Perceived stigma among Tunisian healthcare workers during the COVID-19 pandemic.

BACKGROUND AND OBJECTIVES: Stigma was a major issue during the COVID-19 pandemic. It posed a serious threat to the lives of healthcare workers (HCWs) who were expected to experience higher levels of stigma and increased psychological distress. This is the first survey to investigate forms and correlates of perceived stigma in Tunisian HCWs during the COVID-19 pandemic. METHODS: A cross-sectional web-based survey was conducted between October 8th and November 10th 2020, among 250 Tunisian HCWs. Data were collected using an online questionnaire using the Google Forms® platform. We used a self-reported instrument measuring COVID-19-related stigma, and the Multidimensional Scale of Perceived Social Support (MSPSS) to measure the perceived adequacy of social support from three sources: family, friends, and significant other. RESULTS: The mean stigma score was 18.6±8. Participants sometimes to often experienced stigma in their relationships with friends (22%), neighbors (27.2%), parents (22,4%), and in social activities (30.8%). This stigma was perceived mainly through avoidance (68.4%), and rarely through verbal (6%) or physical aggression (1.2%). The mean MSPSS total score was 5.26±1.24. In multivariate analysis, depression history (P<0.001), long working experience (P<0.001), having presented ageusia/anosmia (P=0.007) and lower total social support scale (P<0.001) were significantly associated with higher perceived stigma score. CONCLUSION: Our findings showed that HCWs perceived stigma in professional, societal and familial domains. Social support from family, friends and others seemed to protect against perceived stigma. Proper health education targeting the public appears to be an effective method to prevent social harassment of both HCWs and COVID-19 survivors.

Impact of a training intervention on knowledge and practices of health-care workers about reprocessing reusable medical devices in a South-Tunisian University Hospital.

INTRODUCTION: Reprocessing of reusable medical devices (RMD) play an important role in the prevention of health-care associated infections. In this perspective, this study aimed to evaluate the impact of a training program intervention on health-care workers' (HCWs) knowledge and hospital practices about the reprocessing of RMD as a main strategic axis of infection control. METHOD: We led a pre-post quasi-experimental study to evaluate knowledge of HCWs and to assess hospital practices in reprocessing RMD before and after a training intervention from May to November 2020 in Hedi Chaker University Hospital. A self-administrated questionnaire was distributed for each participant to assess knowledge. To evaluate practical skills, an audit grid was used. RESULTS: Overall, 30 participants were included. All HCWs had a fair level of knowledge before training. The knowledge score (KS) has significantly risen from pre to post-training (64/100 vs. 80/100; P<0.001). When stratified by RMD type, a significant increase was noted on post intervention in KS about thermo-sensitive RMD reprocessing (P=0.044) and sterilization of thermo-resistant RMD (P=0.004). As for practice assessment, 5 (62.5%) departments had a fair level of practice. The conformity score (CS) did not significantly change from baseline to post-follow-up (53.5 vs. 56.2; P=0.06). According to the audit sections, we did not find a significant change in the pre- and post-intervention CS in sterilization process (70 vs. 80; P=0.06) and in the cleaning and decontamination steps (66.7 vs. 67; P=0.18). CONCLUSION: As opposed to practical skills, positive impact of the training intervention on HCWs knowledge was noted, which underlined the gap between theory and practice.

Detoxification of rats subjected to nickel chloride by a biomaterial-based carbonated orthophosphate.

Recently, the therapeutic approaches of the detoxification against the metals (nickel) in the body are the use of biomaterials such as carbonated hydroxyapatite. The aim of this study is therefore to analyze the physiological and physicochemical parameters of strain white rats "Wistar" receiving nickel chloride and to study the protective associative of apatite against adverse effects of this metal, and this in comparison with control rats. Our results showed that the nickel induced in rats an oxidative stress objectified by elevated levels of thiobarbituric acid-reactive substances and conjugated dienes associated with inhibition of the activity of the antioxidant defense system such as glutathione peroxidase, superoxide dismutase and catalase in the liver, kidney, spleen and erythrocyte. Disorders balances of ferric, phosphocalcic, a renal failure and a liver toxicity were observed in rats exposed to nickel. As well as a significant increase in the rate of nickel in the bones and microcytic anemia was revealed. However, the implantation of carbonated hydroxyapatite in capsule form protects rats intoxicated by the nickel against the toxic effects of this metal by lowering the levels of markers of lipid peroxidation and improving the activities of defense enzymes. Our implantation technique is effective to correct ferric balance and phosphocalcic equilibrium, to protect liver and kidney function, to reduce the rate of bone nickel and to correct anemia. They clearly explain the beneficial and protective of our biomaterial which aims the detoxification of rats receiving nickel by substituting cationic (Ca(2+) by Ni(2+)) and anionic (OH(-) by Cl(-)) confirmed by physicochemical characterization like the IR spectroscopy and X-ray diffraction. These techniques have shown on the one hand a duplication of OH(-) bands (IR) and on the other hand the increase of the volume of the apatite cell after these substitutions (X-ray diffraction).

Biological therapy of strontium-substituted bioglass for soft tissue wound-healing: responses to oxidative stress in ovariectomised rats.

New synthetic biomaterials are constantly being developed for wound repair and regeneration. Bioactive glasses (BG) containing strontium have shown successful applications in tissue engineering account of their biocompatibility and the positive biological effects after implantation. This study aimed to assess whether BG-Sr was accepted by the host tissue and to characterize oxidative stress biomarker and antioxidant enzyme profiles during muscle and skin healing. Wistar rats were divided into five groups (six animals per group): the group (I) was used as negative control (T), after ovariectomy, groups II, III, IV and V were used respectively as positive control (OVX), implanted tissue with BG (OVX-BG), BG-Sr (OVX-BG-Sr) and presented empty defects (OVX-NI). Soft tissues surrounding biomaterials were used to estimate superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) concentration. Our results show that 60 days after operation, treatment of rats with BG-Sr significantly increased MDA concentration and caused an increase of SOD, CAT and GPx activities in both skin and muscular tissues. BG-Sr revealed maturation of myotubes followed a normal appearance of muscle regenerated with high density and mature capillary vessels. High wound recovery with complete re-epithelialization and regeneration of skin was observed. The results demonstrate that the protective action against reactive oxygen species (ROS) was clearly observed in soft tissue surrounding BG-Sr. Moreover, the potential use of BG-Sr rapidly restores the wound skin and muscle structural and functional properties. The BG advantages such as ion release might make BG-Sr an effective biomaterial choice for antioxidative activity.

[Efficiency of mesotherapy in dental medecine. 16 Clinical cases]. / Efficacité de la mésothérapie en médecine dentaire. A propos de 16 cas cliniques.

We often prescribe drugs in large quantities, it may help to relieve, but it also triggers intolerances, allergies or even digestive or skin problems. This is one reason, perhaps the main, to explore elsewhere. The reader will discover, through this article, mesotherapy; a new and simple therapeutic that aims to approximate the location of the therapeutic to the place of the pathology for greater efficiency. To test the effectiveness of this technique in dentistry, we treated by mesotherapy, 16 patients with phenomena of algo-inflammation, and as witnesses, 21 patients with the same symptoms and same diagnosis but conventionally treated by drugs prescriptions. A regression of the inflammation and an improvement in the painful condition were observed at a shorter time among patients treated with mesotherapy; it would be interesting, by evaluating the ratio "quality/cost-effectiveness and safety", to encourage the practice of mesotherapy in dentistry.

Original implementation of low-temperature SPS for bioactive glass used as a bone biomaterial.

Alkali borated bioactive glasses powders with compositions based on the SiO2-Na2O-CaO-P2O5-x B2O3 system (0 < x < 20 wt%); have been consolidated at low temperature using Spark Plasma Sintering (SPS). Through SPS technique under 50 MPa, it was possible to achieve fully dense and completely amorphous borated glasses at temperatures as low as 420 °C. By increasing the sintering temperature up to 430 °C, the dense samples crystallized which is mostly achieved at higher temperatures. This study reveals that the mechanical properties of these new borated biomaterials are suitable to be used as a promising candidate for repairing defects in non-load-bearing bones as well as for coating on the metallic surface implants to improve the bioactivity process bone/implant. The pressure had a weak effect on the crystallization and densification of the glass compared to the temperature during the powder consolidation by SPS. Moreover, by increasing the boron content, the compressive strength and the elastic modulus of the elaborated glasses decreased for being close to those of the natural.

Prevalence and predictors of hypertension self-care practice in primary health-care facilities in Southern Tunisia.

BACKGROUND: Unmanaged hypertension (HTN) is usually accompanied with complications leading to disability in older adults. It has been demonstrated that self-care practice is essential for blood pressure control and reduction of HTN complications. OBJECTIVE OF THE STUDY: This study aimed to estimate the level of implementation of HTN self-care practice and to identify their associated factors. STUDY DESIGN: It was a cross-sectional study conducted in Sfax, Southern Tunisia in April 2020. MATERIALS AND METHODS: A total of 6 primary health-care facilities were approached for the study participants according to a single-stage cluster sample, by selecting six grapes randomly. A total of 270 participants were recruited, among whom 250 cases (92.6%) completed the questionnaire. RESULTS: A total of 250 hypertensive patients were included in the study, giving a male to female ratio of 0.77. There were 125 participants (50%) aged over 65years. Overall, 137 cases (54.8%) had a high total self-care practice score. The independent factors of good HTN self-care practice were≥65years [Adjusted odds ratio (AOR)=9.5; P<0.001], university educational level of the participants (AOR=21.2; P<0.001), as well as receiving a health education, by health-care providers (AOR=2.5; P=0.012) and family members (AOR=4.36; P=0.004). Advanced hypertension stage (II and III) (AOR=0.45; P=0.032) and chronic pulmonary diseases, including asthma (AOR=0.42; P=0.027) and chronic obstructive pulmonary diseases (AOR=0.27; P=0.016) were independently associated with poor HTN self-care practice. CONCLUSION: Advanced hypertension stage, pulmonary co-morbidities, education level and lack of self-care education were predictive factors of poor self-care practice. These findings suggested that such factors should be considered when planning HTN self-care education.

Comparison of hepatitis A seroprevalence in blood donors in South Tunisia between 2000 and 2007.

The aim of the study was to assess hepatitis A virus (HAV) seroprevalence in blood donors from South Tunisia in two periods 2000 and 2007. Serum samples collected from 376 blood donors in each period aged 18 to 30 years from different regions of South Tunisia were analysed for anti-HAV IgG. The global seroprevalence of HAV infection was 85.9% in 2007 as compared with 94.9% in 2000. The seroprevalence in the 18-20 years age group was 91.9% in 2000 vs 80.6% in 2007, and increased to 99% in 2000 and 92% in 2007 in the subjects over 26. Taking account of geographic area, the HAV seroprevalence in Sfax city decreased from 88.9% in 2000 to 62.7% in 2007 (p < 0.001), but it is still approximatively the same in rural areas (98.4% and 96%) and in the governorates of South Tunisia (97.6% and 99.2%). In conclusion, the number of adults in the city of Sfax which are not immunized against HAV is increasing. Thus, adolescents and young adults are at risk to develop symptomatic and potentially severe hepatitis A.

[Active smoking: A major risk factor for human non-communicable diseases in a hospital survey]. / Le tabagisme actif : un facteur de risque majeur des maladies non transmissibles humaines dans une enquête hospitalière.

INTRODUCTION: Tobacco is the main preventable cause of death worldwide. Our study aimed to determine the role of tobacco in the occurrence of non-communicable diseases (NCDs). METHODS: We conducted a retrospective study including all NCDs patients during 2015-2016. NCDs include cardiovascular diseases (CVD), chronic respiratory diseases (CRD), cancers (CS) and diabetes mellitus (DM). RESULTS: We identified 3643 cases of NCDs (43%) among 8478 hospitalizations, all diseases combined. Active smoking was found in 1076 cases (29.5%). Among the NCDs groups, CVD was the most common (65%). Tobacco was significantly associated with CVD (P<0.001), CRD (P=0.002), bronchopulmonary CS (P<0.001), haematological malignancy (P=0.023), and DM (P<0.001). Multivariate analysis performing binary logistic regression revealed that tobacco was an independent factor associated with CVD (OR=2.6, P<0.001), CRD (OR=1.5, P<0.001), bronchopulmonary CS (OR=1.8, P=0.013) and DM (OR=3.6, P<0.001). CONCLUSION: Active smoking was a major risk factor in the occurrence of NCDs. Thus, smoking cessation represents the cornerstone for preventing the spread of these diseases, especially in countries with limited resources.

Vibrational study of phase transition in N-benzyl methyl ammonium dihydrogenmonophosphate monohydrate.

Raman spectra (100-3200 cm(-1)) of polycrystalline samples of C(6)H(5)CH(2)NH(2)CH(3)H(2)PO(4).H(2)O were studied at temperature ranging from 77 to 350 K. By comparison with homologue compounds and calculated wavenumbers, an assignment of the observed bands is proposed. The thermal evolution of Raman spectra reveals an order-disorder phase transition at about 120 K involving the hydrogen bonds coupled with the distortion of the organic cations. The line at 244 cm(-1)assigned to tau(CH(3)) shows a remarkable evolution across the transition. Therefore, a careful analysis of the thermal evolution of this mode was performed using Porto model. The activation energy, obtained from the plot of Deltanu(1/2) versus temperature, is E(a)=1.27 kcal mol(-1). This value is of the same order of magnitude as the one found for homologue hydrogen bonded compounds.

HF, MP2 and DFT calculations and spectroscopic study of the vibrational and conformational properties of N-diethylendiamine.

The conformational stability and vibrational modes of the N-diethylendiamine organic cation (N-DD(2+)) were studied by experimental (Raman) spectroscopy combined with theoretical calculations. Various ab initio theories were used: Hartree-Fock (HF) theory, Möller-Plesset second-order perturbation (MP2) theory and density functional theory (DFT). Three stable conformers of N-DD(2+), trans-trans, gauche-gauche and gauche-trans were calculated. A comparison between the computed structural parameters of the conformers at both levels of theory and the X-ray data was made. It is demonstrated that the N-DD(2+) cation adopts more probably the gauche-gauche conformation at room temperature. In order to make a more detailed interpretation of the low temperature phase transition of N-DDHP, the Raman spectra of N-DDHP were recorded at room and low temperature in the 200-3400 cm(-1) region. The vibrational frequencies of the different conformers of N-DD(2+) were also calculated using the DFT/B3LYP (6-31G(d)) level of theory. By comparison between the experimental and theoretical results, the conformational dynamic of the N-DD(2+) organic cation was confirmed. It is shown that the N-DD(2+) cation configuration changes from gauche-gauche conformer to gauche-trans conformer when decreasing the temperature.

The molecular structure and vibrational spectra of 3-acetyl-4-[N-(2'-aminopyridinyl)-3-amino]-3-buten-2-one by Hartree-Fock and density functional theory calculations.

The molecular structure and vibrational spectra of 3-acetyl-4-[N-(2'-aminopyridinyl)-3-amino]-3-buten-2-one (C(11)H(13)N(3)O(2)) in the ground state have been investigated by Hartree-Fock and density functional method (B3LYP and BLYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of title compound and calculated results by HF and DFT methods indicate that B3LYP is superior to the scaled HF approach for molecular problems.

[Abdominal obesity and knee ostheoarthritis]. / Obésité abdominale et gonarthrose.

UNLABELLED: The objective of our study was to determine whether waist circumference (WC) is a more reliable indicator than body mass index (BMI) of the presence of knee osteoarthritis in obese subjects. PATIENTS AND METHODS: We performed an observational study of obese patients with no other risk factors for knee osteoarthritis. For each patient, we evaluated BMI, WC, duration of obesity and knee pain. Two groups were identified: "asymptomatic patients" (AG), without knee pain, and "symptomatic patients" (SG). For the SG, we measured pain intensity (visual analog scale [VAS], 0-100 mm) and functional repercussions (using the Lequesne and WOMAC indexes). Patients with knee pain underwent standard radiographic procedures to search for signs of osteoarthritis, and the SG was divided into two subgroups: with radiological signs of osteoarthritis (SG-1) and without radiological signs of osteoarthritis (SG-2). The AG and SG groups and SG-1 and SG-2 groups were compared for age, sex, and duration of obesity. Comparisons of BMI, WC, and function involved the Student's t-test. RESULTS: We recruited 56 patients for the study (82.5% females; mean obesity duration (13+/-6.5 years; mean age 43.21+/-9.58 years). The mean BMI was 39.6+/-7.23 kg/m(2) and mean WC was 113+/-14.3 cm. We found 33 patients (59%) with knee pain. Independent of age, sex, duration of obesity and BMI, the SG showed more significant WC (117.27+/-14.71 cm vs. 107+/-11.75 cm for the AG, P 0.01). In the same group and independent of the already mentioned factors, the patients with radiological signs of osteoarthritis showed significant WC [122+/-15.57 cm (SG-1) vs. 108+/-6.88 cm (SG-2) (P 0.01)]. Moreover, the VAS score of pain at rest and during effort and the WOMAC and Lequesne scores were 16+/-25.7 mm, 75+/-18.3 mm, 12.3+/-8.92 and 11.5+/-5.44 (SG-1) and 7+/-18.4 mm, 70+/-19.2 mm, 5.7+/-3.05, and 6.9+/-3.79 (SG-2), respectively. The difference between SG-1 and SG-2 was significant only for the WOMAC (P=0.015) and Lequesne (P=0.026) scores. CONCLUSION: Independent of BMI, WC appears to be a factor associated with the presence of knee pain and osteoarthritis in obese patients. Furthermore, a high WC is associated with significant functional repercussion.

The isokinetic assessment of peripheral muscle function in patients with coronary artery disease: correlations with cardiorespiratory capacity.

OBJECTIVE: We aimed to determine whether diminished cardiorespiratory capacity in patients with coronary artery disease (CAD) is accompanied by impaired skeletal muscle function as measured by isokinetic dynamometry. We also evaluated the correlation between isokinetic strength and aerobic capacity in these patients. MATERIALS AND METHODS: Fifteen CAD patients and 15 age-matched healthy subjects (mean age 60+/-6 vs. 57+/-3.5 years) underwent maximal laboratory exercise testing, a 6-min walking test and an assessment of peripheral skeletal muscle function by use of an isokinetic apparatus. Quadricep and hamstring function was tested at two angular velocities, 150 and 180 degrees s(-1) with simultaneous electrocardiography monitoring. The cardiorespiratory and mechanical parameters (VO(2), ventilatory threshold [VT], heart rate [HR], and power) were measured at VT and at maximal effort. RESULTS: Quadricep and hamstring peak torque was impaired in CAD patients, with quadriceps peak torque at 180 degrees being 71.13 +/- 14 vs. 91.13 +/- 23 Nm (P<0.01) and hamstring peak torque 46.50+/-10 vs. 59.86+/-12 Nm (P<0.01). CAD subjects presented a deficient aerobic capacity as compared with the healthy subjects at maximal effort. At VT, the VO(2), ventilation, and HR were significantly lower in CAD patients, at 13.77+/-2.33 vs. 17.08+/-3.59 ml min(-1) kg(-1) (P<0.05), 29.64 +/- 664 vs. 37.76 +/- 7.2 ml min(-1) (P<0.05), and 86+/-14 vs. 111+/-15 beats min(-1) (P=0.001), respectively. The 6-min walking distance was significantly shorter for CAD patients than healthy subjects (425.93+/-52.77 vs. 551.46 +/- 57.94 m; P<0.01). In CAD patients quadriceps and hamstring strength was not correlated with VO(2) at maximal effort and at VT. Total distance walked during the 6-min walk and VO(2)max were correlated (r=0.869; P<0.001) but not at VT. CONCLUSION: CAD patients showed impaired cardiorespiratory capacity accompanied by increased muscle fatigability as compared with healthy subjects. An isokinetic muscle assessment in these patients must be achieved systematically and seems to have value in cardiovascular rehabilitation.

[Post-partum depressive symptoms: Prevalence, risk factors and relationship with quality of life]. / Symptomatologie dépressive du post-partum : prévalence, facteurs de risque et lien avec la qualité de vie.

OBJECTIVE: The objective of our study was to estimate the prevalence of the post-partum depressive symptomatology in a sample of Tunisian women, to study associated factors and to assess its relationship to quality of life. PATIENTS AND METHODS: This is a prospective study carried out in two stages: during the first week (T1), then between sixth and eighth week post-partum (T2). Depressive symptomatology and quality of life were assessed respectively by the Edinburgh Postnatal Depression Scale and the World Health Organization Quality of Life scale. RESULTS: In the first stage, the prevalence of depressive symptomatology in the total sample (150 women) was 14.7% and was related to age above 35 years, low school level, personal psychiatric history, multiparity, caesarean delivery or forceps in the previous pregnancy and unplanned pregnancy. This prevalence was 19.8% among the 126 women reviewed in T2 and was correlated with the exaggerated sympathetic signs during pregnancy, namely perversion of taste and fatigue. Quality of life was strongly correlated with depressive symptoms in T1 and T2. CONCLUSION: Post-partum depressive symptoms were common in our sample and were correlated with quality of life. Therapeutic measures should be proposed for women with post-partum depressive symptoms and particularly with several risk factors in order to improve their quality of life.

[Transient left myocardial dysfunction: a cause of neonatal hypoxemia]. / Incompétence myocardique gauche transitoire: une cause d'hypoxémie néonatale.

UNLABELLED: Refractory hypoxemia in the newborn requires an accurate diagnostic investigation for an optimal and prompt management. CASE REPORT: After a short delivery, a post-term newborn developed a severe hypoxemia with patchy pulmonary alveolar opacities and systolic right-to-left extrapulmonary shunting through the ductus arteriosus. Echocardiography ruled out a cardiac malformation and showed dilated left atrium with left-to-right shunting by the ovale foramen due to left ventricular dysfunction. Inotropic support associated with mechanical ventilation allowed a rapid improvement. CONCLUSION: A pathophysiological analysis is needed in case of severe neonatal hypoxemia. Doppler ultrasound is a non invasive and rapid method allowing the adjustment of the therapeutic strategy.

[The functional and professional future of lower limb amputees with prosthesis]. / Facteurs liés à l'avenir fonctionnel et professionnel des amputés des membres inférieurs appareillés.

OBJECTIVE: The objective of our study is to evaluate the functional and professional becoming of lower limb amputated population with prosthesis. MATERIAL AND METHODS: Our study is retro-prospective. It interested lower limbs amputated patients who have beneficed during the period between 1982-1998 with prosthesis and have consulted in 1999. Data of our study were gathered by an hetero questionnaire. In order to evaluate the functional results of our patients, we have adopted the score established by the National association of doctors specialized in apparatus in France (ANMA). However, this score was little modified (in fact, we have eliminated the item "use of personalized vehicle for handicapped [VHP]", because no one of our patients possess it). The results were judged favourable: score 6-7; unfavourable: mean score between 3-5 and bad between 0-2. RESULTS: During the year of our survey, we have questioned 85 lower limb amputated patients with prosthesis: 67 were male and 18 were female. The mean age of our patients is 48 years (6 to 86 years). Our population was divided into: 31 traumatic amputated, 28 arteritics and 26 amputated of other etiologies (tumoral, infectious, congenital...). In 76 cases, the amputation is unilateral. It's located upper the knee in 51 cases. The evaluation of functional autonomy of our patients according to score adopted showed those results: 54.11% were favourable and 45.88% were unfavourable. In professional side, only 35 among our 60 active patients before amputation, have been able to resume, 12 have needed a professional rehabilitation. Among the 25 who hadn't taken up again their work, 15 have early retirement and ten are in unemployment. CONCLUSION: The amputation of lower limb constitute a major handicap which involves a functional and professional incapacity. We can reduce the risk of this incapacity by a good and appropriate rehabilitation.

Synthesis, crystal structure, vibrational spectroscopy, optical properties and theoretical studies of a new organic-inorganic hybrid material: [((CH3)2NH2)(+)]6·[(BiBr6)(3-)]2.

A new organic-inorganic hybrid material, [((CH3)2NH2)(+)]6·[(BiBr6)(3-)]2, has been synthesized and characterized by X-ray diffraction, FT-IR, Raman spectroscopy and UV-Visible absorption. The studied compound crystallizes in the triclinic system, space group P1¯ with the following parameters: a=8.4749(6)(Å), b=17.1392(12)(Å), c=17.1392(12)(Å), α=117.339(0)°, ß=99.487(0)°, γ=99.487(0)° and Z=2. The crystal lattice is composed of a two discrete (BiBr6)(3-) anions surrounded by six ((CH3)2NH2)(+) cations. Complex hydrogen bonding interactions between (BiBr6)(3-) and organic cations from a three-dimensional network. Theoretical calculations were performed using density functional theory (DFT) for studying the molecular structure, vibrational spectra and optical properties of the investigated molecule in the ground state. The full geometry optimization of designed system is performed using DFT method at B3LYP/LanL2DZ level of theory using the Gaussian03. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The vibrational spectral data obtained from FT-IR and Raman spectra are assigned based on the results of the theoretical calculations. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental UV-Visible spectrum. The results show good consistent with the experiment and confirm the contribution of metal orbital to the HOMO-LUMO boundary.

Vibrational spectra and non linear optical proprieties of L-histidine oxalate: DFT studies.

This paper presents the results of our calculations on the geometric parameters, vibrational spectra and hyperpolarizability of a nonlinear optical material L-histidine oxalate. Due to the lack of sufficiently precise information on geometric structure in literature, theoretical calculations were preceded by re-determination of the crystal X-ray structure. Single crystal of L-histidine oxalate has been growing by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in the non-Centro symmetric space group P2(1)2(1)2(1) of orthorhombic system. The FT-IR and Raman spectra of L-histidine oxalate were recorded and analyzed. The vibrational wave numbers were examined theoretical with the aid of Gaussian98 package of programs using the DFT//B3LYP/6-31G(d) level of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands obtained in IR and Raman spectroscopy of the studied compound. The geometrical parameters of the title compound are in agreement with the values of similar structures. To investigate microscopic second order non-linear optical NLO behaviour of the examined complex, the electric dipole µ(tot), the polarizability α(tot) and the hyperpolarizability ß(tot) were computed using DFT//B3LYP/6-31G(d) method. According to our calculation, the title compound exhibits non-zero ß(tot) value revealing microscopic second order NLO behaviour.

Molecular structure, vibrational spectra and nonlinear optical properties of orthoarsenic acid-tris-(hydroxymethyl)-aminomethane DFT study.

In this work, we report a theoretical study on molecular structure, vibrational spectra and nonlinear optical properties of orthoarsenic acid-tris-(hydroxymethyl)-aminomethane (OATA). The theoretical geometrical parameters in the ground state have been investigated by density functional method (B3LYP and BLYP) with 6-311G(d,p) basis set. The influence of intermolecular interactions effects on molecular properties has been considered by calculation performed on (OATA) dimer. The optimized geometric bond lengths and bond angles are in well agreement with the experimental data. As compared to theoretical frequencies of the monomer, the calculated values obtained for (OATA) dimer are in much better agreement with the experiment. All experimental vibrational bands have been discussed and assigned to normal modes on the basis of our theoretical calculations. B3LYP method has shown better fit to experimental ones than BLYP in calculation vibrational frequencies. To investigate nonlinear optical behaviour, the electric dipole moment mu, the polarizability alpha and the hyperpolarizability beta were computed using DFT//B3LYP/6-311G(d,p) method.