Effect of supplementation of cryoprotectant solution with hydroxypropyl cellulose for vitrification of bovine oocytes.

BACKGROUND: Successful cryopreservation of bovine oocytes is very important for research and commercial applications. However, the survival and development rate of vitrified-thawed (VT) oocytes are lower than those of non-vitrified-thawed (non-VT) oocytes. OBJECTIVE: To investigate the effect of adding hydroxypropyl cellulose (HPC) to the vitrification solution for bovine oocytes. MATERIALS AND METHODS: For vitrification, bovine metaphase II oocytes were pretreated with a solution containing 10% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 5 min, exposed to a solution containing 30% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 30 s, and then directly plunged into liquid nitrogen. RESULTS: The survival rate of oocytes was significantly higher in the 50 HPC group than in the 0, 10, and 100 HPC groups. The reactive oxygen species level was lower in the non-VT and 50 HPC groups than in the other groups. The mRNA levels of proapoptotic genes (Bax) were lower in the non-VT, 0, and 50 HPC groups than in the other groups. The mRNA levels of antiapoptotic genes (BCl2) were higher in the non-VT than in the other groups. The development rates of embryos (day 8) obtained via parthenogenetic activation (PA) were determined in the non-VT, 0 HPC, and 50 HPC groups. The cleavage rate was significantly higher in the non-VT group. CONCLUSION: Supplementation of vitrification solution with HPC improves the survival of VT bovine oocytes and the development capacity of embryos derived from these oocytes via PA. doi.org/10.54680/fr23110110212.

Long-term outcomes of early stage oral tongue cancer: Main cause of treatment failure and second primary malignancy.

Objective: We attempted to investigate the long-term outcomes, prognostic factors, treatment failures, second primary malignancies, and salvage therapies in early (pT1-2N0) oral tongue squamous cell carcinoma (OTSCC). Methods: We retrospectively analyzed the medical records of 295 early stage OTSCC patients. Results: Two hundred ninety-five patients were enrolled. The average follow-up period was 64.5 months (range, 1-190 months). Five-year recurrence-free survival rate was 84.8% and disease-specific survival rate was 91.2%. On multivariate analysis, only the depth of invasion (DOI) exhibited significant correlations with the disease recurrence. Patient's age and DOI demonstrated a significant association with survival. A total of 53 recurrence and 35 death events occurred, with the main cause of treatment failure being regional or local recurrence. In recurrent cases, the success rate of salvage treatment was 42% at 5 years. During the follow-up period, second primary malignancy occurred in 13 patients, and 8 (61.5%) of those patients were successfully treated. Conclusions: In pT1-2N0 OTSCC, regional or local recurrence is the main recurrence pattern, whereas age and DOI >5 mm are significant prognostic factors related to recurrence and survival. Since several patients experienced second primary malignancies in the head and neck, careful and thorough surveillance may be required to detect second primary lesions. Level of Evidence: 4.

Dataset for influence of visual and haptic feedback on the detection of threshold forces in a surgical grasping task.

The data is related to minimal force thresholds perception in robotic surgical grasping applications. The experimental setup included an indenter-based haptic device acting on the fingertip of a participant and a visual system that displays grasping tasks by a surgical grasper. The experiments included the display of two presentations at different force levels (i.e., grasping and indentation) in three different modes, namely, visual-alone, haptic-alone, and bimodal (i.e., combined). For each mode, the participants were asked to identify which of the two presentations was higher. Each experiment was repeated till the termination conditions were met. Sixty participants took part in these experiments. The experiments were randomized and the threshold forces were calculated based on an algorthim. The datasets contain the individual responses of each participant, the threshold forces calculations, and the number of iterations.

Upgrading the LANSCE accelerator with a SNS RF-driven H- ion source.

The LANSCE accelerator is currently powered by a filament-driven, biased converter-type H- ion source that operates at 10%, the highest plasma duty factor for this type of source, using only ∼2.2 SCCM of H2. The ion source needs to be replaced every 4 weeks, which takes up to 4 days. The measured negative beam current of 12-16 mA falls below the desired 24 mA acceptance of the LANCSE accelerator. The SNS (Spallation Neutron Source) RF-driven, H- ion source injects ∼50 mA of H- beam into the SNS accelerator at 60 Hz with a 6% duty factor and an availability of >99.5% but requires ∼30 SCCM of H2. Up to 7 A h of H- have been produced during the 14-weeks-long source service cycles, which is unprecedented for small emittance, high-current, pulsed H- ion sources. The emittance of the SNS source is slightly smaller than the emittance of the LANSCE source. The SNS source also features unrivaled low Cs consumption and can be installed and started up in <12 h. LANSCE and SNS are working toward the use of SNS H- ion sources on the LANSCE accelerator because they could (a) fill the LANSCE accelerator to its capacity, (b) decrease the source replacement time by a factor of up to 7, and (c) increase source lifetime by a factor of about 4. This paper discusses some of the challenges that emerge when trying to match a different H- source into an existing injector with significantly different characteristics and operating regimes.

Pretreatment Anterior Choroidal Artery Infarction Predicts Poor Outcome after Thrombectomy in Intracranial ICA Occlusion.

BACKGROUND AND PURPOSE: Predictors of outcome after endovascular thrombectomy have not been investigated adequately in patients with intracranial ICA occlusions. This study aimed to assess the impact of anterior choroidal artery infarction in pretreatment DWI on the outcome of patients with acute intracranial ICA occlusion who underwent thrombectomy. MATERIALS AND METHODS: This study included 113 patients with acute intracranial ICA occlusion who underwent DWI followed by thrombectomy between January 2011 and July 2016. Characteristics and outcomes were compared between the groups positive and negative for anterior choroidal artery infarction and patients with good outcomes (90-day mRS 0-2) and poor outcomes (mRS 3-6). Binary logistic regression analyses were performed to identify independent predictors of a good outcome. RESULTS: On pretreatment DWI, anterior choroidal artery infarction was observed in 60 patients (53.1%). Good outcomes were significantly less frequent in the group positive for anterior choroidal artery infarction than in the group negative for it (25% versus 49.1%, P = .008). Parenchymal hemorrhage occurred only in the group positive for anterior choroidal artery infarction (13.3% versus 0%, P = .007). In the multivariate logistic regression analysis, independent predictors of good outcome were an absence of anterior choroidal artery infarction (OR, 0.333; 95% CI, 0.135-0.824; P = .017) and successful reperfusion (OR, 5.598; 95% CI, 1.135-27.604; P = .034). CONCLUSIONS: Pretreatment anterior choroidal artery infarction is associated with parenchymal hemorrhage and poor outcome after thrombectomy in patients with acute intracranial ICA occlusion. In addition, the absence of anterior choroidal artery infarction and successful reperfusion were independent predictors of good outcome after thrombectomy in acute intracranial ICA occlusion.

Energy calibration of high-resolution X-Ray TES microcalorimeters with 3 eV optical photons.

With the improving energy resolution of transitionedge sensor (TES) based microcalorimeters, performance verification and calibration of these detectors has become increasingly challenging, especially in the energy range below 1 keV where fluorescent atomic X-ray lines have linewidths that are wider than the detector energy resolution and require impractically high statistics to determine the gain and deconvolve the instrumental profile. Better behaved calibration sources such as grating monochromators are too cumbersome for space missions and are difficult to use in the lab. As an alternative, we are exploring the use of pulses of 3 eV optical photons delivered by an optical fiber to generate combs of known energies with known arrival times. Here, we discuss initial results of this technique obtained with 2 eV and 0.7 eV resolution X-ray microcalorimeters. With the 2 eV detector, we have achieved photon number resolution for pulses with mean photon number up to 133 (corresponding to 0.4 keV).

Transoral thyroidectomy with a next generation flexible robotic system: A feasibility study in a cadaveric model.

BACKGROUND: Transoral endoscopic thyroidectomy provides access via the oral vestibule and gas insufflation to provide reliable remote access surgery to perform a total thyroidectomy. The da Vinci SP (Intuitive Surgical Inc., Sunnyvale, CA, USA) is a next generation flexible single port system that offers unique advantages over previous robotic rigid systems. Here we sought to evaluate the feasibility of performing transoral thyroidectomy with this next generation flexible robotic system. METHODS: Cadaveric dissection with gas insufflation to test the feasibility of performing transoral thyroidectomy with the da Vinci SP. RESULTS: A 2 cm incision was made in the oral vestibule and the working space created with a 1cm central port and two lateral 5 mm ports. Then an extra small wound protector (Applied Medical, Rancho Santa Margarita, CA) was placed through the central incision after closure of the 5 mm ports. The robotic system was then deployed through the wound protector while insufflation was maintained at ~6 mmHg. Three instrument arms were deployed. A fenestrated bipolar was used to grasp the thyroid gland while Maryland bipolars and monopolar scissors were used to mobilize each hemi lobe of the thyroid. The recurrent laryngeal nerves were seen and preserved bilaterally. After completion of the surgery and removal of the wound protector the vestibular incision was measured to be 3 cm. Further dissection to identify the mental nerves identified each nerve to be >1 cm from the lateral extent of the central incision. CONCLUSIONS: In summary, it is feasible to perform a total thyroidectomy with gas insufflation utilizing this next generation flexible robotic system. Further evaluation will be needed to validate the clinical applicability of this technique.

Therapeutic advantage of genetically engineered Salmonella typhimurium carrying short hairpin RNA against inhibin alpha subunit in cancer treatment.

Background: In contrast to its well-known endocrine function, the role of inhibin in cancer development and therapeutic response is unclear. Salmonella, particularly less toxic attenuated Salmonella strains, are used to treat cancer in two ways. First, Salmonella accumulate around tumors, penetrate the cell barrier, and replicate inside the tumors. Second, Salmonella can act as a vehicle for delivering anticancer agents or proapoptotic genes to attack tumors. In this study, we aimed to develop a suitable cancer therapeutic strategy by genetically modifying attenuated Salmonella typhimurium to harbor short hairpin RNA (shRNA) expression plasmids targeting alpha subunit of inhibin (sh-INHA). Methods: We analyzed the expression of human INHA in normal and cancer cells and tissues. We developed genetically engineered attenuated S. typhimurium harboring sh-INHA (S. typhimurium/sh-INHA) and assessed its cancer therapeutic effects by using cell culture models and syngeneic mouse tumor models. Results: INHA expression levels were markedly higher in colon cancer and melanoma cells and tissues than in their normal counterparts. Suppression of INHA expression mildly reduced cancer cell survival and induced caspase activation and downregulation of anti-apoptotic Bcl-2 and Bcl-xL expressions. Although the genetically engineered S. typhimurium mildly interfered with the invasion of S. typhimurium into host colon cancer and melanoma cells, S. typhimurium/sh-INHA caused remarkable cytotoxicity in cancer compared with unmodified S. typhimurium or S. typhimurium expressing a control scrambled shRNA (S. typhimurium/sh-Cont). Salmonella typhimurium/sh-INHA-treated mice also showed a significantly inhibited growth of colon cancers and melanomas, with a survival advantage. Conclusion: Our results suggest that tumor-targeted therapy using S. typhimurium/sh-INHA may provide a novel cancer treatment option.

The association between serum uric acid and asymptomatic intracranial arterial stenosis in middle-aged Koreans.

BACKGROUND AND AIMS: Intracranial arterial stenosis (ICAS) is one of the most common causes of stroke, especially in Asians. Hyperuricemia has been associated with an increased risk of comorbidities such as metabolic syndrome or cardiovascular diseases. However, there are few studies focusing on the association between serum uric acid (SUA) levels and asymptomatic ICAS. The aim of this study was to explore the association between SUA and the prevalence of ICAS in middle-aged Korean health screening examinees. METHODS AND RESULTS: A cross-sectional study was performed on 9417 males and 7755 females who underwent a comprehensive health examination including transcranial Doppler (TCD) ultrasonography. The association of SUA and ICAS was analyzed using multivariate logistic regression. The prevalence of ICAS among the total examinee population was 3.55%. In females, the multivariate-adjusted odds ratio for ICAS was 1.52 (confidence interval 1.13-2.04) in the 3rd quartile of SUA and 1.45 (1.05-2.00) in the highest quartile, compared to the reference (P for trend 0.008). This trend was evident in all clinically relevant subgroups evaluated, including women with low inflammation status. SUA was not significantly associated with the prevalence of ICAS among males. In a sensitivity analysis, the multivariate-adjusted odds ratio of middle cerebral artery stenosis in females was 1.60 (1.09-2.37) in the highest quartile compared to the reference (P for trend 0.023). CONCLUSIONS: Higher SUA level was associated with increased risk of ICAS among middle-aged females but not males. A further cohort study is warranted to elucidate the effect of SUA on asymptomatic ICAS.

Mapping TES Temperature Sensitivity and Current Sensitivity as a Function of Temperature, Current, and Magnetic Field with IV curve and Complex Admittance Measurements.

We have specialized astronomical applications for X-ray microcalorimeters with superconducting transition edge sensors (TESs) that require exceptionally good TES performance, but which operate in the small-signal regime. We have therefore begun a program to carefully characterize the entire transition surface of TESs with and without the usual zebra stripes to see if there are reproducible local "sweet spots" where the performance is much better than average. These measurements require precise knowledge of the circuit parameters. Here, we show how the Shapiro effect can be used to precisely calibrate the value of the shunt-resistor. We are also investigating the effects of stress and external magnetic fields to better understand reproducibility problems.

Evaluation of cardiopulmonary and inflammatory markers in dogs with heartworm infection treated using the slow kill method.

This study evaluated the changes in the levels of cardiac, hemostatic, and inflammatory biomarkers in 12 dogs with different severities of heartworm infection treated using the slow kill protocol, consisting of 6-10µg/kg of ivermectin and 10mg/kg of doxycycline combination. The serum levels of cardiac troponin-I, D-dimer, C-reactive protein, and interleukin-6 were measured on the day of diagnosis (D0), after termination of doxycycline administration (D30), after termination of the slow kill treatment (D180), and 10 months after the initiation of therapy (D300). Heartworm antigenemia was cleared in 4/4 class I dogs, 3/4 class II dogs, and 1/4 class III dogs at the end of the therapy (D180), and in 4/4 class I, 4/4 class II, and 1/4 class III dogs at the end of the study (D300). The serum levels of the markers in class I dogs on the day of diagnosis (D0) were within the reference range, while the levels in class II and III dogs were above the reference range. Further, the serum levels of the markers in all dogs decreased significantly at the end of the study (D300), although some markers in class III dogs remained at pathological levels. This study revealed that the slow kill method should be used only as an alternative therapeutic protocol for dogs with low worm burden (class I and II). As the slow kill method alone may not effectively reduce all pathological changes in dogs with heavy worm burden and severe clinical signs (class III), adjuvant therapies including steroids and anti-thromboembolics should be used to minimize the risk of complications.

Fabrication of X-ray Microcalorimeter Focal Planes Composed of Two Distinct Pixel Types.

We are developing superconducting transition-edge sensor (TES) microcalorimeter focal planes for versatility in meeting specifications of X-ray imaging spectrometers including high count-rate, high energy resolution, and large field-of-view. In particular, a focal plane composed of two sub-arrays: one of fine-pitch, high count-rate devices and the other of slower, larger pixels with similar energy resolution, offers promise for the next generation of astrophysics instruments, such as the X-ray Integral Field Unit (X-IFU) instrument on the European Space Agency's Athena mission. We have based the sub-arrays of our current design on successful pixel designs that have been demonstrated separately. Pixels with an all gold X-ray absorber on 50 and 75 micron scales where the Mo/Au TES sits atop a thick metal heatsinking layer have shown high resolution and can accommodate high count-rates. The demonstrated larger pixels use a silicon nitride membrane for thermal isolation, thinner Au and an added bismuth layer in a 250 micron square absorber. To tune the parameters of each sub-array requires merging the fabrication processes of the two detector types. We present the fabrication process for dual production of different X-ray absorbers on the same substrate, thick Au on the small pixels and thinner Au with a Bi capping layer on the larger pixels to tune their heat capacities. The process requires multiple electroplating and etching steps, but the absorbers are defined in a single ion milling step. We demonstrate methods for integrating heatsinking of the two types of pixel into the same focal plane consistent with the requirements for each sub-array, including the limiting of thermal crosstalk. We also discuss fabrication process modifications for tuning the intrinsic transition temperature (Tc) of the bilayers for the different device types through variation of the bilayer thicknesses. The latest results on these "hybrid" arrays will be presented.

Acute Basilar Artery Occlusion: Differences in Characteristics and Outcomes after Endovascular Therapy between Patients with and without Underlying Severe Atherosclerotic Stenosis.

BACKGROUND AND PURPOSE: Prediction of underlying intracranial atherosclerotic stenosis before endovascular therapy might be helpful for appropriate therapeutic planning in patients with acute ischemic stroke. This study aimed to compare the characteristics and treatment outcomes in patients with acute basilar artery occlusion relative to the existence or nonexistence of underlying intracranial atherosclerotic stenosis. MATERIALS AND METHODS: Sixty-two patients with acute basilar artery occlusion underwent multimodal endovascular therapy. All patients underwent stent-retriever thrombectomy as a first-line endovascular therapy. Patients with underlying intracranial atherosclerotic stenosis underwent additional intracranial angioplasty and stent placement. The clinical and imaging characteristics and treatment outcomes were retrospectively analyzed and compared between patients with and without intracranial atherosclerotic stenosis. RESULTS: Underlying intracranial atherosclerotic stenosis was identified at the occlusion site in 15 patients (24.1%). Occlusion in the proximal segment of the basilar artery was more common in patients with intracranial atherosclerotic stenosis (60% versus 6.4%, P < .001), whereas occlusion in the distal segment was more common in those without it (91.5% versus 26.7%, P < .001). Bilateral thalamic infarction on a pretreatment DWI was less common in patients with intracranial atherosclerotic stenosis (0% versus 27.7%, P = .027) compared with those without it. There were no significant differences in the rates of successful revascularization, favorable outcome, symptomatic hemorrhage, and mortality between the 2 groups. CONCLUSIONS: Underlying intracranial atherosclerotic stenosis was not uncommon in patients with acute basilar artery occlusion. The occlusion segment of the basilar artery and the presence or absence of bilateral thalamic infarction on a pretreatment DWI might be helpful for predicting underlying intracranial atherosclerotic stenosis in patients with acute basilar artery occlusion. Patients with and without underlying intracranial atherosclerotic stenosis who underwent endovascular therapy had similar outcomes.

Metal diffusion barriers for GaAs solar cells.

In this study accelerated ageing testing (AAT), J-V characterization and TEM imaging in combination with phase diagram data from literature are used to assess the potential of Ti, Ni, Pd and Pt as diffusion barriers for Au/Cu-based metallization of III-V solar cells. Ni barriers show the largest potential as at an AAT temperature of 250 °C both cells with 10 and 100 nm thick Ni barriers show significantly better performance compared to Au/Cu cells, with the cells with 10 nm Ni barriers even showing virtually no degradation after 7.5 days at 250 °C (equivalent to 10 years at 100 °C at an Ea of 0.70 eV). Detailed investigation shows that Ni does not act as a barrier in the classical sense, i.e. preventing diffusion of Cu and Au across the barrier. Instead Ni modifies or slows down the interactions taking place during device degradation and thus effectively acts as an 'interaction' barrier. Different interactions occur at temperatures below and above 250 °C and for thin (10 nm) and thick (100 nm) barriers. The results of this study indicate that 10-100 nm thick Ni intermediate layers in the Cu/Au based metallization of III-V solar cells may be beneficial to improve the device stability upon exposure to elevated temperatures.

Does pre-operative magnetic resonance imaging of the lumbar multifidus muscle predict clinical outcomes following lumbar spinal decompression for symptomatic spinal stenosis?

PURPOSE: To investigate whether pre-operative magnetic resonance imaging (MRI) of the lumbar multifidus muscle (LMM) would predict clinical outcomes following lumbar spinal decompression for symptomatic spinal stenosis. METHODS: A prospective cohort of patients with symptomatic neurogenic claudication, documented spinal stenosis on pre-operative MRI underwent spinal decompression. All subjects completed standardised outcome measures (Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI v2.1) pre-operatively, 1 and 2 years post-surgery. Surgery was performed using a standardised lumbar spinous process osteotomy for access, followed by a decompression of the central canal, lateral recess and foraminal zones as indicated by the pre-operative MRI. Lumbar MRI scans were evaluated by two independent observers who assessed the axial CSA of the LMM bilaterally and the degree of muscle atrophy according to the Kader classification (2000). Changes in COMI and ODI scores at 1 and 2 years were investigated for statistically significant correlations with CSA of LMM and Kader grading. Statistical analyses utilised Student's t test, kappa coefficient for inter-observer agreement and Bland-Altman Limits of Agreement (BALOA). RESULTS: 66 patients (41 female) aged between 29 and 86 years underwent single-level decompression in 44, two-level decompression in 16 and three-level decompression in 6 cases. No significant correlation was observed between improvements in ODI and COMI relative to age, degree of stenosis, posterior fat thickness or psoas CSA. Those subjects with the greatest LMM atrophy relative to psoas CSA and L5 vertebral body area on pre-operative MRI had the least absolute improvement in both ODI and COMI scores (p = 0.006). CONCLUSIONS: Reduced LMM CSA (<8.5 cm2) and muscle atrophy were associated with less favourable outcomes following lumbar spinal decompression. Pre-operative CSA of LMM appeared to be a more reliable predictor of post-operative clinical outcomes compared to the Kader Grading Score. This is the first study to investigate the prognostic value of pre-operative MRI appearance and CSA of LMM with respect to post-operative outcome following lumbar decompression surgery. Healthy pre-operative LMM is associated with better outcomes following lumbar spinal decompression.

Impact of paraaortic lymphadenectomy for endometrial cancer with positive pelvic lymph nodes: A Korean Radiation Oncology Group study (KROG 13-17).

AIM: We investigated the role of paraaortic lymph node dissection (PALND) in patients with stage IIIC1 endometrial carcinoma after surgery followed by adjuvant radiotherapy (RT) alone or chemoradiotherapy (CTRT). METHODS: We performed a subgroup analysis in 151 patients treated with adjuvant pelvic RT. Paraaortic-recurrence free survival, disease-free survival (DFS) and overall survival (OS) were analyzed. RESULTS: In adjuvant RT alone, PALND was significantly related to reduced risk of paraaortic recurrence (0% vs. 17.1%) and distant metastasis (4.5% vs. 19.5%) compared with the no PALND group. PALND affected 5-year DFS (90.2% vs. 58.9%, p = 0.016) and OS (100% vs. 83.1%, p = 0.022). For the CTRT group, the paraaortic recurrence rate was 19.5% for the no PALND group and 12.8% for the PALND group (p = 0.682). Of patients who underwent PALND in the CTRT group, less extensive PALND was significantly related to increased paraaortic recurrence (≤10 vs. >10 dissected LNs, 17.1% vs. 0%). In the no PALND group (n = 82), 5-year paraaortic-recurrence free survival was 79.4% for the CTRT group and 76.2% for the RT alone group (p = 0.941). In multivariate analysis, PALND was significantly associated with reduced risk of disease-specific death (HR, 0.50; 95% CI, 0.26-0.96; p = 0.037). CONCLUSION: PALND provided excellent paraaortic control and improved outcome in stage IIIC1 endometrial cancer with favorable tumor features treated with adjuvant RT alone. Less extensive PALND was associated with significantly increased paraaortic recurrence in patients with advanced tumor features treated with adjuvant CTRT. Combined CTRT did not affect disease control in the paraaortic region compared with RT alone.

Thalamic Visual Prosthesis.

Glaucoma is a neurological disorder leading to blindness initially through the loss of retinal ganglion cells, followed by loss of neurons higher in the visual system. Some work has been undertaken to develop prostheses for glaucoma patients targeting tissues along the visual pathway, including the lateral geniculate nucleus (LGN) of the thalamus, but especially the visual cortex. This review makes the case for a visual prosthesis that targets the LGN. The compact nature and orderly structure of this nucleus make it a potentially better target to restore vision than the visual cortex. Existing research for the development of a thalamic visual prosthesis will be discussed along with the gaps that need to be addressed before such a technology could be applied clinically, as well as the challenge posed by the loss of LGN neurons as glaucoma progresses.

Incidence and Clinical Significance of Acute Reocclusion after Emergent Angioplasty or Stenting for Underlying Intracranial Stenosis in Patients with Acute Stroke.

BACKGROUND AND PURPOSE: A major concern after emergent intracranial angioplasty in cases of acute stroke with underlying intracranial stenosis is the acute reocclusion of the treated arteries. This study reports the incidence and clinical outcomes of acute reocclusion of arteries following emergent intracranial angioplasty with or without stent placement for the management of patients with acute stroke with underlying intracranial atherosclerotic stenosis. MATERIALS AND METHODS: Forty-six patients with acute stroke received emergent intracranial angioplasty with or without stent placement for intracranial atherosclerotic stenosis and underwent follow-up head CTA. Acute reocclusion was defined as "hypoattenuation" within an arterial segment with discrete discontinuation of the arterial contrast column, both proximal and distal to the hypoattenuated lesion, on CTA performed before discharge. Angioplasty was defined as "suboptimal" if a residual stenosis of ≥50% was detected on the postprocedural angiography. Clinical and radiologic data of patients with and without reocclusion were compared. RESULTS: Of the 46 patients, 29 and 17 underwent angioplasty with and without stent placement, respectively. Acute reocclusion was observed in 6 patients (13%) and was more frequent among those with suboptimal angioplasty than among those without it (71.4% versus 2.6%, P < .001). The relative risk of acute reocclusion in patients with suboptimal angioplasty was 27.857 (95% confidence interval, 3.806-203.911). Furthermore, a good outcome was significantly less frequent in patients with acute reocclusion than in those without it (16.7% versus 67.5%, P = .028). CONCLUSIONS: Acute reocclusion of treated arteries was common after emergent intracranial angioplasty with or without stent placement in patients with acute stroke with intracranial atherosclerotic stenosis and was associated with a poor outcome. Suboptimal results of angioplasty appear to be associated with acute reocclusion, irrespective of whether stent placement was performed.

Degradation mechanism(s) of GaAs solar cells with Cu contacts.

Substrate-based GaAs solar cells having a dense Au/Cu front contact grid with 45% surface coverage were exposed to accelerated life testing at temperatures between 200 and 300 °C. TEM analysis of the front contacts was used to gain a better understanding of the degradation process. During accelerated life testing at 200 °C only intermixing of the Au and Cu in the front contact occurs, without any significant influence on the J-V curve of the cells, even after 1320 h (55 days) of accelerated life testing. At temperatures ≥250 °C a recrystallization process occurs in which the metals of the contact and the GaAs front contact layer interact. Once the grainy recrystallized layer starts to approach the window, diffusion via grain boundaries to the window and into the active region of the solar cells occurs, causing a decrease in Voc due to enhanced non-radiative recombination via Cu trap levels introduced in the active region of the solar cell. To be a valid simulation of space conditions the accelerated life testing temperature should be <250 °C in future experiments, in order to avoid recrystallization of the metals with the GaAs contact layer.