Multiphoton Ionization/Dissociation of Molecular Sulfur S2 in the UV Region.

The multiphoton ionization/dissociation dynamics of molecular sulfur (S2) in the ultraviolet range of 205-300 nm is studied using velocity map ion imaging (VMI). In this one-color experiment, molecular sulfur (S2) is generated in a pulsed discharge and then photodissociated by UV radiation. At the three-photon level, superexcited states are accessed via two different resonant states: the B3Σu- (v' = 8-11) valence states at the one-photon level and a Rydberg state at the two-photon level. Among the decay processes of these superexcited states, dissociation to electronically excited S atoms is dominant as compared to autoionization to ionic states S2+ (X2Πg) at wavelengths λ < 288 nm. The anisotropy parameter extracted from these images reflects the parallel character of these electronic transitions. In contrast, autoionization is found to be particularly efficient at S(1D) and S(1S) detection wavelengths around 288 nm. Information obtained from the kinetic energy distributions of S atoms has revealed the existence of vibrationally excited S2+ (X2Πg (v+ > 11)) that dissociates to ionic products following one-photon absorption. This work also reveals many interesting features of S2 photodynamics compared to those of electronically analogous O2.

Structural, Optical, and Magnetic Properties of Pure and Ni-Fe-Codoped Zinc Oxide Nanoparticles Synthesized by a Sol-Gel Autocombustion Method.

Pure and Ni-Fe-codoped Zn1 - 2xNixFexO (x = 0.01, 0.02, 0.03, and 0.04) nanoparticles were effectively synthesized using a sol-gel autocombustion procedure. The structural, optical, morphological, and magnetic properties were determined by using X-ray diffraction (XRD), ultraviolet-visible (UV-vis), scanning electron microscopy, and vibrating sample magnetometer techniques. The XRD confirmed the purity of the hexagonal wurtzite crystal structure. XRD analysis further indicated that Fe and Ni successfully substituted the lattice site of Zn and generated a single-phase Zn1-2xNixFexO magnetic oxide. In addition, a significant morphological change was observed with an increase in the dopant concentration by using high-resolution scanning electron microscopy. The UV-vis spectroscopy analysis indicated the redshift in the optical band gap with increasing dopant concentration signifying a progressive decrease in the optical band gap. The vibrating sample magnetometer analysis revealed that the doped samples exhibited ferromagnetic properties at room temperature with an increase in the dopant concentration. Dopant concentration was confirmed by using energy-dispersive X-ray spectroscopy. The current results provide a vital method to improve the magnetic properties of ZnO nanoparticles, which may get significant attention from researchers in the field of magnetic semiconductors.

Integrated Capacitive- and Resistive-Type Bimodal Relative Humidity Sensor Based on 5,10,15,20-Tetraphenylporphyrinatonickel(II) (TPPNi) and Zinc Oxide (ZnO) Nanocomposite.

The development of high-performance humidity sensors to cater for a plethora of applications, ranging from agriculture to intelligent medical monitoring systems, calls for the selection of a reliable and ultrasensitive sensing material. A simplistic device architecture, robust quantification of ambient relative humidity (% RH), and compatibility with the contemporary integrated circuit technology make a bimodal (capacitive and resistive) surface-type sensor to be a prominent choice for device fabrication. Herein, we have proposed and demonstrated a facile realization of a 5,10,15,20-tetraphenylporphyrinatonickel (II)-zinc oxide (TPPNi-ZnO) nanocomposite-based bimodal surface-type % RH sensor. The TPPNi macromolecule and ZnO nanoparticles have been synthesized by an eco-benign microwave-assisted technique and a thermal-budget chemical precipitation method, respectively. It is speculated from the morpohological study that specific surface area improvement, via the provision of ZnO nanoparticles on micro-pyramidal structures of TPPNi, may reinforce the sensing properties of the fabricated humidity sensor. The relative humidity sensing capacitive and resistive characteristics of the sensor have been monitored in 40-85% relative humidity (% RH) bandwidth. The fabricated sensor under the biasing conditions of 1 V of applied bias (V rms) and 500 Hz AC test frequency exhibits a significantly higher sensitivity of 387.03 pF/% RH and 95.79 kΩ/% RH in bimodal operation. The average values of both the response and recovery times of the capacitive sensor have been estimated to be ∼30 s. It has also been debated why this high degree of sensitivity and considerable reduction in response/recovery time has been obtained. In addition, the intense and wide bandwidth spectral response of the TPPNi-ZnO nanocomposite indicates that it may also be utilized as a potential light-harvesting heterostructured nanohybrid in future studies.

Fabrication of a graphene-based sensor to detect the humidity and the temperature of a metal body with imprecise data analysis.

Graphene is a 2D material with remarkable properties. The present study demonstrates the fabrication of a graphene-based sensor for measuring the temperature and humidity of a metal body. The graphene sensor was fabricated by depositing a thin film of graphene nanoparticles between silver electrodes (separated by ∼50 µm) on a glass substrate. The graphene thin film was characterized by XRD, Raman spectroscopy and UV-vis techniques. The capacitance and resistance for both the relative humidity (in the range of 0-100% RH) and temperature (in the range of 230-310 K) were measured using an LCR meter at 1 kHz in a controlled chamber. The graphene-based sensor expressed high sensitivity with fast response and recovery times for both humidity and temperature with long stability and low hysteresis curves. The sensor was also tested on a metal body, which expressed a good response time. Moreover, the measured data of capacitance and resistance was analyzed with classical and neutrosophic analysis as an application of modern material statistics. It was observed that neutrosophic analysis is more flexible for analyzing the capacitance and resistance of the fabricated sensor.

Quantitative estimation of essential/toxic elemental levels in the serum of esophagus cancer patients in relation to controls.

Esophageal cancer is a very deadly disease ranking 8th most common cancer in terms of incidence and the 6th highest in terms of mortality both in the USA and around the world. A growing body of evidence indicated that changes in the concentrations of essential and toxic elements may affect/increase esophagus carcinoma risk. The aim of this study was to measure serum levels of essential and toxic (Fe, Na, Ca, K, Zn, Mg, Co, Se, Cu, Ni, Mn, Sr, Pb, Li, Sb, Cr, Ag, Cd, As, and Hg) elements in patients with esophagus carcinoma and controls. Atomic absorption spectroscopy was used to determine serum concentrations of essential and toxic elements by using nitric acid/perchloric acid-based wet digestion method. Mean levels of Cu, Ni, Cr, Cd, Pb, As, and Ag were exhibited to be significantly higher and mean Se, Co, Zn, Ca, Fe, Hg, Li, and Mg were noted lower in the serum of cancer patients than controls. The correlation coefficients among the elements in the cancerous patients revealed significantly dissimilar communal relationships than the controls. Furthermore, multivariate methods demonstrated considerably different apportionment between the elements in the cancerous patients and the controls. Significant inequalities in the elemental concentrations were also observed for esophagus cancer types (adenocarcinoma and squamous cell carcinoma) and stages (I, II, III, and IV) between the patients. Majority of the elements exposed perceptible disparities in their levels based on smoking habits, dietary habits, habitat, and gender of the esophagus cancer patients and controls. Multivariate analysis of the essential and toxic elemental data explained significantly divergent apportionment in the serum of esophagus cancer patients when compared to controls.

Multivariate Investigation of Toxic and Essential Metals in the Serum from Various Types and Stages of Colorectal Cancer Patients.

Colorectal cancer (CRC) is currently one of the most frequent malignant neoplasms, ranking 3rd in incidence and 2nd in mortality both in the USA and across the world. The pathogenesis of CRC is a complex interaction between genetic susceptibility and environmental factors such as exposure to metals. Therefore, the present study was intended to assess the imbalances in the concentrations of selected essential/toxic elements (Pb, Cr, Fe, Zn, As, Cd, Cu, Se, Ni, and Hg) in the serum of newly diagnosed colorectal carcinoma patients (n = 165) in comparison with counterpart controls (n = 151) by atomic absorption spectrometry after wet-acid digestion method. Serum carcinoembryonic antigen (CEA) of the CRC patients was determined using immunoradiometric method. Body mass index (BMI) which is an established risk factor for CRC was also calculated for patients and healthy controls. Conversely, average Ni (2.721 µg/g), Cd (0.563 µg/g), As (0.539 µg/g), and Pb (1.273 µg/g) levels were significantly elevated in the serum of CRC patients compared to the healthy donors, while the average Se (7.052 µg/g), Fe (15.67 µg/g), Cu (2.033 µg/g), and Zn (8.059 µg/g) concentrations were elevated in controls. The correlation coefficients between the elements in the cancerous patients demonstrated significantly dissimilar communal relationships compared with the healthy subjects. Significant differences in the elemental levels were also showed for CRC types (primary colorectal lymphoma, gastrointestinal stromal tumor, and adenocarcinoma) and CRC stages (stage-I, stage-II, stage-III, and stage-IV) among the patients. Majority of the elements demonstrated perceptible disparities in their levels based on dietary, habitat, gender, and smoking habits of the malignant patients and healthy subjects. Multivariate methods revealed noticeably divergent apportionment among the toxic/essential elements in the cancerous patients than the healthy counterparts. Overall, the study showed significantly divergent distribution and associations of the essential and toxic elemental levels in the serum of the CRC patients in comparison with the healthy donors.

Capacitive and Conductometric Type Dual-Mode Relative Humidity Sensor Based on 5,10,15,20-tetra Phenyl Porphyrinato Nickel (II) (TPPNi).

(1) Background: A quest for a highly sensitive and reliable humidity monitoring system for a diverse variety of applications is quite vital. Specifically, the ever-increasing demand of humidity sensors in applications ranging from agriculture to healthcare equipment (to cater the current demand of COVID-19 ventilation systems), calls for a selection of suitable humidity sensing material. (2) Methods: In the present study, the TPPNi macromolecule has been synthesized by using a microwave-assisted synthesis process. The layer structure of the fabricated humidity sensor (Al/TPPNi/Al) consists of pair of planar 120 nm thin aluminum (Al) electrodes (deposited by thermal evaporation) and ~160 nm facile spin-coated solution-processable organic TPPNi as an active layer between the ~40 µm electrode gap. (3) Results: Electrical properties (capacitance and impedance) of sensors were found to be substantially sensitive not only on relative humidity but also on the frequency of the input bias signal. The proposed sensor exhibits multimode (capacitive and conductometric) operation with significantly higher sensitivity ~146.17 pF/%RH at 500 Hz and 48.23 kΩ/%RH at 1 kHz. (4) Conclusions: The developed Al/TPPNi/Al surface type humidity sensor's much-improved detecting properties along with reasonable dynamic range and response time suggest that it could be effective for continuous humidity monitoring in multi environmental applications.

Potential consequences of captivity and environmental pollution in endoparasitic prevalence in different antelopes kept at wildlife parks.

Endoparasites are the potential source of substantial health complications in animals; exclusively the endoparasites of zoonotic importance are of great concern to researchers and health authorities for diverse perspectives. A coprological study was conducted to inspect the endoparasitic infestation in antelopes kept at three captive localities, i.e., Safari Park, Jallo Wildlife Park, and Lahore Zoo, situated in Lahore, Pakistan. There were 109 selected species of antelopes including nilgai (Boselaphus tragocamelus), blackbuck (Antilope cervicapra), urial (Ovis orientalis), and chinkara (Gazella bennettii). The fresh fecal samples of each experimental animal from individual and mixed animal enclosures were collected and tested by an appropriate parasitological method. The fecal samples were examined by applying the modified McMaster technique through the Whitlock chamber method and observed by a compound microscope for identification and fecal egg count. The prevalence (%) of egg per gram (EPG) and diversity of endoparasitic eggs identified from fecal samples of experimental animals from three captive localities were recorded. The analysis revealed species from phylogenetic groups of nematodes cestodes and trematodes along with coccidian occurrence. The prevalence of endoparasites was highest in nilgai (B. tragocamelus) with combined average prevalence (23.88 ± 3.13) from three captive localities followed by chinkara (G. bennettii) combined average prevalence (21.68 ± 2.64), urial (O. orientalis) combined average prevalence (21.41 ± 4.69), and blackbuck (A. cervicapra) combined average prevalence (16.88 ± 2.66). To prevent such infestations which prevail more intensely regarding changing climate and increasing pollution levels, there should be regular monitoring and appropriate prophylaxis combined with epizootiological investigation for future studies and implication of advance technology, for captive animals so that best possible adaptations can be made to reduce the spread of infective diseases that are of zoonotic importance also.

Electron number density conservation model combined with a self-absorption correction methodology for analysis of nanostructure plasma using laser-induced breakdown spectroscopy.

We studied laser ablation and plasma property evolution for a nickel (Ni) doped tin (Sn) oxide nanostructures target using laser-induced breakdown spectroscopy (LIBS). The transition metal Ni doped tin oxide nanostructures were synthesized by co-precipitation and hydrothermal methodologies. The size of prepared nanoparticles was verified by X-ray diffraction and transmission electron microscopy techniques. A frequency-doubled pulsed Nd:YAG laser with a wavelength of 532 nm was used to produce ablated plasma nanostructures. Ablation of doped and undoped nanostructures revealed salient-enhanced spectral emissions compared with their bulky counterparts. The emission lines of the constituent elements of doped material were used to find plasma parameters. The plasma temperature was estimated from a Boltzmann plot, and the electron number density was determined from the Saha-Boltzmann equation. The self-absorption effect has been observed in tiny plasma of nanostructures. The affected profiles of spectral lines of Ni and Sn nanoparticles due to self-absorption in LIBS spectra were corrected by the internal reference self-absorption correction (IRSAC) methodology. After correction of emitted line intensities by IRSAC, the electron number density (END) conservation approach was applied for quantitative analysis of doped nanostructures. In the END conservation approach, quantitative analysis of samples was carried out using electron number densities. Quantitative results derived from the END conservation approach at high and low concentrations exhibited good correlation when these were compared and validated with results from a conventional calibration free approach and the standard recognized energy dispersive X-ray technique.

Statistical Assessment of Toxic and Essential Metals in the Serum of Female Patients with Lung Carcinoma from Pakistan.

Lung cancer (LC) is the number one cancer killer of women both in the USA and around the world. Besides cigarette smoking, an important feature in the etiology of LC is its strong association with exposure of toxic metals. The primary objective of the present investigation was to assess the concentrations of toxic/essential elements (Ni, Ca, Se, Zn, Co, K, Cr, As, Cu, Na, Fe, Hg, Cd, Mg, Mn, and Pb) in the serum samples of LC female patients with female controls by atomic absorption spectrometry after wet-acid digestion procedure. Carcinoembryonic antigen (CEA) was also measured in the serum of the patients using immunoradiometric method. Comparative appraisal of the data revealed that concentrations of Cr, Mg, Cd, Pb, Hg, As, and Ni were noted to be high significantly in serum of LC female patients, while the average Fe, Co, Mn, Na, K, Zn, Ca, and Se were observed at higher levels in female controls (p < 0.05). The correlation study revealed significantly different mutual associations among the elements in the both donor groups. Markedly, variations in the elemental levels were also noted for different types (non-small cell lung cancer and small cell lung cancer) and stages (I, II, III, & IV) of LC patients. Multivariate analyses showed substantially diverse apportionment of the metals in the female patients and female controls. Hence, present findings suggest that the toxic and essential metals accumulated in the body may pose a high risk for LC progression in Pakistani females.

Comparative study of calibration-free laser-induced breakdown spectroscopy methods for quantitative elemental analysis of quartz-bearing limestone.

Laser-induced breakdown spectroscopy (LIBS) has been employed for the qualitative and quantitative analysis of quartz-bearing limestone using two different calibration-free LIBS methods, that is, one-line calibration-free LIBS (OLCF-LIBS) and self-calibration LIBS (SC-LIBS) methods in conjunction with energy-dispersive x-ray spectroscopy (EDS) and x-ray fluorescence spectroscopy (XRF). The plasma is generated by focusing a Q-switched Nd:YAG laser (1064 nm, 134 mJ pulse energy, 9 ns pulse duration) in air under atmospheric pressure. Spectral analysis revealed the presence of Ca, Si, and Mg. Plasma temperature is deduced using the neutral spectral lines of pertinent elements using the Boltzmann plot method, and an average value of 3462 K is used for the quantitative analysis. An average value for electron number density is calculated as (1.3±0.3)×1017 cm-3 from the Stark broadening of isolated neutral Ca, Si, and Mg lines and a singly ionized Ca line. The elemental composition determined by different LIBS methods and other traditional analytical techniques are OLCF-LIBS (Ca, 71.82%; Si, 28.12%; Mg, 0.048%), SC-LIBS (Ca, 69.19%; Si, 28.92%; Mg, 1.87%), EDS (Ca, 68.86%; Si, 30.12%; Mg, 0.32%), and XRF (Ca, 68.62%; Si, 27.18%; Mg, 1.56%). By comparing the results of both CF-LIBS methods along with EDS and XRF, it is demonstrated that the SC-LIBS method is more appropriate than the OLCF-LIBS and gives compositions comparable with that determined by EDS and XRF and, hence, displays its ability as a powerful tool for the compositional analysis of complex minerals.

Calibration-Free Laser-Induced Plasma Analysis of Nanoparticle-Doped Material Using Self-Absorption Correction Methodologies.

The qualitative and quantitative analysis of doped nanomaterial containing iron (Fe) and tin (Sn) nanoparticles was investigated using laser-induced breakdown spectroscopy (LIBS). Doped nanoparticles were prepared via co-precipitation and hydrothermal processes. The emission spectra of ablated plasma of doped material revealed the existence of different species in the doped nanomaterial. Simple calibration-free LIBS (CF-LIBS) and internal reference self-absorption correction (IRSAC) CF-LIBS approaches were applied to emission spectra of nanomaterial for quantitative analysis. For both approaches, different spectroscopic parameters such as plasma temperature and electron number density were also determined. Plasma temperature was estimated using a Boltzmann plot and Saha-Boltzmann plot while electron number density was estimated by Stark broadening methods and Saha-Boltzmann equations. Results of both calibration-free approaches were compared with a weight percentage method and other recognized techniques such as laser ablation time of flight (LA-TOF) spectroscopy and energy dispersive X-ray (EDX). We concluded that our results provide good agreement with experimental data obtained using LA-TOF spectroscopy and a small deviation from data obtained using the EDX technique. The current work confirms LIBS as a valid analytical approach for quantitative analysis of nanomaterials.

Singlet oxygen photogeneration from X-O2 van der Waals complexes: double spin-flip vs. charge-transfer mechanism.

The channel of singlet oxygen O2((1)Δg) photogeneration from van der Waals complexes of oxygen X-O2 has been investigated to discriminate between two possible mechanisms based on charge-transfer (CT) or double spin-flip (DSF) transitions. The results obtained in this work for complexes with X = ethylene C2H4, 1,3-butadiene C4H6, deuterated methyl iodide CD3I, benzene C6H6 and water H2O and for those investigated previously indicate the DSF mechanism as a source of singlet oxygen. The formation of O2((1)Δg) is observed only when the energy of exciting quantum is sufficient for DSF transition. Universally detected low vibrational excitation of O2((1)Δg) arising in the photodissociation of van der Waals complexes X-O2 indicates the DSF mechanism as its source. For complex of ethylene C2H4-O2ab initio calculations of vertical energy ΔE(vert) for DSF and CT transitions have been carried out. The positive results of singlet oxygen formation from C2H4-O2 can be explained by the DSF but not by the CT mechanism.

Photodissociation of singlet oxygen in the UV region.

Photodissociation of singlet oxygen, O2 a(1)Δg, by ultraviolet radiation in the region from 200 to 240 nm has been investigated using velocity map imaging of the atomic oxygen photofragments. Singlet oxygen molecules are generated in a pulsed discharge and studied by one-laser photodissociation and detection around 226 nm as well as two color photodissociation at various wavelengths in the range from 200 to 240 nm. A simple model of the discharge on and off signal indicates efficient conversion of O2 X(3)Σg(-)(v = 0) in the parent beam to O2 a(1)Δg(v = 0-2). Minute amounts of highly excited vibrational levels of ground state O2 X(3)Σg(-)(v > 0) are detected but no evidence is found for production of the O2 b(1)Σg(+) state. Over the decreasing wavelength range 240-200 nm the a(1)Δg-state signal relative to the X(3)Σg(-)(v = 0) signal decreases strongly. Around 226 nm the a(1)Δg(v = 0-2) states averaged branching ratio percentage for O((3)Pjj = 2 : 1 : 0) is found to be 56 : 36 : 8 (±5%), respectively. The anisotropy parameter for photodissociation of a(1)Δg(v = 0-2) averages to ß = 1.3 ± 0.4. The a(1)Δg(v = 0) photodissociation cross section is found to 3-10 times stronger than theory predicts. Furthermore, the photodissociation image shows a strong parallel character, (i.e., transition moment parallel to the molecular axis) while theory predicts a predominantly negative character.

Early versus late arterio-venous fistulae: impact on failure rate.

BACKGROUND: Haemodialysis is the primary mode of renal replacement therapy for patients of end stage renal disease. The most important determinant for effective haemodialysis is a reliable vascular access. Arterio-venous (AV) fistula is the closest to be an ideal long-term haemodialysis vascular access. The creation of fistulas or grafts is recommended before starting haemodialysis, this study was undertaken to determine the impact of timing of AV fistula creation on its failure rate. METHODS: It is a descriptive study. All patients with chronic kidney disease (CKD) reporting to Armed Forces Institute of Urology (AFIU) and Military Hospital (MH) Rawalpindi from January 2008 to October 2009 in whom vascular access was created were included. The patients were followed prospectively and a complete data about their haemodialysis and vascular access was maintained. RESULTS: A total of 168 permanent accesses were created in 112 patients in this study. The mean duration of follow-up was 14.05 +/- 4.45 months. Early access creation group included 23 patients and late access creation group included 89 patients. Out of 168 fistulas that were created, 54 fistulas failed with 45 (83.3%) of these from patients of late access creation group. Age, gender and diabetes mellitus (DM) had no significant affect on failure rate of fistulas. CONCLUSION: Timely referral to nephrologists and early creation of permanent vascular access by dedicated team work can improve the success rate of AV fistulae so enhancing quality of life of patients of end stage renal disease.

Ethnoveterinary practices for the treatment of parasitic diseases in livestock in Cholistan desert (Pakistan).

AIM OF THE STUDY: This study was conducted to document the ethnoveterinary medicinal (EVM) practices for the treatment of different parasitic diseases of livestock in Cholistan desert, Pakistan. MATERIALS AND METHODS: An initial reconnaissance survey (rapid rural appraisal) among the local shepherds was conducted to identify the traditional healers. Information was collected from the traditional healers using a well-structured questionnaire through open-ended interviews and guided dialogue technique. RESULTS: The parasitic diseases reported in livestock were: tick and lice infestation, mange, myiasis and helminthiasis. A total of 77 ethnoveterinary practices comprising of 49 based on plant usage and 28 based on dairy products, chemicals and other organic matter were documented. A total of 18 plant species representing 14 families were documented to treat the parasitic diseases. The plants included: Aerva javanica (Amaranthaceae), Aizoon carariense (Aizoaceae), Azadirachta indica (Meliaceae), Brassica campestris (Cruciferae), Capparis decidua (Capparaceae), Capsicum annuum (Solanaceae), Citrullus colocynthis (Cucurbitaceae), Cyperus rotundus (Cyperaceae), Calligonum polygonoides (Polygonaceae), Eruca sativa (Cruciferae), Ferula assafoetida (Umbelliferae), Haloxylon salicornicum (Chenopodiaceae), Mallotus philippinensis (Euphorbiaceae), Nicotiana tabacum (Solanaceae), Pinus roxburghii (Pinaceae), Salsola baryosma (Chenopodiaceae), Solanum surratens (Solanaceae) and Zingiber officinale (Zingiberaceae). CONCLUSION: The EVM practices documented in this study need to be validated using standard parasitological procedures. Issues that should be addressed are efficacy (vis-à-vis claims made by the respondents), quality, safety and standardization of doses.