Green synthesis of silk sericin-embedded silver nanoparticles and their antibacterial application against multidrug-resistant pathogens.

BACKGROUND: The green synthesis strategy of metallic nanoparticles (NPs) has become popular due to being environmentally friendly. Stable silver nanoparticles (AgNPs) have been synthesized by natural products such as starch, soy protein, various extract of leaves, barks, and roots functioning both as reducing and stabilizing agents. Likewise, silk sericin (SS) is a globular protein discarded in the silk factory might be used for NP synthesis. In this research, we focus on the green synthesis and stabilization of AgNPs by SS as well as assessment of their antibacterial activities against some drug-resistant pathogen. RESULTS: SS was extracted from Bombyx mori silkworm cocoons in an aqueous medium. 17 w/w% of dry sericin powder with respect to the cocoon's weight was obtained by freeze-drying. Furthermore, AgNPs conjugated to sericin, i.e., SS-capped silver nanoparticles (SS-AgNPs) were synthesized by easy, cost-effective, and environment-friendly methods. The synthesized SS-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction measurement. It has been found from the absorbance of UV-visible spectroscopy that a higher percent of SS-AgNPs was obtained at a higher concentration of silver nitrate solution. FTIR-ATR spectra showed that the carboxylate groups obtained from silk sericin act as a reducing agent for the synthesis of silver nanoparticles, while NH2+ and COO- act as a stabilizer of AgNPs. The X-ray diffractogram of SS-AgNPs was quite different from AgNO3 and sericin due to a change in the crystal structure. The diameter of AgNPs was around 20-70 nm observed using TEM. The synthesized SS-AgNPs exhibited strong antibacterial activity against multidrug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 20µg/mL. CONCLUSIONS: This study encourages the use of Bombyx mori for the ecofriendly synthesis of SS-AgNPs to control multidrug-resistant microorganisms.

Assessing the effect of regularization on the molecular properties predicted by SCAN and self-interaction corrected SCAN meta-GGA.

Recent regularization of the SCAN meta-GGA functional (rSCAN) has simplified the numerical complexities of the SCAN functional, alleviating SCAN's stringent demand on the numerical integration grids to some extent. The regularization of rSCAN, however, results in the breaking of some constraints such as the uniform electron gas limit, the slowly varying density limit, and coordinate scaling of the iso-orbital indicator. Here, we assess the effects of regularization on the electronic, structural, vibrational, and magnetic properties of molecules by comparing the SCAN and rSCAN predictions. The properties studied include atomic energies, atomization energies, ionization potentials, electron affinities, barrier heights, infrared intensities, dissociation and reaction energies, spin moments of molecular magnets, and isomer ordering of water clusters. Our results show that rSCAN requires less dense numerical grids and gives very similar results to those of SCAN for all properties examined with the exception of atomization energies, which are worsened in rSCAN. We also examine the performance of self-interaction-corrected (SIC) rSCAN with respect to SIC-SCAN using the Perdew-Zunger (PZ) SIC method. The PZSIC method uses orbital densities to compute one-electron self-interaction errors and places an even more stringent demand on numerical grids. Our results show that SIC-rSCAN gives marginally better performance than SIC-SCAN for almost all properties studied in this work with numerical grids that are on average half or less as dense as that needed for SIC-SCAN.

Validation of the Bangla version of Beck Depression Inventory-II.

BACKGROUND: Beck Depression Inventory (BDI-II) is a widely used valid instrument to assess the severity of depression in clinical and normal settings. To meet the necessity of a standard scale for measuring depression among above 265 million Bangla speaking population around the world, this scale was translated and validated. METHODS: Two translations of BDI-II into Bangla were prepared, and then, two back translations were done by medical and language experts in parallel. Thereafter, sentence revision followed by pretest on 20 respondents was done to finalize the Bangla version of BDI-II (BDI-II BV). Afterward, a cross-sectional, comparative, and descriptive study was conducted to validate the scale by purposive sampling technique consisting of 111 persons (both clinical and normal) in three tertiary-level hospitals in Bangladesh. Everyone was given to fill up BDI-II BV at first. Then, they were given to fill up BDI-II BV (n = 49), Bangla version of Depression Anxiety Stress Scales 21-item (DASS21-BV, n = 47) and BDI-II (n = 25) 3-7 days later. The diagnosis of depressive disorder was made according to DSM-5. Correlation study and factor analysis were completed. RESULTS: The mean age was 28.83(±8.70) years. The male-female ratio was 1:0.82. Correlation of scores for BDI-II BV with the DASS21-BV depression subscale was .920; BDI-II BV with BDI-II was .985 (Cronbach's α .993; t test not significant) and BDI-II BV applied first and the second time was .960 (Cronbach's α .979; z test not significant). The interitem correlation for all the items was found highly significant (p < .01). Patients having depressive disorder or episodes had significantly higher BDI-II BV scores than normal (M + SD 30.18 + 10.127 than 8.34 + 5.910; p < .001). Partial confirmatory factor analysis demonstrated two-factor loading comprising Cognitive and Somatic-affective symptoms. CONCLUSIONS: Through the translation and validation process, a validated Bangla version of BDI-II was produced to measure depression and its severity among the Bengali population.

"Stealth cranioplasty:" A novel endeavor for symptomatic adult Chiari I patients with syringomyelia: Technical note, appraisal, and philosophical considerations.

AIM AND OBJECTIVE: In this article, we describe a novel technique of reconstruction of posterior fossa by cranioplasty with use of preshaped titanium mesh following posterior fossa decompression (PFD) for Chiari malformation type I (CMI) with syringomyelia (SM) in symptomatic adults. MATERIALS AND METHODS: Eleven patients underwent limited PFD and expansive cranioplasty with preshaped titanium mesh, what we term as "Stealth Cranioplasty" (SCP), following arachnoid preserving duraplasty (APD) and hexagonal tenting of the duraplasty with the cranioplasty (HTDC) for the management of symptomatic adult CMI with SM. All these patients had syringes extending from 3 to >10 vertebral levels. RESULTS: Seven male and four female symptomatic CMI adult patients, between age ranges of 22 and 44 years (mean 29.45 years), presented with different neurological symptoms related to CMI and SM for 6-84 months (mean 37.09 months). All the patients underwent PFD, APD followed by SCP and HTDC and were followed up for 7-54 months (mean 35.90 months). Of 11 patients, 8 patients improved according to the Chicago Chiari Outcome Scale (CCOS) with score of 13-15 while 3 patients remained unchanged with CCOS of 12, and there was no worsening. There was no complication related to Chiari surgery in any of the patients. All the patients had good reestablishment of cisterna magna. Two patients had marked reduction of syrinx while eight patients had moderate-to-mild reduction and one patient had no change of syrinx. None of the patients needed redo surgery. CONCLUSION: SCP is an effective, fruitful, and cost-effective technique for the management of symptomatic adult CMI with SM. This technique has the advantages of preventing complications and recurrences in addition to the improvement of symptoms by addressing the basic pathology.

Recurrent Lateral Ventricular Enterogenous Cyst: A Report of an Extreme Rare Case.

The patient was a 45-year-old man with a progressive headache. Evaluation in detail revealed it as a case of left lateral ventricular space occupying lesion (SOL) resembling choroid plexus papilloma. A left parietal craniotomy was done and the lesion was removed completely through intraparietal approach. Surgical removal resulted in complete symptomatic relief. Histopathology revealed that it was a case of the enterogenous cyst. One year after surgery, the patient again experienced the same symptom and the images revealed recurrence of the lesion. The patient has undergone 2nd surgery and histopathology was the same as before. The patient was given radiotherapy and now he is completely relieved and well. Although intracranial enterogenous cyst is not uncommon, intraventricular enterogenous cyst as well as recurrent intraventricular enterogenous cyst is a rare entity.

An analytical coupled technique for solving nonlinear large-amplitude oscillation of a conservative system with inertia and static non-linearity.

Based on a new trial function, an analytical coupled technique (a combination of homotopy perturbation method and variational method) is presented to obtain the approximate frequencies and the corresponding periodic solutions of the free vibration of a conservative oscillator having inertia and static non-linearities. In some of the previous articles, the first and second-order approximations have been determined by the same method of such nonlinear oscillator, but the trial functions have not been satisfied the initial conditions. It seemed to be a big shortcoming of those articles. The new trial function of this paper overcomes aforementioned limitation. The first-order approximation is mainly considered in this paper. The main advantage of this present paper is, the first-order approximation gives better result than other existing second-order harmonic balance methods. The present method is valid for large amplitudes of oscillation. The absolute relative error measures (first-order approximate frequency) in this paper is 0.00 % for large amplitude A = 1000, while the relative error gives two different second-order harmonic balance methods: 10.33 and 3.72 %. Thus the present method is suitable for solving the above-mentioned nonlinear oscillator.