Topologically Enabled Ultrahigh-Q Chiroptical Resonances by Merging Bound States in the Continuum.

Ultrahigh-Q chiroptical resonance metasurfaces based on merging bound states in the continuum (BICs) are investigated and numerically demonstrated. The destruction of C2 symmetry results in the leakage of BICs into quasi-BICs, and a chiral quasi-BIC is obtained by oblique incidence or continuous destruction of the mirror symmetry of the structure. Due to the significant topological properties of merging BICs, the Q factor (over 2 × 105) of the chiral resonance peak obtained is much higher than that of the previous work. Moreover, the proposed structure is easy to fabricate because no additional out-of-plane asymmetry is introduced. The proposed scheme is of importance in chiral biosensing applications.

l-glycine and l-glutamic acid protect Pediococcus pentosaceus R1 against oxidative damage induced by hydrogen peroxide.

The effects of l-glycine (Gly) and l-glutamic acid (Glu) on oxidative damage induced by hydrogen peroxide (H2O2) in Pediococcus pentosaceus R1 were investigated. Gly and Glu significantly reduce the production of intracellular reactive oxygen species and the levels of malondialdehyde and carbonylated proteins and concomitantly increase ATP levels in P. pentosaceus R1 under H2O2-induced stress (P < 0.05). Transmission electron microscopy and atomic force microscopy of bacteria under H2O2-induced stress revealed that Gly and Glu suppress bacterial membrane deformation and cell damage. Gly exhibited stronger ferrous ion-chelating ability, whereas Glu has higher radical scavenging activities and reducing power (P < 0.05). The abilities of Gly and Glu to inhibit lipid peroxidation are comparable. Gly and Glu significantly enhance the activities of superoxide dismutase and glutathione peroxidase, respectively, and increase the total antioxidant capacity of bacteria (P < 0.05). These findings indicate that Gly and Glu alleviate H2O2-induced oxidative stress via direct antioxidant effects and increase the activities of bacterial antioxidant enzyme.

Pediatric intramedullary schwannoma with syringomyelia: a case report and literature review.

BACKGROUND: Intramedullary schwannomas without neurofibromatosis are exceedingly rare. They are rarer in children with only 8 cases reported so far. The association of intramedullary schwannomas with syringomyelia is also rare. Here, we present a case of intramedullary schwannoma with syringomyelia treated surgically in an 9-year-old boy. CASE PRESENTATION: We reviewed the clinical course of a 9-year-old boy, who presented with both lower extremity weakness of 6-month duration. Neurophysical examination revealed a decreased sensation below the T10 dermatome. Magnetic resonance imaging (MRI) showed an well-demarcated intramedullary lesion located at the level of T8 vertebra with isointensity on T2WI and hypointensity on T1WI, which was homogeneous enhanced after gadolinium injection. There was associated syringomyelia extending from T7 down to the level of T10. A mild scoliotic deformity was also observed. The lesion was totally resected after an T7-T8 laminoplasty. Histopathological findings were consistent with schwannoma. Postoperative MRI did not reveal the presence of a residual tumor with syringomyelia reducted. By 2 weeks after treatment, the patient had experienced nearly complete recovery. Management with external bracing was performed on this patient for 3 months after surgery to prevent spinal deformity. However, mild spinal kyphosis occurred 5 months after surgery, and a progressive postoperative spinal kyphosis was observed during these 3 years of follow-up. Continued conservative management with observation was performed as there is no association with functional decline and impairment in health-related quality-of-life measures. CONCLUSION: Although extremely rare and uncommonly associated with syringomyelia, schwannomas need to be considered in the preoperative diagnosis of solitary intramedullary tumors in children as total resection can be achieved improving surgical outcome; Pediatric patients should be monitored closely for the development of spinal deformity following resection of intramedullary schwannoma, particularly possessing preoperative scoliotic deformity and/or tumor-associated syringomyelia.

Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating.

This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG) for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE) light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed.

Design of Novel FBG-Based Sensor of Differential Pressure with Magnetic Transfer.

In this paper, a differential pressure sensor with magnetic transfer is proposed, in which the non-electric measurement based on the fiber Bragg grating (FBG) with the position limiting mechanism is implemented without the direct contact of the sensing unit with the measuring fluid. The test shows that the designed sensor is effective for measuring differential pressure in the range of 0~10 kPa with a sensitivity of 0.0112 nm/kPa, which can be used in environments with high temperature, strong corrosion and high overload measurements.

[Microsurgical treatment for giant invasive spinal schwannoma assisted by three-dimensional navigation].

OBJECTIVE: To summarize the clinical experience of microsurgical treatment for giant invasive spinal schwannoma assisted by three-dimensional navigation. METHODS: A total of 15 cases of giant invasive spinal schwannoma were retrospectively analyzed from 2013 to 2014 in Beijing Jishuitan Hospital.All patients were performed microsurgery assisted by three-dimensional navigation and were followed up for at least 12 months.A modified McCormick Scale was used to assess the patients' neurologic status and change. RESULTS: Four lesions were in the cervical region, 3 in the sacral, 2 each in the cervicothoracic, lumbar and thoracic regions, 1 each in the thoracolumbar and lumbosacral regions.A total of 28 pedicle screws were placed satisfactorily in the 5 patients with spinal instability.No severe complications were encountered.Gross total resection was performed in 13 of the 15 patients, and subtotal resection performed in 2 patients.Satisfactory decompression was achieved in all patients for neural compression.Postoperative clinical symptoms were improved in all patients, and none of the patients showed loosening or displacement of the implants. CONCLUSIONS: Three-dimensional navigation provides great help for neurosurgeons in surgical treatment of giant invasive spinal schwannoma, and it has great potential in raising the intraoperative localization accuracy, reducing operational damage and surgical complications.Total resection is suggested for giant invasive spinal schwannoma; if not, total resection of the intraspinal portion is recommended.

[Reorganization of brain cortex after spinal cord injury based on functional magnetic resonance imaging techniques].

OBJECTIVE: To explore the reorganization of brain cortex on spinal cord injury (SCI) patients with functional magnetic resonance imaging (fMRI) techniques and elucidate its recurring patterns so as to provide theoretic rationales for SCI treatment. METHODS: We designed different tasks for 9 SCI patients and 10 normal subjects. The tasks were named block design and it was divided into rest period (R) and stimulating period (S). All subjects underwent fMRI scan while they were performing the tasks. RESULTS: A significant reorganization occurred on brain cortex of SCI patients after spinal cord injury. This phenomenon changed with elapsing time after spinal cord injury. CONCLUSION: Brain cortex undergoes reorganization after spinal cord injury, especially primary sensory and motor cortex.

Clinical features and surgical outcomes of spinal epidural angiolipomas.

To discuss the clinical features and surgical outcomes of spinal epidural angiolipomas. We retrospectively analyzed the medical records of patients with spinal epidural angiolipomas who were performed microsurgery between January 2003 and December 2017. The diagnosis of spinal angiolipomas was based on pathological criteria. Modified McCormick classification was applied to evaluate neurological function. There were 11 females and 9 males with ages ranged from 38 to 74 years. Fourteen lesions were located in the thoracic region, 4 in the lumbar, 1 in the lumbosacral, and 1 in the thoracolumbar region. Patients presented with nonspecific symptoms and the duration of symptoms ranged from 1 to 168 months with a mean 21.3 months. 11 cases exhibited isointense on T1-weighted imaging(T1WI) and hyperintense on T2-weighted imaging(T2WI). The other 9 cases exhibited hyperintense on T1WI and T2WI imaging. Gross total resection (GTR) was performed in 19 patients, and subtotal resection (STR) was performed in 1 patient. Postoperatively, all patients showed a recovery or improvement of neurological functions except the STR patient. There was no recurrence or regrowth of the residual lesions observed on magnetic resonance images (MRI). Usually, spinal epidural angiolipomas have two types of MRI manifestations depending on the ratio of fat to vessels. Total resection of spinal epidural angiolipoma is possible regardless of it is infiltrative or not. Postoperative radiotherapy is not recommended for subtotal resection patients. A favorable functional outcome can be expected if the patient performed early surgery.

Magnetic Properties in Mn-Doped δ-MoN: A Systematic Density Functional Theory Study.

Due to the potential applications of transition metal nitrides in modern electronic and spintronic devices, we have systematically studied the magnetic properties of δ-MoN induced by the Mn dopant, with the goal of identifying the origin of magnetism and figuring out the magnetic coupling mechanism between the Mn dopants. Based on the density functional theory, one Mn atom doped at different Mo sites (2a and 6c in the International Tables) in the unit cell of δ-MoN was firstly studied. It was found that the Mn dopant located at the 2a or 6c site leads to significant spin splitting of the density of states, suggesting that the Mn doping induces magnetism in δ-MoN. The calculations were then extended to a 2 × 1 × 2 supercell, which contains two impurity Mn atoms. Detailed analysis reveals that the different couplings of the Mn-Mn pair cannot be simply attributed to the different Mn-Mn distances but are closely related to the electronic processes that take place in the segment (-N- or -N-Mo-N-) that connects two Mn dopants. The mechanisms responsible for the FM/AFM coupling of the Mn-Mn pairs are the superexchange and the p-d exchange mediated by the N atoms, and the d-d coupling between the host Mo atom and the Mn dopant.

Enhancement expression of bFGF in Chinese patients with Moyamoya disease.

OBJECTIVE: To detect the content of the basic fibroblast growth factor in blood samples of patients with Moyamoya disease, and investigate the relationship between Moyamoya disease and the basic fibroblast growth factor. METHODS: This tissue microarray study included 24 cases of superficial temporal artery samples, 15 cases of Moyamoya disease, and 9 cases of normal arteries as control, and bFGF immunofluorescence assay was applied to test the samples. The number of positive cells and total cells of the muscular layer and the endothelium layer were counted separately in every picture, the positive rates were calculated, and the experimental data were analyzed statistically. RESULTS: The bFGF immunofluorescence staining of smooth muscular layer cells, intima cells and endothelial cells from the moyamoya disease group were obviously stronger than that from the control group (P<0.01). CONCLUSION: The enhancement expression of bFGF in the Moyamaya disease group implicates that bFGF plays an important part in the pathogenesis of Moyamoya disease.

[Clinical study of patients of arachnoid cyst associated with chronic subdural hematoma].

OBJECTIVE: To explore the clinical characteristics and treatment strategy of arachnoid cyst associated with chronic subdural hematoma. METHODS: A retrospective analysis was made for 11 cases of arachnoid cyst associated with chronic subdural hematoma at our hospital from December 1999 to December 2009. There were 9 males and 2 females with a mean age of 23.1 years old (range: 7 - 68). Their clinical characteristics were summarized. The symptoms included headache (n = 10) and facial muscle twitching & eye squinting (n = 1). History of previous head injury were found in 6 cases, strenuous exercise in 1 case and no history of injury in 4 cases. RESULTS: The clinical symptoms of 3 patients worsened after a conservative treatment and underwent a burred-hole procedure with drainage of hematoma. And 7/9 patients undergoing a burred-hole procedure with drainage of hematoma had a full recovery. But 2/9 had recurrent subdural hematoma at Days 20 and 40 post-operation respectively and underwent the same procedure. Another 2 cases underwent craniotomy to remove subdural hematoma and arachnoid cyst and had stayed free of any symptom since then. All patients were followed up for 10 - 154 months after discharge. And none had recurrent subdural hematoma. All could study, work or live normally with a KPS (Karnofsky performance scale) score of 80 or more. CONCLUSION: Arachnoid cysts is a possible risk factor for subdural hematoma, especially in young adults. Chronic subdural hematoma generally develops within 1 - 3 months after head injury. And a common clinical presentation is headache. A burred-hole procedure with drainage of hematoma is adequate as the first-line treatment for arachnoid cyst associated with chronic subdural hematoma.

[Application of intraoperative ultrasound combined with neuronavigation for resection of intracranial cavernous malformations in minimally invasive neurosurgery].

OBJECTIVES: To analyze the reliability and clinical value of intraoperative ultrasound combined with neuronavigation for resection of intracranial cavernous malformations. METHODS: From January 2007 to December 2009, 40 cases of intracranial cavernous malformations were operated under the application of intraoperative ultrasound combined with neuronavigation. There were 18 male and 22 female, aged 18 to 58 years, with a mean age of 34.5 years. Neuronavigation was used for all patients before operation to display the three-dimensional model of nervous system and lesions, so to design the operative approach and determine the scope of the incision. Lesions were allocated by real-time neuronavigation in order to continuously verify the accuracy of operative approach during the operation, supplemented by real-time monitoring of intraoperative ultrasound to guide the process of surgery and determine the extent of resection of lesions. RESULTS: The registration error of neuronavigation was 1.3 - 3.2 mm, with an average of 2.0 mm. All the patients' three-dimensional model of nervous system and lesions were satisfactorily displayed, and the area of lesions were all accurately located. Structural brain-shifts occurred in 4 cases in the remove process of the lesion, with shift degree 5.0 - 10.0 mm, and were corrected by intraoperative ultrasound. All lesions were well displayed by intraoperative ultrasound. Gross total resection was achieved in all patients, with no patient infected or dead. Neurological deterioration was seen in 2 patients, the morbidity was 5.0%. CONCLUSIONS: The combination of neuronavigation and intraoperative ultrasound for resection of intracranial cavernous malformations can provide valuable intraoperative informations of the location and resection level of the lesion, thereby maximize the accuracy of lesion localization and the extent of resection, with less complications and enhanced efficacy of the surgery.

Early microsurgery on thoracolumbar spinal extradural arachnoid cysts: Analysis of a series of 41 patients.

BACKGROUND: We designed this study to share our management experiences on spinal extradural arachnoid cysts (SEACs) to add more to the body of evidence for their treatment. METHODS: We retrospectively reviewed 41 patients who underwent microsurgery for thoracolumbar SEACs at our hospital from June 2009 to June 2019. All clinical data, including medical history, clinical features, imaging manifestation, operative findings, and prognosis, were extracted from medical records and databases. Perioperative differences of the Visual Analogue Scale (VAS), the Oswestry disability index (ODI) score, and postoperative Odom's criteria were used to assess the surgical outcome. RESULTS: The most common and very first clinical symptom in the 41 patients was pain (VAS = 2.82 ± 0.89), and the mean ODI value was 61.7 ± 8.9%. Imaging revealed that the cystic lesions in the thoracolumbar spine involved an average of 2.85 segments. Of the 41 patients, 39 underwent total cyst excisions, and 36 had their dural defect repaired by one of three methods. The mean postoperative follow-up time was 52.3 months. Postoperatively, one case developed kyphoscoliosis and two cases experienced a recurrence. The majority of patients showed excellent outcomes according to Odom's criteria, the postoperative VAS (0.80 ± 1.08), and the ODI (15.4 ± 9.3%). CONCLUSIONS: Themost commonclinicalsymptoms of thoracolumbar SEACs included progressive discomfort and pain around the involved spinal segments. Early surgical intervention relieved the patients from their symptoms. Microsurgery was recommended to resect the complete cyst and to repair the dural defect, but resection of the complete cyst is more necessary than just repairment of the dural defect for providing promising outcomes.

Surgical management of spinal "Subpial" lipomas.

BACKGROUND: This study reports five cases of subpial lipomas via a new grouping method with respect to the cases' distinctive magnetic resonance imaging characteristics to provide insight into the management of this entity. METHOD: From January 2013 to December 2014, five cases of pathologically diagnosed subpial lipomas that received surgical treatment in our department were included. The clinical histories and medical records were carefully reviewed, and the radiological characteristics were periodically inspected after surgery. The preoperative radiology and symptoms were reviewed with regard to outcome. RESULTS: All five patients were confirmed as having lipomas based on their histological results. Total removal was achieved in one patient only, with partial removal in the other four patients. Neurological deterioration was observed in all patients immediately after surgery, with a typically lower McCormick score. Two of the patients returned to preoperative level one year later. Based on radiological traits, the lipomas could be divided into "simple" and "invasive." The syrinx formation and neurological recovery were different between these two kinds of lipoma. CONCLUSION: Surgery for subpial lipomas without dysraphisms is frequently accompanied by neurological deterioration, temporally or permanently. Thus, this new classification of subpial lipomas into "simple" and "invasive" based on radiological traits may be valuable for making better surgical decisions.

Recurrent intracranial meningioma with multiple pulmonary metastases: A case report.

Meningiomas are slow-growing tumors, which are generally considered to be benign and rarely metastasize. Although cases of extracranial metastatic meningioma have previously been reported, multiple pulmonary metastases from a benign intracranial meningioma is particularly rare. In the present report, a case of recurrent transitional meningioma with multiple lung nodules, which were demonstrated to be metastatic meningioma, is presented. A 54-year-old female patient received surgical resection of the tumor located in the left base of the middle cranial fossa in 2006. Post-surgery pathological examination indicated a transitional meningioma of World Health Organization grade I. The tumor recurred at the original site 1 year and 3 months later and was completely surgically removed once again. Radiotherapy was administered following the second surgery. Gamma Knife was used to remove the recurrent tumor 18 months following the second surgery. Simultaneously, a chest computed tomography scan revealed multiple pulmonary nodules, which were demonstrated to be metastatic meningioma following wedge resection of the superior lobe of the right lung. The clinical behavior of meningioma does not always correlate with the classification of meningioma. A higher rate of cellular proliferation is not essential for extracranial metastasis, and an individual meningioma of any type may metastasize. Comprehensive examinations should be performed for patients with a history of recurrent intracranial meningioma to detect any distant metastases as early as possible, even when the primary tumor is benign.

Near-infrared photoluminescence in germanium oxide enclosed germanium nano- and micro-crystals.

We have studied the near-infrared photoluminescence properties of free-standing germanium nano-crystals (20 nm on average) and micro-crystals (60 µm on average) at 80-300 K. Two peaks were observed at ∼1.0 and ∼1.4 eV from both the nano- and micro-crystals. The integrated PL (I(PL)) intensity of the nano-crystals is about an order of magnitude stronger than that of the micro-crystals and the I(PL) is also enhanced by ageing in air for both crystals. The ∼1.0 eV peak position does not change with either the crystal size or temperature. We suggest that the deep traps located at the interfacial region between the surface GeO(2) layer and the bulk crystal Ge is responsible for the near-infrared PL.