Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Neuropathol Appl Neurobiol ; 45(7): 681-697, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-30947376

RESUMEN

AIMS: Carotid artery disease (CAD) is an important risk factor for stroke. We first evaluated CAD and stroke pathology in elderly post-stroke survivors. To simulate CAD, we assessed long-term consequences of bilateral common carotid artery stenosis (BCAS) in mice and exposed them to environmental enrichment (EE). METHODS: Histopathological methods were used to determine degrees of CAD (% area stenosis), brain infarct types, sizes and distribution in post-stroke survivors and BCAS mice. Adult male C57BL/6J mice after BCAS or sham surgery were randomly assigned to standard housing (Std) or limited (3 h) or full-time (Full) exposure to EE per day for 12 weeks. RESULTS: High frequencies of moderate carotid artery stenosis (51-75%) were evident in post-stroke survivors whereas those with severe CAD (>75% stenosis) exhibited greater numbers of cortical rather than subcortical infarcts and, were at higher risk of developing dementia. BCAS in mice reduced cerebral blood flow by 52% (P < 0.01) and thickened carotid artery walls, regardless of EE duration. Remarkably, the total and cortical infarcts declined by >50% in BCAS mice exposed to EE compared with BCAS-Std (P < 0.01). Frontal lobe and cortical strokes were associated with worsening working memory tested in a radial maze paradigm. Proteomic analysis revealed EE, both BCAS-3 h and BCAS-Full attenuated coagulation cascade factors including fibrinogen and von Willebrand factor, markers of blood-brain barrier damage. CONCLUSION: Small cortical and subcortical infarcts were evident in both post-stroke survivors with CAD and BCAS mice. Experimental evidence suggested that moderate exposure to EE is sufficient to reduce subsequent stroke lesions.


Asunto(s)
Enfermedades de las Arterias Carótidas/patología , Estenosis Carotídea/patología , Accidente Cerebrovascular/patología , Anciano , Anciano de 80 o más Años , Animales , Circulación Cerebrovascular/fisiología , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Proteómica
2.
Br J Oral Maxillofac Surg ; 56(6): 546-548, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29908706

RESUMEN

Oral surgery can be difficult in patients with chorea-like dyskinesia, which is common in those on long-term levodopa medication for Parkinson's disease, and we know of no conclusive evidence to indicate whether conscious sedation with midazolam is effective in such cases. We report a patient in whom levodopa-induced chorea-like dyskinesia disappeared when midazolam was given intravenously for conscious sedation.


Asunto(s)
Sedación Consciente/métodos , Atención Dental para Enfermos Crónicos , Discinesias/complicaciones , Hipnóticos y Sedantes/administración & dosificación , Midazolam/administración & dosificación , Enfermedad de Parkinson/complicaciones , Extracción Dental , Anciano , Humanos , Masculino
3.
Artículo en Inglés | MEDLINE | ID: mdl-17418623

RESUMEN

An extensive HF, MP2, B3LYP and CCSD study of the molecular structure and normal vibrations have been performed for the HCN-BF(3) molecule. Calculations with a wide range of basis sets were classified into two groups based on the optimized N-B bond distance. The results for Group A are compared with the experimental structure of the solid phase molecules. The N-B lengths of Group A are approximately linear related to the N-B-F valence angles and also to the N-B stretching frequencies. HF/DZV calculation was used to represent the solid phase model. The N-B lengths of Group B are close to those of the gas phase molecule and both N-B-F angles and N-B sensitive frequencies have roughly the same values. Differences in the chemical bond between gaseous and solid phase HCN-BF(3) are discussed based on the calculated force constants, vibrational frequencies and potential energy distributions. Vibration mode analysis indicates that the nu(4) mode in the 600-700 cm(-1) region can be assigned to the BF(3) symmetric deformation, which shifts upon (10)B/(11)B isotopic substitution. The nu(5) mode which is insensitive to isotope substitution and changes band position with the N-B distance is assigned to the N-B bond stretching vibration.


Asunto(s)
Boranos/química , Cianuro de Hidrógeno/química , Modelos Químicos , Isótopos , Estructura Molecular
4.
J Clin Endocrinol Metab ; 47(5): 1028-33, 1978 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-263333

RESUMEN

A simple and reliable method of paired TSH assay was developed and used in screening for neonatal primary hypothyroidism. In this method, a paired assay is first done. Equal parts of the extracts of dried blood spots on filter paper (9 mm diameter) from two infants 4-7 days old are combined and assayed for TSH by double antibody RIA. If the value obtained is over the cut-off point, the extracts are assayed separately for TSH in a second assay to identify the abnormal sample. Two systems, A and B, with different cut-off points were tested. On the basis of reference blood samples (serum levels of TSH, 80 microU/ml in system A and 40 microU/ml in system B), the cut-off point was selected as follows: upper 5 (A) or 4 (B) percentile in the paired assay and values of reference blood samples in the second individual assay. Four cases (2 in A and 2 in B) of neonatal primary hypothyroidism were found among 25 infants (23 in A and 2 in B) who were recalled from a general population 41,400 infants (24,200 in A and 17,200 in B) by 22,700 assays. This paired TSH neonatal hypothyroidism.


Asunto(s)
Hipotiroidismo Congénito , Recién Nacido , Tirotropina/sangre , Humanos , Hipotiroidismo/diagnóstico , Microquímica , Papel , Radioinmunoensayo
5.
Eur J Hum Genet ; 9(12): 931-7, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11840195

RESUMEN

Congenital hyperinsulinism and hyperammonaemia (CHH) is caused by dysregulation of glutamate dehydrogenase (GDH). We characterised the GDH gene in two Japanese patients with CHH. Patient 1 showed late-onset and mild hypoglycaemic episodes and mild hyperammonaemia, compared with patient 2. In GDH activity of lymphoblasts, patient 1 showed twofold higher basal GDH activity than control subjects and mild insensitivity for GTP inhibition. Patient 2 showed severe insensitivity for GTP inhibition, and similar allosteric stimulation by ADP in the controls. Genetic studies identified heterozygous and de novo L413V and G446D mutations in patients 1 and 2, respectively. COS cell expression study confirmed that both mutations were disease-causing gene. The insensitivity for GTP inhibition in L413V and G446D was emphasised in COS cell expression system as a result of the dosage effect of mutant GDH gene. L413V showed less impairment of GDH than G446D based on biochemical and genetic results, which was consistent with the clinical phenotype. Based on the structure of bovine GDH, G446D was located in GTP binding site of pivot helix and its surroundings, while L413V was located in alpha-helix of antenna-like structure. These different locations of mutations gave different effects on GDH enzyme. The antenna-like structure plays an important role in GDH activity.


Asunto(s)
Glutamato Deshidrogenasa/genética , Hiperamonemia/genética , Hiperinsulinismo/genética , Animales , Células COS , Niño , Preescolar , Genotipo , Humanos , Hiperinsulinismo/congénito , Lactante , Recién Nacido , Japón , Masculino , Mutación Missense , Fenotipo
6.
Am J Surg Pathol ; 15(4): 399-406, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2006720

RESUMEN

A case of primary gastric alveolar soft-part sarcoma is presented. The tumor was found in the gastric remnant of a 67-year-old male who had undergone partial gastrectomy due to hemorrhagic gastric ulcer 13 years before. It was located mostly in the submucosa arising from the muscularis propria. The large eosinophilic cells showed the characteristic alveolar compartmentalization and contained intracytoplasmic periodic acid-Schiff-positive granules and typical crystals. Numerous electron-opaque secretory granules in the tumor cell cytoplasm, in addition to crystals of 9 nm periodicity, were confirmed at the ultrastructural levels. Immunostaining failed to detect muscle-related antigens. In contrast, methionine-enkephalin and neuropeptide Y appeared positive in the tumor cells. Interstitial spindle cells showed an occasional positivity to S-100. This is the first case of such a tumor occurring in the gastrointestinal tract, and the findings suggest that gastric alveolar soft-part sarcomas may have a different origin from those arising in the skeleton.


Asunto(s)
Sarcoma/patología , Neoplasias Gástricas/patología , Anciano , Humanos , Técnicas Inmunológicas , Masculino , Microscopía Electrónica , Reacción del Ácido Peryódico de Schiff , Sarcoma/metabolismo , Sarcoma/ultraestructura , Estómago/patología , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/ultraestructura
7.
J Med Chem ; 38(15): 2964-8, 1995 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-7636857

RESUMEN

(+/-)-(Z)-2-(Aminomethyl)-1-phenylcyclopropane-N,N-diethylcarbo xamide (milnacipran, 1), a clinically useful antidepressant, and its derivatives were prepared by an improved method and were evaluated as NMDA receptor antagonists. Of these, milnacipran (1), its N-methyl and N,N-dimethyl derivatives, 7 and 8, respectively, and its homologue 12 at the aminomethyl moiety had binding affinity for the receptor in vitro (IC50: 1, 6.3 +/- 0.3 microM; 7, 13 +/- 2.1 microM; 8, 88 +/- 1.4 microM; 12, 10 +/- 1.2 microM). These also protected mice from NMDA-induced lethality. These compounds would be important as anovel prototype for designing potent NMDA-receptor antagonists because of their characteristic structure, which clearly differentiated them from known competitive and noncompetitive antagonists to the receptor.


Asunto(s)
Antidepresivos/síntesis química , Antidepresivos/farmacología , Ciclopropanos/síntesis química , Ciclopropanos/farmacología , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Animales , Antidepresivos/metabolismo , Ciclopropanos/metabolismo , Maleato de Dizocilpina/metabolismo , Cinética , Masculino , Ratones , Ratones Endogámicos , Milnaciprán , Ensayo de Unión Radioligante , Ratas , Receptores de N-Metil-D-Aspartato/metabolismo , Relación Estructura-Actividad , Tritio
8.
J Med Chem ; 39(24): 4844-52, 1996 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-8941398

RESUMEN

We recently demonstrated that (+/-)-(Z)-2-(aminomethyl)-1-phenyl-N,N-diethylcyclopropanecarboxamide [milnacipran, (+/-)-1], an inhibitor of the reuptake of serotonin (5-HT), was a noncompetitive NMDA receptor antagonist. On the basis of the cyclopropane structure of (+/-)-1, conformationally restricted analogs with different stereochemistries, namely 1-phenyl-2-(1-aminoalkyl)-N,N-diethylcyclopropanecarboxamindes (2, 3, ent-2, and ent-3), were designed and synthesized. Among these analogs, 2a, 2b, and 2f, with (1S,2R,1'S)-configuration, were more efficient than milnacipran as NMDA receptor antagonists; these compounds significantly inhibited the binding of [3H]MK-801 at IC50 = 0.35 +/- 0.08, 0.20 +/- 0.024, and 0.16 +/- 0.02 microM, respectively, and blocked the response of voltage-clamped oocytes to NMDA, surpassing the effects of (+/-)-1. Although both the 1'-methyl analog 2a and the 1'-vinyl analog 2f, like (+/-)-1, strongly inhibited 5-HT uptake in vitro, the corresponding 1'-ethyl analog 2b was devoid of the inhibitory effect on 5-HT uptake, while it was about 30 times more potent as an NMDA receptor antagonist than (+/-)-1.


Asunto(s)
Ciclopropanos/síntesis química , Animales , Encéfalo/metabolismo , Ciclopropanos/farmacología , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Conformación Molecular , Estructura Molecular , N-Metilaspartato , Oocitos/efectos de los fármacos , Técnicas de Placa-Clamp , Ratas , Receptores de N-Metil-D-Aspartato/metabolismo , Serotonina/metabolismo , Antagonistas de la Serotonina/síntesis química , Antagonistas de la Serotonina/farmacología , Estereoisomerismo , Membranas Sinápticas/efectos de los fármacos , Membranas Sinápticas/metabolismo
9.
Am J Med Genet ; 46(3): 293-6, 1993 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-8488874

RESUMEN

We report the autopsy findings in a 20-month-old boy with Rubinstein-Taybi syndrome and DiGeorge sequence. No visible thymus was demonstrated at the time of autopsy. With careful microscopic examination, a few pieces of thymic tissues found near the thyroid gland showed remarkable depletion of both thymocytes and cortical epithelial cells. Immunohistological staining with T-cell surface antigens resulted in a definite positive reaction. Repeated respiratory infections present in this patient may, in part, be attributable to thymic hypoplasia. Other major anomalies included broad thumbs and great toes, microphthalmia, arrhinencephaly, patent ductus arteriosus, stenosis of the ureterovesicular junction, bilateral cryptorchidism, and minor facial anomalies.


Asunto(s)
Síndrome de DiGeorge/complicaciones , Síndrome de Rubinstein-Taybi/complicaciones , Humanos , Inmunohistoquímica , Lactante , Masculino , Timo/anomalías
10.
J Biochem ; 96(6): 1925-9, 1984 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-6530403

RESUMEN

Histamine metabolism in histidinemic patients was studied by measuring the urinary levels of histamine and its metabolites. The urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid, and its conjugate(s) were higher in patients with histidinemia than in controls, and these levels of excretion were correlated with the plasma histidine level. The urinary histamine levels of patients with eczema-like dermatitis were twice that of those without dermatitis. The urinary excretion of 3-methylhistidine showed a close correlation with the urinary histidine excretion. Thus, it was concluded that histamine metabolism is higher in histidinemic patients than in normal controls.


Asunto(s)
Histamina/metabolismo , Histidina/sangre , Imidazoles/orina , Metilhistaminas/orina , Errores Innatos del Metabolismo de los Aminoácidos/orina , Aminoácidos/análisis , Preescolar , Creatinina/sangre , Eccema/orina , Histamina/orina , Humanos , Lactante
11.
Int J Radiat Biol ; 78(9): 799-806, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12428921

RESUMEN

PURPOSE: To determine the relationship between linear energy transfer (LET) and the relative biological effectiveness (RBE) for survival reduction and chromosome aberration induction in plants. MATERIALS AND METHODS: Tobacco seeds were exposed to carbon ions having LET ranging from 92 to 260 keV microm(-1). Survival ratc was determined at 7 weeks after sowing. Chromosome aberrations were observed when the root length reached about 0.5 mm (immediately after radicle emergence), 3 and 10 mm. RESULTS: The RBE for both endpoints increased with increasing LET and showed the highest value at 230 keV um(-1). The highest RBE was 65.0 for survival reduction and 52.5 for chromosome aberration induction. The types and yield ratio of chromosome aberrations such as fragments and bridges were not affected by radiation type at 0.5mm root length. As the roots elongated from 0.5 to 10 mm, the frequency of aberrant cells gradually decreased. The number of cells with fragments decreased faster than the number of cells with bridges. The decrement of chromosome aberrations appeared to be slower in roots irradiated by carbon ions than in roots irradiated by gamma-rays. CONCLUSIONS: The results show a close relationship between survival reduction and chromosome aberration induction in plants. The types and yield ratio of initial chromosome aberrations did not differ among gamma-rays and carbon ions with different LET.


Asunto(s)
Aberraciones Cromosómicas/efectos de la radiación , Nicotiana/genética , Nicotiana/efectos de la radiación , Carbono/efectos adversos , Supervivencia Celular/efectos de la radiación , Rayos gamma/efectos adversos , Transferencia Lineal de Energía , Radiobiología , Efectividad Biológica Relativa , Nicotiana/citología
12.
Int J Radiat Biol ; 79(8): 681-5, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-14555351

RESUMEN

PURPOSE: To determine the radiation sensitivity and relationship between linear energy transfer (LET) and relative biological effectiveness (RBE) in single plant cells irradiated with heavy ions. MATERIALS AND METHODS: Single cells were isolated from the tobacco BY-2 cell line and irradiated with carbon ions (78.6-309 keV microm(-1)) and gamma-rays (0.2 keV microm(-1)). Two weeks after irradiation, colonies with 16 cells or more derived from the irradiated cells were counted as survivors. The surviving fraction was fitted using the single-hit, multitarget theory. RESULTS: The doses needed to reduce the surviving fraction of the cells to 0.1 (D10) of gamma-rays and carbon ions were 47.2 and 10.5-12.6 Gy, respectively. The RBE based on the D10 peaked at an LET of 247 keV microm(-1). The inactivation cross-section of carbon ions reached a plateau of 11.3 microm2 at an LET of 247 keV microm(-1). CONCLUSIONS: The radiation sensitivity of single tobacco cells was much lower than that of mammalian cells, although the mean number of base pairs per chromosome in the two cell types was similar. The RBE peak based on the D10 of carbon ions in single tobacco cells occurred at a higher LET than it does in other organisms.


Asunto(s)
Carbono/efectos adversos , Iones Pesados/efectos adversos , Nicotiana/efectos de la radiación , Rayos gamma , Transferencia Lineal de Energía , Tolerancia a Radiación , Efectividad Biológica Relativa , Nicotiana/citología
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 56(6): 1035-44, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10845533

RESUMEN

The harmonic force field of thioacetamide has been obtained by Hartree-Fock level ab initio calculations using the 4-31G(d) basis set. The force constants have been scaled to reproduce the infrared fundamental bands of argon matrix isolated CH3CSNH2 and CD3CSNH2. Normal coordinate calculations based on the scaled force field suggested the co-presence of cis-CH3CSNHD and trans-CH3CSNHD in the infrared spectrum measured for CH3CSND2. The prediction of the fundamental bands was made for CD3CSND2, cis-CD3CSNHD and trans-CD3CSNHD.


Asunto(s)
Tioacetamida/química , Deuterio/química , Modelos Químicos , Modelos Teóricos , Espectrofotometría Infrarroja/métodos , Estereoisomerismo , Tioacetamida/análogos & derivados
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 57(7): 1369-75, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11446692

RESUMEN

The polar tensor of allene was calculated from the infrared fundamental band intensities of C3H4 and C3D4. The ambiguities in the signs of the dipole moment derivatives with respect to their normal coordinates were resolved by comparison of tensor elements with ab initio calculations at the B3LYP, MP2(FC) and CCD(FC) levels with a 6/311 + + G(3d,3p) basis set. The results are similar to those previously obtained by Koga and co-workers except for the choice of an average of two sign combinations for the E symmetry elements. The values of the mean dipole moment derivatives for the sp and sp2 carbon atoms obtained in this work, 0.032 and -0.133 e, respectively, are in good agreement with the CCD(FC)/6-311 + + G(3d,3p), 0.061 and -0.128 e, and MP2(FC)/6-311 + + G(3d,3p), 0.072 and -0.153 e, theoretical results. The mean dipole moment derivatives are shown to be consistent with potential models relating 1s electron ionization energies and atomic charges.


Asunto(s)
Alcadienos/química , Espectrofotometría Infrarroja , Modelos Moleculares
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 59(1): 37-45, 2003 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-12509145

RESUMEN

The molecular force field and polar tensor of methyl isocyanide have been determined from its gas phase vibrational frequencies and infrared intensities. Quantum chemical results from MP2(FC), B3LYP and quadratic configuration interaction calculation including single and double substitutions procedures using a 6-311 + +G(3d,3p) basis set have been used to determine the signs of the dipole moment derivatives with respect to the normal coordinates as well as estimate individual fundamental intensities of the overlapped v1-v5 and v3-v6 band systems. Principal component graphical representations of the A1 and E symmetry polar tensor elements were useful in determining preferred sets of tensor elements. The mean dipole moment derivative (GAPT charge) of the methyl carbon in CH3NC, 0.347 e, is between the corresponding values in CH3CN, 0.110 e, and CH3F, 0.541 e. The mean dipole moment derivatives obtained here indicate the correct 1s methyl carbon ionization energy as 293.35 eV which is 0.98 eV higher than the corresponding ionization energy of the terminal atom.


Asunto(s)
Nitrilos/análisis , Nitrilos/química , Espectrofotometría/métodos , Carbono/análisis , Carbono/química , Modelos Estadísticos
16.
No To Hattatsu ; 30(3): 250-4, 1998 May.
Artículo en Japonés | MEDLINE | ID: mdl-9613159

RESUMEN

We report a 4-year-old boy with congenital central hypoventilation syndrome (CCHS) successfully treated with home mechanical ventilation with nasal intermittent positive pressure ventilation (NIPPV) during sleep hours. He had had frequent severe apneic attacks from the neonatal period. At 8 months, he was treated with positive pressure ventilation following a tracheostomy. At 4 year and 2 months, NIPPV was attempted because of recurrent respiratory tract infections and cor pulmonale. The tracheostomy was successfully abandoned 6 months later. Adequate ventilation has been maintained for more than 3 years without troubles. NIPPV is an effective and non-invasive treatment of CCHS that it significantly improves the quality of life during daytime.


Asunto(s)
Servicios de Atención de Salud a Domicilio , Ventilación con Presión Positiva Intermitente/métodos , Síndromes de la Apnea del Sueño/congénito , Síndromes de la Apnea del Sueño/terapia , Preescolar , Humanos , Masculino , Máscaras , Calidad de Vida
17.
Gan To Kagaku Ryoho ; 14(11): 3119-24, 1987 Nov.
Artículo en Japonés | MEDLINE | ID: mdl-2960268

RESUMEN

UNLABELLED: As an intraoperative chemotherapy treatment for the regional lymph nodes in resectable cases of pancreatoduodenal cancer, Neocarzinostatin (NCS) was administered in the duodenal subserosa and the NCS concentration was measured in the resected lymph nodes. EXPERIMENTS: NCS 4,000 units (n = 4), or 10,000 units (n = 4) was administered into the duodenal subserosa of mongrel dogs, and 2 hours after administration, the lymph nodes of the mesentery root were resected. The NCS concentration in the lymph nodes was 0.21 U/g in the 4,000-U group and 1.39 U/g in the 10,000-U group. CLINICAL FINDINGS: NCS 10,000 U was administered into the duodenal subserosa in 6 cases of pancreatoduodenal cancer. The total number of resected lymph nodes was 49 and the mean NCS concentration was 5.65 U/g. According to site, the highest concentration was measured in lymph nodes from the anterior and posterior region of the pancreas head, which were near to the administration site. Also, NCS was well distributed in the lymph nodes in the hepatoduodenal ligament and mesentery root which lay in the direction of lymph flow. NCS concentration was high in lymph nodes resected 1 hour after administration. According to experimental reports of in vitro studies, an NCS concentration of more than 0.5 U/g is required to obtain an anticancer effect. This method is therefore considered to be useful as a form of intraoperative chemotherapy for the regional lymph nodes in pancreatoduodenal cancer.


Asunto(s)
Antibióticos Antineoplásicos/administración & dosificación , Neoplasias Duodenales/tratamiento farmacológico , Neoplasias Pancreáticas/tratamiento farmacológico , Cinostatina/administración & dosificación , Animales , Perros , Neoplasias Duodenales/metabolismo , Neoplasias Duodenales/cirugía , Duodeno , Periodo Intraoperatorio , Hígado/metabolismo , Ganglios Linfáticos/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/cirugía , Membrana Serosa , Cinostatina/farmacocinética
18.
Artículo en Inglés | MEDLINE | ID: mdl-19955013

RESUMEN

An extensive HF, MP2, B3LYP and CCSD study of the molecular structure, force field and normal vibrations has been carried out for the hydrogen cyanide compound with boron tribromide. Most of the calculations agree that the HCN-BBr(3) molecule belongs to C(3v) point group and has a N-B length of 1.55-1.70 A and a N-B-Br angle of 103-105 degrees. These calculations also have estimated the missing low-wavenumber fundamentals in the 190 (nu(5)), 150 (nu(9)) and 105 cm(-1) (nu(10)) regions, instead of the supposed fundamentals at 207, 188 and 150 cm(-1), respectively, based on the combination bands. The quantum chemical force constants, by the B3LYP/6-31G and CCSD/3-21G calculations, have been adjusted by the scaling factors to reproduce the fundamentals in the literature [3] to include the bands below 200 cm(-1) proposed in this study. Normal coordinate analysis using the scaled force constants has been performed to interpret the molecular vibrations of four isotopic molecules, HCN-(10)BBr(3), HCN-(11)BBr(3), DCN-(10)BBr(3) and DCN-(11)BBr(3).


Asunto(s)
Compuestos de Boro/química , Bromuros/química , Cianuro de Hidrógeno/química , Sustancias para la Guerra Química/química , Simulación por Computador , Modelos Teóricos , Análisis Espectral/métodos , Vibración
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA