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This research replaced the traditional hole source layers in a conventional LED with a tunnel junction. In conventional light-emitting diodes (LEDs) two hole injecting layers (p-GaN and p-AlxGa1-xN) have been used, in which holes have to surpass greater energy barriers that hindered holes injection. A heavily doped GaN tunnel junction (TJ) has been used as a replacement for conventionally used hole injection layers, which has reduced the energy barriers for holes and increased the electron confining ability of wells. As a result, the internal quantum efficiency (IQE) of the LED has increased from 52% to 72%. Instead of GaN TJ, Al0.10Ga0.90N – GaN hybrid tunnel junction (HTJ) has been introduced to lower the efficiency droop and raise the efficiency further to 81% simultaneously. Using TJ and HTJ, we have demonstrated that the conventional hole’s source layer can be replaced by TJs, which results in better hole injection because of reduced barrier height, increased electron confinement, greater electron–hole radiative recombination, and higher spontaneous emission intensity.

The continuous drive for miniaturization and enhanced functionality in micro-electronic devices demands highly integrated circuit (IC) packaging. This trend leads to a dense network of micro-electronic packaging interconnections, facilitated by the reduction in traditional solder interconnection sizes. However, these advancements bring about significant challenges, including thermal expansion differences between materials used in the package and the presence of non-planar substrates. Such issues can lead to thermomechanical stresses in interconnections and warpage, resulting in serious reliability issues. In response, nanostructured compliant interconnections have emerged as a promising solution. These interconnections effectively manage thermal expansion variations and substrate non-coplanarity, mitigating the risks associated with miniaturization and high integration demands in IC packaging. This review explores the latest trends and advancements in developing nanostructured compliant interconnections for modern micro-electronics. The focus is on integrating various interconnection materials, including nanoparticles (via sintering), nanoporous materials, nanowires (NWs) and carbon nanotubes (CNTs). This integration aims to improve the performance and mechanical reliability of interconnections under extreme thermal loading conditions. Advanced bonding techniques and their significant impacts on interconnection reliability are also discussed. Additionally, the study provides insights into future developments of nanostructured compliant interconnections, guiding researchers toward specific technical areas for future exploration.

Awake craniotomy (AC) allows intraoperative brain mapping (ioBM) for maximum lesion resection while monitoring and preserving neurological function. Conventionally, language, visuospatial assessment, and motor functions are mapped, while the assessment of executive functions (EF) is uncommon. Impaired EF may lead to occupational, personal, and social limitations, thus, a compromised quality of life. A comprehensive literature search was conducted through Scopus, Medline, and Cochrane Library using a pre-defined search strategy. Articles were selected after duplicate removal, initial screening, and full-text assessment. The demographic details, ioBM techniques, intraoperative tasks, and their assessments, the extent of resection (EOR), post-op EF and neurocognitive status, and feasibility and potential adverse effects of the procedure were reviewed. The correlations of tumor locations with intraoperative EF deficits were also assessed. A total of 13 studies with intraoperative EF assessment of 351 patients were reviewed. Awake-asleep-awake protocol was most commonly used. Most studies performed ioBM using bipolar stimulation, with a frequency of 60 Hz, pulse durations ranging 1–2 ms, and intensity ranging 2–6 mA. Cognitive function was monitored with the Stroop task, spatial-2-back test, line-bisection test, trail-making-task, and digit-span tests. All studies reported similar or better EOR in patients with ioBM for EF. When comparing the neuropsychological outcomes of patients with ioBM of EF to those without it, all studies reported significantly better EF preservation in ioBM groups. Most authors reported EF mapping as a feasible tool to obtain satisfactory outcomes. Adverse effects included intraoperative seizures which were easily controlled. AC with ioBM of EF is a safe, effective, and feasible technique that allows satisfactory EOR and improved neurocognitive outcomes with minimal adverse effects. [ABSTRACT FROM AUTHOR]

Purpose: To study the prescribing pattern of antibiotics in outpatients and emergency departments in the Gulf region. To compare the appropriateness of prescriptions and antibiotics commonly prescribed for respiratory tract infection.Method: The search was limited to the years 2008–2020, and articles had to be in English. Articles were searched from various resources and evaluated using PRISMA. Forty-one articles were selected and screened, and in the end, 17 articles were included in the study. All articles were selected from the gulf region of six countries: UAE, Saudi Arabia, Qatar, Oman, Yemen, and Bahrain. Only primary literature were included. Inpatient and literature from other countries outside the gulf region were excluded.Result: Penicillins, cephalosporins, and macrolides are highly useful antibiotics for respiratory tract infections. Ceftriaxone IV is recommended in acute respiratory tract infection if therapy with penicillin fails. Most of the antibiotic prescriptions in Gulf countries are inappropriate. Inappropriate antibiotic prescribing in the gulf region varies from place to place and reaches a maximum of 80%. Antibiotics may be prescribed with the wrong dosage or frequency and inappropriate guidelines. Penicillins are prescribed at about 50–60%; the most common penicillins prescribed are amoxicillin and co-amoxiclave. Cephalosporins are prescribed at about 30%, and the most common are third-generation. Macrolides are prescribed at about 17–20%, and the most common macrolides are azithromycin and clarithromycin. Fluoroquinolones are prescribed at about 10–12%, of which levofloxacin and ciprofloxacin are more commonly prescribed with metronidazole at 10%.Conclusion: It is suggested that the antibiotic-prescribing pattern in outpatient and emergency departments in the Gulf region are highly inappropriate and need improvement through education, following guidelines, annual vaccination, and stewardship programs; the most prescribed antibiotic is amoxicillin/co-amoxiclave, and the most often encountered infection in outpatients is acute respiratory tract infection.

Background: Growth hormone (GH)--secreting pituitary adenomas can be aggressive and difficult to manage. Surgical resection for GH-secreting tumors remains the gold standard with increasing use of expanded endoscopic endonasal (EEA) techniques. Certain anatomical considerations make postsurgical biochemical remission challenging. Case Description: We describe the case of a 43-year-old male presenting with acromegaly after a lack of biochemical remission from a previous surgery. Resection of the residual tumor invading the retrogenu compartment of the cavernous sinus was challenging for several reasons: (a) its location adjacent to the right parasellar horizontal internal carotid artery (ICA) with involvement of the medial wall, (b) the large kissing bilateral ICAs reducing the intercarotid distance, and (c) potential scar tissue. EEA was undertaken with key surgical steps, including wide bilateral sphenoidotomies, right middle clinoidectomy to access the clinoidal ICA and the retrogenu compartment, identification of the top of the paraclival ICA by drilling across the sella floor, division of the sellar floor dura to increase the intercarotid distance and transcavernous mobilization of medial wall, and the tumor capsule away from the horizontal parasellar ICA and across to the diaphragm and pituitary gland. Postoperatively, biochemical remission was achieved with no new endocrine deficits. Conclusion: These surgical nuances permit biochemical remission in complex revisional cases with acromegaly. [ABSTRACT FROM AUTHOR]

Background: Gliomas make up approximately 26.5% of all primary CNS tumors and 80.7% of malignant tumors. They are classified according to histology, location, and genetics. Grade III and IV gliomas are considered high-grade gliomas (HGGs). The cognitive signs and symptoms are attributed to mass defects depending on location, growth rapidity, and edema. Our purpose is to review the cognitive status of patients diagnosed with HGGs; the effect of treatments including surgical resection, radiotherapy, and chemotherapy; and the predictors of the cognitive status. Methods: We utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines as a template for the methodology. A comprehensive literature search was performed from three databases (PubMed, ScienceDirect, and Cochrane Library) for clinical trials and longitudinal studies on patients diagnosed with HGGs assessing their cognitive status. Results: Thirteen studies were selected among which 9 assessed cognitive function before and after treatment. One assessed the consistency of cognitive complaints and objective cognitive functioning. Three reported factors affecting disease progression and cognitive status. Most HGG patients have impairment in at least one cognitive domain. Treatments including surgical resection or radio-chemotherapy did not impair cognitive status. Discussion: The cognitive status could be used to assess sub-clinical tumor progression. Factors correlated to cognitive status were tumor location, edema, and grade. Patient characteristics correlated were pre-operative epilepsy, corticosteroid use, and age at the time of diagnosis. Conclusion: Assessment of the cognitive status of HGG patients indicates sub-clinical tumor progression and may be used to assess treatment outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Medulloblastoma (MB) is the most common malignant pediatric brain tumor. The mainstay of treatment is maximum surgical resection and craniospinal radiation, which may be followed by chemotherapy. The debilitating effect of the tumor and the intensive treatment approaches in MB lead to long-term neuropsychological, physical, and chronic medical problems. We conducted a systematic review to assess the quality of life (QoL) in the long-term survivors of MB and the factors leading to compromised QoL. Methods: We utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for our review. A comprehensive literature search was performed using PubMed, Cochrane Library, Digital Commons Network, and Wiley Online Library databases to search for articles having quality of life, medulloblastoma, and pediatric survivors in title or abstract. We removed duplicates and screened through titles, and full texts. Twelve articles were included in our study. Articles using and reporting all domains of PaedsQL were included in the meta-analysis. The PaedsQL scores of survivors and their caregivers were compared. Subgroup analysis was conducted for craniospinal and proton radiotherapy groups. Results: As compared to other posterior fossa tumors, MB survivors have the lowest QoL scores. There is a difference in the perception of QoL of survivors between caregivers and survivors themselves with survivors rating themselves higher in several domains. The overall PaedsQL scores were significantly different for both groups (p < 0.001). Subgroup analysis showed that the difference between those who were treated with craniospinal or proton radiation was not significant (p = 0.76). For the subscales, physical (p = 0.005), psychosocial (p = 0.0003), and school (p = 0.03) perceptions were significantly different for the survivors and their caregivers; however, psychosocial (p = 0.80) and emotional (p = 0.93) scales were not different for the survivors or caregivers. Patient characteristics related to a worse QoL included disease severity, metastatic disease, lesser family income, smaller current ventricle size, need for permanent hydrocephalus treatment, and lesser age at diagnosis. Conclusion: An analysis of various studies, using different measures of QoL, concludes that QoL is compromised in all pediatric survivors of MB; however, the perception of QoL of the survivors is better than objective or caretaker-rated QoL. [ABSTRACT FROM AUTHOR]

Background: Access to neuroimaging is limited in low-middle-income countries (LMICs) due to financial and resource constraints. A new, ultra-low-field, low-cost, and portable magnetic resonance imaging (pMRI) device could potentially increase access to imaging in LMICs. Case Description: We have presented the first brain tumor case scanned using an Ultra-low-field pMRI at Aga Khan University Hospital in Karachi, Pakistan. Conclusion: The imaging results suggest that the pMRI device can aid in neuroradiological diagnosis in resource-constrained settings. Further, research is needed to assess its compatibility for imaging other neurological disorders and compare its results with conventional MRI results. [ABSTRACT FROM AUTHOR]

Background: Intraoperative use of portable magnetic resonance imaging (pMRI) has become a valuable tool in a surgeon's arsenal since its inception. It allows intraoperative localization of tumor extent and identification of residual disease, hence maximizing tumor resection. Its utility has been widespread in high-income countries for the past 20 years, but in lower-middle-income countries (LMIC), it is still not widely available due to several reasons, including cost constraints. The use of intraoperative pMRI may be a cost-effective and efficient substitute for conventional MRI machines. The authors present a case where a pMRI device was used intraoperatively in an LMIC setting. Case Description: The authors performed a microscopic transsphenoidal resection of a sellar lesion with intraoperative imaging using the pMRI system on a 45-year-old man with a nonfunctioning pituitary macroadenoma. Without the need for an MRI suite or other MRI-compatible equipment, the scan was conducted within the confinements of a standard operating room. Low-field MRI showed some residual disease and postsurgical changes, comparable to postoperative high-field MRI. Conclusion: To the best of our knowledge, our report provides the first documented successful intraoperative transsphenoidal resection of a pituitary adenoma using an ultra-low-field pMRI device. The device can potentially enhance neurosurgical capacity in resource-constrained settings and improve patient outcomes in developing country. [ABSTRACT FROM AUTHOR]

Background: Glioblastoma is the most common primary malignant brain tumor with characteristic radiological features in most cases. Case Description: We highlight an unusual case of a 54-year-old woman, neurologically intact, with a diagnostically challenging lesion. The patient's magnetic resonance imaging revealed a left frontal lesion with surrounding edema and a hemosiderin ring, misleading it to be a cavernoma. Intraoperatively, the lesion was found to be a solid tumor with hematoma and was confirmed to be glioblastoma on histopathology. Conclusion: The dilemma associated with our patient's radiological findings and longstanding history of epilepsy is rare and a diagnostic challenge. [ABSTRACT FROM AUTHOR]

Background: Syndrome of trephined (SoT) is a well-recognized complication of decompressive craniectomy (DC). The understanding of SoT has improved more recently with the increasing utilization of DC for severely raised intracranial pressure. It usually presents after a period of weeks or months with a cluster of adverse neurological symptoms, most commonly with worsening of motor strength. Case Description: An elderly gentleman with traumatic brain injury underwent DC. He later developed a sinking flap and unexplained agitation which responded to cranioplasty by returning to a state of calm. His cognitive function further improved over a period of 6 months. This is an unusual observation reported in this case. Conclusion: Timely recognition of the cognitive complications of craniectomy that may respond to early cranioplasty promises to decrease the length of hospital stay and enhance rehabilitation in such patients. [ABSTRACT FROM AUTHOR]

Background: Primary melanocytic tumors of the central nervous system accounts for approximately 1% of all melanoma with a peak incidence in the fourth decade. The tumor originates from leptomeningeal melanocytes with a variable degree of belligerence. The proliferation of these melanocytes in large amounts in the dermis and nervous system can raise suspicion of neurocutaneous melanosis (NCM), which is an association between malignant melanoma and the presence of a giant intradermal nevus. Case Description: We present a case of a 62-year-old South Asian male with a large congenital melanocytic nevus (>20 cm in size) in the left hemifacial, and head region who presented with complaints of a single episode of grand-mal seizure followed by neuropsychiatric symptoms. The patient was thoroughly evaluated both clinically and surgically leading to a rare diagnosis of primary leptomeningeal melanoma of the left temporal lobe. The patient subsequently underwent a neuronavigation guided left temporal craniotomy with gross total resection of the lesion. Conclusion: Primary leptomeningeal melanoma with a clinical association with NCM is rarely ever reported within the literature. To date, our case is one of the very few instances where such an association is being reported in this age group along with rare neuropsychiatric symptoms. [ABSTRACT FROM AUTHOR]

Purpose: We hypothesize that lower grade gliomas (LGG) can be identified and classified into two distinct subtypes: radiologically circumscribed Lower-Grade Gliomas (cLGG) and infiltrating Lower-Grade Gliomas (iLGG) based on radiological parameters and that these two different subtypes behave differently in terms of clinical outcomes. Methods: We conducted a retrospective cohort study on surgical patients diagnosed with lower grade glioma over five years. Patient records and MRIs were reviewed, and neurosurgeons classified tumors into cLGG and iLGG groups. Results: From the 165 patients in our cohort, 30 (18.2%) patients were classified as cLGG and 135 (81.8%) patients were classified as iLGG Mean age in cLGG was 31.4 years while mean age in iLGG was 37.9 years (p = 0.004). There was significant difference in mean blood loss between cLGG and iLGG groups (270 and 411 ml respectively, p = 0.020). cLGG had a significantly higher proportion of grade II tumors (p

Cavernomas are vascular malformations that occur commonly in cerebrum, cerebellum, and brainstem, being rare in occurrence within the hypothalamus having only 29 cases known in the literature. They may be clinically asymptomatic or present with symptoms of headache, seizures, hemorrhage, or focal neurologic deficits. The gold standard for diagnosing a cavernoma is magnetic resonance imaging (MRI). The management strategies for hypothalamic cavernoma are expectant, medical, and surgical, along with laser ablation and radiosurgery. Our case is of a 17-years old female who presented with headache and reduced vision secondary to hypothalamic cavernoma on diagnostic imaging. She is on expectant management till date, without worsening of her symptoms. As per the literature, there has been no data on conservatively-managed hypothalamic hamartomas.

BackgroundMost cavernous malformations (CM) usually involve the parenchyma and rarely occur in cranial nerves. Recurrence of CM associated with cranial nerves after surgical resection has not been previously reported.Case descriptionThis paper describes the case of an 11-year-old girl who presented with left otalgia and headache because of a left trigeminal cavernous malformation. She underwent radical resection via a left retrosigmoid approach while sparing the trigeminal nerve. Surveillance imaging at 18 months demonstrated recurrence along the length of the trigeminal nerve into Meckel's cave with significant extension into the middle cerebellar peduncle. Subsequent re-operation via an extended middle fossa approach with anterior petrosectomy enabled complete resection with division of the trigeminal nerve. Postoperatively, she had a transient left facial paresis, and right hemiparesis that resolved within 48 h.ConclusionThis case highlights the importance of close postoperative surveillance in CM associated with cranial nerves as recurrence after nerve-sparing resection is possible. Surgical treatment due to the morphology of significant recurrence required the use of a complex skull base approach through a new corridor to achieve optimal clinical outcome.