The formation and fragmentation of negative ions derived from organic molecules

Ammonia chemical ionization mass spectrometry

I . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 11. Thermochemistry and kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 111. Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 A. Orbital symmetry considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 B. Stereochemical approach . . . . . . . . . . . . . . . . . . . . . . 97 IV. Scope and limitations . . . . . . . . . . . . . . . . 101 A. Substituted cyclohexenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 B. Norbornene derivatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 C. Other bridged systems . . . . . . . . . . . . . . . . . . . . . . . . . 114 D. Ortho-condensed systems . . . . . . . . . . 117 E. Intramolecular RDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 F. Heterocyclic compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Retro-Diels-Alder reaction in mass spectrometry

Surgical Treatment of Thoracic Spinal Tuberculosis: A Multicenter Retrospective Study.

A survey of side reactions such as oxidation, hydrogenation, reductive removal of substituents and radical processes is presented, and the implications for mass spectroscopic analysis are pointed out.

Reactions between substrate molecules and chemical ionization reagent gases prior to ionization

Study Design:Systematic review.Objectives:(1) Study indications for cement-augmented pedicle screws (CAPS) in patients with osteoporosis. Have they changed over the years (2000-2017)? Are there any...

https://journals.sagepub.com/doi/pdf/10.1177/2192568218801570

Surgical Trend Analysis for Use of Cement Augmented Pedicle Screws in Osteoporosis of Spine: A Systematic Review (2000-2017).

Reduction of olefinic bond under ammonia chemical ionization

Study Design:A retrospective study.Objective:To evaluate the results of posterior pedicle-screw fixation with transpedicular decompression in 21 cases of thoracic and thoracolumbar spinal tuberculosis (TB) in terms of functional, neurological, and radiologic outcomes.Summary of Background Data:Spina

Role of Posterior Stabilization and Transpedicular Decompression in the Treatment of Thoracic and Thoracolumbar TB: A Retrospective Evaluation.

Study Design:Prospective cohort study.Objectives:Management of osteoporotic vertebral compression fracture (OVCF) remains an unsolved problem for a spine surgeon. We hypothesize that instability at...

https://journals.sagepub.com/doi/pdf/10.1177/2192568220956954

Posterior Stabilization Without Neural Decompression in Osteoporotic Thoracolumbar Fractures With Dynamic Cord Compression Causing Incomplete Neurological Deficits.

Study design This is a retrospective study. Purpose To determine the efficacy and safety of a posterior transpedicular approach with regard to functional and radiological outcomes in people with thoracic and thoracolumbar spinal tuberculosis. Overview of literature Spinal tuberculosis can cause serious morbidity, including permanent neurological deficits and severe deformities. Medical treatment or a combination of medical and surgical strategies can control the disease in most patients, thereby decreasing morbidity incidence. A debate always existed regarding whether to achieve both decompression and stabilization via a combined anterior and posterior approach or a single posterior approach exists. Methods The study was conducted at the Indian Spinal injuries Centre and included all patients with thoracic and thoracolumbar Pott's disease who were operated via a Posterior transpedicular approach. Data regarding 60 patients were analyzed with respect to the average operation time, preoperative and postoperative, 6 months and final follow-up American Spinal Injury Association (ASIA) grading, bony fusion, implant loosening, implant failure, preoperative, postoperative, 6 months and final follow-up kyphotic angles, a loss of kyphotic correction, Oswestry disability index (ODI) score, and visual analog scale (VAS) score. Data were analyzed using either a paired t -test or a Wilcoxon Signed Rank test. Results The mean operation time was 260±30 minutes. Fifty-five patients presented with evidence of successful bony fusion within a mean period of 6±1.5 months. Preoperative dorsal and lumbar angles were significantly larger than postoperative angles, which were smaller than final follow-up angles. The mean kyphotic correction achieved was 12.11±14.8, with a mean decrease of 5.97 and 19.1 in VAS and ODI scores, respectively. Conclusions Anterior decompression and posterior stabilization via a posterior transpedicular approach are safe and effective procedures, with less intraoperative surgical duration and significant improvements in clinical and functional status.

/pdf/functional-and-radiological-outcomes-of-anterior-1gyebgbrow.pdf

Functional and Radiological Outcomes of Anterior Decompression and Posterior Stabilization via Posterior Transpedicular Approach in Thoracic and Thoracolumbar Pott's Disease: A Retrospective Study.

Kalidutta Das

Papers

Surgical Trend Analysis for Use of Cement Augmented Pedicle Screws in Osteoporosis of Spine: A Systematic Review (2000-2017).

Reduction of olefinic bond under ammonia chemical ionization

Role of Posterior Stabilization and Transpedicular Decompression in the Treatment of Thoracic and Thoracolumbar TB: A Retrospective Evaluation.

Posterior Stabilization Without Neural Decompression in Osteoporotic Thoracolumbar Fractures With Dynamic Cord Compression Causing Incomplete Neurological Deficits.

Functional and Radiological Outcomes of Anterior Decompression and Posterior Stabilization via Posterior Transpedicular Approach in Thoracic and Thoracolumbar Pott's Disease: A Retrospective Study.