Elucidating the Infrared Spectral Properties of Succinic Molecular Acid Crystals: Illustration of the Structure and the Hydrogen Bond Energies of the Crystal and Its Deuterated Analogs.

Herein, the infrared spectroscopic properties of molecular succinic acid crystals (SA) and their four isotopic analogs [C2H4(COOH)2, h6-SA; C2H4(COOD)2, d2-SA; C2D4(COOH)2, d4-SA; C2D4(COOD)2, d6-SA] are reported. The correlation between the structure of succinic acid molecules and their corresponding hydrogen bond energies is elucidated. The effects related to the isotopic dilution as well as the changes in the spectrum recording temperature on the fine structures of the vO-H and vO-D bands are interpreted. The infrared spectral anomalies detected in the spectra of isotopically neat succinic nanocrystal acids are confirmed by theoretical calculations using density functional theory (DFT). According to previous spectroscopic studies of succinic acid and those carried out for α,ω-dicarboxylic acids, a decent agreement between the experimental results and the theoretical DFT simulations is obtained. Moreover, the spectra of single crystals of the h6 and d4 succinic acid variants prove that the vibrational coupling mechanism between the (COOH)2 cycles is rigorously convergent to that detected in the spectra of aromatic carboxylic acids, suggesting thereby that the promotion of symmetry-forbidden high stretching IR transitions plays a crucial role. Furthermore, the obtained experimental results reveal that the succinic acid shows a spectral behavior significantly different from that characteristic of hydrogen associations of other acids of homologous series, such as the glutaric, adipic, malonic, and pimelic acid crystals. The results obtained herein shed light on the way to explore the revealed structure of isotopic derivatives of succinic acid crystals and may prove to be useful results for understanding the nature of unconventional interactions as well as the macroscopic energy effects directing the development of hydrogen associations.

Thirty-day hospital readmission and emergency department visits after vascular surgery: a Canadian prospective cohort study.

BACKGROUND: Rates of hospital readmission following surgery can serve as a marker for quality of care. The aim of this study was to establish the rates and causes of readmission and emergency department visits after vascular surgery and to understand how these patients are managed. METHODS: We conducted a prospective observational cohort study including all inpatients who underwent major vascular surgery between September 2015 and June 2016 at a tertiary vascular care centre in Toronto. Patients were followed at 30 days after discharge via telephone interview. RESULTS: We enrolled 133 patients (94 men [70.7%] and 39 women [29.3%] with a mean age of 65.3 years). The most common index admission diagnosis was peripheral artery disease (67 patients [50.4%]). At 30 days, 19 patients (14.8%) had been readmitted or had visited the emergency department, most commonly after lower extremity revascularization (19.4%). Ten patients were readmitted a mean of 16.8 days following discharge; surgical site infection was the most common cause for readmission (3 patients). The most common treatment was antimicrobial therapy (4 patients). The mean hospital length of stay was 14.4 days. Nine patients presented to the emergency department a mean of 10.6 days after discharge; 6 reported a wound issue, and most (6 of 9) were managed with oral antibiotic treatment. CONCLUSION: Early readmission/emergency department visits after lower extremity revascularization surgery in patients with peripheral artery disease are common and are often due to surgical site infection or wound-related issues. Follow-up within 7-10 days and a specialized wound care team may help reduce the occurrence of these events.

CONTEXTE: Les taux de réadmission à l'hôpital après une chirurgie peuvent servir d'indicateur de la qualité des soins. L'étude visait à déterminer les taux et les causes de réadmissions et de visites à l'urgence chez les patients ayant subi une chirurgie vasculaire et à étudier la façon dont ces patients étaient pris en charge. MÉTHODES: Nous avons mené une étude de cohorte observationnelle prospective portant sur tous les patients qui ont été hospitalisés pour une importante chirurgie vasculaire entre septembre 2015 et juin 2016 dans un centre de soins tertiaires vasculaires à Toronto. Nous avons fait un suivi téléphonique auprès de ces patients 30 jours après leur congé. RÉSULTATS: Nous avons recruté 133 patients (94 hommes [70,7 %] et 39 femmes [29,3 %] dont l'âge moyen était de 65,3 ans). Le diagnostic le plus courant à l'admission initiale était la maladie artérielle périphérique (67 patients [50,4 %]). À 30 jours, 19 patients (14,8 %) avaient été réhospitalisés ou s'étaient présentés à l'urgence; la plupart avaient initialement subi une revascularisation des membres inférieurs (19,4 %). Dix patients ont été réhospitalisés en moyenne 16,8 jours après leur congé; l'infection du site opératoire était la cause la plus courante de réadmission (3 patients). Le traitement le plus courant chez les patients réhospitalisés était le traitement antimicrobien (4 patients). La durée médiane des séjours à l'hôpital était de 14,4 jours. Neuf patients se sont présentés à l'urgence en moyenne 10,6 jours après leur congé; 6 ont signalé un problème avec leur plaie, et la majorité (6 des 9 patients) ont reçu une antibiothérapie orale. CONCLUSION: Les réadmissions ou les visites à l'urgence de patients atteints d'une maladie artérielle périphérique peu après une chirurgie de revascularisation des membres inférieurs sont courantes et souvent attribuables à une infection du site opératoire ou à des problèmes associés à la plaie. Un suivi après 7 à 10 jours ainsi que les services d'une équipe spécialisée en soin des plaies pourraient contribuer à réduire la fréquence de ce type d'événement.

Thirty-day hospital readmission and emergency department visits after vascular surgery: a Canadian prospective cohort study.

BACKGROUND: Rates of hospital readmission following surgery can serve as a marker for quality of care. The aim of this study was to establish the rates and causes of readmission and emergency department visits after vascular surgery and to understand how these patients are managed. METHODS: We conducted a prospective observational cohort study including all inpatients who underwent major vascular surgery between September 2015 and June 2016 at a tertiary vascular care centre in Toronto. Patients were followed at 30 days after discharge via telephone interview. RESULTS: We enrolled 133 patients (94 men [70.7%] and 39 women [29.3%] with a mean age of 65.3 years). The most common index admission diagnosis was peripheral artery disease (67 patients [50.4%]). At 30 days, 19 patients (14.8%) had been readmitted or had visited the emergency department, most commonly after lower extremity revascularization (19.4%). Ten patients were readmitted a mean of 16.8 days following discharge; surgical site infection was the most common cause for readmission (3 patients). The most common treatment was antimicrobial therapy (4 patients). The mean hospital length of stay was 14.4 days. Nine patients presented to the emergency department a mean of 10.6 days after discharge; 6 reported a wound issue, and most (6 of 9) were managed with oral antibiotic treatment. CONCLUSION: Early readmission/emergency department visits after lower extremity revascularization surgery in patients with peripheral artery disease are common and are often due to surgical site infection or wound-related issues. Follow-up within 7-10 days and a specialized wound care team may help reduce the occurrence of these events.

CONTEXTE: Les taux de réadmission à l'hôpital après une chirurgie peuvent servir d'indicateur de la qualité des soins. L'étude visait à déterminer les taux et les causes de réadmissions et de visites à l'urgence chez les patients ayant subi une chirurgie vasculaire et à étudier la façon dont ces patients étaient pris en charge. MÉTHODES: Nous avons mené une étude de cohorte observationnelle prospective portant sur tous les patients qui ont été hospitalisés pour une importante chirurgie vasculaire entre septembre 2015 et juin 2016 dans un centre de soins tertiaires vasculaires à Toronto. Nous avons fait un suivi téléphonique auprès de ces patients 30 jours après leur congé. RÉSULTATS: Nous avons recruté 133 patients (94 hommes [70,7 %] et 39 femmes [29,3 %] dont l'âge moyen était de 65,3 ans). Le diagnostic le plus courant à l'admission initiale était la maladie artérielle périphérique (67 patients [50,4 %]). À 30 jours, 19 patients (14,8 %) avaient été réhospitalisés ou s'étaient présentés à l'urgence; la plupart avaient initialement subi une revascularisation des membres inférieurs (19,4 %). Dix patients ont été réhospitalisés en moyenne 16,8 jours après leur congé; l'infection du site opératoire était la cause la plus courante de réadmission (3 patients). Le traitement le plus courant chez les patients réhospitalisés était le traitement antimicrobien (4 patients). La durée médiane des séjours à l'hôpital était de 14,4 jours. Neuf patients se sont présentés à l'urgence en moyenne 10,6 jours après leur congé; 6 ont signalé un problème avec leur plaie, et la majorité (6 des 9 patients) ont reçu une antibiothérapie orale. CONCLUSION: Les réadmissions ou les visites à l'urgence de patients atteints d'une maladie artérielle périphérique peu après une chirurgie de revascularisation des membres inférieurs sont courantes et souvent attribuables à une infection du site opératoire ou à des problèmes associés à la plaie. Un suivi après 7 à 10 jours ainsi que les services d'une équipe spécialisée en soin des plaies pourraient contribuer à réduire la fréquence de ce type d'événement.

External Ophthalmomyiasis Due to Dermatobia hominis Masquerading As Orbital Cellulitis.

Human parasitization by oestrid flies is a rare occurrence. The authors report a case of ophthalmomyiasis externa caused by Dermatobia hominis infestation in a 10-year-old female. Misdiagnosis resulted in a delay in treatment, which can be potentially devastating in cases of orbital or ocular involvement. The treatment of choice is early surgical removal of the larvae to minimize the inflammatory response and the extent of surgery. Patients should also be screened for multiple sites of cutaneous infestation. When the organism is completely excised, the prognosis is good.

Modelling of Nonthermal Dielectric Barrier Discharge Plasma at Atmospheric Pressure and Role of Produced Reactive Species in Surface Polymer Microbial Purification.

A nonthermal atmospheric plasma reactor was used to sterilize polymer surfaces and satisfy safety constraints in a biological medium. A 1D fluid model was developed using COMSOL Multiphysics software® 5.4 with a helium-oxygen mixture at low temperature for the decontamination of bacteria on polymer surfaces. An analysis of the evolution of the homogeneous dielectric barrier discharge (DBD) was carried out through studying the dynamic behavior of the discharge parameters including the discharge current, the consumed power, the gas gap voltage, and transport charges. In addition, the electrical characteristics of a homogeneous DBD under different operating conditions were studied. The results shown that increasing voltage or frequency caused higher ionization levels and maximum increase of metastable species' density and expanded the sterilization area. On the other hand, it was possible to operate plasma discharges at a low voltage and a high density of plasma using higher values of the secondary emission coefficient or permittivity of the dielectric barrier materials. When the discharge gas pressure increased, the current discharges declined, which indicated a lower sterilization efficiency under high pressure. A short gap width and the admixture of oxygen were needed for sufficient bio-decontamination. Plasma-based pollutant degradation devices could therefore benefit from these results.

Mechanic-elastic properties and radiation attenuation efficiency of TeO2/WO3/K2O composite glass systems for nuclear and medical application.

WO3 effects on neutron and ionizing radiation defending factors of ternary tellurite-based glass blocks with molecular formula 80TeO2 -(20-x)WO3 - xK2O; x = 0-20 mol% (denoted as TKW-glass) has been reported via Phy-X theoretical calculations and Geant4 simulation code. Correlations between shielding factors and kinetics properties of the investigated glasses at different photon energy have been examined. The highest values of mass (MAC) attenuation coefficient were noted at 15 keV of the examined TKW-glass materials with the values of 38.408, 44.388, 49.855, 54.872, 59.492 cm2/g for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. Generally, these values of the TKW-glasses obey the sequence: (TKW-0)MAC< (TKW-5)MAC < (TKW-10)MAC < (TKW-15)MAC < (TKW-20)MAC. The highest mean free path (MFP) values of TKW-glasses were registered at 15 MeV with the values of 6.101, 5.591, 5.097, 4.647, and 4.302 cm for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. The two parameters half value layer (HVL) and MFP follow the pattern: (TKW-0)HVL, MFP > (TKW-5)HVL,MFP > (TKW-10)HVL,MFP > (TKW-15)HVL,MFP > (TKW-20)HVL,MFP. The maximum values of effective atomic number (EAN) took place at gamma energy of 15 keV corresponding to 44.35, 48.86, 52.63, 55.83, and 58.58 for TKW-0, TKW-5, TKW-10, TKW-15, and TKW-20, respectively. The trend of the buildup factors was similar for all of the glass specimens. The fast neutron removal cross-section (ΣR) enhanced as WO3 content increased in the specimens. Thus, the peaked value of ΣR is 0.1059 cm-1 was noted in the TKW-20 sample. Mechanical properties, neutron and γ-rays protection parameters were observed to improve with enhanced WO3 mol% in the TKW-glasses. The current results bear their utilization for neutron and gamma protection purposes.

Elucidating the Structural, Electronic, Elastic, and Optical Properties of Bulk and Monolayer MoS2 Transition-Metal Dichalcogenides: A DFT Approach.

Due to their outstanding properties for optoelectronic and versatile electronic applications, the atomically thin layers of transition-metal dichalcogenide (TMDC) materials have demonstrated a potential candidacy to succeed its analog silicon-based technology. Hence, the elucidation of the most important features of these materials is indispensable. In this study, we provide a theoretical elucidation of the structural, electronic, elastic, and optical characteristics of TMDCs. The study has been carried out by elucidating the material in its two particular forms, namely, bulk and two-dimensional (2D) layered (monolayer). The theoretical investigation was carried out within the framework of the density functional theory (DFT) method using first-principles calculations. The Perdew-Burke-Ernzerhof (PBE) variant of the generalized gradient approximation (GGA) scheme, as performed in the Quantum Espresso package, is used. Van der Waals density functional effects, involving the nonlocal correlation part from the rVV10 and vdW-DF2 methods, were treated to remedy the lack of the long-range vdW interaction. An illustration of the performance of both rVV10 and vdW-DF2 functionalities, with the popular PBE correlations, is elucidated. The Born stability criterion is employed to assess structural stability. The obtained results reveal an excellent stability of both systems. Furthermore, the theoretical results show that band-gap energy is in excellent agreement with experimental and theoretical data. Pugh's rule suggested that both the bulk and MoS2-2D layered systems are ductile materials. The refractive indices obtained herein are in good agreement with the available theoretical data. Moreover, the theoretical results obtained with the present approach demonstrate the ductility of both systems, namely, the bulk and the MoS2-2D layered. The results obtained herein hold promise for structural, elastic, and optical properties and pave the way for potential applications in electronic and optoelectronic devices.

New insights on microscopic properties of metal-porphyrin complexes attached to quartz crystal sensor.

A quartz crystal adsorbent coated with 5,10,15,20-tetrakis(4-methylphenyl) porphyrin was used to examine the complexation phenomenon of three metallic ions [aluminum(III), iron(III) and indium(III)]. The aim is to select the appropriate adsorbate for metalloporphyrin fabrication. The equilibrium adsorption isotherms of tetrakis(4-methylphenyl) porphyrin were performed at four temperatures (from 300 to 330 K) through the quartz crystal microbalance (QCM) method. Subsequently, the experimental data were analyzed in order to develop a thorough explanation of the complexation mechanisms. The experimental results indicated that the aluminum(III) chloride is the adequate material for metalloporphyrin application. Theoretical investigation was established through physics adsorption models in order to analyze the experimental isotherms. The AlCl3 isotherms were modeled via a single-layer adsorption model which is developed using the ideal gas law. Whereas, the FeCl3 isotherms were interpreted via a single-layer adsorption which includes the lateral interactions parameters (real gas law), indicating the lowest stability of the formed iron-porphyrin complex. The participation of the chloride ions in the double-layers adsorption of InCl3 was interpreted via layer by layer formulation. Interestingly, the physicochemical investigation of the three adopted models indicated that the tetrakis(4-methylphenyl) porphyrin adsorption was an endothermic process and that the aluminum(III) chloride can be recommended for an industrial application because it presents the highest adsorption energy (chemical bonds with porphyrins).

A unified quantum model susceptible to elucidate the dissimilarity of IR spectral density of dicarboxylic acid crystals: Phthalic and terephthalic acid crystals cases.

Over the last decades, several approaches have been developed for elucidating the infrared spectral density of dicarboxylic acid crystals, which has been served as prototype for determining hydrogen bonds dynamics. These approaches differ in how accurately the simulated spectra can superimpose the experimental ones. In this study, we present a superdimer quantum approach susceptible to elucidate the infrared spectral properties of some particular dicarboxylic acid crystals using a newly proposed algorithm, which favors the rule of Davydov coupling in the generation of the spectra. The approach, which is herein effectively applied to terephthalic and phthalic acid dimer crystals, ascribes the non-conventional IR spectral properties of these particular acid crystals to the existence of superdimer structure in their lattices. In this superdimer structure, a strong vibronic coupling mechanism, namely Davydov coupling, takes place between the proton stretching vibrations in the (COOH)2 cycles. This strong coupling exciton, generated by the resonance arising in the two coupled (COOH)2 cycles of the aromatic rings of the superdimer, in conjunction with the strong anharmonic coupling between the fast and slow modes of each hydrogen bonds provide a strong support basis for a common explanation of the physical properties of these two different crystalline systems. The numerical simulations, involving the implications of the superdimer model, are systematically correlated with the experimental spectra. A decent agreement between the evaluated spectra and the experimental bandshapes of terephthalic and phthalic dicarboxylic acid crystals was obtained using a set of physically sound parameters as inputs in the theoretical formulation. The superdimer quantum approach thereby underscore the potential of the dynamical cooperative interactions between "Davydov coupling" and "strong anharmonic coupling" mechanisms in the generation of the spectral features of terephthalic and phthalic dicarboxylic acid crystals, suggesting that the congregated effects of these two mechanisms can be considered as the most reliable source of the non-conventional IR spectral properties observed. It is therefore expected that this novel algorithm reduces the discrepancies between the simulated spectra compared to the experimental one and simplify the computation of spectra in more complex hydrogen bonded systems.

Corneal elevation indices and pachymetry values of Saudi myopes using scheimpflug imaging.

OBJECTIVES: To report the corneal elevation and thickness values for Saudi myopes and to evaluate the differences between these parameters in subgroups of this target population. Methods: Pentacam corneal topographic maps of the right eyes of patients visiting Al-Hokama Eye Clinic, Riyadh, Saudi Arabia, a tertiary eye center between January 2009 and December 2015 were retrospectively analyzed in this cross-sectional study. The patients were grouped into 3 categories based on their spherical readings: mild (-0.25 to -2.75D), moderate (-3.00 to -5.75D), and severe (≥-6.00D). Furthermore, patients with cylindrical readings of ≥-1.00 diopter were categorized as having myopic astigmatism, whereas those with less than -1.00 cylindrical diopter were categorized as having simple myopia. Results: Our sample was comprised of 1,276 patients; 838 (65.7%) had simple myopia and 438 (34.3%) had myopic astigmatism. The values for the whole myopic group were as follows:  anterior corneal elevation (AE) at the apex= 2.60±1.48 (standard deviation), thinnest AE= 2.56±1.68, posterior elevation (PE) at the apex= 3.67±3.58, thinnest PE= 4.92±3.81, central pachymetry= 550.09±34.29, apical pachymetry=550.73±34.64, and thinnest pachymetry= 546.30±34.61. All of the measurements, except the apical PE and thinnest PE, were statistically significant across the simple and myopic astigmatism groups (p less than 0.05). Comparing the mild to moderate myopia groups revealed a significant difference in the apical AE (p=0.037). Moreover, the comparison between the mild and severe myopia groups revealed that the apical PE and the thinnest PE, as well as the central, apical, and thinnest pachymetry values were statistically significantly different (p less than 0.05). Conclusion: The corneal elevation indices and thicknesses specific to the Saudi myopes were found to be comparable to the international databases in terms of the elevation and thickness in some of the parameters.

Light intensity output of visible light communication units and clinicians' knowledge and attitude among Riyadh private clinics.

BACKGROUND: With the evolution of bonded restorations, visible light-curing units became inseparable from the practice of dentistry. This study was designed to evaluate light intensity output of light-emitting diode (LED) units used in private clinics in Riyadh, Saudi Arabia, and to investigate dentists' knowledge and attitude regarding the usage of light-curing units. METHODOLOGY: Two hundred randomly selected LED units' light intensity output was evaluated using Demetron ® LED Radiometer-Kerr among evenly distributed private clinics in Riyadh, Saudi Arabia. Three measurements of 20 s were taken, and average values were obtained. Furthermore, Output intensity measurements were subcategorized into three groups; <400 mW/cm2- inadequate intensity, 400-850 - marginal intensity, and more than 850 - adequate intensity. In addition, 100 questionnaires of ten close-ended questions, investigating demographics, knowledge, and attitude toward visible light communication (VLC) units, were filled by the same private clinics' dentists and data were collected and analyzed by SPSS. The investigation was started after official processing and agreement achieved between the investigators and the private clinics' administrators to get their full cooperation. RESULTS: Majority of dentists (78%) reported that they do not measure the light intensity output and 9% of the measured light intensity output of LED units was found of inadequate intensity, 40.5% of marginal intensity, and 50.5% of adequate intensity. Moreover, only 31% knew the minimum accepted wavelength of VLC units. CONCLUSION: Dentists among private clinics express poor knowledge, maintenance, and attitude toward VLC units. Educational programs are advisable, and routinely monitoring of VLC units is recommended.

Depression literacy in women attending university hospital clinics in Riyadh Saudi Arabia.

BACKGROUND: Depression literacy in general population constitutes an ability to understand depression, with knowledge of disease, its risk factors and symptoms. High levels of depression literacy promote early intervention, potentially reducing related disability. AIM: This study investigated the depression literacy in women visitors to clinics of a tertiary care hospital in Riyadh, Saudi Arabia. METHODS: Women of 18 and more years were surveyed during their visit to primary and other healthcare clinics of a public hospital in Riyadh. Knowledge on depression symptoms, causes and management approaches identified depression literate women scoring more than 30 points on a 42-item tool. RESULTS: Of the 409 participants, 65.5% were depression literate, 50% educated as college and above, 64.3% married, 50.7% housewives, 62.4% reported use of multiple information sources (range, 0-8) and had a mean age of 34.9 (standard deviation ( SD), 12.4) years. In a logistic regression model, participants scoring less than 30 for depression literacy were significantly associated with women having less than college-level education, divorced marital status and use of decreasing number of learning resources. CONCLUSION: Women with low education divorced; using fewer information sources need specific considerations by healthcare providers for assessment of depressive disorders in this setting.