Strategies for the preparation of non-amplified and amplified genomic dengue gene samples for electrochemical DNA biosensing applications

The application of electrochemical DNA biosensors in real genomic sample detection is challenging due to the existence of complex structures and low genomic concentrations, resulting in inconsistent and low current signals. This work highlights strategies for the treatment of non-amplified and amplified genomic dengue virus gene samples based on real samples before they can be used directly in our DNA electrochemical sensing system, using methylene blue (MB) as a redox indicator. The main steps in this study for preparing non-amplified cDNA were cDNA conversion, heat denaturation, and sonication. To prepare amplified cDNA dengue virus genomic samples using an RT-PCR approach, we optimized a few parameters, such as the annealing temperature, sonication time, and reverse to forward (R/F) primer concentration ratio. We discovered that the generated methylene blue (MB) signals during the electrochemical sensing of non-amplified and amplified samples differ due to the different MB binding affinities based on the sequence length and base composition. The findings show that our developed electrochemical DNA biosensor successfully discriminates MB current signals in the presence and absence of the target genomic dengue virus, indicating that both samples were successfully treated. This work also provides interesting information about the critical factors in the preparation of genomic gene samples for developing miniaturized PCR-based electrochemical sensing applications in the future. We also discuss the limitations and provide suggestions related to using redox-indicator-based electrochemical biosensors to detect real genomic nucleic acid genes.

The application of electrochemical DNA biosensors in real genomic sample detection is challenging due to the existence of complex structures and low genomic concentrations, resulting in inconsistent and low current signals.     

Clinical and biochemical profile of Guillain Barré Syndrome in Pakistan

Objectives:To evaluate the frequency, distribution, characteristics, and biochemical features of Guillain-Barré syndrome (GBS).Methods:This retrospective, case-control study was conducted between November 2018 and February 2020 at PIMS Hospital, Islamabad and Arid Agriculture University, Rawalpindi, Pakistan. The GBS patients were diagnosed through physical examination and nerve conduction study (NCS). Hemoglobin (Hb), liver function tests, renal function tests, lipid profile, and interleukin-17 levels were investigated through the blood. Cerebrospinal fluid analysis (CSF) was performed to measure albuminocytological dissociation (ACD).Results:One hundred and ten patients and 130 controls participated in this study. Fifty-nine (53.63 %) patients had gastrointestinal infection while 52 (47.27 %) had AIDP. IL-17 serum levels were associated with GBS showing elevated values 18.49 pg/mL (SD=4.10) in cases as compared to controls 10.66 (SD=2.09), p<0.001. The CSF proteins were statistically significant in GBS patients, 127.93 mg/dL (SD=51.28), p=0.002. Ascending weakness was observed in 82 (74.5 %) patients. The results showed that the mean age value of GBS patients was 41.27 years, showing males preponderance. The mean Hb value for males and females was 14.83 g/dL and 10.88 g/dL respectively. Seasonal trends in the disease showed that 40% of GBS patients had infections during the spring.Conclusion:The results of the current study suggest that IL-17 levels trigger autoimmunity in GBS patients. The ACD could be used as a diagnostic marker of GBS along with NCS. Antecedent infections were common in a majority of GBS patients.

Guillain-Barré syndrome (GBS) is diagnosed by ascending weakness of limbs, acute flaccid paralysis, and albuminocytological dissociation (ACD). GBS was first defined in 1916.¹ The GBS has been the utmost cause of flaccid paralysis throughout the world. Several studies about the immunopathogenesis of GBS proposed that this disease encompasses a set of peripheral nerve disorders, each discriminated by underlying pathophysiology, weakness in the limbs, and underlying pathophysiology.² There are many clear indications about the autoimmune basis of this syndrome and autoantibody profile has been supportive in approving clinical and electrophysiological connection of GBS to certain other peripheral nerves conditions.²The global annual incidence of GBS has been reported as 0.81-1.89 cases per 100000 individuals.^1,3 Men are more susceptible than women and are 1.78 times more affected.³ T-lymphocytes produce cell-mediated immunity and have several subclasses. T- helper 17 (Th17), a subclass of T-lymphocytes, links innate immunity with adaptive immunity. Th17 cells are involved in several inflammatory and autoimmune diseases.⁴ These cells produce several cytokines including 1L-17A, IL-17F, IL21, and IL-22A. Many white blood cells (WBCs) produce IL-17 including natural killer T-cells (NKT), neutrophils, CD8+ cells, mast cells, and Th17 cells. A genetic linkage of IL-17A and IL-17F has been found and share 50 % homology. Both cytokines (IL-17A, IL-17F) act similarly on different kinds of cells to bring an expression of cytokines and chemokines.⁵ The IL-17 cytokines are found to be involved in neutrophils aggregation and activating innate immune cells and thus play a central role in the pathogenesis of autoimmune diseases.⁶Campylobacter jejuni infection is the most prevalent preceding event involved in GBS followed by Cytomegalovirus.⁷ The signs and symptoms of GBS consist of symmetrical weakness, numbness, tingling sensation, pain, irregular blood pressure, tachycardia, and bradycardia. Generally, about 2 weeks next to infection, paralysis starts to appear and reaches its peak in one month. Clinical management of GBS includes plasmapheresis and intravenous immunoglobulin therapy.⁸ This study intended to measure the difference of biochemical parameters between cases and controls. It was hypothesized that serum IL-17 levels and ACD in Cerebrospinal fluid (CSF) are associated with GBS.     

Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity,molecular weight,and diene incorporation rate of olefins affect each other?

The kinetics and mechanism of ethylene and cyclic diene 5-ethylidene-2-norbornene (ENB) copolymerization catalyzed by rac-Et(Ind)₂ZrCl₂/[Ph₃C][B(C₆F₅)₄]/triisobutylaluminium (TIBA) were investigated using a quench-labeling procedure using 2-thiophenecarbonyl chloride (TPCC). The E/ENB copolymers were characterized by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and ¹H nuclear magnetic resonance (NMR) spectroscopy and sulfur analysis. To reduce the errors of the ethylene–diene copolymerization for the kinetics study, we selected E/ENB with steric and electronic features that permit us to elucidate the metallocene catalyst behavior against dienes. A quantitative approach of catalyst speciation, stereodynamics, and micro-kinetics assisted the resolution of mechanistic problems, such as the elastomeric synthesis of ethylene propylene diene monomer rubber (EPDM), the catalyst resting state nature, and how much ion-pairing occurs during polymerization. We report here the precise observation of metal–polymer species, explanation of the dynamics of their initiation, propagation, and termination, and ethylene ENB copolymer development. An approach based on acyl chloride was used to selectively quenched transition metal–polymer bonds to evaluate the polymeric catalyst in terms of its reaction rate, R_p, propagation rate content, k_p, and mole fraction of active centers. It is noted that the decline in catalytic activity in the range of 1800 s, and the active center [Zr]/[*C] fraction significantly increased during the initial 1000 s and then tended towards a steady figure of 86%. It is suggested that nearly complete initiation of all olefins catalysts can be obtained after a sufficiently extended reaction. The quick increase in active sites in the first stage can be described by the immediate initiation of active sites positioned on the surfaces of catalyst particles. The initial polymerization rate, R_p, is high and the crystalline properties of the E/ENB copolymer are low due to the greater incorporation of ENB in the polymer backbone, and later the polymerization reaction rates remained stable with a lower mol% of ENB. The melting temperature (T_m) ranges from 108 to 127 °C, whereas the crystalline temperature ranges from 63 to 108 (J g⁻¹). In the E–ENB copolymers, the value of k_pE is much greater than that of k_pENB; at 120 s, the k_pE and k_pENB values are 9115 and 431 L mol⁻¹ s⁻¹, respectively, implying smaller diffusion barriers in the early stages, which are close to the actual propagation rate constant.

The kinetics and mechanism of ethylene and 5-ethylidene-2-norbornene copolymerization catalyzed by rac-Et(Ind)₂ZrCl₂ were investigated using 2-thiophenecarbonyl chloride.     

Molecular Genetic Aspects of Oligodendrogliomas Including Analysis by Comparative Genomic Hybridization

Oligodendroglial neoplasms are a subgroup of gliomas with distinctive morphological characteristics. In the present study we have evaluated a series of these tumors to define their molecular profiles and to determine whether there is a relationship between molecular genetic parameters and histological pattern in this tumor type. Loss of heterozygosity (LOH) for 1p and 19q was seen in 17/23 (74%) well-differentiated oligodendrogliomas, in 18/23 (83%) anaplastic oligodendrogliomas, and in 3/8 (38%) oligoastrocytomas grades II and III. LOH for 17p and/or mutations of the TP53 gene occurred in 14 of these 55 tumors. Only one of the 14 cases with 17p LOH/TP53 gene mutation also had LOH for 1p and 19q, and significant astrocytic elements were seen histologically in the majority of these 14 tumors. LOH for 9p and/or deletion of the CDKN2A gene occurred in 15 of these 55 tumors, and 11 of these cases were among the 24 (42%) anaplastic oligodendrogliomas. Comparative genomic hybridization (CGH) identified the majority of cases with 1p and 19q loss and, in addition, showed frequent loss of chromosomes 4, 14, 15, and 18. These findings demonstrate that oligodendroglial neoplasms usually have loss of 1p and 19q whereas astrocytomas of the progressive type frequently contain mutations of the TP53 gene, and that 9p loss and CDKN2A deletions are associated with progression from well-differentiated to anaplastic oligodendrogliomas.     

Mechanical Experiments on Concrete with Hybrid Fiber Reinforcement for Structural Rehabilitation

Reinforced concrete is used in the construction of bridges, buildings, retaining walls, roads, and other engineered structures. Due to seismic activities, a lot of structures develop seismic cracks. The rehabilitation of such structures is necessary for public safety. The overall aim of this research study was to produce a high-performance hybrid fiber-reinforced concrete (HPHFRC) with enhanced properties as compared to plain high-performance concrete and high-performance fiber-reinforced concrete (HPFRC) for the rehabilitation of bridges and buildings. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 mm and 25 mm, respectively, were added and hybridized to 1.5% by mass of cement to create hybrid fiber-reinforced concrete mixes. Eight mixes were cast in total. The compressive strength (f′_c), flexural strength (f_r), splitting tensile strength (f_s), and other mechanical properties, i.e., energy absorption and toughness index values, were enhanced in HPHFRC as compared to CM and HPFRC. It was found that the concrete hybridized with 0.75% KF and 0.75% GF (HF-G 0.75 K 0.75) had the most enhanced overall mechanical properties, illustrating its potential to be utilized in the rehabilitation of bridges and structures.     

Comparison of depression symptoms between primary depression and secondary-to-schizophrenia depression

Objectives: This study exclusively aimed to clinically assess which symptom pattern discriminates primary depression from depression-secondary to-schizophrenia.

Methods: A total of 98 patients with primary depression and 71 patients with secondary-to-schizophrenia depression were assessed for identifying the clinical phenomena of depression. Diagnosis of schizophrenia was confirmed by Mini International Neuropsychiatric Interview. Each participant was, however, assessed by Patient Health Questionnaire-9 as well as Calgary Depression Scale for Schizophrenia (CDSS) for possible concurrent depressive symptoms.

Results: Depressed mood, loss of interest, reduced energy and pathological guilt were more common in primary depression, whereas sleep disturbance and guilty ideas of reference were more amounting towards the diagnosis of depression secondary-to-schizophrenia.

Conclusions: It is clinically hard to differentiate primary from secondary-to-schizophrenia depression, especially in the absence of obvious psychotic symptoms. However, the classical symptoms of depression like subjective depressed mood, anhedonia, reduced energy and pathological guilt are more prominent in the primary depression.     

Differential scanning calorimetry (DSC) and temperature-modulated DSC study of three mouthguard materials

OBJECTIVES: Employ differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) to investigate thermal transformations in three mouthguard materials and provide insight into their previously investigated energy absorption. METHODS: Samples (13-21mg) were obtained from (a) conventional ethylene vinyl acetate (EVA), (b) Pro-form, another EVA polymer, and (c) PolyShok, an EVA polymer containing polyurethane. Conventional DSC (n=5) was first performed from -80 to 150 degrees C at a heating rate of 10 degrees C/min to determine the temperature range for structural transformations. Subsequently, TMDSC (n=5) was performed from -20 to 150 degrees C at a heating rate of 1 degrees C/min. Onset and peak temperatures were compared using ANOVA and the Tukey-Kramer HSD test. Other samples were coated with a gold-palladium film and examined with an SEM. RESULTS: DSC and TMDSC curves were similar for both conventional EVA and Pro-form, showing two endothermic peaks suggestive of melting processes, with crystallization after the higher-temperature peak. Evidence for crystallization and the second endothermic peak were much less prominent for PolyShok, which had no peaks associated with the polyurethane constituent. The onset of the lower-temperature endothermic transformation is near body temperature. No glass transitions were observed in the materials. SEM examination revealed different surface morphology and possible cushioning effect for PolyShok, compared to Pro-form and EVA. SIGNIFICANCE: The difference in thermal behavior for PolyShok is tentatively attributed to disruption of EVA crystal formation, which may contribute to its superior impact resistance. The lower-temperature endothermic peak suggests that impact testing of these materials should be performed at 37 degrees C.     

Correction: Efficacy of surface-functionalized Mg1−xCoxFe2O4 (0 ≤ x ≤ 1; Δx = 0.1) for hyperthermia and in vivo MR imaging as a contrast agent

Correction for ‘Efficacy of surface-functionalized Mg_1−xCo_xFe₂O₄ (0 ≤ x ≤ 1; Δx = 0.1) for hyperthermia and in vivo MR imaging as a contrast agent’ by M. Aminul Islam et al., RSC Adv., 2022, 12, 7835–7849, DOI: 10.1039/D2RA00768A.

The authors regret that the name of one of the authors (Md. Mahbubul Haque) was shown incorrectly in the original article. The corrected author list is as shown here.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.