cssi/SciSciGPT-SciSciNet huggingface dataset:
T1 weighted Brain Images at 7 Tesla Unbiased for Proton Density, T2* contrast and RF Coil Receive B1 Sensitivity with Simultaneous Vessel Visualization

Abstract At high magnetic field, MR images exhibit large, undesirable signal intensity variations commonly referred to as “intensity field bias”. Such inhomogeneities mostly originate from heterogeneous RF coil B1 profiles and, with no appropriate correction, are further pronounced when utilizing rooted sum of square reconstruction with receive coil arrays. These artifacts can significantly alter whole brain high resolution T1-weighted (T1w) images that are extensively utilized for clinical diagnosis, for gray/white matter segmentation as well as for coregistration with functional time series. In T1 weighted 3D-MPRAGE sequences, it is possible to preserve a bulk amount of T1 contrast through space by using adiabatic inversion RF pulses that are insensitive to transmit B1 variations above a minimum threshold. However, large intensity variations persist in the images, which are significantly more difficult to address at very high field where RF coil B1 profiles become more heterogeneous. Another characteristic of T1w MPRAGE sequences is their intrinsic sensitivity to Proton Density and T2⁎ contrast, which cannot be removed with post-processing algorithms utilized to correct for receive coil sensitivity. In this paper, we demonstrate a simple technique capable of producing normalized, high resolution T1w 3D-MPRAGE images that are devoid of receive coil sensitivity, Proton Density and T2⁎ contrast. These images, which are suitable for routinely obtaining whole brain tissue segmentation at 7 T, provide higher T1 contrast specificity than standard MPRAGE acquisitions. Our results show that removing the Proton Density component can help in identifying small brain structures and that T2⁎ induced artifacts can be removed from the images. The resulting unbiased T1w images can also be used to generate Maximum Intensity Projection angiograms, without additional data acquisition, that are inherently registered with T1w structural images. In addition, we introduce a simple technique to reduce residual signal intensity variations induced by transmit B1 heterogeneity. Because this approach requires two 3D images, one divided with the other, head motion could create serious problems, especially at high spatial resolution. To alleviate such inter-scan motion problems, we developed a new sequence where the two contrast acquisitions are interleaved within a single scan. This interleaved approach however comes with greater risk of intra-scan motion issues because of a longer single scan time. Users can choose between these two trade offs depending on specific protocols and patient populations. We believe that the simplicity and the robustness of this double contrast based approach to address intensity field bias at high field and improve T1 contrast specificity, together with the capability of simultaneously obtaining angiography maps, advantageously counter balance the potential drawbacks of the technique, mainly a longer acquisition time and a moderate reduction in signal to noise ratio.
Compartmentalized growth of hemopoietic stem cells within mouse friend leukemic spleens.

A dose of 4000 rads (r) to the central portion of mouse spleens followed by Friend erythroleukemic virus infection created independent compartments where hemopoietic stem cells exhibited distinct growth kinetics. Rather than suggesting autonomous proliferation, the stem cell kinetics were indicative of the control excercised by the local microenvironment upon stem cell growth within each compartment.
Identification of genes required for recycling reducing power during photosynthetic growth.

Photosynthetic organisms have the unique ability to transform light energy into reducing power. We study the requirements for photosynthesis in the α-proteobacterium Rhodobacter sphaeroides. Global gene expression analysis found that ∼50 uncharacterized genes were regulated by changes in light intensity and O2 tension, similar to the expression of genes known to be required for photosynthetic growth of this bacterium. These uncharacterized genes included RSP4157 to -4159, which appeared to be cotranscribed and map to plasmid P004. A mutant containing a polar insertion in RSP4157, CT01, was able to grow via photosynthesis under autotrophic conditions using H2 as an electron donor and CO2 as a carbon source. However, CT01 was unable to grow photoheterotrophically in a succinate-based medium unless compounds that could be used to recycle reducing power (the external electron acceptor dimethyl sulfoxide (DMSO) or CO2) were provided. This suggests that the insertion in RSP4157 caused a defect in recycling reducing power during photosynthetic growth when a fixed carbon source was present. CT01 had decreased levels of RNA for genes encoding putative glycolate degradation functions. We found that exogenous glycolate also rescued photoheterotrophic growth of CT01, leading us to propose that CO2 produced from glycolate metabolism can be used by the Calvin cycle to recycle reducing power generated in the photosynthetic apparatus. The ability of glycolate, CO2, or DMSO to support photoheterotrophic growth of CT01 suggests that one or more products of RSP4157 to -4159 serve a previously unknown role in recycling reducing power under photosynthetic conditions.
Consumer's Resistance to Genetically Modified Foods: The Role of Information in an Uncertain Environment

Genetically modified (GM) foods have been engulfed in considerable controversy, and the early optimism has been dampened. Information issueslabeling and asymmetric informationare central to the GM-food debate. Furthermore, it is important to understand the reaction in developed countries to GM-foods because they set the tone of the world market in grains, oilseeds, and animal products. New results are reported from a statistical analysis of the market characteristics that push consumers in a high-income country to resist GM foods, with an emphasis on negative information from environmental groups and third-party, verifiable information, which could neutralize private information distributed by interested parties. A unique sample of adult consumers participated in laboratory auctions of three food products with randomized labeling and information treatments. A key finding is that GM information supplied by environmental groups increases the probability that consumers are out of the market for GM-foods. Third-party verifiable information, however, dissipates most of the negative effect of the environmental group perspective. Selective adoption of GM crops seems likely to raise world welfare but Western Europes banning of GM imports and technology will largely affect them negatively.
Acquisition of M. protein by pneumococci through transformation reactions.

MacLeod and Austrian demonstrated in this article a type-specific protein that was not limited to the control of the synthesis of capsular polysaccharides, further indicating that DNA was the carrier of genetic information.
Central nervous system juvenile xanthogranuloma with malignant transformation

Juvenile xanthogranuloma (JXG) is a rare histiocytic disorder that typically manifests in the skin. Here, we describe a patient with JXG diffusely involving the central nervous system (CNS), whose disease responded to therapy but subsequently underwent dissemination to the peritoneum and bone marrow. Repeat biopsy at dissemination revealed pleomorphic histiocytes with tetraploidy, suggesting evolution to a clonal histiocytic neoplasm. Despite further chemotherapy, the patient died of disease progression. This case highlights the clinical and pathological heterogeneity of JXG and the difficulty of treating multi-focal CNS disease.
A technique for the accurate measurement of cardiac ventricular pressures in chronic animals.

Abstract Accurate ventricular pressure measurements are essential in many experimental procedures. However, obtaining this information in the chronic animal is either very expensive or plagued with uncertainties. This paper describes a method for implanting a chronic ventricular catheter which permits the repeated insertion into the left ventricle of a miniature pressure transducer. Since only one such transducer is required it reduces expense and as the transducer is not chronically implanted, it permits repeated calibration, thus eliminating the uncertainty of transducer drift. This procedure has been used successfully in chronically prepared dogs and promises to be a useful technique in working with conscious animals.
Magnetic Resonance Studies of Ferroelectric Methylammonium Alum

The electron paramagnetic resonance of C${\mathrm{H}}_{3}$N${\mathrm{H}}_{3}$Al${(\mathrm{S}{\mathrm{O}}_{4})}_{2}$\ifmmode\cdot\else\textperiodcentered\fi{}12${\mathrm{H}}_{2}$O (MASD) doped with ${\mathrm{Cr}}^{3+}$ was studied from 90 to 300\ifmmode^\circ\else\textdegree\fi{}K. At the first-order ferroelectric Curie point (177\ifmmode^\circ\else\textdegree\fi{}K), an abrupt change in the fine-structure splitting as well as the resonance linewidths was observed. Continuous-wave and pulsed proton-resonance experiments were performed on ordinary and partially deuterated MASD. The relaxation time in the rotating coordinate system (${T}_{1\ensuremath{\rho}}$) exhibited a discontinuity at the transition temperature ${T}_{c}$. The ${T}_{1\ensuremath{\rho}}$ data are interpreted as due to a 180\ifmmode^\circ\else\textdegree\fi{} flip motion of the C${\mathrm{H}}_{3}$N${\mathrm{H}}_{3}^{+}$ ion which changes abruptly at ${T}_{c}$. The ${T}_{1}$ data show a single minimum characteristic of rotation of the C${\mathrm{H}}_{3}$ group about the triad axis. It is suggested that the ferroelectric transition in MASD results from a one-dimensional reorientation of the C${\mathrm{H}}_{3}$N${\mathrm{H}}_{3}^{+}$ ions. Possible reasons for the first-order nature of the transition are given.
Extra views on RNA-dependent DNA methylation and MBD6-dependent heterochromatin formation in nucleolar dominance.

Nucleolar dominance is a widespread epigenetic phenomenon, describing the preferential silencing of ribosomal RNA (rRNA) genes inherited from one progenitor of an interspecific hybrid, independent of maternal or paternal effects. In the allotetraploid hybrid plant species Arabidopsis suecica, A. thalianaderived rRNA genes are silenced whereas the A. arenosa-derived rRNA genes are transcribed. We reported previously on an RNAi-based screen of DNA methyltransferases, methylcytosine binding proteins and RNA-dependent DNA methylation pathway proteins that identified specific activities required for the establishment or enforcement of nucleolar dominance. Here we present additional molecular and cell biological evidence that siRNAdirected cytosine methylation and the methylcytosine binding protein MBD6 bring about large-scale chromosomal effects on rRNA gene loci subjected to nucleolar dominance in A. suecica.
Prediction of nitrogen oxide formation in turbulent coal flames

A model of nitrogen pollutant formation and destruction in pulverized coal reactors, whose foundations were presented recently, is briefly outlined and then evaluated by comparisons of predictions with measurements. The model incorporates effects of turbulence on the NO reactions and subsequent predictions show these effects to be important. Thermal and prompt NO were neglected. The model predicts: 1) An initial decrease followed by a gradual increase in NO emissions with increased swirl number as observed for the particular cases modeled; 2) an increase in NO emissions with increased stoichiometric ratio as observed; at higher values, the model underpredicts NO concentrations, partly because of higher thermal NO contributions which are not modeled, and 3) the observed increase in NO with a decrease in particle size and with increase in moisture percentage. Predicted NO emissions for the four test variables differed by an absolute average of 9% from measured values for 24 comparisons. Comparisons with local NO and HCN concentrations from pulverized-coal flames show some agreement except in regions immediately following ignition where oxygen depletion and devolatilization are overpredicted. Predicted NO effluent emissions for six profile cases differ by an absolute average of 24% from measured values. Results suggest that fuel nitrogen release during devolatilization and gas phase reactions of HCN and oxygen control NO formation, while fuel nitrogen conversion to HCN may be near quantitative and rapid. According to the predictions, NO reduction is dominated by HCN-NO reactions and not by the char-NO reactions, while turbulence has an important impact on the gaseous reactions.
II. Effect of CO2 on afferent vagal endings in the canine lung.

Abstract We have attempted to identify the afferent endings responsible for the pulmonary-CO2 ventilatory reflex. We recorded afferent vagal impulses arising from the left lung in anesthetized dogs with separately ventilated lungs. When the left pulmonary artery was occluded, left lung PCO2 fell to 3 mm Hg and slowly-adapting pulmonary stretch receptor activity increased 46%. Firing declined to its original intensity when left lung PCO2 was raised in steps by administration of CO2, firing decreasing most between 2 and 19 mm Hg, and least between 30 and 50 mm Hg. Irritant receptor activity also increased (from 2.8 to 7.4 impulses/sec) after pulmonary arterial occlusion, the effect being reversed by administration of CO2. These procedures caused trivial changes in pulmonary and bronchial C-fiber activity. Effects on both slowly-adapting stretch receptors and irritant receptors appeared to result from a direct action of CO2 on the endings themselves, rather than from mechanical changes in the lung. Changes in slowly-adapting stretch receptor activity provide an adequate explanation for the pulmonary CO2 ventilatory reflex, the relationship between impulse frequency and lung PCO2 suggesting that these afferents may have a role in limiting CO2 loss under conditions causing hypocapnia, but be less effective in stimulating breathing during hypercapnia.
Nuclear decay properties of light einsteinium isotopes

Abstract The light einsteinium isotopes 248 Es, 249 Es, 250 Es and 251 Es were synthesized by irradiating a 249 Bk target with 3 He and 4 He ions. Because of the short half-life of 248 Es, it was necessary to characterize this isotope by using the recoil technique, whereas the other isotopes were chemically purified before their properties were determined. The half-lives of the above nucleides were found to be 28 ± 5 min, 1.7 ± 0.1 h, 8.3 ± 0.2 h and 33 ± 1 h, respectively. A new isomer of 250 Es was discovered and its half-life was determined to be 2.1 ± 0.2 h. The energies of the main α groups for 248 Es, 249 Es and 251 Es were observed to be 6.87 ± 0.01, 6.770 ± 0.005 and 6.488 ± 0.005 MeV, respectively. The α/K X-rays ratio for 249 Es was found to be 0.007 ± 0.001 and the value for 251 Es was 0.008±0.002. Several gamma rays associated with the electron-capture decay of the einsteinium isotopes were observed. On the basis of the present investigation the ground states of 249 Es and 251 Es have been assigned to the Nilsson states 7 2 + (633↑) and 3 2 − (521↑) , respectively.
The mechanism of the photochemical reactions of SO2 with isobutane excited at 3130 Å

The mechanism of the reactions of electronically excited SO2 with isobutane has been studied through the measurement of the initial quantum yields of product formation in 3130 A irradiated gaseous binary mixtures of SO2 and isobutane and ternary mixtures of SO2, isobutane, C6H6 or CO2. Under low-pressure conditions (P 10 torr) the low-pressure mechanism coupled with the saturation effect on the phosphorescence lifetimes of SO2(3B1) molecules cannot alone rationalize the quantum yields. The evaluation suggests that some nonradiative intermediate state (X) is involved in the formation of “extra” triplet molecules. This ill-defined state decays largely nonradiatively to SO2 in experiments at low pressures, X SO2 (12). In the presence of C6H6 the low-pressure data give k7 = (8.5 ± 1.8) × 1010, and the high-pressure data give k7 = (8.3 ± 0.6) × 1010 and (9.9 ± 0.9) × 1010l./mol·sec; SO2(3B1) + C6H6 nonradiative products (7). These estimates are in good agreement with values directly measured from low-pressure lifetime studies, (8.1 ± 0.7) × 1010 and (8.8 ± 0.8) × 1010l./mol·sec.
Development of revised SAPRC aromatics mechanisms

Abstract The representation of the gas-phase atmospheric reactions of aromatic hydrocarbons in the SAPRC-07 chemical mechanism has been updated to give better simulations of recent environmental chamber experiments carried out under lower NOx conditions than used to develop SAPRC-07. SAPRC-07 consistently underpredicted NO oxidation and O3 formation rates observed in most of the newer experiments. The new aromatics mechanisms, designated as SAPRC-11, gave better simulations of O3 formation in almost all experiments, except for higher (>100 ppb) NOx benzene and (to a lesser extent) toluene experiments where O3 formation rates were consistently overpredicted. This overprediction at higher NOx can be corrected if the aromatics mechanism is parameterized to include a new NOx dependence on photoreactive product yields, but that parameterization was not incorporated in SAPRC-11 because it is inconsistent with available laboratory data. The mechanisms for phenolic compounds were also significantly revised to better simulate the new experiments. The base mechanism for SAPRC-11 incorporates a few minor updates, but otherwise is the same as SAPRC-07. The light source used in the chamber experiments had no significant effect on mechanism evaluation results, except possibly for cresols. The mechanisms still underpredict OH radical levels and further studies are needed to reduce uncertainties in aromatics mechanisms.
Ultrafast processes in metal-insulator and metal-semiconductor nanocomposites

We discuss theoretical predictions for ultrafast (mostly femtosecond) linear and nonlinear optical phenomena in metal/insulator and metal/semiconductor nanocomposites. In metal/insulator nanocomposites, we consider spontaneous and coherently-controlled energy concentration. We show that very strong (many orders of magnitude in local-field intensity) ultrafast concentration of energy on nanoscale is possible. In metal/semiconductor quantum dot nanocomposites, we consider a fascinating possibility of quantum generator due to spaser (surface plasmon amplification by stimulated emission of radiation). Various applications are discussed.
RNA and protein synthesis inhibitors: Effects on sexual behavior in female rats

Abstract Biochemical evidence indicates that many steroid hormone effects on target tissues arc mediated via actions on the genome. Studies on the hormonal control of reproductive behavior have demonstrated several effects of RNA or protein synthesis inhibitors on female sexual behavior in rats. In female rats treated with estrogen and progesterone, intracranial application of actinomycin-D (an RNA synthesis inhibitor) can disrupt lordosis responding if the drug is given in conjunction with estrogen. but not with progesterone. Protein synthesis inhibitors (cycloheximide or anisomycin) applied intracranially at the time of estrogen also disrupt lordosis. with anisomycin antagonizing the progesterone-facilitation of lordosis. Possible neural sites of action of these drugs are considered, as are alternative modes of action of these synthesis inhibitors. Whereas the effects of estrogen on lordosis include the synthesis of some, as yet unidentified, proteins, the exact role for protein synthesis in the mediation of progesterone's actions on lordosis remains less certain.
Percent true calcium absorption, mineral metabolism, and bone mineralization in children with cystic fibrosis: effect of supplementation with vitamin D and calcium.

Objective To assess whether percent true calcium absorption (α) is normal in children with cystic fibrosis (CF) and to assess whether supplementation with 2,000 IU vitamin D3, 1 g calcium, or both will alter α, mineral metabolism, and/or bone mass in children with CF. Study Design Fifteen children ages 7–13 were randomly assigned to one of four different orders to receive all four 6-month treatments including placebos. Change in 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D (1,25(OH)2D), PTH, bone turnover markers, and minerals after 6 months, and bone mineral content (Hologic 1000W) after 9 months was measured. α was measured by a dual stable isotope method using 48Ca intravenously and 46Ca orally and measuring 48Ca, 46Ca, and 42Ca in a 24-hr urine using High Resolution Inductively Coupled Mass Spectroscopy (HR-ICP-MS). Analysis used Wilcoxon Sign Ranks. Results α was in the normal range and did not differ by treatment (P 35 ± 10%, Ca 38 ± 23%, D 36 ± 11%, D + Ca 46 ± 21%). One gram calcium did not increase serum or urine calcium. Two thousand IU D3 did not increase 25-OHD or change 1,25(OH)2D. Serum and urine minerals, markers of bone turnover and bone mineral gains did not differ by treatment. Conclusions α is normal in children with CF. One gram calcium and/or 2,000 IU D3 does not change α or increase 25-OHD, serum calcium, or mineralization. Longer trials of a significantly higher dose of vitamin D3 shown to increase serum 25-OHD are needed to assess effects on mineral metabolism and bone mass accrual. However, study of therapeutic options other than calcium and vitamin D should be encouraged. Pediatr Pulmonol. 2008; 43:772–780. © 2008 Wiley-Liss, Inc.
Acid rain: Predictions and applications

Il est question du nouvel instrument et de la nouvelle methode introduite par Adams et al. (1986) pour mesurer l'acidite de la pluie. Parmi les resultats interessants, il est note la dependance de l'acidite vis-a-vis de la taille des gouttelettes et une baisse de la concentration locale d'un polluant durant un episode de pluie. De ce fait, il est conclu a une capacite predictive limitee des modeles actuels qui ne tiennent pas compte de ces resultats
Accumulation of inorganic polyphosphate in mutants of Neurospora crassa.

1. 1. 53 strains of Neurospora crassa, representing 4 wild types and 40 mutant loci, were examined for accumulation of acid-soluble inorganic polyphosphate. When grown on a limited supply of growth factor, most of the mutants were found to accumulate polyphosphate, though the amounts varied widely. 2. 2. The time sequence of polyphosphate accumulation was studied in shaken cultures of the histidine-requiring strain, C-84. When growth ceased due to exhaustion of the amino acid, the RNA content of the mycelium dropped sharply. Concomitantly, acid-soluble polyphosphate accumulated; the levels of other phosphorus compounds, including the acid-insoluble polyphosphate, were not affected. 3. 3. By the use of 32P it was demonstrated that, in C-84, extensive degradation of RNA occurred upon exhaustion of the histidine. The phosphorus released from RNA was converted to polyphosphate and constituted a major source of phosphorus for polyphosphate accumulation. Similar observations were made with other mutant strains, though the details of the pattern of growth, RNA degradation and polyphosphate accumulation varied from strain to strain. 4. 4. Inhibition of the growth of Neurospora strains by withholding a macronutrient or by addition of a metabolic inhibitor did not, in general, induce either RNA degradation or polyphosphate accumulation. However, when mycelium was transferred to medium lacking the carbon source, sucrose, extensive degradation of RNA took place. Acid-soluble polyphosphate and inorganic orthophosphate accumulated under these conditions. 5. 5. Polyphosphate accumulation was inhibited by certain amino acid analogs. In C-84, the histidine analog 2-thiazolealanine was found to inhibit RNA degradation but had no effect on the accumulation of polyphosphate. 6. 6. The relationship of polyphosphate accumulation to the primary genetic block is discussed. The possible role of RNA degradation as the immediate cause of polyphosphate accumulation is considered.
Induction of the viable but non-culturable condition in Xanthomonas campestris pv. campestris in liquid microcosms and sterile soil

Xanthomonas campestris pathovar campestris was examined for the ability to enter the viable but non-culturable (VBNC) state. When nutrients were removed from a bacterial culture, the culturability dropped to undetectable levels within 6 weeks while the concentration of viable cells remained above 105 cells ml−1. Addition of cupric sulfate facilitated this process. When bacteria were placed in autoclaved soil, culturability dropped by at least four logs within 5 days of the experiment while the concentration of viable cells remained at least two logs higher. These results indicate that the plant pathogen X. campestris can enter the VBNC condition in sterile soil and in liquid cultures and that cupric sulfate decreases the time for entry into the VBNC condition.
Role of the Double-Strand Origin Cruciform in pT181 Replication

pT181 is a small rolling-circle plasmid from Staphylococcus aureus whose initiator protein, RepC, melts the plasmid's double-strand origin (DSO) and extrudes a cruciform involving IR II, a palindrome flanking the initiation nick site. We have hypothesized that the cruciform is required for initiation, providing a single-stranded region for the assembly of the replisome (R. Jin et al., 1997, EMBO J. 16, 4456-4566). In this study, we have tested the requirement for cruciform extrusion by disrupting the symmetry of the IR II palindrome or by increasing its length. The modified DSOs were tested for replication with RepC in trans. Rather surprisingly, disruption of the IR II symmetry had no detectable effect on replication or on competitivity of the modified DSO, though plasmids with IR II disrupted were less efficiently relaxed than the wild type by RepC. However, in conjunction with IR II disruption, modification of the tight RepC binding site IR III blocked replication. These results define two key elements of the pT181 initiation mechanism--the IR II conformation and the RepC binding site (IR III)--and they indicate that pT181 replication initiation is sufficiently robust to be able to compensate for significant modifications in the configuration of the DSO.
A dynamic study of plasma renin activity and aldosterone concentration in normal and hypertensive subjects.

Abstract Variations of plasma renin activity (PRA) and plasma aldosterone concentration have been studied after a water load with a 2-hour period of recumbency followed by furosemide infusion in five normal subjects and seven hypertensive patients. It has been found following furosemide infusion that there is a lag of 15 min between the increase in PRA and that of aldosterone. PRA and aldosterone levels are still elevated when diuresis and natriuresis have returned close to normal. Patients with essential hypertension behave like normal subjects during this dynamic test except for one patient with abnormally low PRA and low normal levels of plasma aldosterone. The two patients with primary aldosteronism were able to modify their aldosterone concentration as normal subjects did, but at all times their levels remained higher. Plasma aldosterone concentration as a diagnostic screening test should be performed in the upright position.
Effect of metathoracic leg ablation upon mesothoracic motor responses to giant interneuron stimulation in the cockroach

1. The influence of ablating metathoracic legs upon the GI-to-motor response was studied inPeriplaneta americana. 2. The motor response to intracellular stimulation of individual dGIs was significantly greater after the metathoracic legs were removed than before ablation. 3. No change was seen in the response of metathoracic motor neurons when mesothoracic legs were removed. 4. This effect could also be detected in long term experiments. Motor responses in animals that had undergone leg ablation 3–7 days prior to recording motor responses also showed significant increases over control animals. 5. A similar effect could be seen by simply tying the metathoracic legs in such a way as to prevent them from making leg contact. 6. Leg removal does not significantly impair the animal's ability to escape from a natural predator. 7. The results indicate that the state of the metathoracic legs influences the response of mesothoracic motor neurons to GI activation. However, the reverse is not the case.
ARTERIAL OXYGEN TENSION DURING APNOEA IN PARTURIENT WOMEN

The decrease in arterial oxygen tension, during 60 sec of apnoea with exposure to room air, was studied in twelve healthy parturient women undergoing Caesarean section under endotracheal fluroxene-oxygen anaesthesia. Eight young gynaecological patients, anaesthetized in an identical manner, served as controls. The reduction in oxygen tension was significantly greater in the pregnant women than in the controls and was greatest in women in labour. The results confirm the presence of a markedly increased oxygen consumption at term and emphasize the importance in obstetric anaesthesia of preoxygenation before and of prompt reoxygenation following endotracheal intubation.
Robustness of the maximum-likelihood estimation procedure in factor analysis.

In order to determine the robustness of the maximum-likelihood estimation procedure, random variates from six distributions were generated independently on a high speed computer and then used to represent the common and specific factors in a factor analysis model in which the coefficients of these factors had been specified. Using Lawley's approximatex 2 statistic in evaluating the estimates obtained, the estimation procedure is found to be insensitive to changes in the distributions considered.
Suicidality, aggression, and other treatment considerations among pregnant, substance-dependent women with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) and other Axis I comorbidity among women with substance use disorders (SUDs) appear similarly prevalent and are associated with comparable negative clinical profiles and treatment outcomes. The relative contribution of comorbid PTSD vs other Axis I psychiatric disorders to clinical characteristics is largely unexamined, however, despite theory and empirical data indicating that PTSD and SUDs may have a unique relationship that confers specific risk for clinical severity and poor treatment outcome. In a sample of pregnant, opioid- and/or cocaine-dependent women entering substance abuse treatment, women with PTSD (SUD-PTSD; n = 23) were compared to those with other Axis I comorbidity (SUD-PSY; n = 45) and those without Axis I comorbidity (SUD-only; n = 37). Data were collected via face-to-face interviews and urinalysis drug assays. Although the study groups had similar substance use severity, the SUD-PTSD group was more likely to report suicidality, aggression, and psychosocial impairment than both the SUD-PSY and SUD-only groups. Findings indicate treatment considerations for substance-dependent women with PTSD are broader and more severe than those with other Axis I conditions or substance dependence alone.
On the long-range detection of radioactivity using electromagnetic radiation

Abstract A series of recent publications (Tech. Phys. Lett. 19 (1993) 184; Atom. Ener. 80 (1996) 47; Atom. Ener. 80 (1996) 135; Physics–Uspekhi 168 (1998) 515; Izvestiya 28 (1992) 262; Geomagn. Aeron. 34 (1994) 229; J. Atmos. Solar-Terres. Phys. 59 (1997) 961; Stud. Geophs. Geod. 42 (1998) 197; Adv. Space Res. 20 (1997) 2173) has provided experimental evidence that radiation fields can be detected well beyond the 10–100-m limit that holds for conventional (direct) approaches for detecting radiation. The techniques that are claimed to provide this capability use remote electromagnetic interrogation to record changes atmospheric electrostatic parameters arising from elevated radiation levels. This paper examines the physics that underlies these proposed new approaches for detecting radiation. If found to be viable for applications, the proposed techniques would be highly significant as they directly address a variety of problems in national security and environmental monitoring.
The importance of hydrogen and formate transfer for syntrophic fatty, aromatic and alicyclic metabolism

Summary We used a combination of genomic, transcriptional and enzymatic analyses to determine the mechanism of interspecies electron transfer by two model syntrophic microorganisms, Syntrophomonas wolfei and Syntrophus aciditrophicus. Both organisms contain multiple hydrogenase and formate dehydrogenase genes, but lack genes for outer membrane cytochromes and nanowire formation. Syntrophically grown cells and cell-free extracts of S. aciditrophicus and S. wolfei had both hydrogenase and formate dehydrogenase activities. Butyrate metabolism and CH4 production by washed cell suspensions of S. wolfei and Methanospirillum hungatei were inhibited by hydrogenase inhibitors (cyanide and carbon monoxide), but not by a formate dehydrogenase inhibitor (hypophosphite). Syntrophic benzoate oxidation and CH4 production by washed cell suspensions of S. aciditrophicus and M. hungatei were inhibited by hypophosphite, but not cyanide and carbon monoxide. All three inhibitors halted syntrophic cyclohexane-1-carboxylate metabolism. Two hydrogenase genes, hydA1 and hydA2, were more highly expressed when S. wolfei was grown syntrophically. S. aciditrophicus expressed multiple hydrogenase and formate dehydrogenase genes during syntrophic benzoate and cyclohexane-1-carboxylate growth, one of which (fdhA2) was highly differentially expressed during syntrophic benzoate growth. Thus, these syntrophic microorganisms have flexible metabolisms that allow them to use either H2 or formate transfer depending on the substrate involved.
Theory of hindered sedimentation of polydisperse mixtures

The theory and application of hindred sedimentation is reviewed. Polydisperse mixtures with size and density distributions are considered. A general solution technique is established for steady-flow regimes where a standard drag correlation for monodisperse systems is applied to each component. Solutions for discrete and continuous particle-size and density distributions are outlined. Results are presented for the sedimentation of mixtures made up of particles of uniform density and varying size suspended in a fluid with fixed properties. Under these conditions, the sedimentation velocities of the components vary significantly with the size distribution of the particles and the total volume fraction occupied by the particles In this context, topics such as maximum flux of particles, classification and density separation are considered.
Robust stability of a family of disc polynomials

In his well-known theorem, V. L. Kharitonov established that Hurwitz stability of a set f1 of interval polynomials with complex coefficients (polynomials where each coefficient varies in an arbitrary but prescribed rectangle of the complex plane) is equivalent to the Hurwitz stability of only eight polynomials in this set. In this paper we consider an alternative but equally meaningful model of uncertainty by introducing a set fD of disc polynomials, characterized by the fact that each coefficient of a typical element P(s) in fD can be any complex number in an arbitrary but fixed disc of the complex plane. Our result shows that the entire set is Hurwitz stable if and only if the ‘center’ polynomial is stable, and the H ∞-norms of two specific stable rational functions are less than one. Our result can be readily extended to deal with the Schur stability problem and the resulting condition is equally simple.
Broadcast consensus based phase synchronization for coherent MIMO radar

Multiple-input multiple-output (MIMO) radar can achieve improved localization performance by employing a coherent processing approach with proper antenna positioning. Different from the noncoherent counterpart, coherent processing entails the challenge of ensuring phase coherence of the carrier signals from different distributed radar elements. In this paper, we propose a broadcast consensus based algorithm for reaching a common notion of phase in coherent MIMO radar. This algorithm is distributed and iterative in nature. It does not require a priori establishment of the time synchronization, and is thus time asynchronous. We mathematically characterize this algorithm, and further study some statistical properties of the resulting phase synchronization error. Simulation results are presented to demonstrate the performance of the proposed algorithm, as well as to validate our theoretical analysis.
Speed and rotor position estimators for PMSM with sliding mode EMF observer front

The paper discusses the problem of speed and rotor position estimation for the Permanent Magnet Synchronous Motor (PMSM) and presents a family of estimation methods. Estimation is done sequentially: first, the EMFs are obtained using a sliding mode observer; then, the speed is estimated. The estimators are based on the model of the PMSM in the stationary reference frame. The paper presents an SM observer for the EMFs (the front observer) and various observers for the speed (the back observers). It is shown that the speed estimation process offers many mathematical options - it can be adaptive, sliding–mode based, algebraic, or it can use a double–manifold sliding mode structure. The properties of the various speed observers and their feasibility and accuracy are discussed. The method can be applied in a sensorless PMSM drive where the speed and rotor position angle are needed for control implementation. The paper presents the design of the observers along with simulation results and experimental tests.
ASSESSMENT OF GUARDRAIL-STRENGTHENING TECHNIQUES

Guardrail-strengthening techniques were assessed by full-scale crash testing according to Service Level 2 conditions of NCHRP Report 230 and by BARRIER VII computer simulation. The Kansas Department of Transportation's standard W-beam with steel posts guardrail was strengthened by nesting the W-beam and by reducing the post spacing. Computer simulations with BARRIER VII were used to assess the various strengthening techniques for guardrails with standard and extended post lengths installed in clay and sand. The soil—post stiffness parameters used in the program were obtained by conducting 21 post impact tests with a 1388-kg bogie striking a post at 33 km/hr. The guardrails constructed with W6 X 8.5 steel posts and 15.2 X 20.3-cm timber posts behaved similarly under all test conditions. The density of the clay has a profound effect on the lateral dynamic deflections. Nesting the W-beam to strengthen the guardrail provides very little benefit, whereas reducing the post spacing by half provides the greatest ...
Effect of static growth and different levels of environmental oxygen on toxA and ptxR expression in the Pseudomonas aeruginosa strain PAO1

Within certain infection sites, such as the lung of cystic fibrosis patients, Pseudomonas aeruginosa grows statically under either decreased oxygen tension or anaerobic conditions, a situation that is likely to influence the production of virulence factors. The goal of this study was to determine the effect of static growth under microaerobic (decreased oxygen) and anaerobic conditions on the expression of the P. aeruginosa exotoxin A (ETA) gene toxA and its positive regulator ptxR. Using toxA-lacZ and ptxR-lacZ fusion plasmids, the level of toxA and ptxR expression was measured throughout the growth cycle of strain PAO1, which was grown in either iron-deficient or iron-sufficient medium under four different conditions: 20%-SH (aerobic, shaking), 20%-ST (aerobic, static), 10%-ST (microaerobic, static) and 0%-ST (anaerobic, static). In iron-deficient medium, toxA expression was higher under 20%-ST and 10%-ST than under 20%-SH. However, the highest level of toxA expression occurred under 0%-ST. Analysis of ETA protein using sandwich ELISA revealed that at time points between 8 and 24 h of the growth curve, PAO1 produced higher levels of ETA under 0%-ST than under 20%-SH. In iron-sufficient medium, toxA expression was significantly repressed under all conditions. Additional analyses using PAO1 strains that carry lacZ fusions with the toxA regulatory genes regA and pvdS revealed that the expression of regA and pvdS is reduced rather than increased at 0%-ST. ptxR expression under different conditions paralleled that of toxA expression, except that it was repressed by iron under 20 %-SH only. Between 6 and 24 h of growth, and under all conditions, the level of dissolved oxygen (DO) within the PAO1 cultures was sharply reduced. These results suggest that (1) the combined effect of static growth and anaerobic conditions produce a significant increase in toxA and ptxR expression in PAO1; (2) this effect appears to be unique to toxA and ptxR, since the level of regA and pvdS expression was reduced under the same conditions; (3) neither static growth nor anaerobic conditions interfere with the repression of toxA expression by iron, although static growth deregulates ptxR expression with respect to iron; and (4) the enhanced expression of toxA and ptxR is not related to the reduced levels of DO in PAO1 cultures.
Evolution and altruism: Combining psychological mediators with naturally selected tendencies

This study integrates psychological predictors of helping intentions and naturally selected tendencies enhancing inclusive fitness for a more comprehensive understanding of altruism. Psychological mediators of helping intentions, empathic concern and oneness, and psychological processes facilitating kin selection and reciprocal altruism were combined in a structural equation model to predict participants’ (N=643) intentions to perform a risky rescue behavior. The tendency for reciprocal altruism and kinship were the strongest predictors of rescue intentions. Confirming previous research, empathic concern made a significant but small contribution in predicting helping intentions. Proximate mechanisms currently in the psychological literature did not entirely account for the effect of kinship on helping intentions. D 2003 Elsevier Science Inc. All rights reserved.
A NEW ORCHARD PEST – THE FRINGED–WING APPLE-BUD MOTH (Nothris? maligemmella, n. sp.).

While experimenting two years ago with the leaf Crumpler and the Leaf Folder, a gentleman asked me to visit his apple orchard, some two miles distant, and to observe the destructive work of what he supposed was the Leaf Folder. The orchard had been in bearing for several years and covered sixty acres. The apple trees had at that time just shed their blooms (petals) and the adjacent orchards appeared green, while the infested one was very conspicuous, appearing as if a fire had swept through it.
Predicting gender and weight from human metrology using a copula model

We investigate the use of human metrology for the prediction of certain soft biometrics, viz. gender and weight. In particular, we consider geometric measurements from the head, and those from the remaining parts of the human body, and analyze their potential in predicting gender and weight. For gender prediction, the proposed model results in a 0.7% misclassification rate using both body and head information, 1.0% using only body information, and 12.2% using only head information on the CAESAR 1D database consisting of 2,369 subjects. For weight prediction, the proposed model gives 0.01 mean absolute error (in the range 0 to 1) using both body and head information, 0.01 using only body information, and 0.07 using only measurements from the head. This leads to the observation that human body metrology contains enough information for reliable prediction of gender and weight. Furthermore, we investigate the efficacy of the model in practical applications, where metrology data may be missing or severely contaminated by various sources of noises. The proposed copula-based technique is observed to reduce the impact of noise on prediction performance.
ECOLOGICAL CONSIDERATIONS OF DETRITAL AGGREGATES IN THE SALT MARSH

More than 98% of the detrital material exported from the investigated Gulf Coast salt marsh is made up of amorphous aggregates. These detrital aggregates, averaging 25–50 µm in diameter, are produced by the benthic microflora of the marsh, rather than by microbial decomposition of the dominant vascular plant Juncus roemerianus as the prevailing view holds. Rising tides lift films of the aggregate material from the dense community of benthic algae that carpet the mud surface of the marsh. Ebbing tides transport the floating films into the tidal creeks where even mild water surface disturbances effect the dispersal of the films, which then sink as detrital aggregates into the water column. Ebb tides occurring during daylight hours carry larger quantities of detrital aggregates than tides that ebb during darkness. Detrital aggregate production follows an annual cycle with high production rates in late summer and low rates in the winter. Vascular plant tissue is decomposed beneath the layer of benthic algae and is retained in the marsh. Previously accepted concepts that stress the role of the decomposers in the production of detritus in tidal marshes are examined.
High efficiency transformation of E.coli by high voltage electroporation

E. coli can be transformed to extremely high efficiencies by subjecting a mixture of cells and DNA to brief but intense electrical fields of exponential decay waveform (electroporation). We have obtained 10(9) to 10(10) transformants/micrograms with strains LE392 and DH5 alpha, and plasmids pUC18 and pBR329. The process is highly dependent on two characteristics of the electrical pulse: the electric field strength and the pulse length (RC time constant). The frequency of transformation is a linear function of the DNA concentration over at least six orders of magnitude; and the efficiency of transformation is a function of the cell concentration. Most of the surviving cells are competent with up to 80% transformed at high DNA concentration. The mechanism does not appear to include binding of the DNA to the cells prior to entry. Possible mechanisms are discussed and a simple procedure for the practical use of this technique is presented.
Thermodynamically accurate modeling of the catalytic cycle of photosynthetic oxygen evolution: a mathematical solution to asymmetric Markov chains.

Abstract Forty-three years ago, Kok and coworkers introduced a phenomenological model describing period-four oscillations in O 2 flash yields during photosynthetic water oxidation (WOC), which had been first reported by Joliot and coworkers. The original two-parameter Kok model was subsequently extended in its level of complexity to better simulate diverse data sets, including intact cells and isolated PSII-WOCs, but at the expense of introducing physically unrealistic assumptions necessary to enable numerical solutions. To date, analytical solutions have been found only for symmetric Kok models (inefficiencies are equally probable for all intermediates, called “S-states”). However, it is widely accepted that S-state reaction steps are not identical and some are not reversible (by thermodynamic restraints) thereby causing asymmetric cycles. We have developed a mathematically more rigorous foundation that eliminates unphysical assumptions known to be in conflict with experiments and adopts a new experimental constraint on solutions. This new algorithm termed STEAMM for S-state Transition Eigenvalues of Asymmetric Markov Models enables solutions to models having fewer adjustable parameters and uses automated fitting to experimental data sets, yielding higher accuracy and precision than the classic Kok or extended Kok models. This new tool provides a general mathematical framework for analyzing damped oscillations arising from any cycle period using any appropriate Markov model, regardless of symmetry. We illustrate applications of STEAMM that better describe the intrinsic inefficiencies for photon-to-charge conversion within PSII-WOCs that are responsible for damped period-four and period-two oscillations of flash O 2 yields across diverse species, while using simpler Markov models free from unrealistic assumptions.