Multiple Magneto-Optical Microrobotic Collectives with Selective Control in Three Dimensions Under Water.

Inspired by natural swarms, various methods are developed to create artificial magnetic microrobotic collectives. However, these magnetic collectives typically receive identical control inputs from a common external magnetic field, limiting their ability to operate independently. And they often rely on interfaces or boundaries for controlled movement, posing challenges for independent, three-dimensional(3D) navigation of multiple magnetic collectives. To address this challenge, self-assembled microrobotic collectives are proposed that can be selectively actuated in a combination of external magnetic and optical fields. By harnessing both actuation methods, the constraints of single actuation approaches are overcome. The magnetic field excites the self-assembly of colloids and maintains the self-assembled microrobotic collectives without disassembly, while the optical field drives selected microrobotic collectives to perform different tasks. The proposed magnetic-photo microrobotic collectives can achieve independent position and path control in the two-dimensional (2D) plane and 3D space. With this selective control strategy, the microrobotic collectives can cooperate in convection and mixing the dye in a confined space. The results present a systematic approach for realizing selective control of multiple microrobotic collectives, which can address multitasking requirements in complex environments.

Acid Radical Tolerance of Silane Coatings on Calcium Silicate Hydrate Surfaces in Aggressive Environments: The Role of Nitrate/Sulfate Ratio.

Silane is known as an effective coating for enhancing the resistance of concrete to harmful acids and radicals that are usually produced by the metabolism of microorganisms. However, the mechanism of silane protection is still unclear due to its nanoscale attributes. Here, the protective behavior of silane on the calcium silicate hydrate (C-S-H) surface is examined under the attack environment of nitrate/sulfate ions using molecular dynamics simulations. The findings revealed that silane coating improved the resistance of C-S-H to nitrate/sulfate ions. This resistance is considered the origin of silane protection against harmful ion attacks. Further research on the details of molecular structures suggests that the interaction between the oxygen in the silane molecule and the calcium in C-S-H, which can prevent the coordination of sulfate and nitrate to calcium on the C-S-H surface, is the cause of the silane molecules' strong adsorption. These results are also proved in terms of free energy, which found that the adsorption free energy on the C-S-H surface followed the order silane > sulfate > nitrate. This research confirms the excellent protection performance of silane on the nanoscale. The revealed mechanism can be further used to help the development of high-performance composite coatings.

Klotho reduces the risk of osteoporosis in postmenopausal women: a cross-sectional study of the National Health and Nutrition Examination Survey (NHANES).

BACKGROUND: Osteoporosis (OP) is one of the diseases that endanger the health of the elderly population. Klotho protein is a hormone with anti-aging effects. A few studies have discussed the relationship between Klotho and OP. However, there is still a lack of research on larger populations. This study aims to evaluate the association between OP and Klotho in American postmenopausal women. METHODS: This is a retrospective study. We searched the National Health and Nutrition Examination Survey (NHANES) database and collected data of 3 survey cycles, finally involving 871 postmenopausal women over 50 years old in the present study. All participants took dual-energy X-ray absorptiometry examination and serum Klotho testing at the time of investigation. After adjusting the possible confounding variables, a multivariate regression model was employed to estimate the relationship between OP and Klotho proteins. Besides, the P for trend and restricted cubic spline (RCS) were applied to examine the threshold effect and calculate the inflection point. RESULTS: Factors influencing the occurrence of OP included age, ethnicity, body mass index and Klotho levels. Multivariate regression analysis indicated that the serum Klotho concentration was lower in OP patients than that in participants without OP (OR[log2Klotho] = 0.568, P = 0.027). The C-index of the prediction model built was 0.765, indicating good prediction performance. After adjusting the above-mentioned four variables, P values for trend showed significant differences between groups. RCSs revealed that when the Klotho concentration reached 824.09 pg/ml, the risk of OP decreased drastically. CONCLUSION: Based on the analysis of the data collected from the NHANES database, we propose a correlation between Klotho and postmenopausal OP. A higher serum Klotho level is related to a lower incidence of OP. The findings of the present study can provide guidance for research on diagnosis and risk assessment of OP.

Effects of "fixation-fusion" sequence of lumbar surgery on surgical outcomes for patients with lumbar spinal stenosis: study protocol for a multicenter randomized controlled trial.

BACKGROUND: New-onset neurological symptoms such as numbness and pain in lower extremities might appear immediately after conventional lumbar interbody fusion (LIF) surgery performed in patients with lumbar spinal stenosis. METHODS AND ANALYSIS: This is a multicenter, randomized, open-label, parallel-group, active-controlled trial investigating the clinical outcomes of modified LIF sequence versus conventional LIF sequence in treating patients with lumbar spinal stenosis. A total of 254 eligible patients will be enrolled and randomized in a 1:1 ratio to either modified LIF sequence or conventional LIF sequence group. The primary outcome measure is the perioperative incidence of new-onset lower extremity neurological symptoms, including new adverse events of pain, numbness, and foot drop of any severity. Important secondary endpoints include visual analogue scale (VAS) pain score and lumbar Japanese Orthopaedic Association (JOA) recovery rate. Other safety endpoints will also be evaluated. The safety set used for safety data analysis by the actual surgical treatment received and the full analysis set for baseline and efficacy data analyses according to the intent-to-treat principle will be established as the two analysis populations in the study. CONCLUSION: This study is designed to investigate the clinical outcomes of modified LIF sequences in patients with lumbar spinal stenosis. It aims to provide clinical evidence that the modified "fixation-fusion" sequence of LIF surgery is effective in treating lumbar spinal stenosis. TRIAL REGISTRATION: http://www.chictr.org.cn/index.aspx ID: ChiCTR2100048507.

The Risk Factors for Developing Clustered Vertebral Compression Fractures: A Single-Center Study.

OBJECTIVE: Vertebral compression fractures (VCFs) are common among elderly individuals, but clustered VCFs (C-VCFs) are rare and more severe. The risk factors for C-VCFs remain unclear. Thus, we investigated the clinical characteristics of C-VCFs to identify the imminent fracture risk and improve the treatment for such patients. METHODS: We reviewed the records of patients with VCF at a single medical center between January 2011 and September 2020. Patients who had 4 or more VCFs within 1 year were categorized into the C-VCF group, and the remaining patients were paired into the control group at a ratio of 2:1. We collected demographic, clinical, laboratory, and radiologic information regarding these patients. Univariate analyses, stratified analyses, and multivariate logistic regression were performed to identify the risk factors for C-VCFs. RESULTS: A total of 156 patients were enrolled, of whom 52 were patients with C-VCF. Patients with C-VCF had more severe fractures and pain, with fractures occurring at uncommon sites of the spine. The independent risk factors for C-VCFs included glucocorticoid (GC) treatment (P < .001; hazard ratio [HR], 12.7), recent fracture history (P = .021; HR, 5.5), and lower trabecular bone score (TBS) (P = .044; HR, 1.6). TBS and bone mineral density had greater predictive values in patients without GC treatment (P < .001). Sex, age, and bone turnover biomarkers were not independent risk factors for C-VCFs. CONCLUSION: C-VCFs are rare adverse consequences of severe osteoporosis, for which GC treatment, recent fracture history, and lower TBS are unique risk factors that are valuable for the early identification and prevention of C-VCFs.

Channel-multiplexing for quasi-distributed acoustic sensing with orthogonal codes.

With the increasing demands for large-scale acoustic sensing in many important fields such as hydrophone, vehicle tracking and pipeline monitoring, optical fiber-based distributed acoustic sensing (DAS) has experienced a rapid development. In recent years, quasi-distributed acoustic sensing (QDAS) based on single mode fiber with enhanced point array has emerged, which is a good approach to improve signal-to-noise ratio and deal with the interference-fading problem in DAS. However, similar to DAS, the performance of QDAS is also limited by the finite frequency domain resources. To break the trade-off between sensing bandwidth and distance, additional frequency domain resources are always needed to multiplex the sensing channel. Multiple-input multiple-output coding technology is an approach to realize QDAS channel-multiplexing with the orthogonal probe waves in the same frequency band. In this paper, the iteration constrain condition of the orthogonal codes is modified, and the generation method of more orthogonal codes with high and consistent suppression ratio for QDAS is provided. In the demonstration experiment, the QDAS has successfully achieved 5 times the sensing bandwidth expansion on a 5.19 km fiber based on 5 new orthogonal codes on the same frequency, with 5 m spatial resolution and 10 p ε/H z strain noise level.

High sensitivity and large measurable range distributed acoustic sensing with Rayleigh-enhanced fiber.

In this Letter, high sensitivity and large measurable range distributed acoustic sensing (DAS) based on sub-chirped-pulse extraction algorithm (SPEA) in time domain and dechirp operation is proposed; moreover, Rayleigh-enhanced fiber is used to further improve the quality of Rayleigh scattering (RS) signal. In the proof-of-concept experiment, the RS pattern with 60 µÉ› strain range is generated during a single-shot measurement, while $80.7 \; {\rm p}\varepsilon /\sqrt {\rm Hz}$ strain sensitivity and 28.4 cm spatial resolution are achieved on 920 m fiber.

Continuous chirped-wave phase-sensitive optical time domain reflectometry.

This Letter proposes a novel phase-sensitive optical time domain reflectometry (Φ-OTDR) with continuous chirped-wave (CCW), which can make full use of both time and frequency domain resources. The principle and benefits of CCW Φ-OTDR are elaborated. With the merit of CCW Φ-OTDR, 1.042 MHz sensing bandwidth and 5pε/Hz strain sensitivity are achieved along a 1013 m fiber with 4.4 m spatial resolution. To the best of the authors' knowledge, this is the first time that a Φ-OTDR achieves megahertz sensing bandwidth with metric spatial resolution, and without limiting the frequency feature of the disturbance. The good performance in long-range sensing is also verified over a 49.7 km fiber. More than that, the digital domain flexibility of the proposed scheme can be used to optimize the measured acoustic signal according to its feature and the practical needs.

Continuous chirped-wave phase-sensitive optical time domain reflectometry: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 685 (2021)OPLEDP0146-959210.1364/OL.415087.

Whole-genome sequencing reveals distinct genetic bases for insulinomas and non-functional pancreatic neuroendocrine tumours: leading to a new classification system.

OBJECTIVE: Insulinomas and non-functional pancreatic neuroendocrine tumours (NF-PanNETs) have distinctive clinical presentations but share similar pathological features. Their genetic bases have not been comprehensively compared. Herein, we used whole-genome/whole-exome sequencing (WGS/WES) to identify genetic differences between insulinomas and NF-PanNETs. DESIGN: The mutational profiles and copy-number variation (CNV) patterns of 211 PanNETs, including 84 insulinomas and 127 NF-PanNETs, were obtained from WGS/WES data provided by Peking Union Medical College Hospital and the International Cancer Genome Consortium. Insulinoma RNA sequencing and immunohistochemistry data were assayed. RESULTS: PanNETs were categorised based on CNV patterns: amplification, copy neutral and deletion. Insulinomas had CNV amplifications and copy neutral and lacked CNV deletions. CNV-neutral insulinomas exhibited an elevated rate of YY1 mutations. In contrast, NF-PanNETs had all three CNV patterns, and NF-PanNETs with CNV deletions had a high rate of loss-of-function mutations of tumour suppressor genes. NF-PanNETs with CNV alterations (amplification and deletion) had an elevated risk of relapse, and additional DAXX/ATRX mutations could predict an increased relapse risk in the first 2-year period. CONCLUSION: These WGS/WES data allowed a comprehensive assessment of genetic differences between insulinomas and NF-PanNETs, reclassifying these tumours into novel molecular subtypes. We also proposed a novel relapse risk stratification system using CNV patterns and DAXX/ATRX mutations.

Quasi-distributed acoustic sensing with interleaved identical chirped pulses for multiplying the measurement slew-rate.

Quasi-distributed acoustic sensing (Q-DAS) based on ultra-weak fiber Bragg grating (UWFBG) is currently attracting great attention, due to its high sensitivity and excellent multiplexing capability. Phase-sensitive optical time-domain reflectometry (Φ-OTDR) based on phase demodulation is one of the most promising interrogation schemes for Q-DAS. In this article, a novel interleaved identical chirped pulse (IICP) approach is proposed on the basis of pulse compression Φ-OTDR with coherent detection. Different from the frequency-division-multiplexing (FDM) method, the identical pulses are used for multiplexing in the IICP scheme, and the mixed reflection signals can be demodulated directly, so the inconsistent phase offsets in FDM can be avoided. As a result, this scheme can enlarge the measurement slew-rate (SR) of Q-DAS by times compared with traditional single pulse scheme. In the proof-of-principle experiment, the SR of 28.9 mɛ/s has been achieved with an 860 m sensing range, which is 5 times as that of the traditional single pulse scheme; meanwhile, the response bandwidth has been enlarged by 5 times. The 277 kHz response bandwidth has been achieved, with 5 m spatial resolution and 2.8 pε/Hz strain sensitivity.

Impact of ischemia on sample quality of human pancreatic tissues.

BACKGROUND: Successful clinical evaluation of human tumors relies on proper handling of tissue samples to maximally preserve the cellular and metabolic states in vivo. Pancreatic samples are particularly sensitive to sample mishandling due to the abundance of digestive enzymes. We study how the duration of ischemia, in vivo and ex vivo, both of which are unavoidable lagging periods following surgical dissection, significantly impact the utility of pancreatic samples. METHODS: We systematically characterize a wide range of tissue integrity features, including histological patterns, cellular structures, DNA/RNA quality and activity of major signaling pathways in normal pancreases and pancreatic ductal adenocarcinoma (PDAC) tumor tissues from 41 patients with different ischemia. RESULTS: We reveal that tissues experiencing longer periods of ischemia exhibit significant deterioration and could potentially mislead disease diagnosis and preclinical research. Based on these analyses, we propose an optimal procedure that balances better clinical practice and high tissue sample quality. CONCLUSIONS: Our work provides a guideline for pancreatic sample handling and could have wide implications in clinical diagnosis and translational research.

Integrated principal component analysis denoising technique for phase-sensitive optical time domain reflectometry vibration detection.

This paper presents an integrated principal component analysis (IPCA) technique for denoising phase-sensitive optical time domain reflectometry (Φ-OTDR) sensing data for vibration detection. As one of the key distributed optical fiber sensing technologies, it has attracted great attention, mainly due to its high sensitivity, fast response time, dynamic range, and vibration detection abilities. To enhance vibration detection along the sensing fiber, an appropriate denoising method must be carefully selected. Hence, the PCA that can effectively reduce noise on signals while preserving significant details of the denoised signal is identified. It was then applied on the said signal after digital down-conversion where the noise was greatly reduced. Then angle and phase unwrapping was performed and the vibration was clearly detected with a significant enhancement of the signal-to-noise ratio. As proof of concept, the theoretical analysis and an experimental demonstration of a vibration sensing range of 800 m are presented.

Analysis of germanium waveguide laser performance under external phonon injection.

We propose and design a germanium (Ge) waveguide laser under external phonon injection to reduce laser threshold. To take the phonon injection and the acousto-optic overlap into consideration, the theory of the photon-phonon laser action is further developed. The phononic crystal waveguide is introduced in the laser structure to intensify acousto-optic interaction, and characteristics of photon-phonon laser action in Ge waveguide are analyzed. With the external phonon injection, the two-quantum transition can be facilitated and the photon-phonon laser action is able to be established. The impacts of phononic crystal waveguide parameters, overlap of optical and acoustic fields, and phonon injection on the laser behavior are discussed. Optimal waveguide structural parameters are obtained to enhance acousto-optic interaction through the enlargement of the overlap of optical and acoustic fields. The results indicate that, for a Ge waveguide with the length of 200 µm, the threshold current is reduced to 0.2 µA and the slope efficiency reaches 0.7 W/A when the average phonon injection concentration is about 2.5 × 1021 cm-3. Our proposed scheme offers an effective approach to achieve laser oscillation in integrated Ge waveguide.

The prognostic impact of primary tumor resection in pancreatic neuroendocrine tumors with synchronous multifocal liver metastases.

BACKGROUND: Whether primary tumor resection benefits patients with synchronous multifocal liver metastases from pancreatic neuroendocrine tumors remains controversial. We investigated whether primary tumor resection significantly affects survival in this study. METHODS: A retrospective study of patients with synchronous multifocal liver metastases from pancreatic neuroendocrine tumors between 1998 and 2016 was performed. Patient demographics, operation details, adjuvant treatment, and pathological and survival information were collected, and relevant clinical-pathological parameters were assessed in univariate and multivariate survival analyses. RESULTS: Sixty-three patients were included in this study, including 35 who underwent primary tumor resection. The median survival time and 5-year survival rate of this cohort were 50 months and 44.5%, respectively. Median survival time in the resected group was significantly longer at 72 months than that of 32 months in the nonresected group (p = 0.010). Multivariate analysis showed that primary tumor surgery was a significant independent prognostic factor (HR 0.312, 95% CI: 0.128-0.762, p = 0.011). CONCLUSIONS: Primary tumor resection significantly benefits patients with synchronous multifocal liver metastases from pancreatic neuroendocrine tumors.

Robotic enucleation for pediatric insulinoma with MEN1 syndrome: a case report and literature review.

BACKGROUND: A patient with a rare pediatric insulinoma and MEN1 syndrome was treated by robotic enucleation surgery. CASE PRESENTATION: We present a case of a 9-year-old girl presenting with repeated loss of consciousness, concomitant with a pale face, palpitations, and convulsions, which had persisted for 2 years and had been aggravated during the previous 2 months. She was previously misdiagnosed with epilepsy in another hospital. We further examined her while she was hospitalized. By combining her medical history and imaging examination and lab test results, a diagnosis of insulinoma was confirmed. Sanger-directed sequencing on a peripheral blood sample revealed an MEN1 gene mutation, indicating pediatric insulinoma with MEN1 syndrome. The patient underwent minimally invasive insulinoma enucleation surgery under the Da Vinci robot-assisted system with intraoperative ultrasound (IOUS) connected. The surgery was successfully completed within 65 min, and the girl recovered well postoperatively and no longer experienced symptoms of hypoglycemia. CONCLUSION: This is the first report of a case of pediatric insulinoma treated using robotic enucleation. This experience demonstrates the feasibility and safety of combining robotic surgery with the enucleation procedure as an excellent strategy for pediatric insulinoma.

Ultra-Long-Distance Hybrid BOTDA/Ф-OTDR.

In the distributed optical fiber sensing (DOFS) domain, simultaneous measurement of vibration and temperature/strain based on Rayleigh scattering and Brillouin scattering in fiber could have wide applications. However, there are certain challenges for the case of ultra-long sensing range, including the interplay of different scattering mechanisms, the interaction of two types of sensing signals, and the competition of pump power. In this paper, a hybrid DOFS system, which can simultaneously measure temperature/strain and vibration over 150 km, is elaborately designed via integrating the Brillouin optical time-domain analyzer (BOTDA) and phase-sensitive optical time-domain reflectometry (Ф-OTDR). Distributed Raman and Brillouin amplifications, frequency division multiplexing (FDM), wavelength division multiplexing (WDM), and time division multiplexing (TDM) are delicately fused to accommodate ultra-long-distance BOTDA and Ф-OTDR. Consequently, the sensing range of the hybrid system is 150.62 km, and the spatial resolution of BOTDA and Ф-OTDR are 9 m and 30 m, respectively. The measurement uncertainty of the BOTDA is ± 0.82 MHz. To the best of our knowledge, this is the first time that such hybrid DOFS is realized with a hundred-kilometer length scale.

Design and analysis of electro-absorption modulators with uniaxially stressed Ge/SiGe multiple quantum wells.

We propose and analyze theoretically electro-absorption modulators with uniaxially tensile strained Ge/Si0.19Ge0.81 multiple quantum wells (MQWs). The effects of uniaxial strain on band structures including Γ-valley and L-valley are discussed. The simulation results indicate that the absorption contrast of TE mode is improved by 3.1 dB while the TM mode absorption is reduced by two-thirds under 1.6% uniaxial tensile strain. Zero-biased electro-absorption modulators covering 1380-1550 nm wavelength can be achieved by introducing 0.18%-1.6% uniaxial tensile strain. Taking into account the TE-polarized mode excited usually in integrated waveguides, the proposed scheme provides a promising approach to design highly efficient Ge/SiGe MQWs electro-absorption modulators for on-chip optical transmission and cross-connect applications.

Analysis of threshold current of uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers.

We propose and design uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers with the stress along <100> direction. The micro-bridge structure is adapted for introducing uniaxial stress in Ge/SiGe quantum well. To enhance the fabrication tolerance, full-etched circular gratings with high reflectivity bandwidths of ~500 nm are deployed in laser cavities. We compare and analyze the density of state, the number of states between Γ- and L-points, the carrier injection efficiency, and the threshold current density for the uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers. Simulation results show that the threshold current density of the Ge/SiGe quantum well laser is much higher than that of the bulk Ge laser, even combined with high uniaxial tensile stress owing to the larger number of states between Γ- and L- points and extremely low carrier injection efficiency. Electrical transport simulation reveals that the reduced effective mass of the hole and the small conduction band offset cause the low carrier injection efficiency of the Ge/SiGe quantum well laser. Our theoretical results imply that unlike III-V material, uniaxially tensile stressed bulk Ge outperforms a Ge/SiGe quantum well with the same strain level and is a promising approach for Si-compatible light sources.