Elementary Reaction Steps That Precede or Follow a Unimolecular Reaction Step Can Obfuscate Interpretation of the Driving-Force Dependence to Its Rate Constant.

Assessing the validity of a driving-force-dependent kinetic theory for a unimolecular elementary reaction step is difficult when the observed reaction rate is strongly influenced by properties of the preceding or following elementary reaction step. A well-known example occurs for bimolecular reactions with weak orbital overlap, such as outer-sphere electron transfer, where bimolecular collisional encounters that precede a fast unimolecular electron-transfer step can limit the observed rate. A lesser-appreciated example occurs for bimolecular reactions with stronger orbital overlap, including many proton-transfer reactions, where equilibration of an endergonic unimolecular proton-transfer step results in a relatively small concentration of reaction products, thus slowing the rate of the following step such that it becomes rate limiting. Incomplete consideration of these points has led to discrepancies in interpretation of data from the literature. Our reanalysis of these data suggests that proton-transfer elementary reaction steps have a nonzero intrinsic free energy barrier, implying, in the parlance of Marcus theory, that there is non-negligible nuclear reorganization. Outcomes from our analyses are generalizable to inner-sphere electron-transfer reactions such as those involved in (photo)electrochemical fuel-forming reactions.

Quantification of Excited-State Brønsted-Lowry Acidity of Weak Photoacids Using Steady-State Photoluminescence Spectroscopy and a Driving-Force-Dependent Kinetic Theory.

Photoacids and photobases constitute a class of molecules that upon absorption of light undergoes a reversible change in acidity, i.e. pKa. Knowledge of the excited-state pKa value, pKa*, is critical for predicting excited-state proton-transfer behavior. A reasonable approximation of pKa* is possible using the Förster cycle analysis, but only when the ground-state pKa is known. This poses a challenge for the study of weak photoacids (photobases) with less acidic (basic) excited states (pKa* (pKb*) > 7), because ground-state pKa (pKb) values are >14, making it difficult to quantify them accurately in water. Another method to determine pKa* relies on acid-base titrations with photoluminescence detection and Henderson-Hasselbalch analysis. This method requires that the acid dissociation reaction involving the thermally equilibrated electronic excited state reaches chemical quasi-equilibrium, which does not occur for weak photoacids (photobases) due to slow rates of excited-state proton transfer. Herein, we report a method to overcome these limitations. We demonstrate that liquid water and aqueous hydroxide are unique proton-accepting quenchers of excited-state photoacids. We determine that Stern-Volmer quenching analysis is appropriate to extract rate constants for excited-state proton transfer in aqueous solutions from a weak photoacid, 5-aminonaphthalene-1-sulfonate, to a series of proton-accepting quenchers. Analysis of these data by Marcus-Cohen bond-energy-bond-order theory yields an accurate value for pKa* of 5-aminonaphthalene-1-sulfonate. Our method is broadly accessible because it only requires readily available steady-state photoluminescence spectroscopy. Moreover, our results for weak photoacids are consistent with those from previous studies of strong photoacids, each showing the applicability of kinetic theories to interpret driving-force-dependent rate constants for proton-transfer reactions.

Survival in persons with traumatic spinal cord injury receiving structured follow-up in South India.

OBJECTIVE: To assess the survival in persons with traumatic spinal cord injury (SCI) receiving structured follow-up in South India. DESIGN: Retrospective study. SETTING: Rehabilitation center. PARTICIPANTS: Persons with traumatic SCI (N=490) residing within a 100-km radius of the institute who were managed and regularly followed up by the rehabilitation center between the years 1981 and 2011. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Survival rates and mortality risk factors. Measures were estimated using the product limit (Kaplan-Meier) method and the Cox model. RESULTS: The survival rate after SCI was 86% after 5 years, 71% after 15 years, and 58% after 25 years. Survival of persons with complete high cervical injury is substantially low compared with other levels of SCI. Level of injury and extent of lesion (Frankel classification and/or American Spinal Injury Association Impairment Scale) play a significant role in predicting survival of this population. CONCLUSIONS: Survival rates of regularly followed-up persons with SCI from this study show promising results, though survival rates are lesser when compared with studies from developed countries. Better understanding of the predictors, causes of deaths, comprehensive rehabilitation, community integration, and regular follow-up could possibly assist in improving survival rates.

Rehabilitation service models for people with physical and/or mental disability living in low- and middle-income countries: A systematic review.

OBJECTIVE: To compare models of rehabilitation services for people with mental and/or physical disability in order to determine optimal models for therapy and interventions in low- to middle-income countries. DATA SOURCES: CINAHL, EMBASE, MEDLINE, CENTRAL, PsycINFO, Business Source Premier, HINARI, CEBHA and PubMed. STUDY SELECTION: Systematic reviews, randomized control trials and observational studies comparing >2 models of rehabilitation care in any language. Date extraction: Standardized forms were used. Methodological quality was assessed using AMSTAR and quality of evidence was assessed using GRADE. DATA SYNTHESIS: Twenty-four systematic reviews which included 578 studies and 202,307 participants were selected. In addition, four primary studies were included to complement the gaps in the systematic reviews. The studies were all done at various countries. Moderate- to high-quality evidence supports the following models of rehabilitation services: psychological intervention in primary care settings for people with major depression, admission into an inpatient, multidisciplinary, specialized rehabilitation unit for those with recent onset of a severe disabling condition; outpatient rehabilitation with multidisciplinary care in the community, hospital or home is recommended for less severe conditions; However, a model of rehabilitation service that includes early discharge is not recommended for elderly patients with severe stroke, chronic obstructive pulmonary disease, hip fracture and total joints. CONCLUSION: Models of rehabilitation care in inpatient, multidisciplinary and specialized rehabilitation units are recommended for the treatment of severe conditions with recent onset, as they reduce mortality and the need for institutionalized care, especially among elderly patients, stroke patients, or those with chronic back pain. Results are expected to be generalizable for brain/spinal cord injury and complex fractures.

Cognitive Impairment and Rehabilitation Strategies After Traumatic Brain Injury.

Traumatic brain injury (TBI) is among the significant causes of morbidity and mortality in the present world. Around 1.6 million persons sustain TBI, whereas 200,000 die annually in India, thus highlighting the rising need for appropriate cognitive rehabilitation strategies. This literature review assesses the current knowledge of various cognitive rehabilitation training strategies. The entire spectrum of TBI severity; mild to severe, is associated with cognitive deficits of varying degree. Cognitive insufficiency is more prevalent and longer lasting in TBI persons than in the general population. A multidisciplinary approach with neuropsychiatric evaluation is warranted. Attention process training and tasks for attention deficits, compensatory strategies and errorless learning training for memory deficits, pragmatic language skills and social behavior guidance for cognitive-communication disorder, meta-cognitive strategy, and problem-solving training for executive disorder are the mainstay of therapy for cognitive deficits in persons with TBI. Cognitive impairments following TBI are common and vary widely. Different cognitive rehabilitation techniques and combinations in addition to pharmacotherapy are helpful in addressing various cognitive deficits.

Mirror Therapy and Transcutaneous Electrical Nerve Stimulation for Management of Phantom Limb Pain in Amputees - A Single Blinded Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Phantom limb pain (PLP) can be disabling for nearly two thirds of amputees. Hence, there is a need to find an effective and inexpensive treatment that can be self administered. Among the non-pharmacological treatment for PLP, transcutaneous electrical nerve stimulation (TENS) applied to the contralateral extremity and mirror therapy are two promising options. However, there are no studies to compare the two treatments. The purpose of this study is to evaluate and compare mirror therapy and TENS in the management of PLP in subjects with amputation. METHODS: The study was an assessor blinded randomized controlled trial conducted at Physiotherapy Gymnasium of Physical Medicine and Rehabilitation Department, Christian Medical College, Vellore. Twenty-six subjects with PLP consented to participate. An initial assessment of pain using visual analogue scale (VAS) and universal pain score (UPS) was performed by a therapist blinded to the treatment given. Random allocation into Group I-mirror therapy and Group II-TENS was carried out. After 4 days of treatment, pain was re-assessed by the same therapist. The mean difference in Pre and Post values were compared among the groups. The change in pre-post score was analyzed using the paired t test. RESULTS: Participants of Group I had significant decrease in pain [VAS ( p = 0.003) and UPS ( p = 0.001)]. Group II also showed a significant reduction in pain [VAS ( p = 0.003) and UPS ( p = 0.002)]. However, no difference was observed between the two groups [VAS ( p = 0.223 and UPS ( p = 0.956)]. DISCUSSION: Both Mirror Therapy and TENS were found to be effective in pain reduction on a short-term basis. However, no difference between the two groups was found. Substantiation with long-term follow-up is essential to find its long-term effectiveness. Copyright © 2015 John Wiley & Sons, Ltd.

Exercise and gait training in persons with paraplegia and its effect on muscle properties.

BACKGROUND: Upper extremity strengthening and gait training with orthoses form a major part of inpatient rehabilitation of paraplegic patients in developing countries. This helps to overcome architectural barriers and limited wheelchair accessible environment in the community. OBJECTIVES: To evaluate the changes in physiological properties of the Triceps Brachii muscle following exercise training in individuals with paraplegia. The authors also explored the correlation between muscle property changes and gait parameters using orthoses in paraplegic persons. METHODS: Twelve subjects with complete paraplegia and neurological level of injury (NLI) from T9 to L1, underwent exercise training for a mean 64.1 ± 4.1 days. Triceps brachii was chosen as the sample muscle. Variables like arm circumference, time to fatigue and mean power frequency (MF) (surface EMG parameter), were recorded at the beginning and the end of training, during a sub-maximal isometric elbow extension. Non-parametric tests were used to assess statistical significance between the two recordings. Additionally, gait parameters like walking speed and distance (with the help of orthoses) were obtained and compared with the above variables, to determine impact of upper extremity strengthening on gait improvements in such patients. RESULTS: Statistically significant changes were noted in bilateral arm circumferences (p= 0.003 bilaterally) and MF drop, expressed as percentage (right p= 0.04, left p= 0.01), indicative of better muscle resilience and adaptation. Significant positive correlation was observed between `time to fatigue' and the orthoses-aided total walking distance (right ρ = 0.65, left ρ = 0.69). CONCLUSIONS: Exercise training induces noticeable changes in the muscles of upper extremities favoring better muscle adaptation. Furthermore, positive correlation between `time to fatigue' and (orthotic) aided walking distance highlights the positive impact of strengthening program on gait parameters in paraplegic patients. These findings are important and relevant in developing countries with environmental barriers. Upper extremity strengthening should be included in the rehabilitation of paraplegic patients who are being trained for ambulation with orthoses.

A rare presentation of subacute progressive ascending myelopathy secondary to cement leakage in percutaneous vertebroplasty.

Percutaneous vertebroplasty is used to manage osteoporotic vertebral body compression fractures. Although it is relatively safe, complications after vertebroplasty ranging from minor to devastatingly major ones have been described. Cement leakage into the spinal canal is one such complication. Subacute progressive ascending myelopathy is an infrequent neurologic complication after spinal cord injury, typically presenting as ascending neurologic deficit within weeks after the initial insult. The precise cause of subacute progressive ascending myelopathy still remains an enigma, considering the rarity of this disorder. The authors present the case of a 62-yr-old woman with osteoporotic vertebral fracture who underwent percutaneous vertebroplasty and developed T6 complete paraplegia because of cement leakage. A few weeks later, the neurologic level ascended to higher cervical level (C3). To date, no case of subacute progressive ascending myelopathy secondary to cement leakage after percutaneous vertebroplasty has been reported. Literature is reviewed regarding subacute progressive ascending myelopathy, and the rehabilitation challenges in the management of this patient are discussed.

Gorham's disease of the spine.

BACKGROUND: Gorham's disease of the spine is very rare and usually associated with poor prognosis. Till date very few cases have been reported in the literature. It is characterized by osseous invasion by angiomatous vascular mass without skip areas, eventually causing lysis of affected bone. Morbidity and mortality are high in those with spinal and/or visceral involvement. Neurological complications increase the mortality to 33% whereas with chylothorax, mortality increases to more than 50%. OBJECTIVES: To describe the clinical course and the challenges in planning and implementing effective rehabilitation services for management of patients with Gorham's disease of the spine. METHODS: We report two patients with Gorham's disease who had neurological deficits secondary to spinal cord involvement, and their rehabilitation perspectives. RESULTS: Both patients achieved satisfactory ambulation and functional outcomes. CONCLUSION: Multiple revision surgeries may be required to ensure spinal stability. When working with these patients, one must remain vigilant about spinal stability as well as about possible serious pulmonary complications, and be prepared to make appropriate management decisions when necessary.