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1.
J Chem Phys ; 160(15)2024 Apr 21.
Article in English | MEDLINE | ID: mdl-38634494

ABSTRACT

Application of the coherent thermodynamic model [W. Holzapfel and S. Klotz, J. Chem. Phys. 155, 024506 (2021)] for H2O ice Ih to the more detailed data for D2O ice Ih provides better insight into the contributions from quenched proton disorder and offers a new basis for understanding the apparent differences between the data for thermal expansion measured with neutron diffraction on polycrystalline samples [A. Fortes, Acta Crystallogr., Sect. B: Struct. Sci., Cryst. Eng. Mater. 74, 196 (2018) and A. Fortes, Phys. Chem. Chem. Phys 21, 8264 (2019)] and macroscopic dilatation measurements on single crystals [D. Buckingham et al., Phys. Rev. Lett. 121, 185505 (2018)]. The comparison points to contributions from defects effecting the two techniques in different ways. The uncertainties in thermodynamic data due to the contributions from proton disorder and additional defects are compared with the "reference data" [R. Feistel and W. Wagner, J. Phys. Chem. Ref. Data 35, 1021 (2006)] for H2O ice Ih.

2.
Phys Rev Lett ; 132(5): 056102, 2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38364173

ABSTRACT

The phonon dispersion of ice VII and that of its proton-ordered analog ice VIII are investigated through a combination of inelastic x-ray scattering (IXS) measurements and first-principles calculations of the oxygen sublattice dynamic structure factor. Particular attention is devoted to hydrogen-disorder in ice VII, addressed theoretically through a statistical ensemble of fictitious ordered supercell configurations. Similar phonon densities of states are found in both phases but are significantly less structured in the case of ice VII. Our data further show that, despite a full proton disorder, the acoustic phonon branches in this phase clearly inherit the periodicity of its body-centered cubic oxygen lattice. The calculations predict, however, the presence of gap openings in the one-atom phonon dispersion. These predictions are supported by revisiting the analysis of previous single-crystal IXS measurements along the longitudinal [111] branch of ice VII.

3.
J Phys Chem Lett ; 14(9): 2301-2307, 2023 Mar 09.
Article in English | MEDLINE | ID: mdl-36847363

ABSTRACT

Solid mixtures of ammonia and water, the so-called ammonia hydrates, are thought to be major components of solar and extra-solar icy planets. We present here a thorough characterization of the recently reported high pressure (P)-temperature (T) phase VII of ammonia monohydrate (AMH) using Raman spectroscopy, X-ray diffraction, and quasi-elastic neutron scattering (QENS) experiments in the ranges 4-10 GPa, 450-600 K. Our results show that AMH-VII exhibits common structural features with the disordered ionico-molecular alloy (DIMA) phase, stable above 7.5 GPa at 300 K: both present a substitutional disorder of water and ammonia over the sites of a body-centered cubic lattice and are partially ionic. The two phases however markedly differ in their hydrogen dynamics, and QENS measurements show that AMH-VII is characterized by free molecular rotations around the lattice positions which are quenched in the DIMA phase. AMH-VII is thus a peculiar crystalline solid in that it combines three types of disorder: substitutional, compositional, and rotational.

4.
Phys Rev Lett ; 125(19): 195501, 2020 Nov 06.
Article in English | MEDLINE | ID: mdl-33216588

ABSTRACT

The phase diagram and melting curve of water ice is investigated up to 45 GPa and 1600 K by synchrotron x-ray diffraction in the resistively and laser heated diamond anvil cell. Our melting data evidence a triple point at 14.6 GPa, 850 K. The latter is shown to be related to a first-order solid transition from the dynamically disordered form of ice VII, denoted ice VII^{'}, toward a high-temperature phase with the same bcc oxygen lattice but larger volume and higher entropy. Our experiments are compared to ab initio molecular dynamics simulations, enabling us to identify the high-temperature bcc phase with the predicted superionic ice VII^{''} phase [J.-A. Hernandez and R. Caracas, Phys. Rev. Lett. 117, 135503 (2016).PRLTAO0031-900710.1103/PhysRevLett.117.135503].

5.
Eur J Neurol ; 27(10): 1856-1866, 2020 10.
Article in English | MEDLINE | ID: mdl-32402145

ABSTRACT

BACKGROUND AND PURPOSE: Argyrophilic grain disease (AGD) is a limbic-predominant 4R-tauopathy. AGD is thought to be an age-related disorder and is frequently detected as a concomitant pathology with other neurodegenerative conditions. There is a paucity of data on the clinical phenotype of pure AGD. In elderly patients, however, AGD pathology frequently associates with cognitive decline, personality changes, urine incontinence and cachexia. In this study, clinicopathological findings were analysed in individuals younger than 75. METHODS: Patients were identified retrospectively based on neuropathological examinations during 2006-2017 and selected when AGD was the primary and dominant pathological finding. Clinical data were obtained retrospectively through medical records. RESULTS: In all, 55 patients (2% of all examinations performed during that period) with AGD were identified. In seven cases (13%) AGD was the primary neuropathological diagnosis without significant concomitant pathologies. Two patients were female, median age at the time of death was 64 years (range 51-74) and the median duration of disease was 3 months (range 0.5-36). The most frequent symptoms were progressive cognitive decline, urinary incontinence, seizures and psychiatric symptoms. Brain magnetic resonance imaging revealed mild temporal atrophy. CONCLUSIONS: Argyrophilic grain disease is a rarely recognized limbic tauopathy in younger individuals. Widening the clinicopathological spectrum of tauopathies may allow identification of further patients who could benefit from tau-based therapeutic strategies.


Subject(s)
Neurodegenerative Diseases , Tauopathies , Aged , Atrophy/pathology , Brain/pathology , Female , Humans , Male , Middle Aged , Retrospective Studies , Tauopathies/complications , Tauopathies/epidemiology , tau Proteins/metabolism
6.
Schmerz ; 32(3): 188-194, 2018 06.
Article in German | MEDLINE | ID: mdl-29693198

ABSTRACT

BACKGROUND: The chronic pelvic pain syndrome (CPPS) can be associated with physiotherapeutic findings. An interprofessional approach is recommended for patients with CPPS; however, no standardized physiotherapeutic assessment and documentation instrument for specific physiotherapeutic assessments exist, which is not only the foundation for physiotherapy but also for interprofessional communication. OBJECTIVE: The aim was the development of a physiotherapeutic assessment instrument for patients with CPPS and therefore, to create a tool for clinical use, research and interprofessional communication. MATERIAL AND METHODS: Based on an explorative literature search and an expert consensus, the first version of the instrument was developed as part of a specialized outpatient clinic. This version was applied clinically for 13 months, edited and finalized after another expert consensus. RESULTS: The developed instrument Physical Therapy Assessment for Chronic Pelvic Pain Syndrome (PTA-CPPS) lists external and internal groups of muscles for a systematic assessment of myofascial findings. Functional capacity, breathing movements as well as scars and regions of pain are recorded. A manual for the assessment protocol was developed as accompanying material. CONCLUSION: The developed instrument provides for the first time a physiotherapeutic assessment tool for patients with CPPS for interprofessional clinical and scientific use.


Subject(s)
Chronic Pain , Pelvic Pain , Prostatitis , Humans , Male , Syndrome
7.
Herz ; 43(1): 26-33, 2018 Feb.
Article in German | MEDLINE | ID: mdl-29147971

ABSTRACT

At the end of August 2017 the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) published new joint guidelines for the treatment of valvular heart disease. These guidelines incorporate the scientific progress since the last version of the guidelines published in 2012. This article reviews current guideline recommendations for antiplatelet and anticoagulative therapy after surgical/interventional treatment of the aortic and mitral valves and discusses the underlying scientific evidence.


Subject(s)
Anticoagulants/therapeutic use , Aortic Valve/surgery , Heart Valve Diseases/surgery , Heart Valve Prosthesis Implantation , Mitral Valve/surgery , Platelet Aggregation Inhibitors/therapeutic use , Administration, Oral , Anticoagulants/adverse effects , Dose-Response Relationship, Drug , Follow-Up Studies , Guidelines as Topic , Hemorrhage/chemically induced , Humans , Platelet Aggregation Inhibitors/adverse effects , Randomized Controlled Trials as Topic , Risk Factors , Thromboembolism/prevention & control
8.
Phys Rev Lett ; 119(24): 245701, 2017 Dec 15.
Article in English | MEDLINE | ID: mdl-29286747

ABSTRACT

Despite the simplicity of its molecular unit, water is a challenging system because of its uniquely rich polymorphism and predicted but yet unconfirmed features. Introducing a novel space of generalized coordinates that capture changes in the topology of the interatomic network, we are able to systematically track transitions among liquid, amorphous, and crystalline forms throughout the whole phase diagram of water, including the nucleation of crystals above and below the melting point. Our approach, based on molecular dynamics and enhanced sampling or free energy calculation techniques, is not specific to water and could be applied to very different structural phase transitions, paving the way towards the prediction of kinetic routes connecting polymorphic structures in a range of materials.

9.
Phys Chem Chem Phys ; 19(3): 1875-1883, 2017 Jan 18.
Article in English | MEDLINE | ID: mdl-28009862

ABSTRACT

We probe the possible inclusion of salt (NaCl) in the ice VII lattice over the pressure range from 2 to 4 gigapascal. We combine data from neutron diffraction experiments under pressure and from computational structure searches based on density functional theory. We observe that the high density amorphous precursor (NaCl·10.2D2O) crystallises during annealing at high pressure in the vicinity of the phase boundary between pure ices VII and VIII. The structure formed is very similar to that of pure ice VII. Our simulations indicate that substituting water molecules in the ice VII lattice with Na+ and Cl- ions would lead to a significant expansion of the lattice parameter. Since this expansion was not observed in our experiments, the ice crystallised is likely to be pure D2O or contains only a small fraction of the ions from the salt solution.

10.
Sci Rep ; 6: 32040, 2016 08 26.
Article in English | MEDLINE | ID: mdl-27562476

ABSTRACT

It has been known for decades that certain aqueous salt solutions of LiCl and LiBr readily form glasses when cooled to below ≈160 K. This fact has recently been exploited to produce a « salty ¼ high-pressure ice form: When the glass is compressed at low temperatures to pressures higher than 4 GPa and subsequently warmed, it crystallizes into ice VII with the ionic species trapped inside the ice lattice. Here we report the extreme limit of salt incorporation into ice VII, using high pressure neutron diffraction and molecular dynamics simulations. We show that high-pressure crystallisation of aqueous solutions of LiCl∙RH2O and LiBr∙RH2O with R = 5.6 leads to solids with strongly expanded volume, a destruction of the hydrogen-bond network with an isotropic distribution of water-dipole moments, as well as a crystal-to-amorphous transition on decompression. This highly unusual behaviour constitutes an interesting pathway from a glass to a crystal where translational periodicity is restored but the rotational degrees of freedom remaining completely random.

11.
J Med Entomol ; 52(4): 719-21, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26335480

ABSTRACT

The kissing bugs--Triatoma rubida (Uhler), Triatoma protracta (Uhler), and Triatoma recurva (Stal)--are common hematophagous bugs in southeastern Arizona and responsible for severe allergic reactions in some individuals who are bitten. They also possess the potential to transmit the blood parasite, Trypanosoma cruzi. We previously found the essential oil, citronella, to be an excellent deterrent of feeding of T. rubida on a restrained mouse. In this work, we tested major components--alcohols, aldehydes, and monoterpenes--of citronella oil for repellency against the three common triatome species endemic in southern Arizona. The following citronella oil components--geraniol, citronellol, limonene, and citronellal--in different concentrations and combinations were tested. All components of citronella oil demonstrated some inhibition of feeding, ranging from very weak inhibition (limonene) to significant inhibition (geraniol and citronellol). A mixture of geraniol and citronellol was found to be repellant at concentrations of .165 and .165 vol%, respectively, for all three triatome species. Citronellal and limonene had no significant repellent activity. The repellent activity of citronella oil appears to be acting through direct contact with the bugs rather than diffusion of vapors.


Subject(s)
Insect Repellents/pharmacology , Insect Vectors/drug effects , Plant Oils/pharmacology , Triatoma/drug effects , Acyclic Monoterpenes , Animals , Insect Control/methods , Insect Repellents/chemistry , Monoterpenes/chemistry , Monoterpenes/pharmacology , Plant Oils/chemistry , Terpenes/chemistry , Terpenes/pharmacology
12.
Plant Biol (Stuttg) ; 17(6): 1203-9, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26206119

ABSTRACT

Variations in seed characteristics observed in heteromorphic species may affect various stages of their life cycles, e.g. seed dormancy, germination characteristics or even adult plant performance. Highly specialised seed morphs - described as colonisers and maintainers - exhibit a trade-off between colonisation capacity and competitive traits. The performance of distinct seed morph progeny under competitive conditions, and especially in multi-species arrangements, had previously not been given much attention. In this study, we compared performance and response to competition among distinct seed morph progenies in two congeneric, co-occurring species: the invasive Bidens frondosa and the non-invasive Bidens tripartita. We hypothesised that maintainer seed morphs of both species would perform better under increased plant densities and within inter-morphic mixtures, while coloniser morphs would show stronger responses to increased densities and perform relatively poorly in inter-morphic mixtures. We conducted a growth trial and a greenhouse experiment, which revealed that seed morph progeny differed significantly in plant height when grown without competition, while under competitive conditions such differences became less apparent. The observed pattern was more strongly pronounced in B. frondosa, which showed a general predominance in stature and biomass over its non-invasive congener. Although seed morphs performed equally well under competitive conditions, increased plant height and more rapid germination can favour the maintainer seed morph on sites where vegetation is already present.


Subject(s)
Bidens/physiology , Biomass , Ecosystem , Germination , Plant Dormancy , Seeds/physiology , Bidens/anatomy & histology , Bidens/growth & development , Ecology , Seeds/anatomy & histology , Seeds/growth & development , Species Specificity , Water
13.
Phys Chem Chem Phys ; 17(21): 14054-63, 2015 Jun 07.
Article in English | MEDLINE | ID: mdl-25955540

ABSTRACT

The structure of amorphous NaCl solutions produced by fast quenching is studied as a function of pressure, up to 4 GPa, by combined neutron diffraction experiments and classical molecular dynamics simulations. Similarly to LiCl solutions the system amorphizes at ambient pressure in a dense phase structurally similar to the e-HDA phase in pure water. The measurement of the static structure factor as a function of pressure allowed us to validate a new polarizable force field developed by Tazi et al., 2012, never tested under non-ambient conditions. We infer from simulations that the hydration shells of Na(+) cations form well defined octahedra composed of both H2O molecules and Cl(-) anions at low pressure. These octahedra are gradually broken by the seventh neighbour moving into the shell of first neighbours yielding an irregular geometry. In contrast to LiCl solutions and pure water, the system does not show a polyamorphic transition under pressure. This confirms that the existence of polyamorphism relies on the tetrahedral structure of water molecules, which is broken here.

14.
J Chem Phys ; 142(12): 124503, 2015 Mar 28.
Article in English | MEDLINE | ID: mdl-25833592

ABSTRACT

Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D2 mixtures that indicate no inclusion compound forms up to 3.7 GPa.

15.
J Appl Microbiol ; 116(6): 1427-37, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24905215

ABSTRACT

AIMS: To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. METHODS AND RESULTS: Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. CONCLUSIONS: In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The expected protein load is one of the most important parameters for selection of a suited active halogen compound.


Subject(s)
Anti-Infective Agents, Local/pharmacology , Bromine Compounds/pharmacology , Chlorine Compounds/pharmacology , Peptones/chemistry , Bromates/pharmacology , Chloramines/pharmacology , Escherichia coli/drug effects , Hypochlorous Acid/pharmacology , Staphylococcus aureus/drug effects , Taurine/analogs & derivatives , Taurine/pharmacology , Tosyl Compounds/pharmacology , Triazines/pharmacology
16.
Phys Rev Lett ; 111(18): 185901, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-24237539

ABSTRACT

First measurements of the self-dynamics of liquid water in the GPa range are reported. The GPa range has here become accessible through a new setup for the Paris-Edinburgh press specially conceived for quasielastic neutron scattering studies. A direct measurement of both the translational and rotational diffusion coefficients of water along the 400 K isotherm up to 3 GPa, corresponding to the melting point of ice VII, is provided and compared with molecular dynamics simulations. The translational diffusion is observed to strongly decrease with pressure, though its variation slows down for pressures higher than 1 GPa and decouples from that of the shear viscosity. The rotational diffusion turns out to be insensitive to pressure. Through comparison with structural data and molecular dynamics simulations, we show that this is a consequence of the rigidity of the first neighbors shell and of the invariance of the number of hydrogen bonds of a water molecule under high pressure. These results show the inadequacy of the Stokes-Einstein-Debye equations to predict the self-diffusive behavior of water at high temperature and high pressure, and challenge the usual description of hot dense water behaving as a simple liquid.

17.
J Med Entomol ; 50(3): 664-7, 2013 May.
Article in English | MEDLINE | ID: mdl-23802464

ABSTRACT

The kissing bug, Triatoma rubida (Uhler) is a common hematophagous bug in Tucson, AZ, and is responsible for causing severe allergic reactions in some bitten individuals. DEET, picaridin, tea tree oil, peppermint oil, and citronella oil were tested for repellency to T. rubida and its ability to probe and feed on a small restrained rat. No long range repellency was observed with any of the test materials. The lowest repellent concentrations observed were: 10% DEET, 7% picaridin; 30% tea tree oil, 3.3% peppermint oil, and 0.165% citronella oil. Only citronella oil was able to stop all probing and feeding by T. rubida. Citronella oil appears to be a promising potential repellent to prevent sleeping people from being bitten by kissing bugs.


Subject(s)
DEET/pharmacology , Insect Repellents/pharmacology , Oils, Volatile/pharmacology , Piperidines/pharmacology , Triatoma/drug effects , Animals , Dose-Response Relationship, Drug , Mentha piperita , Plant Oils/pharmacology , Tea Tree Oil/pharmacology , Triatoma/physiology
18.
Phys Rev Lett ; 110(17): 173004, 2013 Apr 26.
Article in English | MEDLINE | ID: mdl-23679720

ABSTRACT

High pressure viscosity and dielectric measurements were carried out on two monohydroxy alcohols, 2-ethyl-1-hexanol and 5-methyl-2-hexanol, at room temperature. Analysis of the dielectric relaxation times versus viscosity revealed the breakdown of the Einstein-Debye relation above some characteristic pressure. The failure of the Einstein-Debye relation is a manifestation of pressure induced changes of supramolecular hydrogen bonded structures which occur in these liquids.

19.
Cancer Radiother ; 16(4): 257-62, 2012.
Article in French | MEDLINE | ID: mdl-22748977

ABSTRACT

PURPOSE: To evaluate the predictors of acute radiation pneumonitis after conformal thoracic radiotherapy in the treatment of locally advanced non-small cell lung cancer. PATIENTS AND METHODS: Forty-seven consecutive patients were treated with conformal thoracic irradiation for locally advanced non-small cell lung cancer and retrospectively analysed. The mean total dose of radiotherapy was 65 Gy with respiratory gating in 19 cases. Neoadjuvant and concomitant chemotherapy was performed in 33 patients (70%) and 41 patients (87%) respectively. RESULTS: Eleven patients (23%) had an acute radiation pneumonitis, resulting in death for one patient. In univariate analysis, age, sex, pretherapeutic value of forced expiratory volume, non-gated radiotherapy and type of concomitant chemotherapy did not appear as contributing factors in contrast to the administration of neoadjuvant gemcitabine (P=0.03). The occurrence of acute radiation pneumonitis was significantly associated with non-tumour lung volumes irradiated to 13 Gy (V13, P=0.04), 20 Gy (V20, P=0.02) and 25 Gy (V25, P=0.006), the mean lung dose (P=0.008) and lung normal tissue complication probability (P=0.004). In multivariate logistic regression analysis, the occurrence of acute radiation pneumonitis was significantly associated with age above 75 years (odds ratio [OR]=16.72 ; P=0.02) and with administration of neoadjuvant gemcitabine (OR=18.08, P=0.04). CONCLUSION: Acute radiation pneumonitis is a common acute side effect of the conformal thoracic radiotherapy of locally advanced non-small cell lung cancer, requiring close post-treatment follow-up, particularly for elderly patients. The use of gemcitabine before radiation should be avoided. The benefits and risks of conformal thoracic radiotherapy must be carefully analyzed in view of the dosimetric parameters obtained.


Subject(s)
Carcinoma, Non-Small-Cell Lung/radiotherapy , Lung Neoplasms/radiotherapy , Radiation Pneumonitis/etiology , Radiotherapy, Conformal/adverse effects , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Radiation Pneumonitis/epidemiology , Retrospective Studies , Risk Factors
20.
J Phys Condens Matter ; 24(32): 325103, 1-6, 2012 Aug 15.
Article in English | MEDLINE | ID: mdl-22689331

ABSTRACT

We investigated freezing of pure glycerol as well as glycerol-water (GW) mixtures with 3:1 and 3:2 volume fractions as a function of pressure in the 0-10 GPa range by ruby fluorescence spectroscopy and neutron scattering. We find that the glass transition pressure increases from 5.5 GPa for pure glycerol to 6.5 GPa for the 3:1 GW mixture, with unusually small pressure gradients above. For higher water concentrations close to 3:2, phase separation occurs above 2 GPa where most of the water is expelled in the form of ice VII. The results suggest that glycerol is able to effectively hydrogen bond not more than ≈2.5 H(2)O molecules per glycerol, which seems to support conclusions from molecular dynamics simulations. The data indicate that these fluids could become important as pressure transmitting media for neutron scattering in the 0-7 GPa range, including at low temperatures.

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