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1.
Int J Neurosci ; 133(4): 417-425, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33930999

RESUMO

BACKGROUND: Deficiency of vitamin D along with traumatic brain injury (TBI) augments the risk of injury severity. This possibly affects the therapeutic regimen prescribed for TBI which may pessimistically affects its outcome. METHODS: Studies literature search was conducted in Google Scholar and PubMed. The inclusions were studies performed clinically on both male and female. All included studies' references were also reviewed to find any additional relevance related to this review. Studies published in English were considered for this review. This review focuses upon the incidence of vitamin D deficiency in TBI and how it affects the Quality of life of the sufferer. RESULTS: A total of 176 studies were reviewed and 58 were thoroughly focussed for review as they met inclusion criteria. These studies demonstrate that levels of vitamin D influence the recovery outcome after TBI. Vitamin D deficiency has been found to cause more deterioration in severe TBI than in patients with mild TBI. CONCLUSION: Paucity of vitamin D significantly affects the outcome after brain injury. This clearly validates the necessity for screening of vitamin D levels in neurological deficit in order to reduce the risk of morbidity in terms of neurocognitive disorder.


Assuntos
Lesões Encefálicas Traumáticas , Lesões Encefálicas , Deficiência de Vitamina D , Humanos , Masculino , Feminino , Vitamina D , Qualidade de Vida , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/tratamento farmacológico , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/tratamento farmacológico
2.
Br J Neurosurg ; 37(5): 1346-1348, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33507116

RESUMO

BACKGROUND: Cervical hemivertebrae are extremely rare anomalies which usually present with restriction of neck movements and torticollis in childhood. Hemivertebrae within the craniovertebral junction have only been reported once previously in the literature. We report a case of semisegmented C2 vertebra presenting in a young adult with cervical pain and torticollis with no other associated anomalies. CASE DESCRIPTION: A 21-year-old lady presented with a history of neck pain for the past 10 days and longstanding torticollis with head tilt to the left. Computed tomographic scan of the cervical spine revealed a semisegmented hemivertebra located laterally between the C1 lateral mass and C2 on the right side which was not associated with any other bony anomalies, scoliosis or atlantoaxial dislocation. Conservative treatment with physical therapy was the chosen therapeutic strategy. CONCLUSION: Hemivertebrae within the craniovertebral junction are exceedingly rare anomalies which may present with pain and deformity in childhood and are an important cause of congenital torticollis which may be associated with other spinal, craniofacial, cardiac or renal anomalies.


Assuntos
Lesões do Pescoço , Escoliose , Torcicolo , Feminino , Adulto Jovem , Humanos , Adulto , Torcicolo/diagnóstico por imagem , Torcicolo/etiologia , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/anormalidades , Tomografia Computadorizada por Raios X/efeitos adversos , Lesões do Pescoço/complicações
3.
Cytopathology ; 33(1): 107-113, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34390057

RESUMO

BACKGROUND: The squash smear technique was introduced into intra-operative neurosurgical diagnosis as early as 1930. It is becoming increasingly popular in the diagnosis of central nervous system (CNS) lesions, and is fairly accurate even with a small sample. The current study assesses the accuracy and utility of the squash smear and frozen section (FS) techniques in intraoperative consultations. Correlations with histopathological diagnoses are presented. AIMS: To compare two intra-operative diagnostic techniques-squash smear cytology and FS examination-in the context of central nervous system tumours. MATERIALS AND METHODS: A total of 53 cases of CNS tumours were included in the study, and all were subjected to squash smear examination. FS examinations were conducted for 39 of these samples. The results of the two techniques were compared and correlated with histopathological diagnoses. The observed results were then analysed using SPSS software. RESULTS: The most common primary CNS tumours were gliomas and meningiomas (28.3% each). The sensitivity, specificity, positive predictive value and negative predictive value for squash cytology were 86.67%, 87.5%, 81.25% and 91.3%, and for FS were 91.67%, 93.10%, 91.67%, 93.10%, respectively, with a corresponding comparative P-value of 0.56 (insignificant). Cytological diagnosis showed complete correlation with histopathological diagnosis in 39 cases (73.58%), partial correlation in eight cases (15.1%) and no correlation in six cases (11.32%). FS diagnosis showed complete correlation in 29 cases (74.35%), partial correlation in eight cases (20.5%) and no correlation in two cases (5.1%). CONCLUSION: Squash smear is a rapid, self-sufficient and cost-effective method for the intraoperative diagnosis of CNS tumours. The squash smear and FS techniques are complementary procedures that assist the pathologist in reaching a diagnosis.


Assuntos
Neoplasias do Sistema Nervoso Central , Glioma , Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/patologia , Neoplasias do Sistema Nervoso Central/cirurgia , Citodiagnóstico/métodos , Secções Congeladas , Glioma/diagnóstico , Glioma/patologia , Glioma/cirurgia , Humanos , Período Intraoperatório
4.
Surg Neurol Int ; 12: 541, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34754591

RESUMO

BACKGROUND: Hydatid cyst is a common zoonotic condition in endemic areas. Intraventricular hydatid cyst is a rare entity with less than 50 cases published in literature. Floating water lily sign (also called Camalote sign) is very rare in intracranial hydatid cysts. Only a single case report of this sign exists in literature in intraventricular hydatidosis suggesting rupture of hydatid cyst leading to CSF dissemination and frequent poor outcome. CASE DESCRIPTION: This case report describes the successful management of a 5-year-old child who presented with signs and symptoms of raised intracranial pressure due to large intraventricular hydatid cyst in the right frontal horn, and magnetic resonanace imaging of the brain showed hydatid cyst with typical camalote sign. CONCLUSION: Although very rare, the presence of camalote sign in intraventricular cysts is very categorical in establishing preoperative diagnosis of hydatid cyst, especially in endemic areas.

5.
World Neurosurg X ; 12: 100107, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34195601

RESUMO

BACKGROUND: Posttraumatic epilepsy (PTE) is a serious and debilitating consequence of traumatic brain injury (TBI). Sometimes, the management of PTE becomes a challenging task on account of its resistance to existing antiepileptic drugs and often contributes to poor functional and psychosocial outcomes after TBI. We investigated the role of inflammatory markers interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interferon γ (INF-γ) in predicting the development of PTE. METHODS: A prospective analysis was performed of 254 patients who were admitted with head injury to our hospital, 35 of whom had posttraumatic epilepsy (32 males and 3 females); 30 adults (28 men, 2 women) with a similar demographic profile were selected randomly as control individuals. Blood levels of TNF-α, IL-6, and INF-γ were evaluated in all participants. RESULTS: IL-6 levels were significantly higher in the PTE group (121.36 pg/mL; standard deviation [SD], 89.23) than in the nonseizure group (65.30 pg/mL; SD, 74.75; P = 0.01), whereas there was no significant difference between the seizure group (11.42 pg/mL; SD, 7.84) and the nonseizure groups (10.58 pg/mL; SD, 7.84) in terms of TNF-α level (P = 0.343). The level of INF-γ in the seizure group tended to be higher (mean, 1.88 pg/mL, SD, 2.13 in seizure group vs. 1.10 pg/mL, SD, 1.45 in the nonseizure group); however, no statistically significant difference was detected among the 2 groups (P = 0.09). CONCULSIONS: Posttraumatic epilepsy has a strong association with an increased level of IL-6 in the blood. INF-γ may or may not be associated with PTE. However, TNF-α was not associated with PTE.

6.
J Pediatr Neurosci ; 16(2): 113-118, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35018178

RESUMO

BACKGROUND: Head injury is one of the leading causes of mortality and morbidity in the developing as well as developed countries. Extradural hematoma is seen in 1-2% of cases of head injury patients. Extradural hematoma is infrequent in the pediatric age group (less than 18 years) as duramater is tightly adherent to the inner table of the skull and is present in about 1-3% of all pediatric head injuries. MATERIALS AND METHODS: The study was a prospective study conducted in the Department of Neurosurgery at PGIMER, Dr. RML Hospital, New Delhi, over a period of 19 months with a follow-up of 6 months. In total, 38 patients were enrolled in the study. All traumatic extradural hematoma below 18 years of age of both sexes were included. Follow-up of all patients was done at 2 weeks, 1, 2, and 6 months. Noncontrast computed tomography (NCCT) head was done in all patients at the time of admission and whenever their neurological status deteriorated. Routine postoperative NCCT head was done. Outcome assessment was done by Glasgow outcome scale. RESULTS: Of the 38 children, 21 were males and 17 were females. The maximum number of patients was between the ages of 1-5 years (55.26%). Fall from height was the most common cause. Loss of consciousness was the most common presenting symptom (78.94%). Thirty-three patients had GCS of 14-15 at the time of presentation. The parietal region was the most common location of EDH in our study (44.74%). Thirty-five patients had supratentorial and three patients had infratentorial EDH. Eighteen patients had associated brain injury, commonest being brain edema. Six patients were operated. There was no mortality in our study. Two patients had limb paresis. CONCLUSION: Pediatric EDH is a rare entity but a potentially life-threatening condition. Prompt diagnosis and timely intervention decrease morbidity and mortality.

7.
World Neurosurg ; 146: 205-209, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33342760

RESUMO

BACKGROUND: Neurocysticercosis, a common parasitic infection in developing areas, usually exists in supratentorial parenchyma. Literature review shows few case reports published for cerebellopontine angle cysticercosis, but its coexistence with a schwannoma in the same cistern has never been seen before. This leads to confusion in preoperative diagnosis and management. CASE DESCRIPTION: Such a unique case in which dual pathology (i.e., coexisting trigeminal schwannoma along with neurocysticercosis) was present in same location with relevant radiology and histopathology and management is discussed in this case report. CONCLUSIONS: Cysticercosis should be kept as a differential diagnosis in cystic lesions of the CP angle, especially in endemic areas and even in cases showing obvious cystic schwannoma on imaging. Care should be taken to prevent spillage of cyst contents while puncturing the cyst wall for a better outcome.


Assuntos
Doenças Cerebelares/complicações , Ângulo Cerebelopontino/patologia , Neurocisticercose/complicações , Neuroma Acústico/complicações , Adulto , Doenças Cerebelares/patologia , Humanos , Masculino , Neurocisticercose/patologia , Neuroma Acústico/patologia
8.
Surg Neurol Int ; 11: 268, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33024606

RESUMO

BACKGROUND: Spinal dermoid cysts are benign tumors that result from congenital or acquired ectodermal inclusions. Long segment intramedullary involvement of the spinal cord is exceedingly rare, and there are only a handful of case reports found in the literature. CASE DESCRIPTION: A 30-year-old female presented with a 3-month history of myelopathy characterized by progressive quadriparesis and urinary incontinence. Magnetic resonance imaging revealed multifocal heterogeneous intramedullary masses extending from C2 to T4 and at T12-L1 with similar intensity lesions seen within the central cord from T5 to T11 level. Following tumor decompression, she showed significant improvement in neurological function 1 month later. The histopathological examination confirmed the diagnosis of a multifocal intramedullary dermoid cyst. CONCLUSION: Partial surgical extirpation is a reasonable treatment for long segment intramedullary dermoid cysts, particularly when the tumor capsule is adherent to critical adjacent neural tissues.

9.
Clin Drug Investig ; 40(4): 327-334, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32172522

RESUMO

BACKGROUND AND OBJECTIVE: Early management of traumatic brain injury (TBI) is essential. We aimed to evaluate the efficacy of vitamin D over early clinical outcome and serum cytokine levels in patients with moderate to severe brain injury. METHODS: Thirty-five patients with moderate to severe traumatic brain injury who were admitted to the ICU unit were recruited into the study. Subjects were randomly allocated to a treatment regimen comprising either a one-time oral dose of 120,000 IU (two tablets of 60,000 IU each) of vitamin D (n = 20) or 8 mg of saccharide (two tablets of 4 g each) as placebo (n = 15). The main parameters evaluated included duration of mechanical ventilation and ICU stay, Glasgow Coma Scale (GCS) and cytokine levels (interleukin (IL)-6, tumour necrosis factor (TNF)-α, interferon (IFN)-γ, IL-2). RESULTS: The results indicated an improvement in the level of consciousness after 7 days in the vitamin D-treated group compared with placebo. An elevation in GCS score by 3.86 units in the vitamin D-treated group with a 0.19-unit descent in the control group was recorded. Duration of mechanical ventilation was reduced in the vitamin D-treated group compared with the control group (4.7 days vs. 8.2 days, p value 0.0001). A noticeable reduction was recorded in inflammatory biomarkers (cytokines) in the vitamin D-treated group (IL-6 p = 0.08, TNF-α p = 0.02, IL-2 p = 0.36) with notable elevation in IFN-γ (p = 0.65) compared to the control group. CONCLUSION: In the acute phase of moderate to severe traumatic brain injury, vitamin D supplementation plays a vital role and has a favourable effect on the consciousness level of patients. Clinical trial Registry (CTRI) No. CTRI/2019/05/019259.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Estado de Consciência/efeitos dos fármacos , Suplementos Nutricionais , Vitamina D/administração & dosagem , Adolescente , Adulto , Idoso , Biomarcadores/sangue , Citocinas/metabolismo , Método Duplo-Cego , Feminino , Escala de Coma de Glasgow , Humanos , Masculino , Pessoa de Meia-Idade , Respiração Artificial , Adulto Jovem
10.
Neuroradiol J ; 33(2): 186-197, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31992126

RESUMO

AIM: In the present study, we aimed to characterise changes in functional brain networks in individuals who had sustained uncomplicated mild traumatic brain injury (mTBI). We assessed the progression of these changes into the chronic phase. We also attempted to explore how these changes influenced the severity of post-concussion symptoms as well as the cognitive profile of the patients. METHODS: A total of 65 patients were prospectively recruited for an advanced magnetic resonance imaging (MRI) scan within 7 days of sustaining mTBI. Of these, 25 were reassessed at 6 months post injury. Differences in functional brain networks were analysed between cases and age- and sex-matched healthy controls using independent component analysis of resting-state functional MRI. RESULTS: Our study revealed reduced functional connectivity in multiple networks, including the anterior default mode network, central executive network, somato-motor and auditory network in patients who had sustained mTBI. A negative correlation between network connectivity and severity of post-concussive symptoms was observed. Follow-up studies performed 6 months after injury revealed an increase in network connectivity, along with an improvement in the severity of post-concussion symptoms. Neurocognitive tests performed at this time point revealed a positive correlation between the functional connectivity and the test scores, along with a persistence of negative correlation between network connectivity and post-concussive symptom severity. CONCLUSION: Our results suggest that uncomplicated mTBI is associated with specific abnormalities in functional brain networks that evolve over time and may contribute to the severity of post-concussive symptoms and cognitive deficits.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Síndrome Pós-Concussão/diagnóstico por imagem , Adulto , Feminino , Seguimentos , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Índice de Gravidade de Doença , Adulto Jovem
11.
Asian J Neurosurg ; 15(4): 937-940, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33708666

RESUMO

INTRODUCTION: Ventriculoperitoneal (VP) shunt malfunction is common in pediatric age group patients. There is a high complication rate and revision rate of VP shunt. Endoscopic third ventriculostomy (ETV) can alleviate these complications and can act as an effective alternative for the treatment of hydrocephalus in this age group of patients. MATERIALS AND METHODS: The authors retrospectively reviewed the management and outcome of 36 failed VP shunts in pediatric patients for the treatment of hydrocephalus. The surgeries were performed between November 2010 and January 2016 in a tertiary care hospital. The minimal follow-up period was 3 months. We divided the patients into the following age groups: <1 year (eight infants), 1-10 years (18 children), and 10-18 years (10 children). The success of the procedure was determined by age, sex, type of hydrocephalus, and the number of shunt revisions and malfunction before ETV. Children with different age (P = 0.839) and sex group did not show any significant data (P = 0.798). Children with communicating hydrocephalus had a success rate of 52.9% (17 patients), and children with noncommunicating hydrocephalus had a success rate of 84.2% (19 patients). The success rate in children with only one shunt malfunction was 57.1% (21 patients), whereas in 15 children with two or more shunt malfunctions, the success rate of ETV was 86.7%. CONCLUSIONS: The authors conclude that ETV is an effective alternative for the treatment of hydrocephalus in children. Age does not present a contraindication for ETV in failed VP shunt.

12.
Surg Neurol Int ; 11: 454, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33408939

RESUMO

BACKGROUND: Intramedullary spinal schwannomas constitute only 0.3% of primary spine tumors. We could identify only 13 such cases involving the conus that were not associated with neurofibromatosis (NF). Here, we report a 70-year-old male without NF who was found to have a paraparesis due to a schwannoma of the thoracolumbar junction/conus (D11-L2). CASE DESCRIPTION: A 70-year-old male presented with an L1-level paraparesis with urinary incontinence. The magnetic resonance showed an intramedullary mass of 85 × 10 mm extending from D11 to L2; it demonstrated significant patchy enhancement. The patient underwent a D12 and L1 laminectomy with gross total excision of the mass that proved to be a schwannoma. Three months postoperatively, he was able to ambulate with support, and regained sphincter function. CONCLUSION: Intramedullary schwannomas involving the conus/thoracolumbar junction are rare, and can be successfully excised resulting in good outcomes.

13.
Indian J Pathol Microbiol ; 62(1): 114-116, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30706872

RESUMO

Arachnoiditis ossificans (AO) is a rare type of chronic arachnoiditis characterized by the presence of calcification or ossification of the spinal arachnoid which is usually associated with progressive neurological deficits. It is usually followed by prior history of trauma, surgery, infection, or myelography. Magnetic resonance imaging and computed tomography are the characteristics that are helpful in the diagnosis of most cases. Prognosis and treatment depends on the site and clinical presentation of the patients. We present a case of a young female who presented with a long-standing history of neurological symptoms and a intradural lesion mimicking a tumor.


Assuntos
Aracnoidite/diagnóstico , Dor Lombar/etiologia , Ossificação Heterotópica/diagnóstico , Coluna Vertebral/patologia , Adulto , Aracnoidite/complicações , Aracnoidite/cirurgia , Calcinose/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X
14.
Asian J Neurosurg ; 13(4): 1140-1147, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30459883

RESUMO

OBJECTIVES: The objective of this study was to compare safety and efficacy of endoscopic third ventriculostomy (ETV) versus ventriculoperitoneal (VP) shunt in the treatment of hydrocephalus in tuberculous meningitis (TBM) and to assess clinical and radiological profiles of patients with TBM that would be better suited to either VP shunt or ETV. METHODS: This study was a single-center randomized prospective study on 52 patients with TBM hydrocephalus in the pediatric age group (<18 years of age). Patients included in the study were randomized into undergo either VP shunt or ETV. Both groups were followed up for a minimum of 5 months and assessed for success and failure rates as well as procedural complications and neurologic sequelae. RESULTS: Twenty-six patients underwent ETV with a success rate of 65.4% with six of nine failures occurring within the first 16 days after surgery (median time to failure - 3 days). In the VP shunt group, there was a success rate of 61.54% and a median time to failure of 50 days. Modified Vellore grading was found to be a significant factor in determining outcome in both ETV and VP shunt groups with high-grade TBM consistently associated with poor outcome (odds ratio = 4.2). CONCLUSIONS: ETV can be performed effectively in young children including infants, as well as those with communicating hydrocephalus, high cerebrospinal fluid (CSF) cell counts, and protein levels with a lower rate of failure than that of VP shunt. Hence, ETV should be attempted as the first-choice CSF diversion procedure in hydrocephalus secondary to TBM where technical expertise and experience with this procedure is available as it avoids the myriad of lifelong complications associated with shunts.

15.
Asian J Neurosurg ; 13(2): 440-441, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29682055

RESUMO

Pneumorrhachis (PR) - the phenomenon of intraspinal air - is a rare radiological finding. The presence of intraspinal air is usually after epidural injections, spinal manipulations, synovial cysts, degenerative disc disease, and epidural abscess. PR is mostly asymptomatic but can also be symptomatic. We report a case with PR after chest trauma and attempt to explain its development.

16.
Indian J Cancer ; 55(2): 166-169, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30604730

RESUMO

CONTEXT: The most commonly prescribed conventional fractionation radiotherapy uses 1.8-2.2 Gy per fraction for five fractions in a week. Many times, unwanted interruptions are encountered, which ultimately affect the local control and overall survival. AIMS: The present retrospective study was carried out to study the compliance to radiotherapy at our institute and to determine various factors related to it. PATIENTS AND METHODS: The present retrospective study was carried out at the department of Radiotherapy, SMS Medical College and attached group of hospitals, Jaipur; in patients who were treated with curative intent with conventional fractionation radiotherapy over telecobalt machine from January 2017 to April 2017. Noncompliance was studied for association with various factors such as age, sex, site of primary disease, stage of tumor, distance patients had to travel to receive treatment, administration of concurrent chemotherapy, and financial burden of the treatment. RESULTS: Of 203 patients, 138 were of head-and-neck cancer, 42 of cervical cancer, and 23 of breast cancer. The cumulative incidence of noncompliance was 12.8% (15.9% for head-and-neck cancer, 7.2% for cervical cancer, and 4.4% for breast cancer). Statistically significant association was found between noncompliance and higher age of the patients (P = 0.07), male gender (P = 0.002), advanced stage (P = 0.004), administration of concurrent chemoradiotherapy (CCRT) (P < 0.001), and greater distance patients had to travel for radiotherapy (P = 0.03). CONCLUSIONS: The factors with which noncompliance is significantly associated in the present study are higher age, male gender, advanced stage of tumor, administration of CCRT, and greater distance patients had to travel to avail radiotherapy.


Assuntos
Radioterapia Conformacional/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Centros de Atenção Terciária , Adulto Jovem
17.
Inorg Chem ; 56(24): 14859-14869, 2017 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-29218992

RESUMO

A density functional theory (DFT) investigation performed at the B3LYP/TZVP//B3LYP/6-31G(d)-LANL2DZ level of theory on the hydroamination of dimethylamine (Me2NH) on an activated olefin (namely, acrylonitrile (CH2═CHCN)), as catalyzed by a 1,2,4-triazol based nickel(II) N-heterocyclic carbene complex (namely, [1,4-dimethyl-1,2,4-triazole-5-ylidene]2 nickel dichloride) revealed that the olefin coordination pathway is favorable over the amine coordination pathway, although the initial olefin coordination step is higher in energy than the initial amine coordination step. Significantly enough, the reaction involved a crucial 1,3-proton transfer step between the resonance intermediates, i.e., the C-bound [(NHC)2Ni(CH(CN)CH2NHMe2)]+ (D) species or N-bound [(NHC)2Ni(NCCHCH2NHMe2)]+ (E) species and the intermediate [(NHC)2Ni(NCCH2CH2NMe2)]+ (F), depicting the cleavage of a N-H bond and the formation of a C-H bond facilitated by a water-assisted/amine-assisted proton shuttle. Overall, among the various pathways explored, the lowest energy pathway involved alkene coordination, followed by an amine-assisted 1,3-proton transfer step.

18.
Spectrochim Acta A Mol Biomol Spectrosc ; 185: 155-162, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28570986

RESUMO

Er3+/Yb3+ co-doped SrAl2O4 (SRA: Er3+, Yb3+) phosphor has been synthesized by high temperature solid state reaction technique. The pure phase formation has been confirmed by X-ray diffraction (XRD) measurements. The surface morphology is studied by scanning electron microscopy (SEM) technique. The FTIR measurements give the information of vibrational bands arising due to sample. The intense UC emission from SRA: Er3+, Yb3+ phosphor has been monitored on excitation with 980nm diode laser. The SRA: Er3+, Yb3+ samples prepared at 1473K show a dominant green emission. On the other hand it shows dominant red emission when the sample is heated to 1623K. Variation of concentration of Er3+ and Yb3+ ions in SRA: Er3+, Yb3+ phosphor suggests two possible mechanisms involved in UC emission process viz. cross relaxation (CR) process and energy back transfer (EBT) process, respectively. The cross relaxation mechanism seems to play a major role. The UC emission efficiency is enhanced several times on co-doping of Zn2+ ion replacing Al3+ or Sr2+ in SRA: Er3+, Yb3+ phosphor sample. The color of the UC emission can be tuned from green to red region by varying the concentration of zinc.

19.
Injury ; 48(4): 880-884, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28242068

RESUMO

BACKGROUND: The ability of diffusion tensor imaging (DTI) to complement conventional MR imaging by diagnosing subtle injuries to the spinal cord is a subject of intense research. We attempted to study change in the DTI indices, namely fractional anisotropy (FA) and mean diffusivity (MD) after traumatic cervical spinal cord injury and compared these with corresponding data from a control group of individuals with no injury. The correlation of these quantitative indices to the neurological profile of the patients was assessed. MATERIAL AND METHODS: 20 cases of acute cervical trauma and 30 age and sex matched healthy controls were enrolled. Scoring of extent of clinical severity was done based on the Frankel grading system. MRI was performed on a 3T system. Following the qualitative tractographic evaluation of white matter tracts, quantitative datametrics were calculated. RESULTS: In patients, the Mean FA value at the level of injury (0.43+/-0.08) was less than in controls (0.62+/-0.06), which was statistically significant (p value <0.001). Further, the Mean MD value at the level of injury (1.30+/-0.24) in cases was higher than in controls (1.07+/-0.12, p value <0.001). Statistically significant positive correlation was found between clinical grading (Frankel grade) and FA values at the level of injury (r value=0.86). Negative correlation was found between clinical grade and Mean MD at the level of injury (r value=-0.38) which was however statistically not significant. CONCLUSION: Quantitative DTI indices are a useful parameter for detection of spinal cord injury. FA value was significantly decreased while MD value was significantly increased at the level of injury in cases as compared to controls. Further, FA showed significant correlation with clinical grade. DTI could thus serve as a reliable objective imaging tool for assessment of white matter integrity and prognostication of functional outcome.


Assuntos
Vértebras Cervicais/fisiopatologia , Imagem de Tensor de Difusão , Imageamento por Ressonância Magnética , Traumatismos da Medula Espinal/fisiopatologia , Medula Espinal/fisiopatologia , Adolescente , Adulto , Feminino , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/epidemiologia
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