Solvation Free Energies of K+, Rh+ and Cs+ Ions in Methanol-N,N-dimethylformamide Mixtures

The selective solvation of K+,Rb+and Cs+ ions has been studied at 25 DCby solubility measurements. The solubility of tetraphenylboride salts, KBPh4, RbBPh4 and CsBPh4 increases with the addition of N,N-dimethylformamide (DMF) to methanol (CH30H) solutions. From the solubility data, the solvation free energies of the ions under consideration are evaluated on applying the asymmetric tetraphenylarsonium-tetraphenylboride (ΔG° Ph4As+> >ΔG° Ph4B-) assumption and their values are discussed

Solvation Free Energies of K+, Rh+ and Cs+ Ions in Methanol-N,N-dimethylformamide Mixtures

The selective solvation of K+,Rb+and Cs+ ions has been studied at 25 DCby solubility measurements. The solubility of tetraphenylboride salts, KBPh4, RbBPh4 and CsBPh4 increases with the addition of N,N-dimethylformamide (DMF) to methanol (CH30H) solutions. From the solubility data, the solvation free energies of the ions under consideration are evaluated on applying the asymmetric tetraphenylarsonium-tetraphenylboride (ΔG° Ph4As+> >ΔG° Ph4B-) assumption and their values are discussed

Conductometric and volumetric study of copper sulphate in aqueous ethanol solutions at different temperatures

AbstractAn Anton Par Model 55 densimeter was used to measure the densities of copper sulphate solutions in H2O and EtOH–H2O at 298.15K, 303.15K, 308.15K, and 313.15K. The acquired information was used to ascertain the apparent molar volumes, limiting partial molar volumes, and transfer partial molar volumes of copper sulphate. These computed parameters were utilized to decipher the solute–solute and solute–solvent interactions of copper sulphate in an aqueous ethanol solution. The ion solvation behavior of copper sulphate in water and aqueous ethanol over the range of 298.15–313.15K was studied using the electrical conductivity principle. The Kraus–Bray and Shedlovsky models of conductivity were used to analyze the obtained conductance data. From the obtained data, the limiting molar conductance λ°m, association constant KA, energy of activation of the rating process (Ea), and related thermodynamic parameters were determined. The Walden product (λ°mη0) was determined. The standard thermodynamic parameters of association (ΔG°A, ΔH°A) were calculated and discussed. Increased ion–solvent and solvent–solvent interactions are indicated by limiting molar conductance values with an increasing amount of ethanol. The negative ΔG°A values indicate that the association processes in all of the studied systems are spontaneous processes. The negative estimation of (ΔH°A) demonstrates that the association processes is exothermic in nature

Thermodynamic Effect of Bulk and Nano-CuCl2 Salts on Tenoxicam Using a Variety of Different Techniques

Nanoparticles are very important for medicine and environment, because of their increased behaviours. The increasing in the physical and chemical properties of nanomaterials are due to theirs high surface area and small volume, makes them very reactive , catalytic and able to pass through cell membranes. Characterization of nano-CuCl2 is done by using a variety of different techniques, transmission electron microscopy (TEM), infra red spectroscopy (IR) and determination of its thermodynamic parameters using condutometric measurements. The association parameters of both bulk and nano-CuCl2 salts in DMF were easily calculated using using Fuoss-Shedlovsky method from temperatures, 298.15K (degree Kelvin) to 313.15K. In order to have a better understanding of thermodynamics of the complexation reactions between (bulk, nano-CuCl2) salts and tenoxicam in DMF, it is useful to determine the contribution of enthalpy and entropy of the reactions. The thermodynamic parameters were calculated from the temperatures dependence of the complexation constants ( Van't Hoff plot). The formation constants were measured as a function of temperature and increased by increasing temperature. Also, different volumes of tenoxicam in mixed (DMF+H2O) were determined from density measurement

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Molal Solubility, Dissociation, Association and Solvation Parameters for Saturated Phenylalanine Solutions in Various Solvents at 298.15 K

Abstract The molal solubilities for saturated solutions of phenylalanine at 298.15 K in various solvents were determined. The solvents used are, water (W), ethanol (Et), dimethylsulphoxide (DMSO), acetonitrile (AN), methanol (Me), acetone (Ac), 1-4, dioxane (Di) and N, N-dimethylformamide (DMF).From the experimental data for solubilities, pH and densities, the different volumes, molar: electrostriction and Van der Waals and apparent molar volumes were estimated. The free energies of dissociation (∆G d ), free energies of association (∆G A ), difference free energies (∆∆G) and free energies of solvation (∆G s ) for phenylalanine saturated solutions in various solvents were also calculated. The solvation numbers were also estimated. It was concluded that the solute-solvent interaction increased by increasing the solvation free energies due mainly to the greater of the association parameters in the organic solvents

Conductometric Studies of Calcium Ions with Kryptofix 221 in Mixed MeOH-DMF Solvents at Different Temperatures

Abstract On using conductometric technique, the apparent association constant (K A ) of Ca (NO 3 ) 2 were measured in mixed MeOH-DMF mixed solvents at 0