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1.
Rev Sci Instrum ; 95(8)2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39093121

RESUMEN

In the present work, an in-house designed special crucible was developed to fabricate isotopically enriched 28Si targets for a γ-ray spectroscopy experiment. Initially, the crucible was tested with natural Si and then utilized to fabricate isotopically enriched 28Si targets of thickness ∼500 µg/cm2 (∼2.15 µm). The fabricated targets were uniform in thickness and had very little contamination. In addition, one of the fabricated targets was successfully utilized in an in-beam γ-ray spectroscopy experiment. The technique employed in the present work not only facilitates the fabrication of stable and pure targets but also minimizes the wastage of the source material. As a result, these efforts pave the way for future fabrication of low-abundance isotopically enriched nuclear physics targets.

2.
Trop Biomed ; 40(2): 236-240, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37650411

RESUMEN

Oriental theileriosis caused by Theileria orientalis is a growing health concern of lactating cows in its endemic areas. Rapid and sensitive diagnostic tests are demand areas for appropriate and effective prophylactic and therapeutic measures. Quantitative polymerase chain reaction (qPCR) is the answer for both detection and quantification of parasites. Present study deals with qPCR for detection of parasitemia level of T. orientalis in apparently healthy and clinically affected cows. Major piroplasm surface protein (MPSP) gene present in T. orientalis was cloned in pUC57 vector and transformed into E. coli Top 10 cells. Single and mixed infections of hemoprotozoa other than T. orientalis, causing anemia were differentiated through blood smear examination and PCR tests. T. orientalis was detected in 108 (63.15%) ill and 48 (26.66%) healthy cows. Piroplasms detected per 1000 red blood cells (RBCs) was 0-1 in the healthy group as compared to 3-22 in those showing clinical signs. Parasitemia in ill cows ranged between 6.9 × 102 and 4.5 × 103 parasites / µl of blood which was significantly higher (p<0.05) than healthy group (2.6 × 102 - 5.7 × 102 parasites / µl of blood). Phylogenetic study of the isolates showed similarity with Buffeli type that unfolded its pathogenic form in apparently healthy and ill cows.


Asunto(s)
Theileria , Theileriosis , Femenino , Bovinos , Animales , Theileria/genética , Theileriosis/epidemiología , Escherichia coli , Lactancia , Parasitemia/veterinaria , Filogenia , India/epidemiología
3.
Eur Phys J C Part Fields ; 83(6): 467, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37303462

RESUMEN

The ICARUS collaboration employed the 760-ton T600 detector in a successful 3-year physics run at the underground LNGS laboratory, performing a sensitive search for LSND-like anomalous νe appearance in the CERN Neutrino to Gran Sasso beam, which contributed to the constraints on the allowed neutrino oscillation parameters to a narrow region around 1 eV2. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 the cryogenic commissioning began with detector cool down, liquid argon filling and recirculation. ICARUS then started its operations collecting the first neutrino events from the booster neutrino beam (BNB) and the Neutrinos at the Main Injector (NuMI) beam off-axis, which were used to test the ICARUS event selection, reconstruction and analysis algorithms. ICARUS successfully completed its commissioning phase in June 2022. The first goal of the ICARUS data taking will be a study to either confirm or refute the claim by Neutrino-4 short-baseline reactor experiment. ICARUS will also perform measurement of neutrino cross sections with the NuMI beam and several Beyond Standard Model searches. After the first year of operations, ICARUS will search for evidence of sterile neutrinos jointly with the Short-Baseline Near Detector, within the Short-Baseline Neutrino program. In this paper, the main activities carried out during the overhauling and installation phases are highlighted. Preliminary technical results from the ICARUS commissioning data with the BNB and NuMI beams are presented both in terms of performance of all ICARUS subsystems and of capability to select and reconstruct neutrino events.

4.
Tropical Biomedicine ; : 236-240, 2023.
Artículo en Inglés | WPRIM (Pacífico Occidental) | ID: wpr-1006799

RESUMEN

@#Oriental theileriosis caused by Theileria orientalis is a growing health concern of lactating cows in its endemic areas. Rapid and sensitive diagnostic tests are demand areas for appropriate and effective prophylactic and therapeutic measures. Quantitative polymerase chain reaction (qPCR) is the answer for both detection and quantification of parasites. Present study deals with qPCR for detection of parasitemia level of T. orientalis in apparently healthy and clinically affected cows. Major piroplasm surface protein (MPSP) gene present in T. orientalis was cloned in pUC57 vector and transformed into E. coli Top 10 cells. Single and mixed infections of hemoprotozoa other than T. orientalis, causing anemia were differentiated through blood smear examination and PCR tests. T. orientalis was detected in 108 (63.15%) ill and 48 (26.66%) healthy cows. Piroplasms detected per 1000 red blood cells (RBCs) was 0-1 in the healthy group as compared to 3-22 in those showing clinical signs. Parasitemia in ill cows ranged between 6.9 × 102 and 4.5 × 103 parasites / µl of blood which was significantly higher (p<0.05) than healthy group (2.6 × 102 - 5.7 × 102 parasites / µl of blood). Phylogenetic study of the isolates showed similarity with Buffeli type that unfolded its pathogenic form in apparently healthy and ill cows.

5.
Front Immunol ; 13: 956478, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36119096

RESUMEN

Ichthyophthirius multifiliis, a ciliated parasite causing ichthyophthiriasis (white spot disease) in freshwater fishes, results in significant economic loss to the aquaculture sector. One of the important predisposing factors for ichthyophthiriasis is low water temperature (i.e., below 20°C), which affects the health and makes freshwater fishes more susceptible to parasitic infections. During ichthyophthiriasis, fishes are stressed and acute immune reactions are compromised, which enables the aquatic bacterial pathogens to simultaneously infect the host and increase the severity of disease. In the present work, we aimed to understand the parasite-bacteria co-infection mechanism in fish. Later, Curcuma longa (turmeric) essential oil was used as a promising management strategy to improve immunity and control co-infections in fish. A natural outbreak of I. multifiliis was reported (validated by 16S rRNA PCR and sequencing method) in Pangasianodon hypophthalmus from a culture facility of ICAR-CIFRI, India. The fish showed clinical signs including hemorrhage, ulcer, discoloration, and redness in the body surface. Further microbiological analysis revealed that Aeromonas hydrophila was associated (validated by 16S rRNA PCR and sequencing method) with the infection and mortality of P. hypophthalmus, confirmed by hemolysin and survival assay. This created a scenario of co-infections, where both infectious agents are active together, causing ichthyophthiriasis and motile Aeromonas septicemia (MAS) in P. hypophthalmus. Interestingly, turmeric oil supplementation induced protective immunity in P. hypophthalmus against the co-infection condition. The study showed that P. hypophthalmus fingerlings supplemented with turmeric oil, at an optimum concentration (10 ppm), exhibited significantly increased survival against co-infection. The optimum concentration induced anti-stress and antioxidative response in fingerlings, marked by a significant decrease in cortisol and elevated levels of superoxide dismutase (SOD) and catalase (CAT) in treated animals as compared with the controls. Furthermore, the study indicated that supplementation of turmeric oil increases both non-specific and specific immune response, and significantly higher values of immune genes (interleukin-1ß, transferrin, and C3), HSP70, HSP90, and IgM were observed in P. hypophthalmus treatment groups. Our findings suggest that C. longa (turmeric) oil modulates stress, antioxidant, and immunological responses, probably contributing to enhanced protection in P. hypophthalmus. Hence, the application of turmeric oil treatment in aquaculture might become a management strategy to control co-infections in fishes. However, this hypothesis needs further validation.


Asunto(s)
Bagres , Infecciones por Cilióforos , Coinfección , Enfermedades de los Peces , Hymenostomatida , Aceites Volátiles , Aeromonas hydrophila , Animales , Antioxidantes/uso terapéutico , Catalasa , Infecciones por Cilióforos/parasitología , Infecciones por Cilióforos/veterinaria , Curcuma , Brotes de Enfermedades , Proteínas Hemolisinas , Hidrocortisona/uso terapéutico , Inmunoglobulina M/uso terapéutico , Interleucina-1beta , Complejo Hierro-Dextran/uso terapéutico , Aceites Volátiles/farmacología , ARN Ribosómico 16S , Superóxido Dismutasa , Transferrinas/uso terapéutico , Agua
6.
Indian J Pharmacol ; 54(3): 177-182, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35848688

RESUMEN

OBJECTIVE: The objective of the study was to assess the efficacy and safety profiles of combined treatment of prednisolone with thalidomide (Gr-A) and prednisolone with clofazimine (Gr. B) in patients with erythema nodosum leprosum (ENL) or type 2 lepra reactions. MATERIALS AND METHODS: Efficacy of both regimens was assessed on the basis of clinical recovery of recurrent ENL measured by reaction severity score (RSS), Visual Analog Scale (VAS), and recurrence of type 2 lepra reaction. The causality assessment of adverse drug reactions was done using the WHO UMC causality assessment scale. RESULTS: The average age of patients with recurrent ENL was 42.8 years (male) and 51.8yrs (female) and had mean duration of leprosy and recurrent ENL 2.4 years and 2.09 years, respectively. 80% of nonrecurrence was observed in Gr-A versus 66% in Gr-B. Significant (P < 0.05) lower RSS and VAS was found in both the treatment groups as compared to pretreatment value. The reduction in RSS and VAS was statistically significant (P < 0.05) in Gr-A compared to Gr-B treatment. CONCLUSION: Thalidomide combination with steroid was found to be more efficacious than clofazimine combination with steroid in the treatment of ENL both the treatment regimens showed few tolerable side effects. Improved strategies for the treatment and management of these reactions need to be developed.


Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Eritema Nudoso , Lepra Lepromatosa , Adulto , Clofazimina/uso terapéutico , Eritema Nudoso/tratamiento farmacológico , Femenino , Humanos , Leprostáticos/efectos adversos , Lepra Lepromatosa/tratamiento farmacológico , Masculino , Prednisolona/uso terapéutico , Talidomida/efectos adversos
7.
J Hosp Infect ; 122: 173-179, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35124141

RESUMEN

BACKGROUND: An unprecedented rise in the number of COVID-19-associated mucormycosis (CAM) cases has been reported in India. Myriad hypotheses are proposed for the outbreak. We recently reported uncontrolled diabetes and inappropriate steroid therapy as significant risk factors for the outbreak. However, Mucorales contamination of hospital environment was not studied. AIM: To perform a multi-centre study across India to determine possible Mucorales contamination of hospital environment during the outbreak. METHODS: Eleven hospitals from four zones of India representing high to low incidence for mucormycosis cases were included in the study. Samples from a variety of equipment used by the patients and ambient air were collected during May 19th, 2021 through August 25th, 2021. FINDINGS: None of the hospital equipment sampled was contaminated with Mucorales. However, Mucorales were isolated from 11.1% air-conditioning vents and 1.7% of patients' used masks. Other fungi were isolated from 18% of hospital equipment and surfaces, and 8.1% of used masks. Mucorales grew from 21.7% indoor and 53.8% outdoor air samples. Spore counts of Mucorales in air were significantly higher in the hospitals of North and South zones compared to West and East zones (P < 0.0001). Among Mucorales isolated from the environment, Rhizopus spp. were the most frequent genus. CONCLUSION: Contamination of air-conditioning vents and hospital air by Mucorales was found. Presence of Mucorales in these areas demands regular surveillance and improvement of hospital environment, as contamination may contribute to healthcare-associated mucormycosis outbreaks, especially among immunocompromised patients.


Asunto(s)
COVID-19 , Mucorales , Mucormicosis , Brotes de Enfermedades , Hospitales , Humanos , India/epidemiología , Mucormicosis/epidemiología
9.
J Phys Condens Matter ; 33(36)2021 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-34167093

RESUMEN

Near itinerant cubic bulk CoV2O4is at variance with other spinel vanadates by not showing orbital ordering down to low temperature, albeit it displays fragile anomalies related to spin, and lattice structure, signaling a spin/orbital glass transition around 95 K. We investigate tetragonal-like epitaxial CoV2O4films on SrTiO3and (La0.3Sr0.7)(Al0.65Ta0.35)O3substrates that exhibit pronounced signature of spin reorientation transition from toa/bplane around 90 K unlike its bulk counterpart. Using in-plane and out-of-plane magnetic measurements, we demonstrate the intricate link between Co2+and V3+sublattice magnetizations that give rise to anisotropic magnetic switching. In-plane magnetic measurements reveal a wasp-waist shapedM(H) loop below reorientation transition temperature, while the out-of-plane follows antiferromagnet-likeM(H) response. The wasp-waist shaped feature could be linked to in-plane spin-canted (anti)ferromagnetism induced by canting away of V-spins away from antiferromagnetically coupled Co-spin direction below reorientation transition temperature. Further, we uncover the evidence for slow relaxation over a period of ∼104 s at 20 K and memory effect that indicates the possible existence for magnetic glassy phase in the low temperature regime. Using epitaxial strain as a control knob, our results inspire future study to manipulate orbital states, spin texture and itinerant electron character in tailored CoV2O4films away from cubic lattice symmetry.

10.
Rev Sci Instrum ; 92(3): 033309, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33820015

RESUMEN

Characteristics and performance of a time of flight (TOF) spectrometer developed for performing fission mass distribution studies are presented. The spectrometer contains two TOF arms based on multi-wire proportional counters (MWPCs). Each arm has two MWPCs to form a start-stop detection system for TOF measurements. The start detector has an active area of 4 × 4 cm2. The stop detector is a two-dimensional position sensitive MWPC with an active area of 16 × 11 cm2. Salient features of the MWPCs are the use of reduced sub-millimeter wire pitches of 0.635 and 0.317 mm in the electrodes along with the use of gold plated tungsten wires of diameters 10 and 20 µm. A delay line for position electrodes is prepared using chip inductors and capacitors. Ten different configurations of MWPC were investigated for the start detector, which involved the use of three and four electrode geometries, use of different wire pitches, and use of aluminized mylar for timing electrodes. Performance results close to micro-channel plate detectors have been observed with some designs of MWPC, displaying rise times better than 2 ns with an estimated inherent time resolution of ∼100 ps FWHM. A position resolution of ∼1 mm (FWHM) has been observed. Design features of the MWPCs and their test performance results are described in this article.

13.
Water Sci Technol ; 82(6): 1217-1226, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33055411

RESUMEN

Flocculation is a common technique to harvest microalgae, where the negatively charged algal cells coalesce together to form larger flocs that settle under gravity. Although several inorganic flocculants have been applied for algal biomass recovery, the dosage varies depending on the algal strain-specific features. Thus, the selection of inorganic coagulant that can be applied at a low dosage for achieving the maximal biomass recovery under normal physiological conditions is necessary. The present study analyses the influence of different inorganic flocculants like ferric chloride (FeCl3), alum, calcium hydroxide, ferrous sulphate and copper sulphate on the biomass removal efficiency of a mixed microalgal consortium isolated from the open ponds of the National Institute of Technology Rourkela and further enriched with diluted human urine. Flocculation experiments were carried out with varying coagulant dosages, pH between 7.5 and 7.8, and 0.5 g L-1 algal concentration. The results revealed that FeCl3 at the dosage of 0.05 g L-1 and KAl(SO4)2 with the dosage of 0.04 g L-1 could be utilized to achieve the biomass recovery efficiency of 99.5% and 97.9%, respectively, within a duration of 5 min. An economic evaluation of the harvesting process showed KAl(SO4)2 to be the cheapest coagulant that could be feasibly used to recover algae at a large scale.


Asunto(s)
Microalgas , Biomasa , Floculación , Humanos , Estanques
14.
J Phys Chem B ; 123(31): 6728-6739, 2019 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-31290661

RESUMEN

Recently, several artificial nucleobases, such as B, S, J, V, X, K, P, and Z, have been proposed to help in the expansion of the genetic information system and diagnosis of diseases. Among these bases, P and Z were identified to form stable DNA and to participate in the replication. However, the stabilities of P:Z and other artificial base pairs are not fully understood. The abilities of these unnatural nucleobases in mispairing with themselves and with natural bases are also not known. Here, the ωB97X-D dispersion-corrected density functional theoretical and complete basis set (CBS-QB3) methods are used to obtain accurate structural and energetic data related to base pair interactions involving these unnatural nucleobases. The roles of protonation and deprotonation of certain artificial bases in inducing mutations are also studied. It is found that each artificial purine has a complementary artificial pyrimidine, the base pair interactions between which are similar to those of the natural Watson-Crick base pairs. Hence, these base pairs will function naturally and would not impart mutagenicity. Among these base pairs, the J:V complex is found to be the most stable and promising artificial base pair. Remarkably, the noncomplementary artificial nucleobases are found to form stable mispairs, which may generate mutagenic products in DNA. Similarly, the misinsertions of natural bases opposite artificial bases are also found to be mutagenic. The mechanisms of these mutations are explained in detail. These results are in agreement with earlier biochemical studies. It is thus expected that this study would aid in the advancement of the synthetic biology to design more robust artificial nucleotides.


Asunto(s)
Emparejamiento Base , ADN/química , Nucleótidos/química , ADN/genética , Teoría Funcional de la Densidad , Enlace de Hidrógeno , Modelos Químicos , Mutación , Termodinámica
15.
Folia Microbiol (Praha) ; 64(6): 875-887, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31020632

RESUMEN

Intensive fish farming systems have led to increase in disease incidence, due to higher stocking density, high organic matter levels, and poor quality of the aquatic environment. Diseased fish samples showing hemorrhages and reddish lesions were collected from different freshwater fish farms located at three different districts of West Bengal, India (Burdwan, North 24 Parganas, and Nadia). The present study was conducted to evaluate the genetic diversity of ten different Klebsiella pneumoniae strains isolated from different infected freshwater fish samples based on 16S rRNA gene sequence analysis. Primarily, Klebsiella-specific media was used for the isolation and characterization of Klebsiella pneumoniae. Further, through a biochemical test, all the strains were confirmed as K. pneumoniae. PCR analysis of 16S-23S internal transcribed spacer (PCR ribotyping) was carried out to study the species variation within different Klebsiella pneumoniae isolates. For all the isolates, a conserved PCR ribotype pattern was observed while differing from other bacterial species. Phylogenetic study showed the high degree of homology with diverse source of other strains. The multiple antibiotic resistance (MAR) values of the present study for the isolates were found to be 0.468. MAR value above 0.2 indicates that the source of isolation was highly contaminated with antibiotics. Based on the 16S rRNA gene sequence analysis, the present study revealed the genetic diversity of Klebsiella pneumoniae isolated from the different diseased fish farms of West Bengal. All the strains were found to be hypermucoviscous and multidrug-resistant, thus making it pathogenic towards the host organisms. Further, the study revealed a high prevalence of K. pneumoniae in aquaculture farms, representing a risk towards successful aquaculture.


Asunto(s)
Carpas/microbiología , Farmacorresistencia Bacteriana Múltiple , Enfermedades de los Peces/microbiología , Infecciones por Klebsiella/veterinaria , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Animales , Antibacterianos/farmacología , Acuicultura , ADN Bacteriano/genética , ADN Espaciador Ribosómico/genética , Genes Bacterianos/genética , Variación Genética , Hemólisis , India/epidemiología , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/clasificación , Klebsiella pneumoniae/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Filogenia , Prevalencia , ARN Ribosómico 16S/genética , Ribotipificación , Análisis de Secuencia de ADN
16.
J Phys Chem A ; 123(9): 1830-1839, 2019 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-30730143

RESUMEN

Blue-shifting H-bonded complexes between CHCl3 and CH/D3CN have been identified by Fourier transform infrared spectroscopy in the gas phase at room temperature. The change in FTIR peak intensity of the mixture of the two components as a function of temperature and composition provides the basis for identification of the H-bonded band in the infrared spectrum. On complex formation with CH3CN and CD3CN, the C-H stretching frequency of CHCl3 shifts to the blue by +8.7 and +8.6 cm-1, respectively. The molecular electrostatic potential calculation at the MP2/6-311++G** level has been used to arrive at the geometry of the complex. It has been reported in the literature that CHCl3 and CH/D3CN form red-shifting H-bonded complex in Ar matrix. The red shifting has been verified by doing ab initio calculations in the presence of Ar atoms, which has been attributed to the matrix effect at low temperature. The interaction of Ar with CH3CN makes the CH3CN more basic and as a result it becomes better hydrogen bond acceptor and causes red shift. The potential energy scans and NBO analysis of the Cl3CH···NCCH3 complex have been compared with those of F3CH···NCCH3 and Cl3CH···NH3 complexes. The change in electron density of the CHCl3 as a function of C-H···N distance shows that the approach of CH3CN to CHCl3 induces a shift in electron density from the H atom to the Cl atoms of CHCl3 which leads to C-H bond contraction and blue shifting of C-H stretching frequency. However, in the complex Cl3CH···NH3, where frequency shift to the red is reported, charge transfer and electrostatic interaction dominate.

18.
J Phys Chem B ; 122(34): 8134-8145, 2018 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-30063353

RESUMEN

To artificially expand the genetic information system and to realize artificial life, it is necessary to discover new functional DNA bases that can form stable duplex DNA and participate in error-free replication. It is recently proposed that the 2-amino-imidazo[1,2- a]-1,3,5-triazin-4(8 H)one (P) and 6-amino-5-nitro-2(1 H)-pyridone (Z) would form a base pair complex, which is more stable than that of the normal G-C base pair and would produce an unperturbed duplex DNA. Here, by using quantum chemical calculations in aqueous medium, it is shown that the P and Z molecules can be modified with the help of electron-withdrawing and -donating substituents mainly found in B-DNA to generate new bases that can produce even more stable base pairs. Among the various bases studied, P3, P4, Z3, and Z5 are found to produce base pairs, which are about 2-15 kcal/mol more stable than the P-Z base pair. It is further shown that these base pairs can be stacked onto the G-C and A-T base pairs to produce stable dimers. The consecutive stacking of these base pairs is found to yield even more stable dimers. The influence of charge penetration effects and backbone atoms in stabilizing these dimers are also discussed. It is thus proposed that the P3, P4, Z3, and Z5 would form promiscuous artificial genetic information system and can be used for different biological applications. However, the evaluations of the dynamical effects of these bases in DNA-containing several nucleotides and the efficacy of DNA polymerases to replicate these bases would provide more insights.


Asunto(s)
ADN/química , Código Genético , Emparejamiento Base , ADN/genética , Enlace de Hidrógeno , Imidazoles/química , Piridonas/química , Teoría Cuántica , Electricidad Estática , Triazinas/química
19.
J Phys Chem A ; 122(18): 4481-4489, 2018 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-29683668

RESUMEN

Blue-shifting H-bonded (C-D···O) complexes between CDCl3 and CH3HCO, (CH3)2CO, and C2H5(CH3)CO, and red-shifting H-bonded (C-D···S) complexes between CDCl3 with (CH3)2S and (C2H5)2S have been identified by Fourier transform infrared spectroscopy in the gas phase at room temperature. With increasing partial pressure of the components, a new band appears in the C-D stretching region of the vibrational spectra. The intensity of this band decreases with an increase in temperature at constant pressure, which provides the basis for identification of the H-bonded bands in the spectrum. The C-D stretching frequency of CDCl3 is blue-shifted by +7.1, +4, and +3.2 cm-1 upon complexation with CH3HCO, (CH3)2CO, and C2H5(CH3)CO, respectively, and red-shifted by -14 and -19.2 cm-1 upon complexation with (CH3)2S and (C2H5)2S, respectively. By using quantum chemical calculations at the MP2/6-311++G** level, we predict the geometry, electronic structural parameters, binding energy, and spectral shift of H-bonded complexes between CDCl3 and two series of compounds named RCOR' (H2CO, CH3HCO, (CH3)2CO, and C2H5(CH3)CO) and RSR' (H2S, CH3HS, (CH3)2S, and (C2H5)2S) series. The calculated and observed spectral shifts follow the same trends. With an increase in basicity of the H-bond acceptor, the C-D bond length increases, force constant decreases, and the frequency shifts to the red from the blue. The potential energy scans of the above complexes are done, which show that electrostatic attraction between electropositive D and electron-rich O/S causes bond elongation and red shift, and the electronic and nuclear repulsions lead to bond contraction and blue shifts. The dominance of the two opposing forces at the equilibrium geometry of the complex determines the nature of the shift, which changes both in magnitude and in direction with the basicity of the hydrogen-bond acceptor.

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