Complex anisotropy ratio of third harmonic generation in a semiconductor using a terahertz free electron laser.

The nonlinear susceptibility in the terahertz region is expected to have a non-negligible imaginary part originating from the momentum-dependent scattering time of free carriers, but it has been scarcely reported. By utilizing an intense 4 THz beam from a terahertz free electron laser, we investigated the azimuth angle dependence of the third harmonic generation (THG) from semiconductors. The observed angular anisotropy of THG revealed the contribution of the imaginary part of the nonlinear susceptibility originating from the momentum-scattering time relation in addition to its real part originating from the band nonparabolicity. The results provide a deeper understanding of nonlinear optics in the terahertz region.

Evaluation of partial resheathing of EmboTrap III using the microcatheter (PREMIER) technique for fibrin-rich hard clots in an in vitro vessel model.

Background and purpose: Despite the ongoing advancements in mechanical thrombectomy for large vessel occlusions causing acute ischemic stroke, successful recanalization is not achieved in all patients. One contributing factor is the presence of fibrin-rich hard clots. We proposed a new technique called the PREMIER technique, which aims to retrieve fibrin-rich clots. This study evaluated the efficacy of the PREMIER technique on fibrin-rich and erythrocyte-rich clots by comparing it with the simple use of EmboTrap III in an in vitro vessel model. Methods: The PREMIER technique involves partially resheathing a fully deployed EmboTrap III (CERENOVUS, Johnson & Johnson Medical Devices, Irvine, California, USA) using a microcatheter to capture and retrieve a hard clot between the inner channel and outer cages of EmboTrap III. We compared recanalization rate of the PREMIER technique with the simple use of EmboTrap III in an in vitro vessel model, occluding the M1 segment with fibrin-rich hard clots (0% erythrocyte composition) and erythrocyte-rich clots (50% erythrocyte composition). Results: Among the 40 procedures (10 each for the PREMIER technique and the simple use of EmboTrap III for two different clots) for fibrin-rich clots, the PREMIER technique achieved successful recanalization in all 10 cases, with a significantly higher recanalization rate than the EmboTrap III (100% vs. 50%, p = 0.03). For erythrocyte-rich clots, the recanalization rate was not significantly different in the PREMIER technique compared with the simple use of EmboTrap III (80% vs. 70%, p = 1.00). Conclusion: The PREMIER technique is a novel technique for acute large-vessel occlusions caused by fibrin-rich hard clots that hinders successful recanalization during mechanical thrombectomy.

Impact of the COVID-19 Pandemic on Acute Stroke Rehabilitation in Japanese Primary Stroke Centers: A Nationwide Cross-Sectional Study Using a Web-Based Questionnaire Survey.

INTRODUCTION: Acute stroke rehabilitation is crucial for achieving good functional recovery, even during the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to clarify the impact of the COVID-19 pandemic on acute stroke rehabilitation and identify which components in the acute stroke rehabilitation provision system were susceptible to the pandemic. METHODS: A web-based questionnaire survey was conducted in all primary stroke centers (PSCs) in Japan between February 7 and April 21, 2022. The survey included questions about the current status of acute stroke rehabilitation and the influence of the pandemic. We classified the influences and investigated the relationship between the influence of the pandemic and the provision of rehabilitation. Additionally, we investigated a group of prefectures divided according to the grade of the pandemic. RESULTS: The survey response rate was 67% (639 of 959 PSCs). Among them, 387 PSCs (61%) reported that the COVID-19 pandemic affected acute stroke rehabilitation. In PSCs affected by the pandemic, more rehabilitation-related staff were working, and the proportion of weekend/holiday rehabilitation implementation was higher compared to those unaffected. In PSCs from highly infected prefectures, no significant relationship was observed between the influence of the pandemic and the rehabilitation provision system. CONCLUSIONS: PSCs that provide denser acute stroke rehabilitation may be affected to a greater extent by the pandemic. We conclude that stroke hospitals should formulate infection control procedures for acute stroke rehabilitation in advance, depending on the conditions of the region and facility.

Delayed cerebral complications associated with endovascular catheter coil embolization for pulmonary venous shunts mimicking cerebral inflammatory diseases.

Introduction: Hydrophilic polymer embolism in the brain is a delayed complication of cerebral angiography or endovascular therapy. Herein, we report a rare case of a hydrophilic polymer embolism in the brain due to endovascular catheter coil embolization of pulmonary venous shunts. Case report: A 16-year-old female presented with headache, dizziness, nausea, and dysesthesia in the left upper limb. Brain magnetic resonance imaging (MRI) revealed multiple bilateral subcortical white matter lesions with nodular gadolinium enhancement lesions surrounded with edema. Two weeks before onset, the patient underwent endovascular catheter coil embolization with two coils for two systemic-to-pulmonary venous shunts. We suspected that her multiple cerebral lesions were delayed allergic complications due to a catheter hydrophilic polymer-coating embolism after endovascular catheter coil embolization. Corticosteroid treatment rapidly improved neurological symptoms and MRI findings. Conclusion: To avoid unnecessary brain biopsy, careful history taking of previous catheterization is essential among patients presenting with focal deficits and punctate-enhancing brain lesions for the diagnosis of hydrophilic polymer embolism.

Near-infrared imaging via upconversion in Er3+:CaF2 crystal with dual wavelength excitation.

We propose a system for imaging 1510 nm near-infrared (NIR) wavelength via upconversion (UC) luminescence in an Er3+-doped CaF2 crystal. Er3+ ions are excited from the ground to the excited state levels by an 800-nm pre-excitation wavelength, followed by the promotion of these ions to a higher energy level by the NIR excitation wavelength. Relaxation of these excited ions gives rise to 540 nm UC luminescence in the visible region, enabling the detection of the 1510 nm NIR wavelength. Using this UC scheme, 1510 nm was successfully imaged. Our system enables imaging of NIR wavelengths using low-cost optics and readily available Si-based detectors that are sensitive only to visible wavelengths, opening new possibilities for detection and imaging of NIR wavelengths.

Observation of 2D-magnesium-intercalated gallium nitride superlattices.

Since the demonstration of p-type gallium nitride (GaN) through doping with substitutional magnesium (Mg) atoms1,2, rapid and comprehensive developments, such as blue light-emitting diodes, have considerably shaped our modern lives and contributed to a more carbon-neutral society3-5. However, the details of the interplay between GaN and Mg have remained largely unknown6-11. Here we observe that Mg-intercalated GaN superlattices can form spontaneously by annealing a metallic Mg film on GaN at atmospheric pressure. To our knowledge, this marks the first instance of a two-dimensional metal intercalated into a bulk semiconductor, with each Mg monolayer being intricately inserted between several monolayers of hexagonal GaN. Characterized as an interstitial intercalation, this process induces substantial uniaxial compressive strain perpendicular to the interstitial layers. Consequently, the GaN layers in the Mg-intercalated GaN superlattices exhibit an exceptional elastic strain exceeding -10% (equivalent to a stress of more than 20 GPa), among the highest recorded for thin-film materials12. The strain alters the electronic band structure and greatly enhances hole transport along the compression direction. Furthermore, the Mg sheets induce a unique periodic transition in GaN polarity, generating polarization-field-induced net charges. These characteristics offer fresh insights into semiconductor doping and conductivity enhancement, as well as into elastic strain engineering of nanomaterials and metal-semiconductor superlattices13.

Stent Retriever Angioplasty for Acute Restenosis of the Middle Cerebral Artery: A Case Report.

We present a case of ischemic stroke treated by stent retriever angioplasty for restenosis during mechanical thrombectomy. An 85-year-old man was admitted to our hospital because of left hemiplegia and left-sided hemispatial neglect caused by an occlusion at the origin of the right middle cerebral artery. Although mechanical thrombectomy transiently resulted in recanalization of the occluded lesion, restenosis immediately occurred and recurred repeatedly. On an angiogram, the stent retriever appeared poorly dilated at the stenosis and showed a contrast deficit. We concluded that restenosis was due to a secondary thrombus resulting from a ruptured atherosclerotic plaque. The stent retriever was kept deployed for 15 minutes. After the stent was retrieved, restenosis did not occur. Stent retriever angioplasty may be effective for determining the cause of restenosis after mechanical thrombectomy as well as for the treatment of restenosis.

Stent-retriever characteristics and strategies associated with recanalization in thrombectomy for acute ischemic stroke.

INTRODUCTION: Predictive factors for successful reperfusion in mechanical thrombectomy for acute ischemic stroke, and especially technical factors, remain controversial. We investigated various techniques for better angiographic outcomes. METHODS: In this retrospective study, acute ischemic stroke patients with large vessel occlusion treated with mechanical thrombectomy with combined technique were included. Scoring of the reperfusion grade for each attempt was conducted, and each attempt was divided into two groups based on successful reperfusion, which was defined using the presence or absence of modified thrombolysis in cerebral infarction 2b-3. The following characteristics were evaluated: the choice of stent-retriever, its length, occlusion site, thrombus position relative to deployed stent-retriever, methods of thrombectomy, and successful advancement of the distal access catheter to the proximal end of the thrombus. RESULTS: Among 251 patients who underwent mechanical thrombectomy, 154 patients (255 attempts: mTICI 0-2a group, n = 119; mTICI 2b-3 group, n = 136) were included in the analysis. The thrombus position relative to the deployed stent-retriever was likely associated with successful reperfusion, although it was not statistically significant (proximal two-thirds 56.8 %; distal one-third 44.3 %, p = 0.09). Successful advancement of the distal access catheter was related to successful reperfusion both in univariate analysis (success 57.9 %; fail 35.8 %, p < 0.01) and in multivariate regression analysis (odds ratio 2.45; 95 % confidence interval: 1.30-4.61, p < 0.01). CONCLUSIONS: Successful advancement of the distal access catheter to the proximal end of thrombus might be a key component for successful reperfusion in mechanical thrombectomy.

[Transient neurological deficits in a patient with chronic subdural hematoma].

A 62-year-old, right-handed man was diagnosed with asymptomatic bilateral chronic subdural hematomas and underwent hematoma removal on the left side only. At 1 month after surgery, he was admitted to our hospital because he began to have one or two attacks/day of apraxia of speech and dysesthesia of the right hand with a duration of approximately 5 |min. The left hematoma had not re-expanded, but fluid-attenuated inversion resonance imaging showed hyperintense lesions in the sulci adjacent to the hematoma. Moreover, single-photon emission computed tomography revealed low-uptake lesions in the left cerebrum adjacent to the hematoma. Electroencephalogram showed no abnormalities, and CT angiography showed a slight deviation of the left middle cerebral arteries due to the hematoma. The attacks disappeared within 10 days, although the volume of the hematoma was unchanged. It was suggested that his transient neurological deficits were caused by cerebral ischemia related to chronic subdural hematoma.

Evidence and Recommendations for Acute Stroke Rehabilitation from the Japan Stroke Society: Abridged Secondary Publication of the Japanese-language Version.

Objectives: In Japan, acute stroke rehabilitation has been expanding more steadily than previously with the nationwide establishment of primary stroke centers. However, Japan previously had no established guidelines for the rehabilitation. Consequently, rehabilitation programs and the provision systems for acute stroke varied among the facilities. To equalize and standardize acute stroke rehabilitation in Japan, it is necessary to develop clinical recommendations for rehabilitation. Therefore, the rehabilitation project team of the Japan Stroke Society aimed to develop the first recommendations for acute stroke rehabilitation in Japan. Methods: The recommendations are based on the results of a survey on the current status of acute stroke rehabilitation at primary stroke centers in Japan, which was completed in 2022, and on a literature review conducted by the rehabilitation project team. Results: The recommendations consist of 19 clinical questions regarding the following topics of acute stroke rehabilitation: (1) head elevation and mobilization training, (2) acute complications, (3) training time and frequency for acute stroke rehabilitation, (4) dysphagia in the acute phase, and (5) acute rehabilitation during pandemics of novel and re-emerging infections, particularly novel coronavirus disease 2019 (COVID-19). The team members agreed on all answers for these 19 clinical questions. Conclusions: These recommendations suggest broad principles of rehabilitative intervention in the acute phase of stroke. In the near future, it is expected that the dissemination of these recommendations will result in an increase in the quality of acute stroke rehabilitation in Japan.

Fermentation of coffee fruit with sequential inoculation of Lactiplantibacillus plantarum and Saccharomyces cerevisiae: effect on sensory attributes and chemical composition of the beans.

This study has innovative aspects related to the use of sequential inoculation technique in the coffee bean fermentation process: the inoculation of Lactiplantibacillus plantarum followed by Saccharomyces cerevisiae, in the fermentation of coffee fruit for the production of specialty natural coffees. The objective was to evaluate the effect of this technique and of the total fermentation time on the sensory attributes of the coffee beverage and on the organic acid profile, bioactive compounds, and fatty acid profile of the beans. The fermentation of coffee fruit with sequential inoculation resulted in greater acidity of the beverage and contributed to increases of up to 2 points in coffee fermented. The total fermentation time was directly related to the organic acid content, and the longer the total fermentation time was, the greater the organic acid content. The fatty acid content and bioactive compound content showed little variation among treatments.

Carotid Free-Floating Thrombus Treated With a Combined Technique Using Embotrap III for Distal Protection.

Carotid free-floating thrombus (FFT) is a rare condition in patients with acute ischemic stroke. Recently, endovascular therapy for carotid FFT has been increasingly reported, but the strategy has not yet been established. We report a case of an acute stroke patient with a carotid FFT, who was successfully treated with a combination of the direct aspiration first-pass technique (ADAPT) and the Embotrap III (Cerenovus, Irvine, CA), specifically designed to prevent distal embolization. We propose the utility of distal embolic protection with Embotrap III for the treatment of patients with carotid FFT. A 71-year-old man who presented with sudden left hemiparesis was admitted to our hospital. Ultrasonography on admission revealed severe stenosis and an FFT at the origin of the right internal carotid artery. Thrombectomy with an aspiration catheter, accompanied by a stent retriever with distal basket Embotrap III for distal protection, was performed. After the FFT was safely aspirated, a carotid Wallstent (Boston Scientific, Marlborough, MA) was deployed in the stenosis. Follow-up ultrasonography showed neither FFT nor in-stent protrusion. The patient did not experience recurrence, as per clinical or radiological findings, and was discharged on day 11 without any neurological deficits. Embotrap III may be useful for a patient with a carotid FFT as distal protection during mechanical thrombectomies.

Changes in SARS-CoV-2 viral load and titers over time in SARS-CoV-2-infected human corpses.

High viral titers of infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been detected in human corpses long after death. However, little is known about the kinetics of infectious SARS-CoV-2 in corpses. In this case series study, we investigated the postmortem kinetics of infectious SARS-CoV-2 in human corpses by collecting nasopharyngeal swab samples at multiple time points from six SARS-CoV-2-infected patients after their death. SARS-CoV-2 RNA was detected by quantitative reverse transcription-polymerase chain reaction from nasopharyngeal swab samples collected from all six deceased patients. A viral culture showed the presence of infectious virus in one deceased patient up to 12 days after death. Notably, this patient had a shorter time from symptom onset to death than the other patients, and autopsy samples showed pathological findings consistent with viral replication in the upper respiratory tract. Therefore, this patient died during the viral shedding phase, and the amount of infectious virus in the corpse did not decrease over time up to the date of autopsy (12 days after death). The findings of this study indicate that the persistence of SARS-CoV-2 in corpses can vary among individuals and may be associated with the stage of the disease at the time of death. These important results complement many previously reported findings on the infectivity of SARS-CoV-2 at postmortem.

Optimizing High-Resolution MR Angiography: The Synergistic Effects of 3D Wheel Sampling and Deep Learning-Based Reconstruction.

OBJECTIVE: The aim of this study was to assess the utility of the combined use of 3D wheel sampling and deep learning-based reconstruction (DLR) for intracranial high-resolution (HR)-time-of-flight (TOF)-magnetic resonance angiography (MRA) at 3 T. METHODS: This prospective study enrolled 20 patients who underwent head MRI at 3 T, including TOF-MRA. We used 3D wheel sampling called "fast 3D" and DLR for HR-TOF-MRA (spatial resolution, 0.39 × 0.59 × 0.5 mm 3 ) in addition to conventional MRA (spatial resolution, 0.39 × 0.89 × 1 mm 3 ). We compared contrast and contrast-to-noise ratio between the blood vessels (basilar artery and anterior cerebral artery) and brain parenchyma, full width at half maximum in the P3 segment of the posterior cerebral artery among 3 protocols. Two board-certified radiologists evaluated noise, contrast, sharpness, artifact, and overall image quality of 3 protocols. RESULTS: The contrast and contrast-to-noise ratio of fast 3D-HR-MRA with DLR are comparable or higher than those of conventional MRA and fast 3D-HR-MRA without DLR. The full width at half maximum was significantly lower in fast 3D-MRA with and without DLR than in conventional MRA ( P = 0.006, P < 0.001). In qualitative evaluation, fast 3D-MRA with DLR had significantly higher sharpness and overall image quality than conventional MRA and fast 3D-MRA without DLR (sharpness: P = 0.021, P = 0.001; overall image quality: P = 0.029, P < 0.001). CONCLUSIONS: The combination of 3D wheel sampling and DLR can improve visualization of arteries in intracranial TOF-MRA.

Fermentation of coffee fruit with sequential inoculation of Lactiplantibacillus plantarum and Saccharomyces cerevisiae: Effects on volatile composition and sensory characteristics.

Mixed starter cultures of lactic acid bacteria and yeasts used in the production of fermented foods, including coffee, can improve the sensory quality and food safety. The objective of this study was to evaluate the effects of fermentation of coffee with inoculation of Lactiplantibacillus plantarum followed by Saccharomyces cerevisiae and the effects of fermentation time on the aroma and flavor of the coffee beverage and on the volatile composition of the roasted coffee beans. The coffee was fermented for 48 h or 96 h after inoculation of Lactiplantibacillus plantarum followed by inoculation of Saccharomyces cerevisiae or the respective controls. The aroma and flavor of the coffee beverage fermented with sequential inoculation showed complexity, with a predominance of fruity and fermented sensory notes. Forty-seven volatile compounds were identified. In addition, the sequentially inoculated coffees had greater formation of volatiles and led to greater perception of fruity and fermented flavor and aroma.

Third harmonic generation due to free carrier in InSb using a terahertz free electron laser.

We report on the third harmonic generation (THG) in InSb semiconductor irradiated by a terahertz (THz) free electron laser (FEL). The conversion of 4 THz (wavelength 70 µm) FEL outputs into its third harmonic 12 THz was observed. We found that by tuning the sample temperature to 360 K, high conversion efficiency up to 1% can be obtained and is the highest in the THz and FIR regions below 10 THz. We also discuss the observed intensity dependence of the THG with the nonlinear order lower than 3 when the pumping intensity was high.

Detection of diatoms in a case of mud aspiration at a coastal area.

The source of diatoms detected in non-drowned bodies have been attributed to postmortem invasion, contamination during autopsy or diatom testing, or "natural load." However, sand aspiration has not been reported as a source. Herein, we report an autopsy case in which diatoms were detected in a non-drowned human who had aspirated mud. A man in his 60 s was found dead at a harbor park in Japan. His whole body was covered with sand, including his face. A situational investigation suggested that he may have entered the sea. Autopsy revealed intratracheal mud, with no obvious findings indicating drowning, suggesting that he died from mud aspiration probably due to hypothermia or non-lethal ethanol intoxication. In the diatom test, 10-100 diatoms/g were detected in bilateral lung samples, which were similar to those found in the intraoral and intratracheal mud and the sand samples from around the discovery site and not similar to those found in the seawater samples. The diatoms in the stomach content exhibited an intermediate trend between those found in the sand and seawater. Therefore, careful qualitative and quantitative analyses are required to differentiate between true drowning and false-positives in non-drowning cases to determine the cause of death.

Timing of Initiation of Acute Stroke Rehabilitation and Management Corresponding to Complications at Primary Stroke Centers in Japan: A Nationwide Cross-Sectional Web-Based Questionnaire Survey.

INTRODUCTION: Many guidelines now recommend early rehabilitation for acute stroke patients. However, evidence remains lacking regarding the specific timings for initiation of various rehabilitation steps and management when complications are encountered in acute stroke rehabilitation. This survey aimed to investigate actual clinical situations in acute stroke rehabilitation in Japan and to improve the medical systems for rehabilitation and plan further studies. METHODS: This nationwide, cross-sectional, web-based questionnaire survey was administered between February 7, 2022, and April 21, 2022, targeting all primary stroke centers (PSCs) in Japan. Among several components of the survey, this paper focused on the timing of the initiation of three rehabilitation steps (passive bed exercise; head elevation; and out-of-bed mobilization), along with the management of rehabilitation (continued or suspended) in the event of complications during acute stroke rehabilitation. We also investigated the influence of facility features on these contents. RESULTS: Responses were obtained from 639 of the 959 PSCs surveyed (response rate: 66.6%). In cases of ischemic stroke and intracerebral hemorrhage, most PSCs initiated passive bed exercise on day 1, head elevation on day 1, and out-of-bed mobilization on day 2 (with day of admission defined as day 1). In cases with subarachnoid hemorrhage, rehabilitation steps were delayed compared to other stroke subtypes or showed wide variation depending on the facility. Passive bed exercise was accelerated by the presence of protocols for rehabilitation and weekend rehabilitation. Out-of-bed mobilization was accelerated by the presence of a stroke care unit. Facilities with board-certified rehabilitation doctors were cautious regarding the initiation of head elevation. Most PSCs suspended rehabilitation training in the event of symptomatic systemic/neurological complications. CONCLUSION: Our survey revealed the actual situation of acute stroke rehabilitation in Japan and indicated that some facility features appear to influence early increases in physical activity levels and early mobilization. Our survey provides fundamental data to improve the medical systems for acute stroke rehabilitation in the future.

A nationwide survey for the provision of acute stroke rehabilitation in Japan: initial dose and weekend/holiday rehabilitation.

OBJECTIVES: The early initiation of acute stroke rehabilitation with a sufficient dose, including at weekends/holidays, is important to improve functional outcome. We investigated the status of acute stroke rehabilitation in Japan by using a nationwide survey. MATERIALS AND METHODS: Facility features, rehabilitation dose provided in the first week in each stroke subtype, and weekend/holiday rehabilitation were investigated by using the results of a web-based survey among primary stroke centers. The relationships between facility features and weekend/holiday rehabilitation were also analyzed. RESULTS: A total of 639 stroke centers (66.6%) completed the questionnaire. The overall median dose was 2.0 (interquartile range, 1.7-3.0) U/day (1U = 20 min). After 7 days, the overall median dose increased to 4.0 (2.0-5.4) U/day. Almost 50% of facilities replied that they could not provide a sufficient dose of rehabilitation; the main reason was a lack of therapists (31%). For rehabilitation on long weekends, no rehabilitation was provided on 3-day weekends in 19% of facilities, and in 5% of facilities on ≥4-day weekends. The mean number of therapists was almost 50% less in the facilities that provided no rehabilitation on 3-day weekends compared to those that provided daily rehabilitation (19.4 vs. 36.2 therapists, respectively, p < 0.001). CONCLUSIONS: In this survey, the provision of acute stroke rehabilitation, including non-working days, was clarified. According to the results, prospective interventional or observational studies are needed to design more effective rehabilitation programs to improve outcome. In particular, it is important to determine the optimal dose and intensity of acute stroke rehabilitation.

Design and fabrication of a microcoil metamaterial absorber for the sub-terahertz region.

The development of electromagnetic wave absorbers operating in the sub-terahertz (sub-THz) region is necessary in 6G communications. We designed and fabricated a sub-THz metamaterial absorber based on metal microcoils embedded and periodically arranged in a dielectric substrate. The microcoil parameters were optimized by calculating the electromagnetic response of the metamaterial using finite element analysis. An actual metamaterial was then fabricated based on the optimized parameters and characterized using THz time-domain spectroscopy. Our microcoil absorber exhibits an absorptance of >80% and a high shielding performance at about 250 GHz. The resonance frequency can be precisely adjusted by modifying the microcoil array dimensions.