793 research outputs found
3-Ammoniopyridinium tetrabromidomercurate(II) monohydrate
The asymmetric unit of the title compound, (C5H8N2)[HgBr4]·H2O, consists of one cation, one anion and one water molecule. The anion exhibits a distorted tetrahedral arrangement about the Hg atom. The crystal structure contains alternating sheets of cations (in the ac plane) and stacks of anions. Several strong hydrogen-bonding interactions (pyN—H⋯Br and C—H⋯Br; py is pyridine), along with O—H⋯Br interactions, connect the sheets of cations to the stacks of anions. Cation–cation π–π stacking is also present (C⋯C distances in the range 3.424–3.865 Å). The shortest Br⋯Br distance is 3.9527 (9) Å
Bis(2,6-dimethylpyridinium) tetrabromidocobaltate(II)
In the crystal structure of the title compound, (C7H10N)2[CoBr4], the [CoBr4]2− anion is connected to two cations through N—H⋯Br and H2C—H⋯Br hydrogen bonds to form two-dimensional cation–anion–cation layers normal to the crystallographic b axis. Interactions of the π–π type are absent between cations in the stacks [centroid–centroid separation = 5.01 (5) Å]. Significant intermolecular Br–aryl interactions are present in the structure, especially an unusually short Br–ring centroid interaction of 3.78 (1) Å. The coordination geometry of the anion is approximately tetrahedral and a twofold rotation axis passes through the Co atom
Bis(2-amino-6-methylpyridinium) tetrabromidocuprate(II)
In the crystal structure of the title compound, (C6H9N2)2[CuBr4], the geometry around the Cu atom is intermediate between tetrahedral (Td) and square planar (D4h). Each [CuBr4]2− anion is connected non-symmetrically to four surrounding cations through N—H⋯X (pyridine and amine proton) hydrogen bonds, forming chains of the ladder-type running parallel to the crystallographic b axis. These layers are further connected by means of offset face-to-face interactions (parallel to the a axis), giving a three-dimensional network. Cation π–π stacking [centroid separations of 3.69 (9) and 3.71 (1) Å] and Br⋯aryl interactions [3.72 (2) and 4.04 (6) Å] are present in the crystal structure. There are no intermolecular Br⋯Br interactions
Bis(2,6-diamino-3,5-dibromopyridinium) hexabromidostannate(IV)
The asymmetric unit of the title compound, (C5H6Br2N3)2[SnBr6], contains one cation and one half-anion in which the Sn atom is located on a crystallographic centre of inversion and is in a quasi-octahedral geometry. The crystal structure is assembled via hydrogen-bonding interactions of two kinds, N(pyridine/amine)—H⋯Br—Sn, along with C—Br⋯Br—Sn interactions [3.4925 (19) Å]. The cations are involved in π–π stacking, which adds an extra supramolecularity as it presents a strong case of offset-face-to-face motifs [centroid–centroid distance = 3.577 (3) Å]. The intermolecular hydrogen bonds, short Br⋯Br interactions and π–π stacking result in the formation of a three-dimensional supramolecular architecture
Bis(2-bromopyridinium) hexabromidostannate(IV)
The asymmetric unit of the title compound, (C5H5BrN)2[SnBr6], contains one cation and one half-anion. The [SnBr6]2− anion is located on an inversion center and forms a quasi-regular octahedral arrangement. The crystal structure consists of two-dimensional supramolecular layers assembled via hydrogen-bonding interactions of N—H⋯Br—Sn [D⋯A = 3.375 (13)–3.562 (13) Å and D—H⋯A = 127–142°, along with C—Br⋯Br synthons [3.667 (2) and 3.778 (3) Å]. These layers are parallel to the bc plane and built up from anions interacting extensively with the six surrounding cations
Effect of Protocol of Care on Clinical Outcomes of Patients with Chest Tube Post Cardiothoracic Surgery
Cardiothoracic surgery is a surgical specialty, which deals with the diagnosis and management of surgical conditions of the heart, lungs and esophagus (1) .Chest tube (CT) is an invasive procedure which inserted post cardiothoracic surgery to facilitate lung expansion and allowing the drainage of fluids from the chest cavity. Aim: this study aimed to evaluate the effect of protocol of care on clinical outcomes of patients with chest tube post cardiothoracic surgery. Materials and method a quasi-experimental research design was conducted at Cardiothoracic Surgery Department at Tanta University hospital. A purposive sample of 80 adult patients with chest tube based on statistical power analysis were selected and divided into two equal group 40 patients in each group as follows: Group 1: (Study group): consist of 40 adult patients were received protocol of care implemented by the researcher. Group 2: (Control group): consists of 40 adult patients who were received routine nursing care by hospital nursing staff. Three Tools were used to collect the data .Tool (I) Biosocio-demographic characteristics. Tool (II) Chest tube assessment, Tool (III) Pain assessment. Results:- The mean duration of ICU stay in control group (6.77) was higher than in the study group (4.97) days, more than half (52.6%)of the patients in the control group at the 7th day of the study had elevated body temperature comparing to none in the study group, nearly two third (62.5%) of patients has a positive culture swab in the control group at the 7th day of the study group ,compared to about third(35%) of patients in the study group. More than half of patients (52.5%) in the control group had a severe pain during removal of chest tube compared to small percentage (5.0%) in the study group. Conclusions and recommendations:-Protocol of nursing care which was composed of deep breathing and coughing exercises, sterile technique during chest tube dressing, and cold application, are recommended for all cardiothoracic surgical patients with chest tube. Keywords: Protocol of Care, Clinical Outcomes, Cardiothorathic Surger
A Novel Approach by SPME-GC/MS for the Determination of gammahydroxybutyric acid (GHB) in Urine Samples after Conversion into gamma-butyrolactone (GBL)
The quantitative determination of gamma-hydroxybutyric acid (GHB) in urine samples is very important to assess illicit intake or administration. To this end we evaluated several analytical methods: headspace gas-chromatography coupled to flame ionization detection (HS-GC/FID), headspace gas-chromatography coupled to mass spectrometry (HS-GC/MS), headspace gas-chromatography coupled to solid phase microextraction and mass spectrometry (HS-SPME-GC/MS). All these methods were endowed with a not sufficient sensitivity, and then we moved to solid phase microextraction coupled to gas-chromatography with mass spectrometry detection (SPME-GC/MS). At first, GHB was extracted from urine with an organic solvent and analyzed after derivatization. Under these conditions, however, there was a partial overlapping between the chromatographic peak of GHB and that of urea, also extracted by the organic solvent. Then we decided to change analytical approach and to convert GHB to gamma-butyrolactone (GBL), which is not an endogenous compound. A SPME method was optimized and validated for the determination of GBL. The limit of detection (LOD) of the method resulted to be 0.25 \u3bcg/mL for GBL, corresponding to 0.5 \u3bcg/mL for GHB. The lower limit of quantification (LLOQ) was 0.4 \u3bcg/mL for GBL and 0.8 \u3bcg/mL for GHB. The LLOQ of the method resulted 10 times lower than the endogenous level, thus allowing to distinguish between physiological conditions and exogenous assumption
Bis(2-bromopyridinium) hexachloridostannate(IV)
The asymmetric unit of the title compound, (C5H5BrN)2[SnCl6], contains one cation and one half-anion. The [SnCl6]2− anion is located on an inversion center and forms a quasi-regular octahedral arrangement. Hydrogen-bonding interactions of two kinds, viz. N—H⋯Cl—Sn and C—H⋯Cl—Sn, along with Cl⋯Br interactions [3.4393 (15) Å], connect the ions in the crystal structure into two-dimensional supramolecular arrays. These supramolecular arrays are arranged in layers approximately parallel to (110) built up from anions interacting with six symmetry-related surrounding cations
An Overview of Solar Thermal Power Generation Systems
In the world today, fossil fuels as conventional energy sources have a crucial role in energy supply since they are substantial drivers of the “Industrial Revolution”, as well as the technical, social, and economic developments. Global population growth along with high levels of prosperity have resulted in a significant increase in fossil fuels consumption. However, fossil fuels have destructive impacts on the environment, being the major source of the local air pollution and emitter of greenhouse gases (GHGs). To address this issue, using renewable energy sources especially solar energy as an abundant and clean source of energy, has been attracted considerable global attention, which can provide a large portion of electricity demand. To make the most of solar energy, concentrated solar power (CSP) systems integrated with cost effective thermal energy storage (TES) systems are among the best options. A TES system has the ability to store the thermal energy during sunshine hours and release it during the periods with weak or no solar radiation. Thus, it can increase the working hours as well as the reliability of a solar system. In this paper, the main components of the solar thermal power systems including solar collectors, concentrators, TES systems and different types of heat transfer fluids (HTFs) used in solar farms have been discusse
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