The goal of this study was to determine the physicochemical properties of a variety of geologic materials using inverse gas chromatography (IGC) by varying probe gas selection, temperature, carrier ...gas flow rate, and humidity. This is accomplished by measuring the level of interaction between the materials of interest and known probe gases. Identifying a material’s physicochemical characteristics can help provide a better understanding of the transport of gaseous compounds in different geologic materials or between different geological layers under various conditions. Our research focused on measuring the enthalpy (heat) of adsorption, Henry’s constant, and diffusion coefficients of a suite of geologic materials, including two soil types (sandy clay-loam and loam), quartz sand, salt, and bentonite clay, with various particle sizes. The reproducibility of IGC measurements for geologic materials, which are inherently heterogeneous, was also assessed in comparison to the reproducibility for more homogeneous synthetic materials. This involved determining the variability of physicochemical measurements obtained from different IGC approaches, instruments, and researchers. For the investigated IGC-determined parameters, the need for standardization became apparent, including the need for application-relevant reference materials. The inherent physical and chemical heterogeneities of soil and many geologic materials can make the prediction of sorption properties difficult. Characterizing the properties of individual organic and inorganic components can help elucidate the primary factors influencing sorption interactions in more complex mixtures. This research examined the capabilities and potential challenges of characterizing the gas sorption properties of geologic materials using IGC.
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•Relative humidity affects the amount of dimethyl methylphosphonate (DMMP) sorbed on office materials.•Cardboard retains captured DMMP longer than paint layer and polyurethane ...foam.•DMMP, a nerve agent simulant, was retained after 6 weeks on office materials.
Dimethyl methylphosphonate (DMMP) was used as a simulant to investigate the sorption and desorption of G-series nerve agents such as sarin (GB) released into an office space. DMMP was disseminated systematically as an aerosol and vapor on three common office materials, cardboard, polyurethane foam, and cured acrylic-based paint. The amount of DMMP initially captured on the office materials and the amount retained over a period of 10 h was tracked gravimetrically and by solvent extraction and gas chromatography/mass spectrometry (GC/MS). Physicochemical properties of the office media including the surface area per mass, polarity, and Henry’s constant were determined to help explain the capture and release of DMMP that was observed. Polyurethane foam was found to have the largest sorption capacity for DMMP in a low-humidity setting, however, cardboard was found to have the largest sorption capacity at higher humidity. A fraction of the collected DMMP desorbed with first-order kinetics from all of the office materials in an open-air atmosphere over 8 h. However, importantly for forensic purposes relevant to an indoor attack, a significant quantity (most notably on cardboard) of the nerve agent simulant was retained after 6 weeks and could be analyzed efficiently using solvent extraction followed by GC/MS.
Hyponatremia is frequent in hospitalized patients, especially in those receiving total parenteral nutrition (TPN). Furthermore, the presence of hyponatremia is associated with increased ...morbimortality in both groups. The goal of this study is to describe the prevalence of hyponatremia developing during TPN in non-critical patients, and identify risk factors for its appearance.
This prospective multicenter study involved 19 Spanish hospitals. Noncritically-ill patients prescribed TPN over a 9-month period were studied. Variables analyzed demographic characteristics, prior comorbidities, drug therapy, PN composition, additional iv fluids, and serum sodium levels.
A total of 543 patients were recruited, 60.2% males. Age: 67 (IR 57–76). Of 466/543 who were eunatremic when starting TPN, 18% developed hyponatremia (serum sodium < 135 mmol/L) during TPN. Independent risk factors identified by logistic regression analysis: female (OR 1.74 95% CI = 1.04–2.92, p = 0.036); severe malnutrition (OR 2.15 95% CI = 1.16–4.35, p = 0.033); opiates (OR 1.97 95% CI = 1.10–3.73, p = 0.036); and nausea/vomiting (OR 1.75 95% CI = 1.04–2.94, p = 0.036).
Previously eunatremic patients frequently develop hyponatremia while receiving TPN. In this group, severe malnutrition is an independent risk factor for hyponatremia, as well as previously described risk factors: opiates, nausea/vomiting, and female gender.
•Total Parenteral Nutrition (TPN) patients are at high risk for development of hyponatremia, with 18% of previously eunatremic patients developing it during TPN.•Severe malnutrition was the most important risk factor for development of hyponatremia during TPN.•The total amount of sodium and liquids administered did not influence the development of hyponatremia during total parenteral nutrition.
In patients receiving total parenteral nutrition (TPN), the frequency of hyponatraemia is high. However, the causes of hyponatraemia in TPN have not been elucidated, although diagnosis is required ...for appropriate therapy. The aim of this study is to describe the aetiology of hyponatraemia in non-critical hospitalised patients receiving TPN.
Prospective multicentre study in 19 Spanish hospitals. Non-critically hyponatraemic patients receiving TPN and presenting hyponatraemia over a 9-month period were studied. Data collected included sex, age, previous comorbidities, and serum sodium levels (SNa) before and following TPN initiation. Parameters for study of hyponatraemia were also included: clinical volaemia, the presence of pain, nausea, gastrointestinal losses, diuretic use, oedema, renal function, plasma and urine osmolality, urinary electrolytes, cortisolaemia, and thyroid stimulating hormone.
162 patients were included, 53.7% males, age 66.4 (SD13.8) years. Volume status was evaluated in 142 (88%): 21 (14.8%) were hypovolaemic, 96 (67.6%) euvolaemic and 25 (17.6%) hypervolaemic. In 111/142 patients the analytical assessment of hyponatraemia was completed. Hypovolaemic hyponatraemia was secondary to GI losses in 10/111 (9%), and to diuretics in 3/111 (2.7%). Euvolaemic hyponatraemia was due to Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) in 47/111 (42.4%), and to physiological stimuli of Arginine Vasopressin (AVP) secretion in 28/111 (25.2%). Hypervolaemic hyponatraemia was induced by heart failure in 19/111 (17.1%), cirrhosis of the liver in 4/111 (3.6%).
SIADH was the most frequent cause of hyponatraemia in patients receiving TPN. The second most frequent cause was physiological stimuli of AVP secretion induced by pain/nausea.
La hiponatremia es una complicación frecuente en pacientes con nutrición parenteral total (NPT). Aunque su diagnóstico es esencial para indicar el tratamiento apropiado, sus causas no han sido evaluadas. El objetivo del presente estudio es describir la etiología de la hiponatremia en pacientes no críticos que reciben NPT.
Estudio multicéntrico prospectivo en 19 hospitales españoles. Se incluyeron pacientes no críticos que recibieron NPT y presentaron hiponatremia durante un periodo de 9meses. Se recogieron datos demográficos, comorbilidades previas, natremia sérica antes y durante la administración de NPT, y parámetros del estudio de hiponatremia: volemia clínica, presencia de dolor/náuseas, pérdidas gastrointestinales, uso de diuréticos, edema, función renal, osmolalidad plasmática y urinaria, iones en orina, cortisolemia y hormona estimulante del tiroides.
Se incluyeron 162 pacientes, 53,7% varones, con una media de edad de 66,4 (DE 13,8) años. La volemia clínica se evaluó en 142 (88%): 21 (14,8%) hipovolémicos, 96 (67,6%) euvolémicos y 25 (17,6%) hipervolémicos. En 111/142 pacientes se completó el estudio bioquímico de hiponatremia. La hiponatremia hipovolémica fue secundaria a pérdidas gastrointestinales en 10/111 (9%) y diuréticos en 3/111 (2,7%). La hiponatremia euvolémica fue por síndrome de secreción inadecuada de la hormona antidiurética (SIADH) en 47/111 (42,4%) y por estímulo fisiológico de arginina-vasopresina (AVP) en 28/111 (25,2%). La hiponatremia hipervolémica fue inducida por insuficiencia cardiaca en 19/111 (17,1%) y por cirrosis hepática en 4/11 (3,6%).
El SIADH fue la causa más frecuente de hiponatremia en pacientes que reciben NPT, seguida del estímulo fisiológico de AVP por dolor/náuseas.
In patients receiving total parenteral nutrition (TPN), the frequency of hyponatraemia is high. However, the causes of hyponatraemia in TPN have not been elucidated, although diagnosis is required ...for appropriate therapy. The aim of this study is to describe the aetiology of hyponatraemia in non-critical hospitalised patients receiving TPN.
Prospective multicentre study in 19 Spanish hospitals. Non-critically hyponatraemic patients receiving TPN and presenting hyponatraemia over a 9-month period were studied. Data collected included sex, age, previous comorbidities, and serum sodium levels (SNa) before and following TPN initiation. Parameters for study of hyponatraemia were also included: clinical volaemia, the presence of pain, nausea, gastrointestinal losses, diuretic use, oedema, renal function, plasma and urine osmolality, urinary electrolytes, cortisolaemia, and thyroid stimulating hormone.
162 patients were included, 53.7% males, age 66.4 (SD13.8) years. Volume status was evaluated in 142 (88%): 21 (14.8%) were hypovolaemic, 96 (67.6%) euvolaemic and 25 (17.6%) hypervolaemic. In 111/142 patients the analytical assessment of hyponatraemia was completed. Hypovolaemic hyponatraemia was secondary to GI losses in 10/111 (9%), and to diuretics in 3/111 (2.7%). Euvolaemic hyponatraemia was due to Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) in 47/111 (42.4%), and to physiological stimuli of Arginine Vasopressin (AVP) secretion in 28/111 (25.2%). Hypervolaemic hyponatraemia was induced by heart failure in 19/111 (17.1%), cirrhosis of the liver in 4/111 (3.6%).
SIADH was the most frequent cause of hyponatraemia in patients receiving TPN. The second most frequent cause was physiological stimuli of AVP secretion induced by pain/nausea.
The increase in telemedicine in the mental health field has led to psychometric instruments changing from paper-and-pencil administration to an electronic format. A study is performed to determine if ...both formats are equivalent for well-known questionnaires such as GHQ-12, WHO-5, and PHQ-9.
Forty-seven volunteers completed GHQ-12, WHO-5 and PHQ-9 questionnaires in paper-and-pencil format, and in the following 24h they completed their electronic versions via the web site www.memind.net. An electronic-Likert format was used by 24 participants, and 23 used an electronic-slider format. Internal consistency was measured by α-Cronbach index and omega coefficient, and test-retest was measured by the intraclass correlation coefficient (ICC). Agreement between individual items was compared using Weighted Kappa coefficients, and dimensional structure between formats using the Comparative Fit Index (CFI).
Internal consistency was higher than 0.8 for GHQ-12 and WHO-5. The ICC ranged between 0.655 for PHQ-9 paper-and-pencil/electronic-slider and 0.901 for GHQ-12 paper-and-pencil/electronic- slider. Agreement for individual items in paper-and-pencil and electronic-Likert versions was variable, ranging from low agreement in PHQ-1 (weighted κ=0.143; P=.384) to high agreement in PHQ-5 (weighted κ=0.769; P=.000). The CFI results showed an adequate equivalence between formats.
Except for the PHQ-9 electronic-Likert, questionnaires keep their structure in electronic formats. Discrepancies were found in items agreement. This study supports previous works indicating that the change from paper-and-pencil to electronic formats is not an immediate process, and needs a proper adaptation.
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