Giant strong coupling in a Q-BICs' tetramer metasurface.

Due to their ultrahigh Q-factor and small mode volume, bound states in the continuum (BICs) are intriguing for the fundamental study of the strong coupling regime. However, the strong coupling generated by BICs in one metasurface is not always strong enough, which highly limits its efficiency in applications. In this work, we realize a giant strong coupling of at most 60 meV in a quasi-BICs' (Q-BICs) tetramer metasurface composed of four Si cylinders with two different sets of diagonal lengths. The Q-BICs are induced from two types of electric quadrupole (EQ), for which detuning can be flexibly controlled by manipulating the C4v symmetry breaking Δd. The giant Rabi splitting in our proposed metasurface performs more than 15 times of the previous works, which provides more possibilities for important nonlinear and quantum applications, such as nanolaser and quantum optics.

Analysis of cervical and global spine alignment under Roussouly sagittal classification in Chinese cervical spondylotic patients and asymptomatic subjects.

PURPOSE: To explore the relationship between cervical spine and the global spine alignment and to postulate the hypotheses that a lordotic alignment of cervical spine is not the only standard to identify asymptomatic subjects, and the degenerative modification of cervical curves depends primarily on their spinal-pelvic alignment. METHODS: A cohort of 120 cases of Chinese asymptomatic subjects and a cohort of 121 cases of Chinese cervical spondylotic patients were recruited prospectively from 2011 to 2012. Roussouly Classification was utilized to categorize all subjects and patients according to their thoracic spine, lumbar spine and pelvic alignment. The cervical alignments were evaluated as lordosis, straight, sigmoid or kyphosis. Through the lateral X-ray images of neutral cervical and global spine, a number of parameters were measured and analyzed, including pelvic incidence, pelvic tilt, sacral slope, thoracic kyphosis (TK), lumbar lordosis, global cervical angles (angles between two lines parallel with posterior walls of C2 and C7), practical cervical angles (the addition of different cervical end plate angles from C3 to C7, and inter-vertebral angles from C23 to C67), T1 slope, spinal sacral angles (SSA), Hip to C7/Hip to Sacrum and C0-C2 angle. RESULTS: The percentages of cervical lordosis were 28.3% and 36.4% in asymptomatic and spondylotic group, respectively. The cervical spine alignments correlated with Roussouly types of global spine alignment in both asymptomatic and cervical spondylotic group (P < 0.001). And there were significant differences between Roussouly Type 2 and 4, Type 3 and 4, Type 1 and 3 in cervical angles in spondylotic group (P < 0.05). In the comparison of the two cohorts, significant differences were found in both general and practical cervical angles in Roussouly Type 4 (P = 0.00 and 0.01, respectively), and there were significant differences in inter-vertebral angle in Roussouly Type 2 at C4-5 and C5-6 levels (P = 0.04 and 0.04, respectively), and in Roussouly Type 3 at C6-7 level (P = 0.01). The SSA showed significant difference between Roussouly Type 2 and 4 in asymptomatic subjects (P = 0.00), and between Type 1 and 3, 1 and 4, 2 and 3, 2 and 4 in cervical spondylotic patients (P = 0.01, 0.02, 0.00 and 0.01, respectively). The T1 slope was significantly different among Roussouly types (P = 0.04) with its largest value in Type 1 in cervical spondylotic group. There are significant differences in C0-C2 angles in all Roussouly types (P = 0.01, 0.02, 0.00 and 0.01, respectively), as well as in the ratio of Hip to C7/hip to sacrum in Type 2 (P = 0.01), and Type 3 (P = 0.00) in the comparison of the two cohorts. The multiple linear regression of all parameters showed both general and practical cervical angles were significantly related to TK, C0-C2 and T1 slope (P = 0.01, 0.00 and 0.00, respectively). CONCLUSION: The cervical alignment correlates with their global spine and pelvic curves. And lordosis is not the only presentation in asymptomatic subjects. The degenerative modification of cervical disc angles was the compensation of global spine degeneration for horizontal gaze. Cervical angles are influenced by their TK angles, occipital-C2 joint and the tilt of T1 vertebral body. The occipital-C2 joint has a compensating mechanism in all Roussouly types in cervical spondylosis.

Full-Endoscopic Foraminotomy with a Novel Large Endoscopic Trephine for Severe Degenerative Lumbar Foraminal Stenosis at L5 S1 Level: An Advanced Surgical Technique.

To (i) introduce the technical notes of a novel full-endoscopic foraminotomy with a large endoscopic trephine for the treatment of severe degenerative lumbar foraminal stenosis at L5 S1 level; (ii) assess the primary clinical outcomes of this technique; (iii) compare the effectiveness of this full-endoscopic foraminotomy technique and other previous techniques for lumbar foraminal stenosis. From January 2019 to August 2019, a retrospective study of L5 S1 severe degenerative lumbar foraminal stenosis was performed in our center. All patients who were diagnosed with severe foraminal stenosis at L5 S1 level and failed conservative treatment for at least 6 weeks were identified. Patients with segmental instability or other coexisting contraindications were excluded. A total of 21 patients were enrolled in the study. All patients were treated by full-endoscopic foraminotomy using large endoscopic trephine. The visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated preoperatively and at 1, 3, 6 months, and 1 year after the surgery, and the modified MacNab criteria were used to evaluate clinical outcomes at the last follow-up. There were 10 males and 11 females with a mean age of 66.38 ± 9.51 years. Five patients had a history of lumbar surgery. The mean operative time was 63.57 ± 25.74 min. The mean follow-up time was 13.29 ± 1.38 months. The mean postoperative hospital stay time was 1.29 ± 0.56 days. The mean preoperative VAS score significantly decreased from 7.38 ± 1.02 to 2.76 ± 1.09 (t = 19.759, P < 0.01), 2.25 ± 1.02 (t = 21.508, P < 0.01), 1.60 ± 1.05 (t = 31.812, P < 0.01), and 1.45 ± 1.10 (t = 25.156, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. The mean preoperative ODI score significantly decreased from 64.66% ± 4.91% to 30.69% ± 4.59% (t = 33.724, P < 0.01), 29.44% ± 4.50% (t = 32.117, P < 0.01), 24.22% ± 4.14% (t = 33.951, P < 0.01), and 22.44% ± 4.94% (t = 30.241, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. At the last follow-up, 19 patients (90.48%) got excellent or good outcomes. One patient suffered postoperative dysesthesia, and the symptoms were controlled by conversion treatment. One patient took revision surgery due to the incomplete decompression. There were no other major complications. Percutaneous endoscopic decompression is minimally invasive spine surgery. However, the application of endoscopic decompression for L5 S1 foraminal stenosis is relatively difficult due to the high iliac crest and narrow foramen. Full-endoscopic foraminotomy with the large endoscopic trephine is an effective and safe technique for the treatment of degenerative lumbar foraminal stenosis.

Common underlying diseases do not contribute in determining the causes of sudden unexplained death.

BACKGROUND: Underlying diseases have a statistically significant positive correlation to sudden death. However, sudden unexplained death (SUD) is different from sudden death, as there is no clinical evidence to support the sudden death due to the original underlying disease, nor a lethal pathological basis to be found during autopsy. In addition, SUD are more common in young, previously healthy individuals, usually without any signs of disease, with no positive lesions found after autopsy. Therefore, a causal relationship between SUD and the underlying disease needs to be further explored. This study aimed to explore the role that common underlying diseases play in patients with SUD and to reveal the correlation between them. METHODS: The medical records, history and case information of 208 patients with SUD were collected for the survey. All these SUD occurred in the emergency room of Peking University Third Hospital from January 2006 to December 2009. The patients were stratified by with and without common underlying diseases. To examine possible associations between the underlying diseases and the cause of unexplained sudden death, the chi-squared and Fisher's exact tests were used. RESULTS: Among the 208 patients, 65 were diagnosed with common underlying diseases while 143 were not. Within these two groups, there were 45 patients for whom the clear cause of death was determined. However, there were no statistically significant differences or strong associations (χ(2) = 1.238, P > 0.05) between the 11 patients with (16.90%) and 34 without (23.78%) common underlying disease among these 45 patients. We also found that occurrence of the common underlying diseases, such as neurological system, cardiovascular and pulmonary system diseases, are not statistically significant (P > 0.05) in the diagnosis of the SUD. CONCLUSION: Common underlying diseases make no obvious contributions to SUD and are not useful in diagnosing the underlying reasons for death.

Time-series analysis of the relationship between air quality, temperature, and sudden unexplained death in Beijing during 2005 - 2008.

BACKGROUND: There is a yearly increase in the rate of sudden unexplained death (SUD), even through extensive physical examination and the testing of a large number of biomarkers, the cause of sudden death in patients previously in good health cannot be fully determined. During clinical practice, a spatial aggregation phenomenon has been observed in the incidence of sudden unexplained death. Previous research has shown that environmental factors, such as air pollution, weather conditions, etc., have a significant impact on human health. In the wake of the continuous environmental damage, the relationship between environmental factors and sudden unexplained death still needs to be studied. To study the relationship between sudden unexplained death and air quality and temperature, commonly used markers such as particulate matter of aerodynamic diameter < 10 µm (PM(10)), daily average concentration of the gaseous pollutants sulfur dioxide (SO2) and nitrogen dioxide (NO2), and the daily average temperature were investigated. METHODS: The methods include collecting the data of sudden unexplained death; air quality monitoring; meteorological monitoring from January 1, 2005 to December 31, 2008; utilizing generalized additive models (GAM); controlling the influential factors such as secular trend, seasonal trend, and Sunday dummy variable; and analyzing the correlation between daily inhalable particle concentration, daily average temperature, and the number of daily SUD. RESULTS: There was no statistical significance between the daily inhalable particle and daily incidence of sudden unexplained death. Incidence rate of sudden unexplained death had nonlinear positive correlation with daily temperature. When the temperature was 5°C above the daily average temperature, the daily incidence of sudden unexplained death went up with the rising temperature. CONCLUSION: Temperature may be one of the key risk factor or precipitating factor of SUD.

Analysis of the prodromal symptoms of unexplained sudden death in patients with or without underlying diseases.

BACKGROUND: In recent years, the incidence of unexplained sudden death has risen significantly across the world. However, it occurred suddenly, often in young apparently healthy individuals and almost 50% of the patients did not have any warning signals or symptoms. Therefore, the prodromal symptoms before the incident are extremely important for early prediction of sudden death. In this article, we aimed to explore the value of prodromal symptoms for unexplained sudden death and whether the prodromal symptoms have a predictive function to unexplained sudden death (USD) without underlying diseases. METHODS: A total of 208 sudden death cases were selected for the survey in the Emergency Department of Peking University Third Hospital from January 2006 to December 2009 and their medical records were reviewed. The patients were divided into two groups, 65 patients had underlying diseases while 143 had not underlying diseases. In the meantime, their prodromal symptoms were collected and compared, prodromal symptoms including chest distress, dyspnea, syncope, fever, headache, vomiting, etc. RESULTS: Patients with underlying diseases were compared to those without underlying diseases associated with sudden death; there was no significant difference in gender and age distribution. Among the 208 cases, 39 cases (18.75%) had prodromal symptoms, patients with underlying diseases had prodromal symptoms in 12 cases (18.46%), while patients without underlying diseases had prodromal symptoms in 27 cases (18.88%). The difference between the two groups with prodromal symptoms was not statistically significant (P > 0.05). CONCLUSIONS: Prodromal symptoms are extremely important warning signals in the occurrence of USD. It has equally important predictive value for patients both with and without underlying diseases, especially in predicting sudden death caused by cardiopulmonary and neurological diseases.