Nanoscopic length scale dependence of hydrogen bonded molecular associates' dynamics in methanol.

In a recent paper [C. E. Bertrand et al., J. Chem. Phys. 145, 014502 (2016)], we have shown that the collective dynamics of methanol shows a fast relaxation process related to the standard density-fluctuation heat mode and a slow non-Fickian mode originating from the hydrogen bonded molecular associates. Here we report on the length scale dependence of this slow relaxation process. Using quasielastic neutron scattering and molecular dynamics simulations, we show that the dynamics of the slow process is affected by the structuring of the associates, which is accessible through polarized neutron diffraction experiments. Using a series of partially deuterated samples, the dynamics of the associates is investigated and is found to have a similar time scale to the lifetime of hydrogen bonding in the system. Both the structural relaxation and the dynamics of the associates are thermally activated by the breaking of hydrogen bonding.

Dynamic signature of molecular association in methanol.

Quasielastic neutron scattering measurements and molecular dynamics simulations were combined to investigate the collective dynamics of deuterated methanol, CD3OD. In the experimentally determined dynamic structure factor, a slow, non-Fickian mode was observed in addition to the standard density-fluctuation heat mode. The simulation results indicate that the slow dynamical process originates from the hydrogen bonding of methanol molecules. The qualitative behavior of this mode is similar to the previously observed α-relaxation in supercooled water [M. C. Bellissent-Funel et al., Phys. Rev. Lett. 85, 3644 (2000)] which also originates from the formation and dissolution of hydrogen-bonded associates (supramolecular clusters). In methanol, however, this mode is distinguishable well above the freezing transition. This finding indicates that an emergent slow mode is not unique to supercooled water, but may instead be a general feature of hydrogen-bonding liquids and associating molecular liquids.

Reorientational Dynamics in Y(BH4)3·xNH3 (x = 0, 3, and 7): The Impact of NH3 on BH4- Dynamics.

The reorientational dynamics of Y(BH4)3·xNH3 (x = 0, 3, and 7) was studied using quasielastic neutron scattering (QENS) and neutron spin echo (NSE). The results showed that changing the number of NH3 ligands drastically alters the reorientational mobility of the BH4- anion. From the QENS experiments, it was determined that the BH4- anion performs 2-fold reorientations around the C2 axis in Y(BH4)3, 3-fold reorientations around the C3 axis in Y(BH4)3·3NH3, and either 2-fold reorientations around the C2 axis or 3-fold reorientations around the C3 axis in Y(BH4)3·7NH3. The relaxation time of the BH4- anion at 300 K decreases from 2 × 10-7 s for x = 0 to 1 × 10-12 s for x = 3 and to 7 × 10-13 s for x = 7. In addition to the reorientational dynamics of the BH4- anion, it was shown that the NH3 ligands exhibit 3-fold reorientations around the C3 axis in Y(BH4)3·3NH3 and Y(BH4)3·7NH3 as well as 3-fold quantum mechanical rotational tunneling around the same axis at 5 K. The new insights constitute a significant step toward understanding the relationship between the addition of ligands and the enhanced ionic conductivity observed in systems such as LiBH4·xNH3 and Mg(BH4)2·xCH3NH2.

Dynamical transition in a large globular protein: Macroscopic properties and glass transition.

Hydrated soy-proteins display different macroscopic properties below and above approximately 25% moisture. This is relevant to the food industry in terms of processing and handling. Quasi-elastic neutron spectroscopy of a large globular soy-protein, glycinin, reveals that a similar moisture-content dependence exists for the microscopic dynamics as well. We find evidence of a transition analogous to those found in smaller proteins, when investigated as a function of temperature, at the so-called dynamical transition. In contrast, the glass transition seems to be unrelated. Small proteins are good model systems for the much larger proteins because the relaxation characteristics are rather similar despite the change in scale. For dry samples, which do not show the dynamical transition, the dynamics of the methyl group is probably the most important contribution to the QENS spectra, however a simple rotational model is not able to explain the data. Our results indicate that the dynamics that occurs above the transition temperature is unrelated to that at lower temperatures and that the transition is not simply related to the relaxation rate falling within the spectral window of the spectrometer.

Fever, abdominal pain, and lymphocytic ascites in a young immigrant from western Africa.

Tuberculous peritonitis is an uncommon disease in countries with low tuberculosis (TB) incidence, most often affecting non-white race, foreign-born individuals. We describe a case of TB with peritoneal involvement in a 32-year-old man immigrated to Italy from Burkina Faso, who presented with a history of fever, malaise, abdominal pain and abdominal swelling. Due to its nonspecific clinical presentation and paucibacillary nature, diagnosis of tuberculous peritonitis can be challenging, and requires a high index of suspicion. This report highlights the diagnostic challenges posed by tuberculous peritonitis and emphasizes the importance of imaging (computed tomography, CT) in identifying typical findings, and the value of histological examination of tissue specimens from peritoneum or any site of suspected TB as a tool for diagnosis confirmation.

Prevalence and in-hospital outcome of patients with sepsis in an internal medicine ward.

OBJECTIVES: Sepsis is a "life-threatening organ dysfunction caused by a dysregulated host response to infection", which is identified by a >2 point increase from patient baseline in the Sequential Organ Failure Assessment score (SOFAs). The prevalence and outcome of patients with sepsis has been mainly assessed in ICU patients, while few data are available for patients admitted to internal medicine wards. Our purpose was to evaluate the prevalence and the clinical outcome of patients with sepsis in an internal medicine-ward. DESIGN: This is a single-center retrospective observational study evaluating all patients admitted over a 2-month period (October and Novembre 2015) in the internal medicine ward of the San Giovanni di Dio Hospital in Florence. Patients with clinical and/or instrumental signs of bacterial infection were evaluated with SOFAs and divided into patients with and without sepsis. RESULTS: 635 patients were evaluated, and 279 of them (43.9%) were diagnosed with a bacterial infection. The diagnosis of sepsis was made in 93 patients (14.6%). In-hospital mortality and transfer to ICU were observed in 16% of patients with sepsis and in 2.5% of patients without sepsis (p<0.0001). A SOFAs value <2 had a negative predic-tive value of 97.5%, and increasing values of SOFAs were associated with a worse prognosis. CONCLUSIONS: The results suggest that: a) a high proportion of patients hospitalized in an internal medicine ward are affected by sepsis; b) these patients are burdened with high in-hospital mortality or transfer to ICU; c) SOFA score has a high prognostic power.

Frustrated spin correlations in diluted spin ice Ho(2-x)La(x)Ti(2)O(7).

We have studied the evolution of the structural properties as well as the static and dynamic spin correlations of spin ice Ho(2)Ti(2)O(7), where Ho was partially replaced by non-magnetic La. The crystal structure of diluted samples Ho(2-x)La(x)Ti(2)O(7) was characterized by x-ray and neutron diffraction and by Ho L(III)-edge and Ti K-edge extended x-ray absorption fine structure (EXAFS) measurements. It is found that the pyrochlore structure remains intact until about x = 0.3, but a systematic increase in local disorder with increasing La concentration is observed in the EXAFS data, especially from the Ti K edge. Quasi-elastic neutron scattering and ac susceptibility measurements show that, in x≤0.4 samples at temperatures above macroscopic freezing, the spin-spin correlations are short ranged and dynamic in nature. The main difference with pure spin ice in the dynamics is the appearance of a second, faster, relaxation process.

Glycerol Hydrogen-Bonding Network Dominates Structure and Collective Dynamics in a Deep Eutectic Solvent.

The deep eutectic solvent glyceline formed by choline chloride and glycerol in 1:2 molar ratio is much less viscous compared to glycerol, which facilitates its use in many applications where high viscosity is undesirable. Despite the large difference in viscosity, we have found that the structural network of glyceline is completely defined by its glycerol constituent, which exhibits complex microscopic dynamic behavior, as expected from a highly correlated hydrogen-bonding network. Choline ions occupy interstitial voids in the glycerol network and show little structural or dynamic correlations with glycerol molecules. Despite the known higher long-range diffusivity of the smaller glycerol species in glyceline, in applications where localized dynamics is essential (e.g., in microporous media), the local transport and dynamic properties must be dominated by the relatively loosely bound choline ions.

Purification and characterization of a novel glutathione transferase from Serratia marcescens.

Four forms of glutathione transferase were resolved from the cytosol of Serratia marcescens CIP 6755 by GSH-affinity chromatography followed by isoelectric focusing. The major isoenzyme, named Sm-GST-7.3, is composed of two subunits each with a molecular mass of 22 kDa and has an isoelectric point at pH 7.3. Sm-GST-7.3, appears to be distinct from Pm-GST-6.0, previously characterized from Proteus mirabilis AF 2924 as indicated by its substrate specificity, immunological reactivity, subunit molecular mass as well as by its N-terminal amino acid sequence. None of the antisera raised against a number of human, rat and mouse GSTs cross-reacted with Sm-GST-7.3 indicating major structural differences between them and bacterial GST. This is further supported by the fact that the N-terminal sequence of Sm-GST-7.3 also differs significantly from the known sequences of mammalian GSTs of alpha, mu and pi classes. In addition, comparison with the known N-terminal amino acid sequences of helminth, plant and insect GSTs demonstrate that the latter enzymes are distantly related (less than 25% identity) to the Sm-GST-7.3. Immunoblotting experiments performed with antisera raised against Sm-GST-7.3 indicate that a GST immunologically identical to Sm-GST-7.3 is present in a number of other bacterial strains. All together the results obtained suggest that Sm-GST-7.3 is distinct from any known GST, including microbial and mammalian GSTs.

Simulation of exposure and SAR estimation for adult and child heads exposed to radiofrequency energy from portable communication devices.

The level and distribution of radiofrequency energy absorbed in a child's head during the use of a mobile phone compared to those in an adult head has been a controversial issue in recent years. It has been suggested that existing methods that are used to determine specific absorption rate (SAR) and assess compliance with exposure standards using an adult head model may not adequately account for potentially higher levels of exposure in children due to their smaller head size. The present study incorporates FDTD computations of locally averaged SAR in two different anatomically correct adult and child head models using the IEEE standard (Std. C95.3-2002) SAR averaging algorithm. The child head models were obtained by linear scaling of the adult head model to replicate the conditions of previous studies reported in the literature and also by transforming the different adult head models based on data on the external shapes of children's heads. The tissue properties of the adult and corresponding child head models were kept the same. In addition, modeling and experimental measurements were made using three spheres filled with a tissue-equivalent mixture to approximate heads of increasing size. Results show that the peak local average SAR over 1 g and 10 g of tissue and the electromagnetic energy penetration depths are about the same in all of the head models under the same exposure conditions. When making interlaboratory comparisons, the model and the SAR averaging algorithm used must be standardized to minimize controversy.

beta 1-selective adrenoceptor antagonists. 1. Synthesis and beta-adrenergic blocking activity of a series of binary (aryloxy)propanolamines.

A series of binary (aryloxy)propanolamines has been prepared and examined in vitro and in vivo for beta-adrenoreceptor blocking activity. These symmetrical compounds consist of two (S)-(phenyloxy)propanolamine pharmacophores coupled through alkylenedioxy or poly(oxyethylenedioxy) linking units of varying lengths. Examples of such binary compounds linked through the 2,2', 3,3', and 4,4' positions in the aromatic rings of the pharmacophores have been prepared. In vitro and in vivo test data indicate that the 2,2' compounds tend to be selective beta 2-adrenergic blocking agents, the 4,4' binaries tend to be selective beta 1-blocking agents, and those compounds with 3,3' linkages exhibit intermediate selectivities. One of the 4,4'-linked binary compounds, 4s, exhibited potent, cardioselective beta-blockade in vivo, which was of short duration and was accompanied by a prolonged tachycardia.

Estimation of the SAR in the human head and body due to radiofrequency radiation exposure from handheld mobile phones with hands-free accessories.

It was reported by others that hands-free accessories increase the absorption of RF energy in a human head compared to a handset alone. The results of this study show that the opposite is observed when proper dosimetric methods are employed. It is pointed out that for correct estimation of the exposure level it is necessary to use appropriate physical and experimental models and measurement instrumentation, following internationally recommended standards. The human phantoms used for measurements involving the hands-free accessories should include the torso; i.e., measurements should not be performed on the head phantom alone. This has a significant impact on the results because the RF energy coupled into the leads of hands-free accessories is strongly attenuated by the body. Numerical simulations using the Finite-Difference Time-Domain (FDTD) method and experimental measurements with a miniature electric-field probe are in good agreement and show a decrease, not an increase, in RF energy exposure in the human head from hands-free accessories.

Purification of a GSH-affinity binding protein from Bacteroides fragilis devoid of glutathione transferase activity.

An affinity binding protein from the cytosolic fraction of Bacteroides fragilis was purified by using epoxy activated-Sepharose 6B resin immobilized with GSH or with hexyl-GSH. This protein showed a subunit molecular mass (22 kDa) similar to that of glutathione transferase purified from Proteus mirabilis (22.5 kDa). However, the affinity binding protein of Bacteroides fragilis, unlike the GSH-affinity binding protein of Proteus mirabilis, was devoid of the capacity to conjugate GSH to the most commonly used glutathione transferase substrates. The GSH-affinity binding protein of Bacteroides fragilis was also antigenically different from the GSH-affinity bound protein of Proteus mirabilis. It was concluded that the anaerobic microorganism is not able to express glutathione transferase even though it contains a GSH-affinity binding protein with a structural characteristic reminiscent of aerobic glutathione transferase.

Purification and characterisation of two GST's forms from Rhizobium leguminosarum with a high affinity to herbicides.

Cytosolic glutathione transferases are a family of multifunctional proteins that catalyse the conjugation of GSH to a large variety of endogenous and exogenous compounds. These enzymes have been widely studied in mammals and, to a lesser extent, in plants. In plants, GSTs can detoxify herbicides; they are also induced by pathogenic infection and are likely to be involved in defence responses. GSTs are found in pathogenic and not pathogenic prokaryotes but the functional role played by these enzymes in the cell still remains to be clarified. Here we report the purification and characterisation of two GST forms from Rhizobium leguminosarum that play a very important role in agriculture by inducing nitrogen-fixing nodules on the roots of legumes. These bacterial GSTs from R. leguminosarum have immunological characteristics that are different among them and they are characterised both by a high affinity to herbicides.

Dynamics of supercooled water in mesoporous silica matrix MCM-48-S.

Using three different quasielastic neutron spectrometers with widely different resolutions, we have been able to study the microscopic translational and rotational dynamics of water, in a mesoporous silica matrix MCM-48-S, from T=300 K to 220 K, with a single consistent model. We formulated our fitting routine using the relaxing cage model. Thus, from the fit of the experimental data, we extracted the fraction of water bound to the surface of the pore, the characteristic relaxation times of the long-time translational and rotational decays, the stretch exponent describing the shape of the relaxation processes, and the power exponent determining the Q-dependence of the translational relaxation time. A tremendous slowing down of the rotational relaxation time, as compared to the translational one, has been observed.

Rotational dynamics of hydration water in dicalcium silicate by quasielastic neutron scattering.

Quasielastic neutron scattering (QENS) has been used to investigate the single-particle dynamics of interfacial water in dicalcium silicate (C2S)/water paste. Our previous neutron-scattering studies on interfacial water have focused attention on the translational dynamics of the center of mass of water molecules. In this paper, we have collected QENS data on a wider range of wave-vector transfer so that both translational and rotational motions of water molecules are detected. The data have been analyzed by models for translation and rotation we recently proposed for supercooled water. The evolution of the parameters describing the relaxational dynamics of water embedded in the C2S matrix is given at temperature T=303 K as a function of the curing time.

Morphological and biochemical variations of Haemophilus influenzae type b induced by pH and temperature changes.

Haemophilus influenzae type b ATCC 10211 was cultured at different temperatures (25 degrees C-49 degrees C) and pH values (5.7-8.7) either in liquid or semisolid medium. Morphological variations of individual cells were noted by optical microscopy depending upon the conditions of growth. At higher temperatures filaments were produced whereby the length of individual cells increased compared to cultures grown at 37 degrees C. Filaments were also observed at lower pH values. Culture conditions also affected colonial morphology. At low pH values colonies had an enhanced lobulated contour and were more wrinkly and rougher than at higher pH. The changes in cellular and colonial morphology were correlated with distinct outer membrane protein profiles. The changes in temperature and pH did not affect identification of the microorganism by the API system.

A low-temperature crossover in water dynamics in an aqueous LiCl solution: diffusion probed by neutron spin-echo and nuclear magnetic resonance.

Aqueous solutions of lithium chloride are an excellent model system for studying the dynamics of water molecules down to low temperatures without freezing. The apparent dynamic crossover observed in an aqueous solution of LiCl at about 220 to 225 K [Mamontov, JPCB 2009, 113, 14073] is located practically at the same temperature as the crossover found for pure water confined in small hydrophilic pores. This finding suggests a strong similarity of water behavior in these two types of systems. At the same time, studies of solutions allow more effective explorations of the long-range diffusion dynamics, because the water molecules are not confined inside an impenetrable matrix. In contrast to the earlier incoherent quasielastic neutron scattering results obtained for the scattering momentum transfers of 0.3 Å(-1) ≤ Q ≤ 0.9 Å(-1), our present incoherent neutron spin-echo measurements at a lower Q of 0.1 Å(-1) exhibit no apparent crossover in the relaxation times down to 200 K. At the same time, our present nuclear magnetic resonance measurements of the diffusion coefficients clearly show a deviation at the lower temperatures from the non-Arrhenius law obtained at the higher temperatures. Our results are consistent with a scenario in which more than one relaxational component may exist below the temperature of the dynamic crossover in water.