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1.
Virol J ; 21(1): 223, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39300514

RESUMO

BACKGROUND: Dengue infection poses a significant global health challenge, particularly in tropical and subtropical regions. Among its severe complications, Acute kidney injury (AKI) stands out due to its association with increased morbidity, mortality, and healthcare burdens. This Meta-analysis aim to identify and evaluate the predictors of AKI among dengue patients, facilitating early detection and management strategies to mitigate AKI's impact. METHODS: We searched PubMed, EMBASE, and Web of Science databases, covering literature up to February 2024. We included human observational studies reporting on AKI predictors in confirmed dengue cases. Nested-Knowledge software was used for screening and data extraction. The Newcastle-Ottawa Scale was used for quality assessment. R software (V 4.3) was utilized to compute pooled odds ratios (ORs) and 95% confidence intervals (CIs) for each predictor. RESULTS: Our search yielded nine studies involving diverse geographic locations and patient demographics. A total of 9,198 patients were included in the studies, with 542 diagnosed with AKI. in which key predictors of AKI identified include severe forms of dengue (OR: 2.22, 95% CI: 1.02-3.42), male gender (OR: 3.13, 95% CI: 1.82-4.44), comorbidities such as diabetes mellitus (OR: 3.298, 95% CI: 0.274-6.322), and chronic kidney disease (OR: 2.2, 95% CI: 0.42-11.24), as well as co-infections and clinical manifestations like rhabdomyolysis and major bleeding. CONCLUSION: Our study identifies several predictors of AKI in dengue patients. These findings indicate the importance of early identification and intervention for high-risk individuals. Future research should focus on standardizing AKI diagnostic criteria within the dengue context and exploring the mechanisms underlying these associations to improve patient care and outcomes.


Assuntos
Injúria Renal Aguda , Dengue , Injúria Renal Aguda/etiologia , Humanos , Dengue/complicações , Fatores de Risco , Masculino , Feminino , Comorbidade
2.
BMC Infect Dis ; 24(1): 847, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39169304

RESUMO

BACKGROUND: Multisystem Inflammatory Syndrome in Children (MIS-C) associated with SARS-CoV-2 can lead to severe cardiovascular complications. Anakinra, an interleukin-1 receptor antagonist, is proposed to benefit the hyperinflammatory state of MIS-C, potentially improving cardiac function. This systematic review evaluated the effectiveness of early Anakinra administration on cardiac outcomes in children with MIS-C. METHODS: A comprehensive search across PubMed, Embase, and Web of Science until March 2024 identified studies using Anakinra to treat MIS-C with reported cardiac outcomes. Observational cohorts and clinical trials were included, with data extraction focusing on cardiac function metrics and inflammatory markers. Study quality was assessed using the Newcastle-Ottawa Scale. RESULTS: Six studies met the inclusion criteria, ranging from retrospective cohorts to prospective clinical studies, predominantly from the USA. Anakinra dosages ranged from 2.3 to 10 mg/kg based on disease severity. Several studies showed significant improvements in left ventricular ejection fraction and reductions in inflammatory markers like C-reactive protein, suggesting Anakinra's role in enhancing cardiac function and mitigating inflammation. However, findings on vasoactive support needs were mixed, and some studies did not report significant changes in acute cardiac support requirements. CONCLUSION: Early Anakinra administration shows potential for improving cardiac function and reducing inflammation in children with MIS-C, particularly those with severe manifestations. However, the existing evidence is limited by the observational nature of most studies and lacks randomized controlled trials (RCTs). Further high-quality RCTs are necessary to conclusively determine Anakinra's effectiveness and optimize its use in MIS-C management for better long-term cardiac outcomes and standardized treatment protocols.


Assuntos
COVID-19 , Proteína Antagonista do Receptor de Interleucina 1 , Síndrome de Resposta Inflamatória Sistêmica , Humanos , Proteína Antagonista do Receptor de Interleucina 1/uso terapêutico , Síndrome de Resposta Inflamatória Sistêmica/tratamento farmacológico , Criança , COVID-19/complicações , SARS-CoV-2/efeitos dos fármacos , Tratamento Farmacológico da COVID-19 , Resultado do Tratamento , Pré-Escolar
3.
Indian Pediatr ; 59(5): 388-392, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35348124

RESUMO

OBJECTIVE: To evaluate the persistence of antibodies three years after primary vaccination with typhoid conjugate vaccine (TCV) of either Cadila Healthcare Ltd. (Cadila-TCV) or Bharat Biotech International Ltd. (Bharat-TCV) administered in a previous phase II/III study, and to study the booster dose response to Cadila-TCV. METHODS: This was an open-label, phase IV extension study conducted in tertiary care and multispecialty hospitals in India. 112 subjects (Cadila-TCV-57, Bharat-TCV-55) who had participated in previous study were enrolled. Of these, eligible subjects received a single-dose of Cadila-TCV and were followed-up for 28 days post-booster. Primary outcome was persistence of antibodies 3 years after primary vaccination and seroconversion (≥4-fold rise in antibody titre from baseline) 28 days post-booster. Safety was based on reported adverse events (AEs) post-booster. RESULTS: The baseline GMT reported in the current study was significantly higher than pre-vaccination GMT reported in the previous study. 89/112 (79.5%) subjects had antibody titer ≥10 IU/mL at baseline; eligible subjects (n=17) who had baseline antibody titre <10 IU/mL were administered booster dose. All the vaccinated subjects showed seroconversion post-booster. The GMTs reported at 10 days and 28 days post-booster were significantly higher as compared to GMTs reported after primary vaccination in previous study. 4 (23.5%) vaccinated subjects reported 9 AEs; all were solicited and of mild/moderate intensity. CONCLUSIONS: There was a significant persistence of immunogenicity after primary vaccination with both the TCVs, and robust immune response after booster vaccination with Cadila-TCV.


Assuntos
Febre Tifoide , Vacinas Tíficas-Paratíficas , Humanos , Imunização Secundária , Soroconversão , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/efeitos adversos , Vacinação , Vacinas Conjugadas/efeitos adversos
4.
Sci Rep ; 11(1): 7148, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785836

RESUMO

The Covid-19 pandemic created havoc and forced lockdowns in almost all the countries worldwide, to inhibit social spreading. In India as well, as a precautionary measure, complete and partial lockdowns were announced in phases during March 25 to May 31, 2020. The restricted human activities led to a drastic reduction in seismic background noise in the high frequency range of 1-20 Hz, representative of cultural noise. In this study, we analyse the effect of anthropogenic activity on the Earth vibrations, utilizing ambient noise recorded at twelve broadband seismographs installed in different environmental and geological conditions in Gujarat. We find that the lockdowns caused 1-19 dB decrease in seismic noise levels. The impact of restricted anthropogenic activities is predominantly visible during the daytime in urban areas, in the vicinity of industries and/or highways. A 27-79% reduction in seismic noise ground displacement (drms) is observed in daytime during the lockdown, in populated areas. However, data from station MOR reveals a drastic decrease in drms amplitude both during the day (79%) and night times (87%) since factories in this area operate round the clock. The noise at stations located in remote areas and that due to microseisms, shows negligible variation.

5.
Sci Rep ; 8(1): 16816, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30429508

RESUMO

The 2004 Sumatra-Andaman tsunami emphasized the catastrophic nature of such disasters and exposed our knowledge gap of the historical and palaeo events. In the aftermath of this deadly event, the thrust in palaeotsunami studies was restricted to areas in the Indian Ocean, affected by this tsunami. The northern Arabian Sea, which hosts a similar tsunamigenic source i.e. the Makran Subduction Zone (MSZ), has so far remained 'Terra-Incognita'. Here, for the first time, we report geological evidence of the 1008 AD tsunami, also mentioned as 'an enigma' in the historical reports, by identifying a >250 km long sand sheet with a landward extent of more than 250 m from the Indian coastline. Detailed sedimentology and geochemistry reveals an offshore origin of this sand sheet, from where it was eroded by a high energy wave and deposited in a supratidal environment. Optical and AMS 14C chronology constrains its age of deposition around 1000 AD. The shear size of the sand sheet, laterally and across the coast, along with grain size, a characteristically different provenance, are some of the major indicators, which can be useful in palaeotsunami/palaeostorm deposit distinction. Our report of the AD 1008 event from the Indian coastline, also supports the claim that the Western MSZ, albeit at longer intervals, has experienced major thrust earthquakes (Mw > 8) in the historical past. The proximity of this sand sheet to the shoreline does not discount the role of extremely unlikely, large storms as its causal mechanism.

6.
Curr Top Med Chem ; 14(17): 2031-41, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25322771

RESUMO

Fibroblast growth factor receptor 1 (FGFR1) a tyrosine kinase receptor, plays important roles in angiogenesis, embryonic development, cell proliferation, cell differentiation, and wound healing. The FGFR isoforms and their receptors (FGFRs) considered as a potential targets and under intense research to design potential anticancer agents. Fibroblast growth factors (FGF's) and its growth factor receptors (FGFR) plays vital role in one of the critical pathway in monitoring angiogenesis. In the current study, quantitative pharmacophore models were generated and validated using known FGFR1 inhibitors. The pharmacophore models were generated using a set of 28 compounds (training). The top pharmacophore model was selected and validated using a set of 126 compounds (test set) and also using external validation. The validated pharmacophore was considered as a virtual screening query to screen a database of 400,000 virtual molecules and pharmacophore model retrieved 2800 hits. The retrieved hits were subsequently filtered based on the fit value. The selected hits were subjected for docking studies to observe the binding modes of the retrieved hits and also to reduce the false positives. One of the potential hits (thiazole-2-amine derivative) was selected based the pharmacophore fit value, dock score, and synthetic feasibility. A few analogues of the thiazole-2-amine derivative were synthesized. These compounds were screened for FGFR1 activity and anti-proliferative studies. The top active compound showed 56.87% inhibition of FGFR1 activity at 50 µM and also showed good cellular activity. Further optimization of thiazole-2-amine derivatives is in progress.


Assuntos
Antineoplásicos/síntese química , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Tiazóis/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Tiazóis/farmacologia
7.
PLoS One ; 9(7): e101688, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24991929

RESUMO

Genome-wide association studies (GWAS) have been instrumental in identifying novel genetic variants associated with altered plasma lipid levels. However, these quantitative trait loci have not been tested in the Indian population, where there is a poorly understood and growing burden of cardiometabolic disorders. We present the association of six single nucleotide polymorphisms in 1671 sib pairs (3342 subjects) with four lipid traits: total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C). We also investigated the interaction effects of gender, location, fat intake and physical activity. Each copy of the risk allele of rs964184 at APOA1 was associated with 1.06 mmol/l increase in triglycerides (SE = 0.049; p = 0.006), rs3764261 at CETP with 1.02 mmol/l increase in both total cholesterol (SE = 0.042; p = 0.017) and HDL-C (SE = 0.041; p = 0.008), rs646776 at CELSR2-PSRC1-SORT1 with 0.96 mmol/l decrease in cholesterol (SE = 0.043; p = 0.0003) and 0.15 mmol/l decrease in LDL-C levels (SE = 0.043; p = 0.0003) and rs2954029 at TRIB1 with 1.02 mmol/l increase in HDL-C (SE = 0.039; p = 0.047). A combined risk score of APOA1 and CETP loci predicted an increase of 1.25 mmol/l in HDL-C level (SE = 0.312; p = 0.0007). Urban location and sex had strong interaction effects on the genetic association of most of the studied loci with lipid traits. To conclude, we validated four genetic variants (identified by GWAS in western populations) associated with lipid traits in the Indian population. The interaction effects found here may explain the sex-specific differences in lipid levels and their heritability. Urbanization appears to influence the nature of the association with GWAS lipid loci in this population. However, these findings will require replication in other Indian populations.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Metabolismo dos Lipídeos , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , População Branca/genética , Adulto , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Humanos , Índia/etnologia , Masculino , Pessoa de Meia-Idade , Triglicerídeos/sangue , População Urbana , Adulto Jovem
8.
Pak J Biol Sci ; 17(5): 735-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-26031010

RESUMO

The present study aimed at the production of cellulase enzyme from the cellulolytic fungi Trichoderma reesei CEF19 and subsequent application of the cellulase for the fermentation of ethanol. For the same, the cellulolytic fungi, Trichoderma reesei CEF19 was isolated and was allowed to produce cellulase enzyme using optimized conditions. The cellulase enzyme was extracted and purified with the help of ammonium sulphate precipitation, dialysis followed by ion exchange chromatography with DEAE-Sephadex column. The purified cellulase enzyme was characterized using SDS-PAGE analysis. The saccharification of the cellulosic substrates was done using the cellulase enzyme. The fermentation of saccharified cellulosic substrates into ethanol was carried out using Saccharomyces cerevisiae. From the results obtained, rice straw was found to be the better source for the ethanol production when compared to the other substrates.


Assuntos
Celulase/biossíntese , Etanol/metabolismo , Trichoderma/enzimologia , Sequência de Bases , Primers do DNA , Trichoderma/genética
9.
Pak J Biol Sci ; 17(4): 529-34, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25911841

RESUMO

The present study aimed at the production, purification and characterization of fibrinolytic nattokinase enzyme from the bacteria isolated from natto food. For the purpose, a fibrinolytic bacterium was isolated and identified as Bacillus subtilis based on 16S rDNA sequence analysis. The strain was employed for the production and optimization of fibrinolytic enzyme. The strain showed better enzyme production during 72nd h of incubation time with 50 degrees C at the pH 9. The lactose and peptone were found to be increasing the enzyme production rate. The enzyme produced was purified and also characterized with the help of SDS-PAGE analysis. The activity and stability profile of the purified enzyme was tested against different temperature and pH. The observations suggesting that the potential of fibrinolytic enzyme produced by Bacillus subtilis RJAS 19 for its applications in preventive medicines.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/biossíntese , Fibrinolíticos/metabolismo , Microbiologia Industrial/métodos , Subtilisinas/biossíntese , Bacillus subtilis/classificação , Bacillus subtilis/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/farmacologia , DNA Bacteriano/genética , Estabilidade de Medicamentos , Estabilidade Enzimática , Fibrina/metabolismo , Fibrinolíticos/isolamento & purificação , Fibrinolíticos/farmacologia , Concentração de Íons de Hidrogênio , Hidrólise , Lactose/metabolismo , Peptonas/metabolismo , Ribotipagem , Alimentos de Soja/microbiologia , Subtilisinas/isolamento & purificação , Subtilisinas/farmacologia , Fatores de Tempo
10.
Rapid Commun Mass Spectrom ; 22(2): 204-10, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18088066

RESUMO

A set of DNA tetranucleotides, which are 3'- or 5'-end extended versions of GCA, was used as chiral selectors for the discrimination of enantiomers of alpha-amino acids. The [X+Y-2H](2-) ions of the 1:1 complexes were generated by electrospraying a mixture of tetranucleotide (X) and amino acid (Y) solution. Chiral discrimination was achieved by studying the collision-induced dissociation spectra of the [X+Y-2H](2-) ion and the ratio of relative abundance of precursor ion to that of the product ion was used to measure the extent of discrimination. Among the tetranucleotides used, GCAA and GGCA exhibited better discrimination, in which GCAA showed D-selectivity and GGCA showed L-selectivity for the studied amino acids. In addition, binding constants were measured for the 1:1 complexes of phenylalanine enantiomers with GCAA and GGCA. Ltd.


Assuntos
Aminoácidos/química , DNA/química , Oligonucleotídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Conformação Molecular , Estereoisomerismo
11.
Nature ; 449(7164): 894-7, 2007 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-17943128

RESUMO

The breakup of the supercontinent Gondwanaland into Africa, Antarctica, Australia and India about 140 million years ago, and consequently the opening of the Indian Ocean, is thought to have been caused by heating of the lithosphere from below by a large plume whose relicts are now the Marion, Kerguelen and Réunion plumes. Plate reconstructions based on palaeomagnetic data suggest that the Indian plate attained a very high speed (18-20 cm yr(-1) during the late Cretaceous period) subsequent to its breakup from Gondwanaland, and then slowed to approximately 5 cm yr(-1) after the continental collision with Asia approximately 50 Myr ago. The Australian and African plates moved comparatively less distance and at much lower speeds of 2-4 cm yr(-1) (refs 3-5). Antarctica remained almost stationary. This mobility makes India unique among the fragments of Gondwanaland. Here we propose that when the fragments of Gondwanaland were separated by the plume, the penetration of their lithospheric roots into the asthenosphere were important in determining their speed. We estimated the thickness of the lithospheric plates of the different fragments of Gondwanaland around the Indian Ocean by using the shear-wave receiver function technique. We found that the fragment of Gondwanaland with clearly the thinnest lithosphere is India. The lithospheric roots in South Africa, Australia and Antarctica are between 180 and 300 km deep, whereas the Indian lithosphere extends only about 100 km deep. We infer that the plume that partitioned Gondwanaland may have also melted the lower half of the Indian lithosphere, thus permitting faster motion due to ridge push or slab pull.

12.
J Am Soc Mass Spectrom ; 18(4): 651-62, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17223353

RESUMO

High-resolution electrospray ionization (ESI) quadrupole time-of-flight and ion trap tandem mass spectrometry has been used to distinguish the positional isomers of a new class of N-blocked hybrid peptides containing repeats of the amino acids, L-Ala-gamma(4)Caa ((l))/gamma(4)Caa((l))-L-Ala [Caa((l)) = Carbo (lyxose) amino acid, derived from D-mannose]. Both MS/MS and MS(3) of protonated isomeric peptides produce characteristic fragmentation involving the peptide backbone, Boc-group, and the side-chain. It is interesting to observe that the abundant y(n)(+) ions are formed when the corresponding amide -NH does not participate in the helical structures in solution phase and relatively low abundance y(n)(+) ions resulted when the amide -NH involves in the H-bonding. Thus, it was possible to identify the amide -NH hydrogens that participate in the helical structures through H-bonding in solution phase. Further, negative ion ESI MS/MS has also been found to be useful for differentiating these isomeric peptide acids.


Assuntos
Peptídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem , Estrutura Molecular , Estereoisomerismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-16531646

RESUMO

Alkoxide anions, [M-H](-) from a series of aliphatic diols and alcohols are generated in the source under negative ion electrospray ionisation conditions by cone-voltage fragmentation of the corresponding [M + F](-) ions. The collision-induced dissociation (CID) spectra of [M-H](-) ions consist of [M-H-2H](-) ions, in addition to the other characteristic fragment ions, and the relative abundance of [M-H-2H(-) ions among the series of diols varies as a function of chain length that could be explained based on their stabilities through intramolecular hydrogen bonding. The reactivity of alkoxide anions is studied through ion-molecule reactions with CO(2) in the collision cell of a triple quadrupole mass spectrometer. All the alkoxide anions reacted with CO(2) and formed corresponding carbonate anions, [M-H + CO(2)](-) ions. The reactivity of alkoxide anions within the series of diols also reflected the stability of their [M-H](-) ions.

14.
Inorg Chem ; 45(4): 1463-70, 2006 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-16471957

RESUMO

The high-yield preparation of metallo-benzoylbiliverdins 9, 10, and 11 from either oxidation of dodeca-substituted porphyrin 6 in the presence of NaNO2/TFA and air followed by metalation or by reaction of the Ni(II) or Cu(II) complexes of 6 with m-chloroperoxybenzoic acid in pyridine under air is reported. The X-ray structures of complexes 9 and 10 and the electrochemistry and spectroelectrochemistry of metallo-benzoylbiliverdins 9-11 are presented and discussed.


Assuntos
Biliverdina/análogos & derivados , Metais/química , Biliverdina/química , Eletroquímica , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta , Difração de Raios X
16.
Rapid Commun Mass Spectrom ; 19(2): 113-20, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15593065

RESUMO

Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand (lactic acid, methyl lactate or ethyl lactate), were generated in the gas phase under electrospray ionization conditions. The collision-induced dissociation spectra of [M(A-H)A]+ ions were recorded to study the behaviour of ligand and metal ions in decomposition of these dimeric complex ions. Based on the fragmentation pathways observed for complex ions of lactic acid, it is found that both the carboxylic and hydroxyl groups of lactic acid are involved in the complex formation following displacement of a proton by the metal ion. The dimeric complex ions of Co, Ni, and Zn dissociated to yield similar types of ions, whereas that of Cu behaved differently. The dissociations of Co-, Ni-, and Zn-bound dimeric complexes involved losses of neutral molecules while keeping the oxidation state of the metal ion unchanged. However, elimination of radicals is found in the dissociation of dimeric complex ions of Cu, and the oxidation state of copper is reduced from Cu(II) to Cu(I) in the resulting fragment ions. The deprotonated ligand is involved in the fragmentation pathway of Cu complexes, whereas it is intact in other complexes. The oxidation state of the metal ion, nature of the ligand, and site of attachment to the metal ion are found to control the dissociation of these dimeric complex ions.


Assuntos
Ácido Láctico/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Elementos de Transição/química , Dimerização , Gases/química , Oxirredução
17.
Rapid Commun Mass Spectrom ; 18(10): 1103-8, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15150834

RESUMO

The gas-phase coordination behavior of the [Cr(III)(Salen)]PF(6) complex at the free axial positions has been studied in the presence of amines as ligands (propylamine and a series of diamines) under electrospray ionization conditions. The [Cr(III)(Salen)](+) complex formed stable five- and six-coordinated complex ions, [Cr(III)(Salen)(L)](+) and [Cr(III)(Salen)(L)(2)](+), respectively, where L = solvent molecule or amine. When diamines were used as ligands, abundant [Cr(III)(Salen)(L)](+) ions were observed in which two axial positions of the [Cr(III)(Salen)](+) species are occupied by the two amino groups of the diamine ligand. The relative abundances of ligated complex ions, fragment ions, and solvent adducts of fragment ions in the ESI mass spectra, were found to depend on the cone voltage used to record the spectrum. The ESI mass spectra of [Cr(III)(Salen)](+) in the presence of diamines as ligands, and experiments on ligand-pickup in the collision cell, clearly demonstrated that the [Cr(III)(Salen)(L)](+) complex ion is stable for 1,2-diaminoethane and 1,3-diaminopropane. The stability of [Cr(III)(Salen)(L)](+) ions gradually decreased from 1,4-diaminobutane to 1,6-diaminohexane, and then showed a slight increase for 1,7-diaminoheptane and 1,8-diaminooctane. The collision-induced dissociation spectra of [Cr(III)(Salen)(L)](+) ions support the above observations.

18.
Rapid Commun Mass Spectrom ; 18(10): 1109-15, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15150835

RESUMO

The negative ion electrospray ionization (ESI) mass spectra of a series of dicarboxylic acids, a pair of isomeric (cis/trans) dicarboxylic acids and two pairs of isomeric (positional) substituted benzoic acids, including a pair of hydroxybenzoic acids, were recorded in the presence of halide ions (F(-), Cl(-), Br(-) and I(-)). The ESI mass spectra contained [M--H](-) and [M+X](-) ions, and formation of these ions is found to be characteristic of both the analyte and the halide ion used. The analytes showed a greater tendency to form adduct ions with Cl(-) under ESI conditions compared with the other halide ions used. The isomeric compounds yielded distinct spectra by which the isomers could be easily distinguished. The collision-induced dissociation mass spectra of [M+X](-) ions reflected the gas-phase basicities of both the halide ion and [M--H](-) ion of the analyte. However, the relative ordering of gas-phase basicities of all analyte [M--H](-) and halide ions could not account for the dominance of chloride ion adducts in ESI mass spectra of the analytes mixed with equimolar quantities of the four halides.

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