog. We describe our relevancy testing approach, present the implementation, prove soundness and completeness, and provide examples that demonstrate the power of relevancy testing.
Behavioral tactics for reinstating natural breathing in infants with tracheostomy.

Extract: Two 8-month-old, Caucasian male infants with long-standing difficulties in decannulation following tracheostomy were subjected to a program designed to facilitate a return to normal breathing. Both infants had previously experienced numerous unsuccessful attempts at decannulation; they possessed a tolerance for breathing normally for a period of less than five minutes. After a 3-week behaviorial treatment program, their ability to breathe normally rapidly improved when the tracheostomy cannula was occluded. At the end of treatment, the patients progressed from a tolerance of less than 5 minutes to 36 continuous hours of occlusion, and the cannula was successfully removed without complication. The patients have fared well since that time. Speculation: It is hypothesized that the principles of conditioning and behavioral modification applied in this investigation offer a practical, effective solution to the problem of decannulation following tracheostomy. The unique advantages of the techniques employed include: (1) The patient is better prepared for decannulation by virtue of having the ability to breathe normally before such procedures are attempted, and (2) the longer periods of independent breathing by the patient indicate when decannulation may occur with predictable success.
GPCR–Gα fusion proteins: molecular analysis of receptor–G-protein coupling

The efficiency of interactions between G-protein-coupled receptors (GPCRs) and heterotrimeric guanine nucleotide-binding proteins (G proteins) is greatly influenced by the absolute and relative densities of these proteins in the plasma membrane. The study of these interactions has been facilitated by the use of GPCR-Galpha fusion proteins, which are formed by the fusion of GPCR to Galpha. These fusion proteins ensure a defined 1:1 stoichiometry of GPCR to Galpha and force the physical proximity of the signalling partners. Thus, fusion of GPCR to Galpha enhances coupling efficiency can be used to study aspects of receptor-G-protein coupling that could not otherwise be examined by co-expressing GPCRs and G proteins as separate proteins. The results of studies that have made use of GPCR-Galpha fusion proteins will be discussed in this article, along with the strengths and limitations of this approach.
Long-term Outcome for Obstructive Sleep Apnea Syndrome Patients: Mortality

As the actual mortality and morbidity of obstructive sleep apnea syndrome (OSAS) have been unknown heretofore, we undertook a follow-up study of 198 OSAS patients seen at the Stanford Sleep Disorders Clinic between 1972 and 1980, for whom either tracheostomy (71 patients) or weight loss (127 patients) had been recommended. At five-year follow-up, all of the deaths (14) had occurred among those conservatively treated with weight-loss (a mortality rate of 11 per 100 patients per five years). These patents also had a higher five-year crude vascular mortality rate: 6.3 per 100 patients per five years, with an age-standardized vascular mortality rate of 5.9 per 100 patients per five years (95 percent confidence interval [CI] 2.5-11.6) vs 0 per 100 for the surgically treated population; this despite a lower mean apnea index (43 versus 69) and a lower mean body mass index (31 versus 34 kg/m2) in the conservatively treated group. With the fictional adjunction of one possible death at five-year follow-up in the surgically treated group, the age-adjusted odds of vascular mortality at five years for the conservatively treated group was 4.7. Our data therefore encourage "aggressive" treatment for patients with OSAS.
Comparison between dopamine transporter affinity and self-administration potency of local anesthetics in rhesus monkeys.

Abstract Local anesthetics bind to dopamine transporters and inhibit dopamine uptake in rodent brain. Additionally, local anesthetics are self-administered in rhesus monkeys. The present study determined binding affinities of cocaine and five local anesthetics at dopamine transporters in rhesus monkey brain, and compared binding affinities to published self-administration potencies in rhesus monkeys. The affinity order at dopamine transporters was cocaine>dimethocaine>tetracaine>procaine≥chloroprocaine>lidocaine. The correlation between dopamine transporter affinities and self-administration potencies was significant. Binding affinities were also determined at sodium (Na 2+ ) channels in rhesus monkey brain. There was not a significant correlation between Na 2+ channel affinities and self-administration potencies Local anesthetics with high dopamine transporter and low Na 2+ channel affinities were self-administered, whereas those with either high or low affinity at both sites were not consistently self-administered. These data suggest that affinity at dopamine transporters is related to the reinforcing effects of local anesthetics in rhesus monkeys, and Na 2+ channel effects may interfere with the reinforcing effect of these drugs.
Simplifying potato irrigation scheduling—the Idaho program

Etude des effets d'un stress hydrique sur le rendement et la qualite de production de la pomme de terre, en fonction du stade de vegetation
A 3He4He dilution refrigerator cryostat system for nuclear orientation experiments

Abstract A description is given of a system which has been used to cool radioactive sources to temperatures in the vicinity of 15 mK. A special aspect of the design is a set of easily demountable aluminum shields with a maximum diameter of 5 cm around the source and with beryllium windows for the transmission of low-energy photons. Two pairs of superconducting coils are used to produce a rotatable magnetic field at the source.
Detection of single base substitutions by ribonuclease cleavage at mismatches in RNA:DNA duplexes

Single base substitutions can be detected and localized by a simple and rapid method that involves ribonuclease cleavage of single base mismatches in RNA:DNA heteroduplexes. A 32P-labeled RNA probe complementary to wild-type DNA is synthesized in vitro and annealed to a test DNA containing a single base substitution. The resulting single base mismatch is cleaved by ribonuclease A, and the location of the mismatch is then determined by analyzing the sizes of the cleavage products by gel electrophoresis. Analysis of every type of mismatch in many different sequence contexts indicates that more than 50 percent of all single base substitutions can be detected. The feasibility of this method for localizing base substitutions directly in genomic DNA samples is demonstrated by the detection of single base mutations in DNA obtained from individuals with beta-thalassemia, a genetic disorder in beta-globin gene expression.
The impact of regression towards the mean on probing changes in studies on the effect of periodontal therapy.

Abstract The purpose of this report was to evaluate the magnitude of the regression towards the mean (RTM) relative to the observed changes in probing measurements following periodontal therapy in 2 groups of patients. Regression lines were calculated for observed changes in probing depths and probing attachment levels related to the initial probing depths of the individual sites. Regression lines, adjusted for the RTM effect, were also calculated. For the extreme subgroups of recorded shallow and deep sites, the RTM effect (mm) was found to amount to a maximum of 0.6 mm. It appears unlikely that erroneous conclusions have been made in previous clinical studies evaluating probing depth changes in deep sites, since the RTM accounts for a limited portion of the observed changes. For probing depth changes in shallow sites and for probing attachment level changes in both shallow and deep sites, the RTM accounts for a larger proportion of the observed mm changes. It therefore seems prudent to be careful about interpretation of these changes in clinical studies, where the RTM effect has not been adjusted for. Whenever possible, duplicate initial recordings should be taken to allow determination of and subsequent adjustment for the RTM effect.
Mesenteric venous thrombosis

Percutaneous intervention is increasingly being used as an adjunct or alternative to surgical therapy for the treatment of acute, symptomatic, mesenteric venous thrombosis and noncavernous, chronic, portal vein thrombosis. The authors' review of the literature revealed 16 cases of acute mesenteric venous thrombosis and 38 cases of chronic portal vein thrombosis that have been treated with thrombolytic therapy, mechanical recanalization, or a combination of these two therapies. This article reviews the diagnosis and management of patients with mesenteric venous thrombosis, the literature which describes percutaneous intervention for management of this condition, and presents the authors' early experience and preliminary conclusions.
Examining the Cost-effectiveness of 2-Level Cervical Total Disc Replacement

Cervical total disc replacementwasdeveloped to treat symptomsassociatedwithdiscdegenerationwhilepreservingphysiological motion. Several clinical trials have compared its use with traditional anterior cervical discectomy and fusion for both single-level and multilevel disease.1,2 Ament et al3 analyzed data from a published multicenter randomizedclinical trial by Davis et al4 that demonstrated the clinical superiority of the Mobi-C cervical artificial disc vs anterior discectomy and fusion for 2-level contiguous degenerative disc disease and proposed that 2-level total cervical disc replacement is a cost-effective intervention. This is a potentially significant conclusion. As health care costs continue to increase, there is growing scrutiny ofmedical and surgical treatments offered topatients that, despite efficacy,maybecostprohibitive.Using thequality-adjusted lifeyear scale, the authors showed that 2-level cervical total disc replacement is a cost-effective treatment modality.3 However, several limitationsneed tobeconsidered.First, datawere derived from a multicenter randomized clinical study with strict inclusionandexclusion criteria.As such, the resultsmay not be generalizable to the general populationof patientswho are candidates for anterior cervical surgery. In addition, although thedecisionanalyticmodelingused in thestudyseems reasonable, assumptions that may not be valid were used for the analysis. Even so, the results of this study provide compelling evidence that cervical total disc replacement is a costeffective option for 2-level symptomatic cervical spondylitic disease.
Water Quality Trends (1970 to 2005) Along Delaware Streams in the Delaware and Chesapeake Bay Watersheds, USA

Water quality trends from 1970 to 2005 were defined along 30 Delaware streams in the Delaware and Chesapeake Bay watersheds in the USA. Water quality improved or was constant at 69% of stations since 1990 and at 80% of stations since 1970/1980. Dissolved oxygen (DO) improved or was constant at 73% of streams since 1990 and 32% of streams since 1970/1980. Total suspended sediment improved or was constant at 75% of streams since 1990 and 100% of streams since 1970/1980. Enterococcus bacteria improved or remained constant at 80% of streams since 1990 and 93% of streams since 1970/1980. Total Kjeldahl nitrogen improved or was constant at 48% of streams since 1990 and 100% of streams since 1970/1980. Total phosphorus improved or was constant at 66% of streams since 1990 and 85% of streams since 1970/1980. During 2001–2005, median levels were good or fair at 100% of the stations for DO, 78% for sediment, 50% for bacteria, 59% for nitrogen, and 56% for phosphorus. Good water quality correlates with high amounts of forest area (>25%) in Delaware watersheds. Since the Federal Clean Water Act Amendments of the 1970s, improving Delaware water quality stations (50) outnumbered degrading stations (23) by a 2:1 margin. Since 1990, degrading water quality stations (46) exceeded improving stations (38) mostly due to deteriorating nitrogen levels in half of Delaware streams, a reversal from early gains achieved since the 1970s. Over the last three and a half decades, watershed strategies have improved or preserved water quality along Delaware streams; however, greater emphasis is needed to curb recently resurging increases in nitrogen levels.
Factors associated with physical activity in women across the life span: implications for program development.

ABSTRACT This study examined the rates and factors associated with physical activity in women of various ages. Adult women (n = 653) from four community-based family medicine clinics completed a self-administered behavioral and health questionnaire while waiting to see their physician. Findings suggested variation in physical activity over the life span, with older women performing less physical activity than younger women. Family characteristics (e.g., having children) were strongly associated with performing less structured, less intense physical activities of daily living among women 49 years and younger. Younger women reported having high self-efficacy for physical activity, but also reported the greatest numbers of barriers. Women in the oldest age category reported health as the most common motivator for physical activity, but were also least likely to perform physical activity. Interventions designed to meet the unique needs of women at different stages in their lives will potentially reduce the ra...
Insertion of bacteriorhodopsin into polymerized diacetylenic phosphatidylcholine bilayers

Abstract We have developed a method to incorporate the membrane protein bacteriorhodopsin into polymerized bilayers composed of a diacetylenic phosphatidylcholine, 1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine (DC8,9PC) and a non-polymerizable phospholipid, dinonanoylphosphatidylcholine (DNPC). The extent of DC8,9PC polymerization in the bilayer was significantly improved when 2:1 mole ratio DNPC-DC8,9PC was used. Octyl glucopyranoside-solubilized bacteriorhodopsin was inserted into the polymerized DNPC-DC8,9PC bilayers by overnight incubation at 4°C followed by dialysis to remove the detergent. The protein was inserted into the membranes after photo-polymerization to avoid inactivation of the protein due to the UV irradiation. The insertion of bacteriorhodopsin into the polymerized DNPC-DC8,9PC membranes was confirmed by density gradient centrifugation, UV/visible spectroscopy, and freeze fracture electron microscopy. The polymerized DNPC-DC8,9PC membranes containing bacteriorhodopsin were about 10% protein by weight. These results suggest that mixed lipid systems such as the DNPC-DC8,9PC can be used to improve both the extent of polymerization and the efficiency of membrane protein incorporation in the polymerized bilayer.
Absorption and scattering of thermal radiation by a cloud of small particles

An experimental investigation was made of the absorption and scattering of thermal radiation by a cloud of small, spherical, micronsized, aluminum oxide particles in a plane-parallel enclosure. By using carbon tetrachloride and carbon disulphide as suspendign media, transmission measurements were made with collimated and diffuse sources for wavelengths from 2 to 11μ. By employing a two-flux diffuse model, the data were correlated to obtain absorption and back-scattering cross sections. From the diffuse and collimated data, a backscattering coefficient was found which varied linearly with relative refractive index. With the developed coefficients, the absorptivities of the cloud of particles were determined.
Phenotypic discordance in a family with monozygotic twins and non-syndromic cleft lip and palate.

Despite considerable research, the cause of non-syndromic cleft lip with or without cleft palate (NSCLP) is still an enigma. Case-control and cohort studies have searched for environmental factors that might influence the development of this common malformation, such as maternal cigarette smoking, periconceptional supplementation of folic acid and multivitamins, agricultural chemical use, and place of residence, among others. However, these studies are subject to numerous biases, and their results have often been contradictory and inconclusive. 41 refs., 1 fig.
A new bound on the local density of sphere packings

It is shown that a packing of unit spheres in three-dimensional Euclidean space can have density at most 0.773055..., and that a Voronoi polyhedron defined by such a packing must have volume at least 5.41848... These bounds are superior to the best bounds previously published [5] (0.77836 and 5.382, respectively), but are inferior to the tight bounds of 0.7404... and 5.550... claimed by Hsiang [2]. Our bounds are proved by cutting a Voronoi polyhedron into cones, one for each of its faces. A lower bound is established on the volume of each cone as a function of its solid angle. Convexity arguments then show that the sum of all the cone volume bounds is minimized when there are 13 faces each of solid angle 4?/13.
Soft rock pillars

Soft rock pillars can be designed by several methods available in the mining literature. All of these methods include the effect of shape, or geometry, on the average strength of specimens and pillars. All of the pillar design methods include some measurement of the strength of specimens of the pillar rock. The most common rock specimen strength property measured is the unconfined compressive strength. However, the average strength of triaxially confined rock specimens is much greater than the unconfined specimen strength, which can be more important to pillar strength. The estimation of the strength of a pillar is complicated by the decrease in rock specimen strength with increase in specimen size.
Phase effects on reflection of optical narrow-extent pulses from axially excited chiral sculptured thin films

Sculptured thin films (STFs) comprise parallel bent nanowires that are 30-100 nm in diameter. Using a finite-difference algorithm, we solved the time-domain Maxwell equations to investigate the reflection of optical narrow-extent pulses from both linear and nonlinear chiral STFs. Although he axial component of the Poynting vector -- the pulse shape -- is invariant to changes of carrier wave phase in the incident pulse, we determined that the reflected pulse shape is affected by those changes.
A cross-continental test of the Enemy Release Hypothesis: leaf herbivory on Acer platanoides (L.) is three times lower in North America than in its native Europe

Acer platanoides (Norway maple) is a widespread native tree species in Europe. It has been introduced to North America where it has often established dense stands in both secondary woodlands and relatively undisturbed mature woodlands. In Europe A. platanoides is also extending its original range, but generally seems to exist at much lower densities. One explanation for the ‘aggressiveness’ of invasive plants such as A. platanoides is that they have left behind pests and diseases which limit their population densities in their native lands (the enemy release hypothesis or ERH). To assess the ERH for Norway maple, a large network of collaborators assessed leaf herbivory rates in populations throughout Europe and North America. We found significantly lower total leaf herbivory (1.6% ± 0.19, n = 21 vs. 7.4% ± 1.94, n = 34) and lower fungal damage (1.0% ± 0.35, n = 13 vs. 3.7% ± 0.85, n = 34) in North America than in Europe over a 2 year period, which is consistent with the predictions of the Enemy Release Hypothesis. Across years, the average total leaf herbivory was significantly correlated with average annual temperature of the site (P 0.05). Furthermore, only populations in Europe showed very high levels of herbivory (e.g., nine sites had total leaf herbivory ranging from 10.0 to 51.2% in at least 1 year) or leaf fungal damage (only one site in North America showed high levels of fungal damage in 1 year), suggesting the possibility of more frequent episodic outbreaks in the native range. Leaf herbivory and fungal damage are only two aspects of consumer pressure and we do not know whether the differences reported here are enough to actually elicit release from top-down population control, but such large scale biogeographic differences in herbivory contribute towards understanding exotic invasions.
Allogeneic graft-versus-tumor effects: Mechanistic insights and therapeutic promise

Cellular and molecular mechanisms of allogeneic graft-versus-tumor (GVT) effects include Th1 and Tc1 cell interleukin-2 (IL-2) and interferon-γ (IFN-γ) secretion, antigen-presenting cell (APC) IL-1-α and tumor necrosis factor-α (TNF-α) secretion, and cytolytic effectors operating through perforin, fas and TNF-related apoptosis inducing ligand (TRAIL) pathways. Because such mechanisms also contribute to graft-versus-host disease (GVHD), separation of GVT effects from GVHD has proven problematic. Research advances in allograft T cell engineering and cytokine, vaccine and molecularly targeted therapy hold promise for improved harnessing of GVT effects.
Clinical dilemma in triplet pregnancy: when is it appropriate to intervene for a jeopardized fetus?

Clinical Dilemma in Triplet Pregnancy: When Is It Appropriate to Intervene for a Jeopardized Fetus?
Conantokins inhibit NMDAR-dependent calcium influx in developing rat hippocampal neurons in primary culture with resulting effects on CREB phosphorylation

Abstract The effects of conantokin (con)-G, con-R[1-17], and con-T on ion flow through N-methyl- d -aspartate receptor (NMDAR) ion channels were determined in cultured primary rat hippocampal neurons. The potency of con-G diminished, whereas inhibition by con-R[1-17] and con-T did not change, as the neurons matured. Con-G, con-R[1-17], and con-T effectively diminished NMDA-induced Ca 2+ influx into the cells. A similar age-dependent decrease in con-G-mediated inhibition of the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) was observed, compared to con-R[1-17] and con-T. The effects of the conantokins on NMDA-induced cAMP response element-binding protein (CREB) phosphorylation in immature (DIV 9) and mature (DIV 16) neurons showed that, at DIV 9, con-G, con-R[1-17], and con-T inhibited NMDA-mediated P-CREB levels, whereas in DIV 16 neurons the conantokins did not inhibit overall levels of NMDA-induced P-CREB. In contrast, P-CREB levels were enhanced through inhibition of the protein phosphatases, PP1 and PP2B (calcineurin). This ability of conantokins to sustain CREB phosphorylation can thus enhance neuronal survival and plasticity.
Measurement of radiation-induced demagnetization of Nd-Fe-B permanent magnets

Abstract Nd–Fe–B permanent magnets are highly desirable for use in the insertion devices of synchrotron radiation sources due to their high remanence, or residual magnetic induction, and intrinsic coercivity. However, the radiation environment within high-energy storage rings makes essential the determination of the degree of radiation sensitivity as well as the mechanisms of radiation-induced demagnetization. Sample Nd–Fe–B permanent magnets were irradiated at the Advanced Photon Source with bending magnet X-rays up to an absorbed dose of approximately 280 Mrad (1 Mrad=10kGy). Sample magnets were also irradiated with 60Co γ-rays up to an absorbed dose of 700 Mrad at the National Institute of Standards and Technology's standard gamma irradiation facility. Changes in the residual induction were found to be within the experimental uncertainties for both the X-ray and γ-ray irradiations. Sample Nd–Fe–B permanent magnets were then irradiated at Oak Ridge National Laboratory's Californium User Facility for Neutron Science with fast neutrons up to a total fast fluence of 1.61×1014 n/cm2, and with thermal neutrons up to a total thermal fluence of 2.94×1012 n/cm2. The fast-neutron irradiation revealed changes between residual induction measurements of the sample magnets before and after irradiation of 0.6% and greater for fast-neutron fluence levels of 2×1013 n/cm2 and above. Thermal-neutron irradiation revealed changes in the residual induction measurements of the sample magnets before and after irradiation that were within the experimental uncertainties for thermal-neutron fluence levels up to 3×1012 n/cm2.
An algorithm based on queue migration for mutual exclusion in computer networks

A non-symmetric algorithm is presented that achieves mutual exclusion in a decentralized computer network by exchanging messages and a synchronization queue. The algorithm is unique in the sense that the number of messages required to achieve mutual exclusion is a function of the workload enabling it to provide acceptable performance in a lightly loaded system with a significant improvement as the workload increases. The algorithm outperforms other previously proposed algorithms in a heavily loaded system, is robust and comparatively easy to implement.
Radioimmunoassay of rat apolipoprotein A-IV

We have developed a specific and sensitive radioimmunoassay for rat apolipoprotein A-IV (apoA-IV). The protocol includes treatment of the samples for 1 h at 60 degrees C with 0.7% Tween 20. Under these conditions, linear logit-log plots have been obtained for apoA-IV in lymph and plasma lipoprotein fractions as well as for purified apoA-IV. The sensitivity of the assay is to 20 ng. Absolute mass values obtained with the assay were validated by comparison with values obtained with an independent method of colorimetric reading of apoA-IV separated by polyacrylamide gel electrophoresis from plasma high density lipoproteins. The concentration of apoA-IV in fasting plasma averaged 10.2 mg/dl and in the mesenteric duct lymph 15.8 and 12.6 mg/dl during the fasting and the fat absorption states, respectively.
A numerical experiment of radiant heat interchange by the monte carlo method

Abstract Radiant heat interchange between simply arranged surfaces having direction dependent characteristics has been studied by the statistical method known as Monte Carlo. The diffuse and specular constant property, the specular directional emission and reflection, and the directional emission and the bidirectional reflection models have been explored with the preliminary goal of understanding what level of detail is important in the description of the radiation properties of surfaces. Four simple configurations which permit a critical examination of the directional effects have been examined. Results showed that under some conditions the choice of the model for radiation surface characteristics can be very critical for both the local radiant heat flux and for overall radiant interchange calculations.
Global Learning by Distance: Principles and Practicalities for Learner Support

The knowledge economy demands a highly skilled and well-rounded work force. However, because traditional institutions cannot meet the demand for post-secondary education, technological innovations, particularly distance learning, are becoming the solution for increased access. As distance programs are developed for global delivery, cultural and linguistic issues must be considered. Pedagogical methods, modes of learning, communication styles, English proficiency, and delivery logistics potentially interfere with the success of such endeavors. This article addresses the opportunities and obstacles of creating distance courses for international learners. It reviews the need for international educational access, provides an overview of the issues, and shares a learner-centered framework to demonstrate principles and practicalities for mitigating potential obstacles to distance learning as a global venture. The framework is illustrated with examples from distance English language learning courses.
Determination of cadmium by flow injection atomic absorption spectrometry with cold vapor generation by a tetrahydroborate-form anion-exchanger

A volatile derivative was formed on passage of an acidified cadmium solution through a strong anion-exchange resin in the tetrahydroborate(III) form. The efficiency of four resins, Amberlite IRA-400, Amberlite IRA-410, Amberlyst A-26 and Dowex-1, were investigated. Amberlite IRA-400 (160 mg, 50 mm × 3 mm id) gave the highest sensitivity for both peak height and peak area. The effects of column dimensions, concentration of tetrahydroborate, loading time, carrier reagent flow rate, carrier gas flow rate, acidity of sample, stripping coil length, the direction of loading and injection were studied and the relationship between sample volume and limit of detection were evaluated. The column was regenerated after each determination. From a study of masking agents, thiourea, L-cysteine, sodium fluoride, cupferron, EDTA, tartaric acid, 5-sulfosalicylic acid for the plant and soil matrices, it was found that thiourea and L-cysteine were suitable, whereas cupferron, EDTA, tartaric acid and 5-sulfosalicylic acid suppressed the signal. Passing the sample through an anion-exchange column before the immobilized tetrahydroborate column improved the signal for plant and soil matrices. Less suppression by some elements was observed than for generation by reaction with tetrahydroborate in aqueous solution, and smaller amounts of reagents were required. The limits of detection (3s) in 0.2 mol l−1 nitric acid solution with 1% thiourea, and with 1% thiourea plus 1 mg l−1 Co, were 40 and 30 ng l−1, respectively, with a sampling frequency of 30–45 h−1. The relative standard deviation (n = 5) was 5%, 2.0% and 3.2% at 0.5, 1.0 and 3.0 μg l−1, respectively. The method was applied to the analysis of natural waters, wine, human saliva, orange juice, human urine and human hair, for which 1% thiourea and 1 mg l−1 Co were added. For plant and soil analysis, 0.1% L-cysteine and 1 mg l−1 Co were added. Pre-digestion spike recoveries were in the range of 81–110%. The detection limits (3s) were in the range of 0.04–0.05 μg l−1 in natural water samples and 0.02–0.40 μg g−1 in human hair and plant samples. The results obtained for the analysis of four NIST standard reference materials, freeze-dried urine (SRM 2670), Montana soil (SRM 2711), spinach leaves (SRM 1570a), and tomato leaves (SRM 1573a), were in agreement with the certified values.
Surface-enhanced Raman spectroscopy of soft-landed polyatomic ions and molecules.

Surface-enhanced Raman spectroscopy (SERS) was used to detect and characterize polyatomic cations and molecules that were electrosprayed into the gas phase and soft-landed in vacuum on plasma-treated silver substrates. Organic dyes such as crystal violet and Rhodamine B, the nucleobase cytosine, and nucleosides cytidine and 2‘-deoxycytidine were immobilized by soft landing on plasma-treated metal surfaces at kinetic energies ranging from near thermal to 200 eV. While enhancing Raman scattering 105−106-fold, the metal surface effectively quenches the fluorescence that does not interfere with the Raman spectra. SERS spectra from submonolayer amounts of soft-landed compounds were sufficiently intense and reproducible to allow identification of Raman active vibrational modes for structure assignment. Soft-landed species appear to be microsolvated on the surface and bound via ion pairing or π-complexation to the Ag atoms and ions in the surface oxide layer. Comparison of spectra from soft-landed and solution s...
Maternal sensitivity: within-person variability and the utility of multiple assessments.

In this study, we examined within-person variability in maternal sensitivity among a culturally diverse sample of high-risk mother-infant dyads (N = 25). We also examined incremental increases in effect sizes between maternal sensitivity and two related variables, attachment state of mind and child removal from the home, as a function of increasing observations of maternal sensitivity. The dyads were videotaped during 10 1-hour-long home visits and maternal sensitivity was coded using the abbreviated (25-item) version of the Maternal Behavior Q-Sort (MBQS). Attachment state of mind was assessed using the Adult Attachment Interview (AAI). Within-person variability in maternal sensitivity was greater for nonautonomous mothers compared to autonomous mothers. Mothers who were relatively low in maternal sensitivity were more likely to be nonautonomous and also more likely to have their child removed from their home by child protective services. Results from data sampling trials showed incremental increases in these effect sizes as the number of observations of maternal sensitivity increased. Fewer observations of maternal sensitivity resulted in systematic underestimates of effect sizes between maternal sensitivity and related variables. We discuss the implications for maltreatment researchers and interventionists. Language: en