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Abstract To conduct a systematic review of the literature regarding rates and predictors of favorable seizure outcome after resective surgery for epileptic spasms (ES) in pediatric patients. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses standards were followed. We searched PubMed, EMBASE, and Cochrane CENTRAL for articles published on the prevalence or incidence of epileptic spasm since 1985. Abstract, full‐text review, and data extraction were conducted by two independent reviewers. Meta‐analysis was performed to assess overall seizure freedom rate. Subject‐level analysis was performed on a subset of studies to identify prognostic indicators. A total of 21 retrospective studies (n = 531) were included. Meta‐analysis of all studies demonstrated a pooled seizure freedom rate of 68.8%. Subject‐level analysis on 18 studies (n = 360) demonstrated a significant association between duration of spasms and recurrence of spasms after surgery, with an estimated increased risk of 7% per additional year of spasms prior to operation. Patients who underwent resective surgery that was not a hemispherectomy (i.e., lobectomy, lesionectomy, etc.) had an increased recurrence risk of 57% compared to patients who had undergone hemispherectomy. Resective surgery results in seizure freedom for the majority of pediatric patients with epileptic spasms. Patients who undergo hemispherectomy have lower risk of recurrence than patients who undergo other types of surgical resection. Increased duration of spasms prior to surgery is associated with increased recurrence risk after surgery. Plain Language Summary Children with epileptic spasms (ES) that do not respond to medications may benefit from surgical treatment. Our study reviewed existing research to understand how effective surgery is in treating ES in children and what factors predict better outcomes. Researchers followed strict guidelines to search for and analyze studies published since 1985, finding 21 studies with a total of 531 patients. They found that, on average, nearly 70% of children became seizure‐free after surgery. Further individual analysis of 360 patients showed that longer duration of spasms before surgery increased the risk of spasms returning by 7% per year. Additionally, children who had less extensive surgeries, such as removal of only a specific part of the brain, had a 57% higher risk of seizure recurrence compared to those who had a hemispherectomy, which removed or disconnected half of the brain. Overall, the study concludes that surgery can often stop seizures, especially when more extensive surgery is performed and when the surgery is done sooner rather than later.

Epileptic spasms are a unique, age-dependent manifestation of epilepsies in infancy and early childhood, commonly occurring as part of infantile epileptic spasms syndrome. Developmental stagnation and subsequent decline may occur in children with epileptic spasms, partly due to the abundant high-amplitude interictal epileptiform and slow wave abnormalities. Early recognition and treatment of epileptic spasms, along with the reversal of the electroencephalography (EEG) findings, are critical for improving outcomes. Recognizing hypsarrhythmia and its variations is key to confirming the diagnosis. The various patterns of hypsarrhythmia are not etiology specific, but could indicate the severity of the disease. Several scoring systems have been proposed to improve the inter-rater reliability of recognizing hypsarrhythmia and to assess EEG progress in response to treatment. Ictal patterns during spasms are brief and composed of slow waves, sharp transients, fast activity, and voltage attenuation, either in isolation or more commonly as a combination of these waveforms. Ictal patterns are commonly diffuse, but may be lateralized to one hemisphere in children with structural etiology. A subset of patients with epileptic spasms has a surgically remediable etiology, with readily identifiable lesions on neuroimaging in most cases. Asymmetry in epileptic spasms, concurrent focal seizures, and asymmetric interictal and ictal EEG findings may be present, but a lack of focality in electrophysiological findings is not uncommon. Intracranial EEG features of epileptic spasms have been described, but the utility of intracranial EEG monitoring in surgical candidates with overt focal epileptogenic lesions on magnetic resonance imaging is questionable, and surgery could be performed using noninvasive data.

Abstract Background CDKL5 deficiency disorder (CDD) is associated with refractory infantile onset epilepsy, global developmental delay, and variable features that include sleep, behavioral disturbances, and movement disorders. Current treatment is primarily symptom-based and informed by experience in caring for this population. Methods We describe medication and non-medication approaches to treatment of epilepsy and additional key neurologic symptoms (sleep disturbances, behavioral issues, movement disorders, and swallowing dysfunction) in a cohort of 177 individuals meeting criteria for CDD, 154 evaluated at 4 CDKL5 Centers of Excellence in the USA and 40 identified through the NIH Natural History Study of Rett and Related Disorders. Results The four most frequently prescribed anti-seizure medications were broad spectrum, prescribed in over 50% of individuals. While the goal was not to ascertain efficacy, we obtained data from 86 individuals regarding response to treatment, with 2-week response achieved in 14–48% and sustained 3-month response in 5–36%, of those with known response. Additional treatments for seizures included cannabis derivatives, tried in over one-third of individuals, and clinical trial medications. In combination with pharmacological treatment, 50% of individuals were treated with ketogenic diet for attempted seizure control. Surgical approaches included vagus nerve stimulators, functional hemispherectomy, and corpus callosotomy, but numbers were too limited to assess response. Nearly one-third of individuals received pharmacologic treatment for sleep disturbances, 13% for behavioral dysregulation and movement disorders, and 43% had gastrostomy tubes. Conclusions Treatment for neurologic features of CDD is currently symptom-based and empiric rather than CDD-specific, though clinical trials for CDD are emerging. Epilepsy in this population is highly refractory, and no specific anti-seizure medication was associated with improved seizure control. Ketogenic diet is commonly used in patients with CDD. While behavioral interventions are commonly instituted, information on the use of medications for sleep, behavioral management, and movement disorders is sparse and would benefit from further characterization and optimization of treatment approaches. The heterogeneity in treatment approaches highlights the need for systematic review and guidelines for CDD. Additional disease-specific and disease-modifying treatments are in development.

To conduct a systematic review of the literature regarding rates and predictors of favorable seizure outcome after resective surgery for epileptic spasms (ES) in pediatric patients. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses standards were followed. We searched PubMed, EMBASE, and Cochrane CENTRAL for articles published on the prevalence or incidence of epileptic spasm since 1985. Abstract, full‐text review, and data extraction were conducted by two independent reviewers. Meta‐analysis was performed to assess overall seizure freedom rate. Subject‐level analysis was performed on a subset of studies to identify prognostic indicators. A total of 21 retrospective studies (n = 531) were included. Meta‐analysis of all studies demonstrated a pooled seizure freedom rate of 68.8%. Subject‐level analysis on 18 studies (n = 360) demonstrated a significant association between duration of spasms and recurrence of spasms after surgery, with an estimated increased risk of 7% per additional year of spasms prior to operation. Patients who underwent resective surgery that was not a hemispherectomy (i.e., lobectomy, lesionectomy, etc.) had an increased recurrence risk of 57% compared to patients who had undergone hemispherectomy. Resective surgery results in seizure freedom for the majority of pediatric patients with epileptic spasms. Patients who undergo hemispherectomy have lower risk of recurrence than patients who undergo other types of surgical resection. Increased duration of spasms prior to surgery is associated with increased recurrence risk after surgery. Plain Language Summary: Children with epileptic spasms (ES) that do not respond to medications may benefit from surgical treatment. Our study reviewed existing research to understand how effective surgery is in treating ES in children and what factors predict better outcomes. Researchers followed strict guidelines to search for and analyze studies published since 1985, finding 21 studies with a total of 531 patients. They found that, on average, nearly 70% of children became seizure‐free after surgery. Further individual analysis of 360 patients showed that longer duration of spasms before surgery increased the risk of spasms returning by 7% per year. Additionally, children who had less extensive surgeries, such as removal of only a specific part of the brain, had a 57% higher risk of seizure recurrence compared to those who had a hemispherectomy, which removed or disconnected half of the brain. Overall, the study concludes that surgery can often stop seizures, especially when more extensive surgery is performed and when the surgery is done sooner rather than later. [ABSTRACT FROM AUTHOR]

Epileptic spasms are a unique, age-dependent manifestation of epilepsies in infancy and early childhood, commonly occurring as part of infantile epileptic spasms syndrome. Developmental stagnation and subsequent decline may occur in children with epileptic spasms, partly due to the abundant high-amplitude interictal epileptiform and slow wave abnormalities. Early recognition and treatment of epileptic spasms, along with the reversal of the electroencephalography (EEG) findings, are critical for improving outcomes. Recognizing hypsarrhythmia and its variations is key to confirming the diagnosis. The various patterns of hypsarrhythmia are not etiology specific, but could indicate the severity of the disease. Several scoring systems have been proposed to improve the inter-rater reliability of recognizing hypsarrhythmia and to assess EEG progress in response to treatment. Ictal patterns during spasms are brief and composed of slow waves, sharp transients, fast activity, and voltage attenuation, either in isolation or more commonly as a combination of these waveforms. Ictal patterns are commonly diffuse, but may be lateralized to one hemisphere in children with structural etiology. A subset of patients with epileptic spasms has a surgically remediable etiology, with readily identifiable lesions on neuroimaging in most cases. Asymmetry in epileptic spasms, concurrent focal seizures, and asymmetric interictal and ictal EEG findings may be present, but a lack of focality in electrophysiological findings is not uncommon. Intracranial EEG features of epileptic spasms have been described, but the utility of intracranial EEG monitoring in surgical candidates with overt focal epileptogenic lesions on magnetic resonance imaging is questionable, and surgery could be performed using noninvasive data. [ABSTRACT FROM AUTHOR]

Aim: To differentiate phenotypic features of individuals with CDKL5 deficiency disorder (CDD) from those of individuals with other infantile‐onset epilepsies. Method: We performed a retrospective cohort study and ascertained individuals with CDD and comparison individuals with infantile‐onset epilepsy who had epilepsy gene panel testing. We reviewed records, updated variant classifications, and compared phenotypic features. Wilcoxon rank‐sum tests and χ2 or Fisher's exact tests were performed for between‐cohort comparisons. Results: We identified 137 individuals with CDD (110 females, 80.3%; median age at last follow‐up 3 year 11 months) and 313 individuals with infantile‐onset epilepsies (156 females, 49.8%; median age at last follow‐up 5 years 2 months; 35% with genetic diagnosis). Features reported significantly more frequently in the CDD group than in the comparison cohort included developmental and epileptic encephalopathy (81% vs 66%), treatment‐resistant epilepsy (95% vs 71%), sequential seizures (46% vs 6%), epileptic spasms (66% vs 42%, with hypsarrhythmia in 30% vs 48%), regression (52% vs 29%), evolution to Lennox–Gastaut syndrome (23% vs 5%), diffuse hypotonia (72% vs 36%), stereotypies (69% vs 11%), paroxysmal movement disorders (29% vs 17%), cerebral visual impairment (94% vs 28%), and failure to thrive (38% vs 22%). Interpretation: CDD, compared with other suspected or confirmed genetic epilepsies presenting in the first year of life, is more often characterized by a combination of treatment‐resistant epilepsy, developmental and epileptic encephalopathy, sequential seizures, spasms without hypsarrhythmia, diffuse hypotonia, paroxysmal movement disorders, cerebral visual impairment, and failure to thrive. Defining core phenotypic characteristics will improve precision diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Children with leukemia are at risk for epilepsy due to primary disease or neurotoxic therapies. We describe the phenotypes of drug-resistant epilepsy in 10 children with history of leukemia.Of 10 cases, 6 had features of Lennox-Gastaut syndrome, and 4 had focal epilepsy. Mean age of epilepsy onset was 5 years in Lennox-Gastaut cases and 6.5 years in focal epilepsy cases. Mean latency between leukemia diagnosis and seizure onset was about 3 years. Brain MRI of 2 patients with epileptic encephalopathy had structural abnormalities – unclear if causative for epilepsy, and 4 had no overt structural abnormalities. In focal epilepsy group, 3 had temporal lobe epilepsy and one had fronto-temporal localization. All 10 patients had received intrathecal chemotherapy; 2 also had received whole brain irradiation. Seizures were poorly controlled in the epileptic encephalopathy group. Three underwent corpus callosotomy with variable response. Two patients with temporal lobe epilepsy had temporal lobectomy with Engel 1 outcome at 2 year follow-up in both.Two phenotypes of refractory epilepsy were observed in children with previous history of leukemia, focal epilepsy and epileptic encephalopathy. Children with temporal lobe epilepsy had good response to temporal lobectomy; response to palliative surgery was variable.

Objective: We aimed to assess the treatment response of infantile‐onset epileptic spasms (ES) in CDKL5 deficiency disorder (CDD) vs other etiologies. Methods: We evaluated patients with ES from the CDKL5 Centers of Excellence and the National Infantile Spasms Consortium (NISC), with onset from 2 months to 2 years, treated with adrenocorticotropic hormone (ACTH), oral corticosteroids, vigabatrin, and/or the ketogenic diet. We excluded children with tuberous sclerosis complex, trisomy 21, or unknown etiology with normal development because of known differential treatment responses. We compared the two cohorts for time to treatment and ES remission at 14 days and 3 months. Results: We evaluated 59 individuals with CDD (79% female, median ES onset 6 months) and 232 individuals from the NISC database (46% female, median onset 7 months). In the CDD cohort, seizures prior to ES were common (88%), and hypsarrhythmia and its variants were present at ES onset in 34%. Initial treatment with ACTH, oral corticosteroids, or vigabatrin started within 1 month of ES onset in 27 of 59 (46%) of the CDD cohort and 182 of 232 (78%) of the NISC cohort (p <.0001). Fourteen‐day clinical remission of ES was lower for the CDD group (26%, 7/27) than for the NISC cohort (58%, 106/182, p =.0002). Sustained ES remission at 3 months occurred in 1 of 27 (4%) of CDD patients vs 96 of 182 (53%) of the NISC cohort (p <.0001). Comparable results were observed with longer lead time (≥1 month) or prior treatment. Ketogenic diet, used within 3 months of ES onset, resulted in ES remission at 1 month, sustained at 3 months, in at least 2 of 13 (15%) individuals with CDD. Significance: Compared to the broad group of infants with ES, children with ES in the setting of CDD often experience longer lead time to treatment and respond poorly to standard treatments. Development of alternative treatments for ES in CDD is needed. [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to better understand the long‐term palliative and disease‐modifying effects of surgical resection beyond seizure freedom, including frequency reduction and both late recurrence and remission, in patients with drug‐resistant epilepsy. Methods: This retrospective database‐driven cohort study included all patients with >9 years of follow‐up at a single high‐volume epilepsy center. We included patients who underwent lobectomy, multilobar resection, or lesionectomies for drug‐resistant epilepsy; we excluded patients who underwent hemispherectomies. Our main outcomes were (1) reduction in frequency of disabling seizures (at 6 months, each year up to 9 years postoperatively, and at last follow‐up), (2) achievement of seizure remission (>6 months, >1 year, and longest duration), and (3) seizure freedom at last follow‐up. Results: We included 251 patients; 234 (93.2%) achieved 6 months and 232 (92.4%) experienced 1 year of seizure freedom. Of these, the average period of seizure freedom was 10.3 years. A total of 182 (72.5%) patients were seizure‐free at last follow‐up (defined as >1 year without seizures), with a median 11.9 years since remission. For patients not completely seizure‐free, the mean seizure frequency reduction at each time point was 76.2%, and ranged from 66.6% to 85.0%. Patients decreased their number of antiseizure medications on average by.58, and 53 (21.2%) patients were on no antiseizure medication at last follow‐up. Nearly half (47.1%) of those seizure‐free at last follow‐up were not seizure‐free immediately postoperatively. Significance: Patients who continue to have seizures after resection often have considerable reductions in seizure frequency, and many are able to achieve seizure freedom in a delayed manner. [ABSTRACT FROM AUTHOR]

In the present study, we determined the functional role of 15 positively charged amino acid residues at or within 1 of the predicted 11 transmembrane helixes of the flounder renal sodium-dicarboxylate cotransporter fNaDC-3. Using site-directed mutagenesis, histidine (H), lysine (K), and arginine (R) residues of fNaDC-3 were replaced by alanine (A), isoleucine (I), or leucine (L). Most mutants showed sodium-dependent, lithium-inhibitable [[sup.14]C]succinate uptake and, in two-electrode voltage-clamp (TEVC) experiments, [K.sub.m] and [DELTA]Imax values comparable to wild-type (WT) fNaDC-3. The replacement of R109 and R110 by alanine and isoleucine (RR109/110AI) prevented the expression of fNaDC-3 at the plasma membrane. When the lysines at positions 232 and 235 were replaced by isoleucine (KK232/235II), the transporter was expressed but showed small transport rates and succinate-induced currents. K1141, located within transmembrane helix 4, showed [[sup.14]C]succinate uptake similar to WT but relatively small inward currents. When K114 was replaced by arginine, glutamic acid (E), or glutamine (Q), all mutants were expressed at the cell surface. In [[sup.14]C]succinate uptake and TEVC experiments performed simultaneously on the same oocytes, uptake was similar to or higher than WT, whereas succinate-induced currents were either comparable (K114R) to, or considerably smaller (K114E, K1141, K114Q) than, those evoked by WT. These results suggest that a positively charged residue at position 114 is required for electrogenic sodium-dicarboxylate cotransport. sodium/dicarboxylate cotransport; electrogenicity; SLC13A3; mutational analysis; basic amino acids

The upper Turonian–Maastrichtian Kawagarh Formation represents a thick sequence of carbonates in the Kalachitta Range, Pakistan and it is the only stratigraphic record of Late Cretaceous sedimentation in northwestern Lesser Himalayas. Global sea-level marks a gradual fall of ∼40 to 50 m during the deposition of the Kawagarh Formation. This study is based on detailed outcrop and petrographic investigations of six stratigraphic sections exposed in Kalachitta Range. Carbonate grains are dominantly composed of pelecypods, oysters, trigonia and plankton distributed in a micritic groundmass. Five microfacies, (1) Planktonic Mudstone, Wackestone and Packstone Microfacies, (2) Pelecypodic Planktonic Mudstone and Wackestone Microfacies, (3) Pelecypodic Wackestone and Packstone Microfacies, (4) Marl Microfacies and (5) Dolostone Microfacies, were identified using distribution of faunal types and matrix. Based on faunal paleoecology, microfacies analysis and sedimentary structures, a shallow open-marine, northward-dipping ramp model has been proposed for the deposition of the Kawagarh Formation beginning with a transgressive cycle, which also corresponds to global sea-level rise, and possibly terminated by uplift owing to initial collision of the Indian Plate with the Kohistan-Ladakh Arc at the end of the Cretaceous. Paleontological and paleoecological evidence is used to develop a shallow, open-marine ramp deposition model for the Kawagarh Formation. The initiation of Kawagarh sedimentation with transgression in the late Turonian synchronise with global sea-level curve. Sedimentation was terminated by initial collision of the Indian Plate with the Kohistan-Ladakh Arc. [ABSTRACT FROM AUTHOR]

Background: coronary artery bypass surgery (CABG) is expensive, uses disposable appliances and patients require more perioperative intensive care, long stay in hospital and often have a lengthy recovery time. These complications, together with the growing trend towards less invasive techniques in other areas of surgery, have encouraged cardiac surgeons to see if minimally invasive cardiac surgery can become a reality with improved outcomes and costs. Methods: This is a prospective nonrandomized comparative clinical study done at the Department of Cardiac Surgery in National Institute of Cardiovascular Diseases (NICVD) Sher-E-Bangla Nagar, Dhaka from July 2006 to June 2008 among routine CABG patients. Purposive sampling was done with 26 patients in group A selected for MIDCAB and 24 patients in Group B selected for conventional CABG surgery. Patients were followed up for three months. Postoperative outcomes were assessed to evaluate the safety and efficacy of MIDCAB in relation to conventional CABG. Results: Mean age were 54.19 vs 53.87 in group A and Group B. 92.3% vs 87.5% were male respectively. Mean duration of operation, per operative blood loss transfusion and arrythmia were lower in MIDCAB group (p<0.05) number of grafts were also statistically significant (p< 0.001). Regarding post-operative outcome ventilation time in hours ICU stay post-operative hospital stay in days, postoperative MI and stroke rate were lower in favor of group A MIDCAB patients (p<0.001). Three months postoperatively six-meter walking distance is also statistically significant in favor of Group A MIDCAB (p<0.01) patients. However, pain score in early post-operative period was higher in group A significantly but it decreased significantly in late post-operative period which is also highly statistically different (p<0.001). However, mortality and quality of life at three months were similar in both groups. Conclusion: No difference in mortality rates detected between MIDCAB and CCABG group. But there was evidence that MIDCAB is associated with less perioperative and early postoperative morbidity and improved quality of life. The MIDCAB surgery is an effective procedure of complete revascularization in ischemic heart diseases like CCABG. The procedure is associated with shorter operating time, shorter ICU stay time, shorter hospital stays and better quality of life than for CCABG. [ABSTRACT FROM AUTHOR]

Problem-based learning (PBL) is one of the effective teaching strategies that motivate learners to understand physiological concepts at the Aga Khan University School of Nursing (AKUSON). At AKUSON, a number of programs are offered such as post-RN BSCN, generic BSCN, and diploma nursing. One of the important disciplines in the nursing curriculum is physiology, in which nurses require competency to work efficiently. A number of strategies are being used to teach physiology at AKUSON. This study was designed to explore the effectiveness of PBL in teaching physiology at AKUSON. The target group was year I students of the diploma nursing program. Sixty students were divided into two groups of thirty each randomly. One group received didactic instructions, and the other group was taught by the PBL approach. It was a comparative study, in which a quantitative/ qualitative approach was utilized for collecting data and the relevant information. The instrument consisted of a pretest and a posttest. The tests were administered to both groups simultaneously. The results of the study show that 86% students of the PBL group scored [is greater than] 50% marks in the posttest, whereas about 29% of students who were given didactic teaching scored [is greater than] 50% marks. This shows that PBL is an effective method of teaching physiology to the diploma nursing students.

Tailoring sub-bandgaps using intermediate states or bands with wide bandgap semiconductors is a promising and novel technique for the application in high efficiency solar cells. Pure and chromium (Cr) doped chalcopyrite CuGaS2 (CGS) thin films were prepared by facile chemical spray pyrolysis technique and annealed in vacuum, nitrogen and argon atmospheres. Structural characterization confirmed that the prepared films are in tetragonal chalcopyrite structure with polycrystalline nature. No secondary phases were present in both pure and Cr doped CGS thin films. Presence of Cr ions was confirmed by X-ray photoelectron spectroscopy and energy dispersive analysis of X-rays analyses. The optical direct and sub band gap of pristine and Cr doped CGS thin films were measured from UV absorption data. It was revealed that the pure CGS film has a band gap of 2.40 eV sub-band gap values were observed at 2.25 and 2.15 eV for 1 and 2 wt% of Cr doping, respectively. These gaps can be ascribed to the formation of intermediate bands due to hybridization of Cr d-states into the host electronic structure. Meanwhile, photoconductivity study demonstrated the photo-electric activity of the intermediate bands in the Cr doped thin films. [ABSTRACT FROM AUTHOR]

Summary: Objective: Detection of focal cortical dysplasia (FCD) is of paramount importance in epilepsy presurgical evaluation. Our study aims at utilizing quantitative positron emission tomography (QPET) analysis to complement magnetic resonance imaging (MRI) postprocessing by a morphometric analysis program (MAP) to facilitate automated identification of subtle FCD. Methods: We retrospectively included a consecutive cohort of surgical patients who had a negative preoperative MRI by radiology report. MAP was performed on T1‐weighted volumetric sequence and QPET was performed on PET/computed tomographic data, both with comparison to scanner‐specific normal databases. Concordance between MAP and QPET was assessed at a lobar level, and the significance of concordant QPET‐MAP+ abnormalities was confirmed by postresective seizure outcome and histopathology. QPET thresholds of standard deviations (SDs) of −1, −2, −3, and −4 were evaluated to identify the optimal threshold for QPET‐MAP analysis. Results: A total of 104 patients were included. When QPET thresholds of SD = −1, −2, and −3 were used, complete resection of the QPET‐MAP+ region was significantly associated with seizure‐free outcome when compared with the partial resection group (P = 0.023, P < 0.001, P = 0.006) or the no resection group (P = 0.002, P < 0.001, P = 0.001). The SD threshold of −2 showed the best combination of positive rate (55%), sensitivity (0.68), specificity (0.88), positive predictive value (0.88), and negative predictive value (0.69). Surgical pathology of the resected QPET‐MAP+ areas revealed mainly FCD type I. Multiple QPET‐MAP+ regions were present in 12% of the patients at SD = −2. Significance: Our study demonstrates a practical and effective approach to combine quantitative analyses of functional (QPET) and structural (MAP) imaging data to improve identification of subtle epileptic abnormalities. This approach can be readily adopted by epilepsy centers to improve postresective seizure outcomes for patients without apparent lesions on MRI. [ABSTRACT FROM AUTHOR]

Extensive literature and publications on intermediate band solar cells (IBSCs) are reviewed. A detailed discussion is given on the thermodynamics of solar energy conversion in IBSCs, the device physics, and the carrier dynamics processes with a particular emphasis on the two-step inter-subband absorption/recombination processes that are of paramount importance in a successful implementation high-efficiency IBSC. The experimental solar cell performance is further discussed, which has been recently demonstrated by using highly mismatched alloys and high-density quantum dot arrays and superlattice. IBSCs having widely different structures, materials, and spectral responses are also covered, as is the optimization of device parameters to achieve maximum performance. [ABSTRACT FROM AUTHOR]

Rock physics is a significant tool to describe lithologic characteristics of subsurface rock units. In the present study, seismic lines have been used to depict lithologic characteristics of Khewra Sandstone. Interval velocity was used to calculate elastic parameters. The study revealed that Vp/Vs ratio contour values indicate mixing of shale content increases and overall lithology is not clean sandstone. Bulk density indicates water saturation. Bulk modulus values and shear modulus range below typical sandstones. [ABSTRACT FROM AUTHOR]

Background: Acute lower extremity ischemia is a common vascular disease and considered limb- and life- threatening. The present study evaluated and compared the outcome of early and late surgical intervention in acute lower limb ischemia due to thromboembolism. Methodology: This non randomized comparative parallel study was conducted at the Department of Cardiovascular Surgery, NICVD, Dhaka, Bangladesh from January 2007 to December 2008 for duration of two year. Total 80 patients were enrolled in this study. The patients were divided into equal two groups, Group A, for early surgical intervention (with in 24 hours) and Group B, late surgical intervention (more than 24 hours). Results: Mean (±SD) age of both Group A and Group B was 51.93 (±11.73) and 47.00 (± 11.01) years. Male and female ratio of the total study population was 1.76:1 Pain and absence of pulse distal to occlusion was common for all. Cold extremity, sensory deficit, motor deficit, diminish vascular flow was the commonest findings of both group. In Group A, 57.5% had superficial femoral artery occlusion, 22.5% had iliac artery and 20.0% popliteal artery occlusion. In Group B, 42.5% had superficial femoral artery occlusion, 32.5% had popliteal artery occlusion and 25.0% had iliac artery occlusion. Fasciotomy was performed in 15.0% patients of Group A and in 22.0% patients of Group B. After Fogarty embolectomy in group A and group B had warm extremity (80.0% vs. 65.0%), pulsation distal to occlusion (90.0% vs. 75.0%), intact sensory function (82.5% vs. 67.5%), intact motor function (80.0% vs. 65.0%), and normal vascular flow by Doppler US (80.0% vs. 65.0%). During postoperative period history of bleeding, infection, reperfusion injury, muscle necrosis and limb amputation were 12.5% vs. 10.0%, 5.0% and 7.5%, 17.5% vs. 35.0%, 15.0% vs. 12.5% and 37.5% vs. 32.5% respectively. Conclusion: Duration of embolism may be the significant factor determining the outcomes of the management of acute arterial embolism in the lower extremities. The 24-hour duration of arterial embolism is a crucial factor influencing the surgical the management and early diagnosis and shifting of patients to specified centre as early as possible to save limb as well as life. [ABSTRACT FROM AUTHOR]