Seed-Mediated Electrodeposition of Silver Nanowires and Nanorods.

Here, we compare the amount and morphology of silver (Ag) nanostructures electrodeposited at varied potentials and times in the presence of cetyltrimethylammonium bromide (CTAB) onto glass/indium tin oxide (glass/ITO) electrodes functionalized with mercaptopropyltrimethoxysilane (MPTMS) and coated or not coated with 4 nm average diameter Au nanoparticle (Au NP) seeds. There is a significantly larger amount of Ag deposited on the seeded electrode surface compared to that in the nonseeded electrode at potentials of -150 to -300 mV (vs Ag/AgCl) since the Au NP seeds act as catalysts for Ag deposition. At more negative overpotentials of -400 to -500 mV, the amount of Ag deposited on both electrodes is similar because the deposition kinetics are fast enough on glass/ITO that the Au seed catalyst does not make as big of a difference. Ag nanorods (NRs) and nanowires (NWs) form on the seeded surfaces, especially at more positive potentials, where deposition primarily occurs on the Au seed catalysts. Deposition of Ag onto the Au seeds appears as a separate peak in the voltammetry. This procedure mimics the seed-mediated growth of Ag NRs observed in solution in the presence of CTAB using ascorbic acid as a reducing agent. The yield, length, and aspect ratio of the Ag NRs/NWs depend on the deposition time and potential with the average length ranging from 300 nm to 3 µm for times of 30-120 min and potentials of -150 to -200 mV. The electrochemical seed-mediated growth of Ag NRs/NWs across electrode gaps could find use for resistive and surface-enhanced Raman-based sensing and molecular electronic applications.

The complexity of basophobia and aging: covariates and consequences.

OBJECTIVE: The study aim is to determine the drug-induced incidence of basophobia, falls, its' related variables and the consequences among older adults. PATIENTS AND METHODS: A descriptive, cross-sectional study was adopted with 210 older adult samples. The tool consisted of 6 sections: a standardized, semi-structured questionnaire and physical examination. Descriptive and inferential statistics were used to analyze the data. RESULTS: Among the study participants, 49% had falls or near falls and 51% had basophobia in the past 6 months. As per final simultaneous regression analysis model of the study, the covariates to activity avoidance were age (ß=-0.129, CI=-0.087 to -0.019), having >5 chronic diseases (ß=-0.086, CI=-1.41 to -1.182), depressive symptoms (ß=-0.09, CI=-0.089 to -0.189), vision impairment (ß=-0.075, CI=-1.28 to -1.56), basophobia (ß=-0.26, CI=-0.059 to -0.415), taking regular antihypertensives (ß=-0.096, CI= -1.21 to -1.56), oral hypoglycemics and insulin (ß=-0.17, CI=-0.442 to -0.971) and sedatives and tranquilizers (ß=-0.37, CI=-1.32 to -1.73). Use of antihypertensives (p<0.001), oral hypoglycemics and insulin (p<0.01), sedatives and tranquilizers (p<0.001) were strongly associated with fall related to activity avoidance. CONCLUSIONS: The result of this current study suggests that the falls, basophobia and its related activity avoidance among elderly may set in a "vicious cycle" of falls, basophobia, and the numerous negative outcomes such as functional impairment, a decrease in quality of life, and hospitalization. Preventive strategies such as tittering dosage, home- and community -based exercises, cognitive behavioral therapy, yoga, meditation and sleep hygiene may be the choice to break this vicious cycle.

Effect of COVID-19 vaccination on influenza-associated respiratory infection (IARI): benefit or backfire.

OBJECTIVE: Undoubtfully, COVID-19 vaccine (C19V) has significantly changed the pandemic's trajectory positively. At the same time, reports of transient local and systemic post-vaccination reactions leave a concern about its unknown impact on common ailments. Its effect on IARI is unclear because the present IARI epidemic began immediately after C19V in the previous season. PATIENTS AND METHODS: A retrospective observational cohort study among 250 Influenza-associated respiratory infection (IARI) patients by a structured interview questionnaire was conducted with the comparison between 3 groups with 1 dose, 2 doses and 2 doses plus booster dose of C19V. The p<0.05 was considered significant in this study. RESULTS: Among samples 21.2% received one dose of the C19V, only 3.6% got Flu vaccination, 30% had ≥2 comorbidities such as diabetes (22.8%), hypertension (28.4%) and ionically, 77.2% were on chronic medications. Significant differences (p<0.05) were found between groups with duration of illness, cough, headache, fatigue, shortness of breath and hospital visits. The logistic regression analysis shows that the extended IARI symptoms and hospital visits were significantly high among Group 3 (OR=9.17, 95% CI=3.01-29.0) and the same trend remained significant after adjusting the incidence of comorbidities among samples, the chronic conditions (OR=5.13, 95% CI=1.37-14.91) and flu vaccination status (O=4.96, 95% CI=1.41-16.2). Also, 66.4% of the patients were indecisive about getting vaccinated further. CONCLUSIONS: It has been challenging to reach any definitive conclusions regarding the effects of C19V on IARI, conducting extensive, substantial population-based studies that integrate clinical and virological data from more than one season is absolutely required, despite the fact that the majority of the reported effects were mild and temporary.

Electrophoretic Deposition of Hybrid Calcium Alginate-Gold Nanoparticle Hydrogel Films via Catalyzed Electrooxidation of Hydroquinone.

The electrophoretic deposition (EPD) of hybrid alginate (Alg)-Au nanoparticle (NP) films results from the localized pH drop at the electrode surface due to oxidation of hydroquinone (HQ) catalyzed by 4 and 15 nm diameter citrate-coated gold NPs (cit-Au NPs). The localized pH drop at the electrode leads to neutralization of both Alg and cit, leading to EPD of both Alg and cit-Au NPs simultaneously. Post-treatment of the film with Ca2+ solution leads to hybrid Ca-Alg-Au NP hydrogel films. The EPD of Alg in the presence of 4 nm cit-Au NPs occurs at ∼0.8 V (vs Ag/AgCl) as compared to ∼1.0 V in the presence of 15 nm cit-Au NPs and ∼1.4 V in the absence of cit-Au NPs. This is due to the higher catalytic activity of 4 nm cit-Au NPs compared to 15 nm cit-Au NPs for the oxidation of HQ. UV-vis spectra of Ca-Alg-Au NP hydrogel films show absorbance features for both Ca-Alg and Au NPs entrapped within the hydrogel. As the concentration of Au NPs in the EPD solution increases, the Ca-Alg absorbance and localized surface plasmon resonance (LSPR) peak of the Au NPs increases, confirming the role of the Au NPs as a catalyst for EPD of Alg. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of the Ca-Alg-Au NP hydrogel films show characteristic peaks for Ca-Alg and protonated alginic acid groups. The hydrogel thickness is greater with cit-Au NPs compared to without cit-Au NPs at constant EPD potential and time. Forming Ca-Alg and hybrid Ca-Alg-Au NP hydrogel films at low potentials has potential applications in electrochemical and optical sensor development, catalysis, and biological studies.

Classification of SARS-CoV-2 viral genome sequences using Neurochaos Learning.

The high spread rate of SARS-CoV-2 virus has put the researchers all over the world in a demanding situation. The need of the hour is to develop novel learning algorithms that can effectively learn a general pattern by training with fewer genome sequences of coronavirus. Learning from very few training samples is necessary and important during the beginning of a disease outbreak when sequencing data is limited. This is because a successful detection and isolation of patients can curb the spread of the virus. However, this poses a huge challenge for machine learning and deep learning algorithms as they require huge amounts of training data to learn the pattern and distinguish from other closely related viruses. In this paper, we propose a new paradigm - Neurochaos Learning (NL) for classification of coronavirus genome sequence that addresses this specific problem. NL is inspired from the empirical evidence of chaos and non-linearity at the level of neurons in biological neural networks. The average sensitivity, specificity and accuracy for NL are 0.998, 0.999 and 0.998 respectively for the multiclass classification problem (SARS-CoV-2, Coronaviridae, Metapneumovirus, Rhinovirus and Influenza) using leave one out crossvalidation. With just one training sample per class for 1000 independent random trials of training, we report an average macro F1-score [Formula: see text] for the classification of SARS-CoV-2 from SARS-CoV-1 genome sequences. We compare the performance of NL with K-nearest neighbours (KNN), logistic regression, random forest, SVM, and naïve Bayes classifiers. We foresee promising future applications in genome classification using NL with novel combinations of chaotic feature engineering and other machine learning algorithms.

Effect of Metal Nanoparticle Aggregate Structure on the Thermodynamics of Oxidative Dissolution.

Here, we compare the electrochemical oxidation potential of 15 nm diameter citrate-stabilized Au NPs aggregated by acid (low pH) to those aggregated by tetrakis(hydroxymethyl) phosphonium chloride (THPC). For acid-induced aggregation, the solution changes to a blue-violet color, the localized surface plasmon resonance (LSPR) band of Au NPs at 520 nm decreases along with an increase in absorbance at higher wavelengths (600-800 nm), and the peak oxidation potential (Ep) in anodic stripping voltammetry (ASV) obtained in bromide has a positive shift by as large as 200 mV. For THPC-induced aggregation (Au/THPC mole ratio = 62.5), the solution changes to a blue color as the LSPR band at 520 nm decreases and a new distinct peak at 700 nm appears, but the Ep does not exhibit a positive shift. Scanning transmission electron microscopy (STEM) images reveal that acid-induced aggregates are three-dimensional with strongly fused Au NP-Au NP contacts, while THPC-induced aggregates are linear or two-dimensional with ∼1 nm separation between Au NPs. The surface area-to-volume ratio (SA/V) decreases for acid-aggregated Au NPs due to strong Au NP-Au NP contacts, which leads to lower surface free energy and a higher Ep. The SA/V does not change for THPC-aggregated Au NPs since space remains between them and their SA is fully accessible. These findings show that metal NP oxidative stability, as determined by ASV, is highly sensitive to the details of the aggregate structure.

Assessment of gamma radiation and associated radiation hazards in coastal sediments of south east coast of Tamilnadu, India with statistical approach.

Gamma spectroscopy was performed to determine the concentrations of 226Ra, 232Th and 40K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg-1 for 226Ra, 85.67 Bq kg-1 for 232Th and 425.72 Bq kg-1 for 40K. The average activity concentration of 232Th and 40K are slightly higher and 226Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Raeq) Absorbed Gamma Dose Rate (DR), Annual Effective Dose Rate (HR), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE), Internal Hazard Index (Hin) and External Hazard index (Hex) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides.

Data on natural radioactivity and associated radiation hazards in coastal sediment of Chennai Coast, Tamilnadu, India using gamma ray spectrometry.

This article contains data on the activity concentration of natural radionuclides in coastal sediment samples collected from Pulicat Lake to Vadanemmeli, East coast of Tamil Nadu using NaI(Tl) detector based γ-spectrometry. As marine sediments are found to be the repository of many radioactive pollutants, studied the objectives like (i) determine natural radionuclide activity concentrations in sediment samples in and around Chennai coast (ii) evaluate the radiological hazards due to natural radioactivity associated with coastal sediments and (iii) identify areas which may be radiological hazardous for the public along the study area. The average activity concentration of 238U, 232Th and 40K in the present study is lower than world median value. The radiological hazard indices such as External hazard index (Hex) and Gamma representative level index, (Iγ) were evaluated to assess radiation hazard associated with the sediments. The simulated results show sediments do not pose any significant radiation hazards due to concentration of natural radionuclides.

Statistical assessment to magnetic susceptibility and heavy metal data for characterizing the coastal sediment of East coast of Tamilnadu, India.

A rapid urbanization and industrialization enhances the significant heavy metal pollution in the sediments of coastal area and introduced a serious threat to the human health. In the present study, concentration of heavy metals such as Al, Ti, Fe, V, Cr, Mn, Co, Zn, La, Pb, Mg, Ca, Ni, Cd and Ba are determined in sediments along Periyakalapet to Parangaipettai coastal area, Tamilnadu using energy dispersive X-ray fluorescence spectrometer (EDXRF).These metals have more affinity to establish metallic bond with ferrous material leading to enhancement of sediment magnetic susceptibility. Hence, a magnetic susceptibility (χLF, χHF, χFD) measurement was carried for sediments by using MS2B dual frequency susceptibility meter. Multivariate statistical analysis (Pearson correlation, factor and cluster analysis) was carried out between heavy metals and magnetic susceptibility to assess the anthropogenic impact in the sediments. The study revealed that a magnetic susceptibility measurement is an inexpensive, fast, non-destructive and suitable method to identify the heavy metal pollution sources.

Data on heavy metal and magnetic relationships in coastal sediments from South East Coast of Tamilnadu, India.

In this data, the heavy metal concentration and magnetic susceptibility in coastal sediment samples collected from Periyakalapet to Parangaipettai of East Coast of Tamilnadu using Energy Dispersive X-ray Fluorescence (EDXRF) technique and dual frequency susceptibility meter. We aimed to (i) determine the heavy metal concentration in the sediments from Periyakalapet to Parangaipettai of East Coast of Tamilnadu (ii) assess the magnetic mineral property of sediments (iii) study the correlation between heavy metal and magnetic susceptibility. The determined heavy metal concentration found in the order of Mn> Ba > V > Cr > Zn > La > Ni >Pb> Co > As > Cd > Cu > Al > Fe >Ca> Ti > K > Mg. The magnetic susceptibility (χlf) measurements show that they vary from 5.92×10-8 m3 kg-1to 29.06×10-8 m3 kg-1 with an average of 20.39×10-8 m3 kg-1. Analysed data confirmed that magnetic susceptibility has the potential tool to indicate the heavy metal pollution sources.

Assessment of Heavy Metal Contamination in Marine Sediments of East Coast of Tamil Nadu Affected by Different Pollution Sources.

The aim of this study was to determine the concentration of heavy metals in the sediments of Periyakalapet to Parangipettai coast, east coast of Tamil Nadu, by using energy-dispersive X-ray fluorescence (EDXRF) technique. The average heavy metal concentrations in the sediment samples were found in the order Al>Fe>Ca>Ti>K>Mg>Mn>Ba>V>Cr>Zn>La>Ni>Pb>Co>Cd>Cu. The average heavy metal concentrations were below the world crustal average. The degree of contamination by heavy metals was evaluated using pollution indices. The results of pollution indices revealed that titanium (Ti) and cadmium (Cd) were significantly enriched in sediments. Pearson correlation analysis was performed among heavy metal concentrations to know the existing relationship between them. Multivariate statistical technique was employed to identify the heavy metal pollution sources.

Multivariate statistical analysis of heavy metal concentration in soils of Yelagiri Hills, Tamilnadu, India--spectroscopical approach.

Anthropogenic activities increase the accumulation of heavy metals in the soil environment. Soil pollution significantly reduces environmental quality and affects the human health. In the present study soil samples were collected at different locations of Yelagiri Hills, Tamilnadu, India for heavy metal analysis. The samples were analyzed for twelve selected heavy metals (Mg, Al, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni and Zn) using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. Heavy metals concentration in soil were investigated using enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) to determine metal accumulation, distribution and its pollution status. Heavy metal toxicity risk was assessed using soil quality guidelines (SQGs) given by target and intervention values of Dutch soil standards. The concentration of Ni, Co, Zn, Cr, Mn, Fe, Ti, K, Al, Mg were mainly controlled by natural sources. Multivariate statistical methods such as correlation matrix, principal component analysis and cluster analysis were applied for the identification of heavy metal sources (anthropogenic/natural origin). Geo-statistical methods such as kirging identified hot spots of metal contamination in road areas influenced mainly by presence of natural rocks.

Analysis of electrokinetic transport of a spherical particle in a microchannel.

Electrokinetically driven microfluidic devices that are used for biological cell/particle manipulation (e.g., cell sorting, separation) involve electrokinetic transport of these particles in microchannels whose dimension is comparable with particles' size. This paper presents an analytical study on electrokinetic transport of a charged spherical particle in a charged parallel-plate microchannel. Under the thin electric double-layer assumption, solutions in closed-form solutions for the particle velocity and disturbed electrical and fluid velocity fields are obtained for plane-symmetric (along the channel centerline) and asymmetric (off the channel centerline) motions of a sphere in a parallel-plate microchannel. The effects of relative particle size and eccentricity (i.e., off the centerline distance) on a particle's translational and rotational velocities are analyzed.