Aggregation behavior of sodium dioctylsulfosuccinate in aqueous ethylene glycol medium. A case of hydrogen bonding between surfactant and solvent and its manifestation in the surface tension isotherm

The dependence of critical micelle concentration (cmc) of sodium dioctylsulfosuccinate (AOT) on the amount of ethylene glycol (EG) in water + EG medium was reported to be unusual and different from that of other surfactants to the extent that the cmc of AOT in EG is lower than in water. It is yet to be understood why AOT behaves so in water + EG medium, although AOT is known to have some special properties. Hence in the present study cmc of AOT in water + EG medium in the range from 0 to 100% (by weight) EG is measured by using surface tension and fluorescence emission methods. In contrast to what was reported, this study revealed that with respect to EG amount the cmc of AOT follows the general trend and AOT has higher cmc in EG than in water. On the other hand, it was surprisingly found that a break in the surface tension isotherm occurs in the premicellar region when the amount of EG exceeds 50% rendering a bisigmoidal shape to the surface tension isotherm. UV spectral study showed that AOT and EG undergo hydrogen bonding in the premicellar region when the EG amount is ≥50% and this hydrogen bonding becomes less on adding NaCl. The density functional theory calculations also showed formation of hydrogen bonds between EG and AOT through the sulfonate group of AOT providing thereby support to the experimental findings. The calculations predicted a highly stable AOT-EG-H(2)O trimer complex with a binding energy of -37.93 kcal mol(-1). The present system is an example, which is first of its kind, of a case where hydrogen bonding with surfactant and solvent molecules results in a surface tension break.

Influence of hydrotropic coions on the shape transitions of sodium dioctylsulfosuccinate aggregates in an aqueous medium

The slope change of the CH plot is a manifestation of the shape change of the ionic micelles. However, binding of the salicylate coion to ionic micelles is an exception to this inference.

Knockdown of NEAT1 restricts dengue virus replication by augmenting interferon alpha-inducible protein 27 via the RIG-I pathway

The lncRNA NEAT1 plays a vital role in mitochondrial function and antiviral response. We have previously identified NEAT1 as dysregulated lncRNAs and found an inverse correlation with interferon alpha-inducible protein 27 (IFI27) expression associated with developing dengue severity. However, the role of NEAT1 in dengue virus (DV) infection remains elusive. Here, we undertook a study to evaluate the functional consequences of NEAT1 and IFI27 modulation on antiviral response and viral replication in dengue infection. We observed that the knockdown of NEAT1 augmented IFI27 expression and antiviral response via the RIG-I pathway. Increased antiviral response leads to a decrease in dengue viral replication. Further study suggested that the knockdown of IFI27 augmented expression of the activating transcription factor 3 (ATF3), a negative regulator of antiviral response, and increased dengue virus replication suggesting an important role played by IFI27 in mediating antiviral response. RNA sequencing study confirmed several mitochondrial genes significantly altered upon knockdown of NEAT1 in DV-infected cells. We further verified the effect of NEAT1 knockdown on mitochondrial functions. We observed a reduced level of phospho-DRP1(S616) expression along with elongated mitochondria in DV2-infected cells. Further, NEAT1 knockdown or ectopic expression of IFI27 increased mitochondrial ROS production and cell death via activation of caspase 3. Our study points to the crucial role of NEAT1 and IFI27 in mediating antiviral response and mitochondrial dysfunction in dengue infection.

Dysnatremia in Traumatic Brain Injury and its Association with Outcome

Background Traumatic brain injury on its own results in significant mortality and morbidity but it also contributes to complications that manifest as dysnatremia in the majority of cases. Objective The objective of this study is to assess the association of hyponatremia and hypernatremia with the severity of traumatic brain injury and its impact on mortality. Method This is a retrospective, descriptive, and analytic study conducted during a 1-year period from March 2018 to March 2019. The study population was selected from the patients presenting to the emergency department with TBI in the Upendra Devkota Memorial National Institute of Neurological and Allied Sciences, Bansbari, Kathmandu, Nepal. All the patients that fulfilled the inclusion criteria of age were enrolled in the study. Patients with known renal disease due to the higher incidence of electrolyte disbalance were excluded. Association of outcome with hyponatremia and hypernatremia were sought using chi-square, fisher exact test and independent t test using SPSS ver 20. Result Over a period of 1 year, 367 patients with traumatic brain injuries were treated in our hospital. Hyponatremia was seen among 55 patients (14.9%) and hypernatremia was seen among 22 patients (5.99%). The age range of patients included in the study was 16 to 87 with a mean age of 37.96 ± 16.512 years. The male to female ratio was calculated as 3.2:1. Mild, moderate, and severe head injuries were 286 (77.9%), 37 (10.1%), and 44 (12%) respectively. Surgical intervention was performed among 77(21%) individuals. Our series showed an association between the severity of traumatic brain injury and hyponatremia however didn't show an association between the severity of traumatic brain injury and the development of hypernatremia. Conclusion We concluded that the severity of head injury is associated with severity of hyponatremia but not with severity of hypernatremia. Similarly, a strong association existed between the severity of hypernatremia and outcome of patients. However, such association was not seen with hyponatremia.