Cation disordering is commonly found in multinary cubic compounds, but its effect on electronic properties has been neglected because of difficulties in determining the ordered structure and defect ...energetics. An absence of rational understanding of the point defects present has led to poor reproducibility and uncontrolled conduction type. AgBiSe2 is a representative compound that suffers from poor reproducibility of thermoelectric properties, while the origins of its intrinsic n‐type conductivity remain speculative. Here, it is demonstrated that cation disordering is facilitated by BiAg charged antisite defects in cubic AgBiSe2 which also act as a principal donor defect that greatly controls the electronic properties. Using density functional theory calculations and in situ Raman spectroscopy, how saturation annealing with selenium vapor can stabilize p‐type conductivity in cubic AgBiSe2 alloyed with SnSe at high temperatures is elucidated. With stable and controlled hole concentration, a peak is observed in the weighted mobility and the density‐of‐states effective mass in AgBiSnSe3, implying an increased valley degeneracy in this system. These findings corroborate the importance of considering the defect energetics for exploring the dopability of ternary thermoelectric chalcogenides and engineering electronic bands by controlling self‐doping.
AgBiSe2‐based thermoelectric materials show poor p‐type dopability, but an underlying mechanism remains controversial. In this work, it is revealed that charged antisites are principal hole‐killer defects by density functional theory calculations, and that selenium vapor annealing is an effective strategy to effectively stabilize p‐type conductivity in AgBiSe2–SnSe solid solutions.
External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures. It was first performed as early as 1744 by Claude-Nicholas Le Cat. Since then, there have been ...numerous changes in technique, materials used, indications for the procedure, and safety. The history of EVD is best appreciated in 4 eras of progress: development of the technique (1850-1908), technological advancements (1927-1950), expansion of indications (1960-1995), and accuracy, training, and infection control (1995-present). While EVD was first attempted in the 18th century, it was not until 1890 that the first thorough report of EVD technique and outcomes was published by William Williams Keen. He was followed by H. Tillmanns, who described the technique that would be used for many years. Following this, many improvements were made to the EVD apparatus itself, including the addition of manometry by Adson and Lillie in 1927, and continued experimentation in cannulation/drainage materials. Technological advancements allowed a great expansion of indications for EVD, sparked by Nils Lundberg, who published a thorough analysis of the use of intracranial pressure (ICP) monitoring in patients with brain tumors in 1960. This led to the application of EVD and ICP monitoring in subarachnoid hemorrhage, Reye syndrome, and traumatic brain injury. Recent research in EVD has focused on improving the overall safety of the procedure, which has included the development of guidance-based systems, virtual reality simulators for trainees, and antibiotic-impregnated catheters.
A long-standing goal of spinal cord injury research is to develop effective repair strategies, which can restore motor and sensory functions to near-normal levels. Recent advances in clinical ...management of spinal cord injury have significantly improved the prognosis, survival rate and quality of life in patients with spinal cord injury. In addition, a significant progress in basic science research has unraveled the underlying cellular and molecular events of spinal cord injury. Such efforts enabled the development of pharmacologic agents, biomaterials and stem-cell based therapy. Despite these efforts, there is still no standard care to regenerate axons or restore function of silent axons in the injured spinal cord. These challenges led to an increased focus on another therapeutic approach, namely neuromodulation. In multiple animal models of spinal cord injury, epidural electrical stimulation of the spinal cord has demonstrated a recovery of motor function. Emerging evidence regarding the efficacy of epidural electrical stimulation has further expanded the potential of epidural electrical stimulation for treating patients with spinal cord injury. However, most clinical studies were conducted on a very small number of patients with a wide range of spinal cord injury. Thus, subsequent studies are essential to evaluate the therapeutic potential of epidural electrical stimulation for spinal cord injury and to optimize stimulation parameters. Here, we discuss cellular and molecular events that continue to damage the injured spinal cord and impede neurological recovery following spinal cord injury. We also discuss and summarize the animal and human studies that evaluated epidural electrical stimulation in spinal cord injury.
Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus (VIM) has proven to be efficacious in the treatment of essential tremor (ET). The authors report on long-term ...follow-up of a series of patients treated at 1 institution by 1 neurosurgeon.
Thirty-four patients with ET received unilateral or bilateral VIM DBS. The tremor and handwriting components of the Fahn-Tolosa-Marin clinical tremor rating scale were assessed pre- and postoperatively. Visual analog scale scores for overall patient satisfaction and tremor control were recorded. Stimulation parameters at different intervals after surgery were also recorded.
The average follow-up period was 56.9 months. The average tremor score improved from 3.27 preoperatively to 0.64 postoperatively (on stimulation; p < 0.001) and the average handwriting score improved from 2.94 to 0.89 (p < 0.001). The average visual analog scale score for overall satisfaction was 8.12 and for tremor control was 1.43. Overall, there was an 80.4% improvement in tremor and 69.7% improvement in handwriting. In 12 patients both tremor and handwriting scores were compared between 57.3 months and 90.7 months after surgery and no significant changes were discovered. Comparison of stimulation parameters at onset and at 1-3, 3-5, 5-7, and > 7 years after surgery showed significant differences, with a gradual increase in stimulation parameters within 5 years after surgery. The overall hardware-related complication rate was 23.5%.
Deep brain stimulation of the VIM is an efficient and safe treatment for ET. Tremor and handwriting improvements in long-term follow-up are stable. The patients' perception of their outcome is quite good. However, tolerance may develop in some patients requiring changes in stimulation parameters.
Object
Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus (VIM) has proven to be efficacious in the treatment of essential tremor (ET). The authors report on long-term ...follow-up of a series of patients treated at 1 institution by 1 neurosurgeon.
Methods
Thirty-four patients with ET received unilateral or bilateral VIM DBS. The tremor and handwriting components of the Fahn-Tolosa-Marin clinical tremor rating scale were assessed pre- and postoperatively. Visual analog scale scores for overall patient satisfaction and tremor control were recorded. Stimulation parameters at different intervals after surgery were also recorded.
Results
The average follow-up period was 56.9 months. The average tremor score improved from 3.27 preoperatively to 0.64 postoperatively (on stimulation; p < 0.001) and the average handwriting score improved from 2.94 to 0.89 (p < 0.001). The average visual analog scale score for overall satisfaction was 8.12 and for tremor control was 1.43. Overall, there was an 80.4% improvement in tremor and 69.7% improvement in handwriting. In 12 patients both tremor and handwriting scores were compared between 57.3 months and 90.7 months after surgery and no significant changes were discovered. Comparison of stimulation parameters at onset and at 1–3, 3–5, 5–7, and > 7 years after surgery showed significant differences, with a gradual increase in stimulation parameters within 5 years after surgery. The overall hardware-related complication rate was 23.5%.
Conclusions
Deep brain stimulation of the VIM is an efficient and safe treatment for ET. Tremor and handwriting improvements in long-term follow-up are stable. The patients' perception of their outcome is quite good. However, tolerance may develop in some patients requiring changes in stimulation parameters.
Incidental or intentional durotomy in spine surgery is associated with a risk of cerebrospinal fluid (CSF) leakage and reoperation. Several strategies have been introduced, but the incomplete closure ...is still relatively frequent and troublesome. In this study, we review current evidence on spinal dural repair strategies and evaluate their efficacy.
PubMed, Web of Science, and Scopus were used to search primary studies about the repair of the spinal dura with different techniques. Of 265 articles found, 11 studies, which specified repair techniques and postoperative outcomes, were included for qualitative and quantitative analysis. The primary outcomes were CSF leakage and postoperative infection.
The outcomes of different dural repair techniques were available in 776 cases. Pooled analysis of 11 studies demonstrated that the most commonly used technique was a combination of primary closure, patch or graft, and sealant (22.7%, 176/776). A combination of primary closure and patch or graft resulted in the lowest rate of CSF leakage (5.5%, 7/128). In this study, sealants as an adjunct to primary closure (13.7%, 18/131) did not significantly reduce the rate of CSF leakage compared with primary closure alone (17.6%, 18/102). The rates of infection and postoperative neurologic deficit were similar regardless of the repair techniques.
Although the use of sealants has become prevalent, available sealants as an adjunct to primary closure did not reduce the rate of CSF leakage compared with primary closure. The combination of primary closure and patches or grafts could be effective in decreasing postoperative CSF leakage.
Glioblastoma
GBM
is the most malignant brain tumor with profound genomic alterations. Tumor suppressor genes regulate multiple signaling networks that restrict cellular proliferation and present ...barriers to malignant transformation. While bona fide tumor suppressors such as
and
often undergo inactivation due to mutations, there are several genes for which genomic deletion is the primary route for tumor progression. To functionally identify putative tumor suppressors in GBM, we employed in vivo RNAi screening using patient-derived xenograft models. Here, we identified PIP4K2A, whose functional role and clinical relevance remain unexplored in GBM. We discovered that PIP4K2A negatively regulates phosphoinositide 3-kinase (PI3K) signaling via p85/p110 component degradation in
-deficient GBMs and specifically targets p85 for proteasome-mediated degradation. Overexpression of
suppressed cellular and clonogenic growth in vitro and impeded tumor growth in vivo. Our results unravel a novel tumor-suppressive role of PIP4K2A for the first time and support the feasibility of combining oncogenomics with in vivo RNAi screen.
Percutaneous endoscopic lumbar discectomy (PELD) presents a challenging learning curve, and the correlation between surgeon experience and clinical outcomes remains contentious. This retrospective ...study aimed to compare the outcomes of PELD performed by a single surgeon at beginner and experienced stages. Propensity score matching selected 150 patients (75 per group) with a minimum 3-year follow-up. Clinical and radiological outcomes, perioperative complications, and adverse events were assessed. Baseline characteristics, pain improvement, patient satisfaction, and radiological outcomes did not differ between the groups. However, operation time was longer in the beginner group than in the experienced group (57.5 min IQR, 50.0-70.0 versus 50.0 min IQR, 45.0-55.0,
< 0.001). The beginner group had higher perioperative complication rates (eight patients 10.7% versus one patient 1.3%, with a hazard ratio of 8.836 95% CI, 1.077-72.514,
= 0.034) and lower 3-year survival without adverse events (19 patients 25.3% in the beginner group and 10 patients 13.3% in the experienced group,
= 0.045). Our findings indicate that the clinical outcomes were more favorable in patients operated on at the experienced stage compared to those treated at the beginner stage.
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