Dynamic and large field of view photonic resonator absorption microscopy for ultrasensitive digital resolution detection of nucleic acid and protein biomarkers.

In this paper, we describe a biosensing instrument based on our previously developed photonic resonator absorption microscope (PRAM) that incorporates autofocus, digital representation of the gold nanoparticle (AuNP) accumulation, and the ability to gather time-series image sequences of AuNP attachment and detachment from the photonic crystal (PC) surface. The combined capabilities are used to fully automate PRAM image collection during biomolecular assays to enable tiling of PRAM images to provide millimeter-scale field of view. The instrument can also gather PRAM "movies" that enables digital showcasing and dynamic counting AuNPs as they arrive and depart from the PC surface. We utilize the capabilities in the context of two biomolecular assays for detection of protein biomarkers in a conventional AuNP-tagged sandwich format. Utilizing dynamic counting of AuNP attachment and detachment events during the assay we present a detection for microRNA-375 (miRNA-375) down to 1 aM with a 10-min, room temperature, enzyme-free approach, while revealing characteristics of the binding-rate and unbinding-rate of the biomolecular interactions. Our instrument can potentially find broad applications in multiplexed point-of-care diagnostic testing, and as a general-purpose tool for quantitative characterization of biomolecular binding kinetics with single-molecule resolution.

Digital Immunoassay for Rapid Detection of SARS-CoV-2 Infection in a Broad Spectrum of Animals.

The ability of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) to infect a wide-range of species raises significant concerns regarding both human-to-animal and animal-to-human transmission. There is an increasing demand for highly sensitive, rapid, and simple diagnostic assays that can detect viral infection across various species. In this study, we developed a biosensor assay that adapted a monoclonal-antibody (mAb)-based blocking ELISA format into an Activate Capture + Digital Counting (AC + DC)-based immunoassay. The assay employs a photonic crystal (PC) biosensor, gold-nanoparticle (AuNP) tags, SARS-CoV-2 nucleocapsid (N) protein, and specific anti-N mAb to detect antibody responses in animals exposed with SARS-CoV-2. We demonstrated a simple 2-step 15-min test that was capable of detecting as low as 12.5 ng of antibody in controlled standard serum samples. Based on an evaluation of 176 cat serum samples with known antibody status, an optimal percentage of inhibition (PI) cut-off value of 0.588 resulted in a diagnostic sensitivity of 98.3% and a diagnostic specificity of 96.5%. The test is highly repeatable with low variation coefficients of 2.04%, 2.73%, and 4.87% across different runs, within a single run, and on a single chip, respectively. The test was further employed to detect antibody responses in multiple animal species as well as investigate dynamics of antibody response in experimentally infected cats. This test platform provides an important tool for rapid field surveillance of SARS-CoV-2 infection across multiple species.

A Machine Learning Framework for Screening Plasma Cell-Associated Feature Genes to Estimate Osteoporosis Risk and Treatment Vulnerability.

Osteoporosis, in which bones become fragile owing to low bone density and impaired bone mass, is a global public health concern. Bone mineral density (BMD) has been extensively evaluated for the diagnosis of low bone mass and osteoporosis. Circulating monocytes play an indispensable role in bone destruction and remodeling. This work proposed a machine learning-based framework to investigate the impact of circulating monocyte-associated genes on bone loss in osteoporosis patients. Females with discordant BMD levels were included in the GSE56815, GSE7158, GSE7429, and GSE62402 datasets. Circulating monocyte types were quantified via CIBERSORT, with subsequent selection of plasma cell-associated DEGs. Generalized linear models, random forests, extreme gradient boosting (XGB), and support vector machines were adopted for feature selection. Artificial neural networks and nomograms were subsequently constructed for osteoporosis diagnosis, and the molecular machinery underlying the identified genes was explored. SVM outperformed the other tuned models; thus, the expression of several genes (DEFA4, HLA-DPB1, LCN2, HP, and GAS7) associated with osteoporosis were determined. ANNs and nomograms were proposed to robustly distinguish low and high BMDs and estimate the risk of osteoporosis. Clozapine, aspirin, pyridoxine, etc. were identified as possible treatment agents. The expression of these genes is extensively posttranscriptionally regulated by miRNAs and m6A modifications. Additionally, they participate in modulating key signaling pathways, e.g., autophagy. The machine learning framework based on plasma cell-associated feature genes has the potential for estimating personalized risk stratification and treatment vulnerability in osteoporosis patients.

Simultaneous measurement of bidirectional magnetic field and temperature with a dual-channel sensor based on the whispering gallery mode.

What we believe is a novel dual-channel whispering gallery mode (WGM) sensor for concurrently measuring bidirectional magnetic field and temperature is proposed and demonstrated. Two sensing microcavities [magnetic fluid (MF)-infiltrated capillary and polydimethylsiloxane (PDMS)-coated microbottle, respectively, referred as Channel 1 (CH1) and Channel 2 (CH2)] are integrated into a silica capillary to facilitate the dual-channel design. Resonant wavelengths corresponding to CH1 and CH2 mainly depend on the change in the magneto-induced refractive index and the change in the thermo-induced parameter (volume and refractive index) of the employed functional materials, respectively. The MF-infiltrated capillary enables bidirectional magnetic field sensing with maximum sensitivities of 46 pm/mT and -3 pm/mT, respectively. The PDMS-coated structure can realize the temperature measurement with a maximum sensitivity of 79.7 pm/°C. The current work possesses the advantage of bidirectionally magnetic tunability besides the temperature response, which is expected to be used in field such as vector magnetic fields and temperature dual-parameter sensing.

High-sensitivity vector magnetic field sensor based on a V-shaped multimode-no-core-multimode fiber structure.

This work proposes and investigates a bent multimode-no-core-multimode optical fiber structure for vector magnetic field sensing applications. The bent no-core fiber (NCF) serves as the sensing area, and the gold film is deposited on its surface to excite the surface plasmon resonance effect. Due to the strong evanescent field of the unclad and bent NCF, the as-fabricated sensor exhibits a high sensitivity of 5630 nm/RIU in the refractive index range of 1.36-1.39. Magnetic fluid is employed as the magneto-sensitive material for magnetic field sensing, exhibiting a high magnetic field intensity sensitivity of 5.74 nm/mT and a high magnetic field direction sensitivity of 0.22 nm/°. The proposed sensor features a simple structure, low cost, point sensing, and excellent mechanical performance.

Enhanced sensitivity of temperature and magnetic field sensor based on FPIs with Vernier effect.

A kind of temperature and magnetic field sensor using Fabry-Perot interferometers (FPIs) and Vernier effect to enhance sensitivity is proposed. The sensor structure involves filling the FP air cavities with polydimethylsiloxane (PDMS) and magnetic fluid (MF) to create the PDMS and MF cavities for temperature and magnetic field detection, respectively. The two cavities are reflective structures, which are interconnected in series through a fiber-optic circulator. Experimental data demonstrates that the Vernier effect effectively enhances the sensor sensitivity. The average temperature sensitivity of the sensor is 26765 pm/°C within the range of 35∼39.5°C. The magnetic field intensity sensitivity is obtained to be -2245 pm/mT within the range of 3∼11 mT. The sensitivities of the temperature and magnetic field using the Vernier effect are about five times larger than those of the corresponding single FP cavity counterparts.

Yam Gruel alone and in combination with metformin regulates hepatic lipid metabolism disorders in a diabetic rat model by activating the AMPK/ACC/CPT-1 pathway.

BACKGROUND: As independent and correctable risk factors, disturbances in lipid metabolism are significantly associated with type 2 diabetes mellitus (T2DM). This research investigated the mechanism underlying the lipid-regulating effects of Yam Gruel in diabetic rats. METHODS: First, rats in the control group were given a normal diet, and a diabetic rat model was established via the consumption of a diet that was rich in both fat and sugar for six weeks followed by the intraperitoneal injection of streptozotocin (STZ). After the model was established, the rats were divided into five distinct groups: the control group, model group, Yam Gruel (SYZ) group, metformin (MET) group, and combined group; each treatment was administered for six weeks. The fasting blood glucose (FBG), body and liver weights as well as liver index of the rats were determined. Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), aspartic acid transaminase (AST), alanine aminotransferase (ALT), and nonesterified fatty acid (NEFA) levels were measured. Oil Red O staining was used to assess hepatic steatosis. In addition, the levels of Phospho-acetyl-CoA carboxylase (p-ACC), acetyl coenzyme A carboxylase (ACC), AMP-activated protein kinase (AMPK), Phospho-AMPK (p-AMPK), carnitine palmitoyl transferase I (CPT-1), and Malonyl-CoA decarboxylase (MLYCD) in liver tissues were measured by real-time PCR (q-PCR) and western blotting. RESULTS: After 6 weeks of treatment, Yam Gruel alone or in combination with metformin significantly reduced FBG level, liver weight and index. The concentrations of lipid indices (TG, TC, NEFA, and LDL-C), the levels of liver function indices (ALT and AST) and the degree of hepatic steatosis was improved in diabetic rats that were treated with Yam Gruel with or without metformin. Furthermore, Yam Gruel increased the protein levels of p-ACC/ACC, p-AMPK/AMPK, MLYCD, and CPT-1, which was consistent with the observed changes in gene expression. Additionally, the combination of these two agents was significantly more effective in upregulating the expression of AMPK pathway-related genes and proteins. CONCLUSIONS: These results demonstrated that Yam Gruel may be a potential diet therapy for improving lipid metabolism in T2DM patients and that it may exert its effects via AMPK/ACC/CPT-1 pathway activation. In some respects, the combination of Yam Gruel and metformin exerted more benefits effects than Yam Gruel alone.

The incidence and risk factors of unplanned removal of peripherally inserted central catheters among adult patients: A multi-centre cohort study.

AIMS AND OBJECTIVES: (i) To estimate the national incidence of unplanned removal of peripherally inserted central catheters (PICCs) in China. (ii) To explore the associated risk factors to provide evidence for the prevention. DESIGN: A multi-centre prospective cohort study. METHODS: A representative sample of 3222 Chinese adult patients with successful PICC insertion was recruited for the PICC Safety Management Research (PATH) using a two-stage cluster sampling method from December 2020 to June 2022. Sixty hospitals from seven Chinese provinces representing all geographical regions were selected. Demographic information and PICC characteristics were collected using a standard online case report form. Risk factors for the unplanned removal of PICCs were assessed using a cause-specific hazard model and verified using a sub-distribution hazard model. STROBE guidelines were followed in reporting this study. RESULTS: Three thousand one hundred and sixty-six patients were included in the final analysis with a mean age of 59 years and a total of 344,247 catheter days. The incidence of unplanned removal was 10.04%. Female, with thrombosis history, PICC insertion due to infusion failure, valved catheter and double-lumen catheter were risk factors, whereas longer insertion and exposure length were protective factors in the cause-specific hazard model. Higher BMI became an independent risk factor in the sub-distribution hazard model. CONCLUSIONS: Unplanned removal of PICCs is a serious clinical challenge in China. Our findings call for prevention strategies targeting the identified risk factors. RELEVANCE TO CLINICAL PRACTICE: Our study characterised the epidemiology of unplanned removal of PICCs among Chinese adult inpatients, highlighting the need for prevention among this population and providing a basis for the formulation of relevant prevention strategies. PATIENT OR PUBLIC CONTRIBUTION: Patients contributed through sharing their information required for the case report form. Healthcare professionals who provide direct care to the patient at each medical centre contributed by completing the online case report form.

Comprehensive treatment of deep frostbite of multiple fingers after trauma: A case report.

BACKGROUND: Frostbite is becoming increasingly common in urban environments, and severe cases can lead to tissue loss. The treatment goal is to preserve tissue and function; the sooner appropriate treatment is administered, the more tissue can be saved. However, not every patient with deep frostbite seeks medical care promptly. CASE SUMMARY: We report the case of a 73-year-old male patient who was lost in the wilderness for 2 d due to trauma and confusion. He experienced deep frostbite on multiple fingers. Treatment should not be discontinued for patients with deep frostbite who present after the optimum treatment timing. Bullae that no longer form (bloody) blisters within 24 h of aspiration should be removed. Mucopolysaccharide polysulfate cream has clinical value in frostbite treatment. The patient was transferred to Chinese Academy of Medical Sciences and Peking Union Medical College Hospital 12 h after being rescued. The patient had contraindications for thrombolysis, the most effective treatment, due to intracranial hemorrhage and presenting past the optimum treatment timing. We devised a comprehensive treatment plan, which involved delayed use vasodilators and high-pressure oxygen therapy at day 49 post-injury. We experimented with mucopolysaccharide polysulfate cream to treat the frostbite. The aim of the treatment was to safeguard as much tissue as possible. In the end, the fingers that suffered from frostbite were able to be partially preserved. CONCLUSION: The case indicated that patients with severe frostbite who missed the optimal treatment time and had contraindications for thrombolysis could still partially preserve the affected limbs through comprehensive treatment.

Bauhinia championii alleviates extracellular matrix degradation in IL-1ß induced chondrocytes via miRNA-145-5p/TLR4/NF-κB axis.

Bauhinia championii is a herbal medicine used to treat osteoarthritis (OA) in Chinese traditional medicine. However, the molecular mechanisms underlying the therapeutic effects of this medicinal herb against OA have rarely been reported. Given that it has been established that extracellular matrix metabolism plays an important role in the pathogenesis of OA, the present study focused on the effects and mechanisms of Bauhinia championii in the regulation of extracellular matrix metabolism in chondrocytes induced by IL-1ß. Rat chondrocytes were isolated, cultured and identified in vitro. The CCK-8 method was used to detect the cell viability of Bauhinia championii aqueous extract (BCAE)-treated chondrocytes. The chondrocyte inflammatory and degeneration models were induced by 10 ng/mL IL-1ß, then chondrocytes were grouped into different groups to evaluate the effect of BCAE on extracellular matrix degradation and the regulation of TLR4/NF-κB signaling pathway. Furthermore, whether the regulatory effect of BCAE on TLR4/NF-κB signaling pathway is related to miRNA-145-5p was also investigated by cell transfection. We found that BCAE promoted chondrocyte viability in a dose- and time-dependent manner. BCAE delayed chondrocyte degeneration induced by IL-1ß. BCAE could reduce the degradation of the cartilage extracellular matrix by inhibiting the TLR4/NF-κB signaling pathway. miRNA-145-5p negatively regulated the expression of TLR4 in chondrocytes, while BCAE could upregulate the expression of miRNA-145-5p in chondrocytes induced by IL-1ß. These results suggest that BCAE upregulates the expression of miRNA-145-5p to inhibit the TLR4/NF-κB signaling pathway, thereby alleviating the metabolic imbalance of the extracellular matrix and protecting chondrocytes from degeneration.

In-line temperature-compensated vector magnetic field sensor with side-polished fiber.

A novel, to the best of our knowledge, vector magnetic field sensor with temperature compensation is proposed and investigated. The proposed sensor is realized by side polishing a multi-mode optical fiber and adopting the surface plasmon resonance (SPR) effect. The side-polished surface is coated with a magnetic fluid (MF) and polydimethylsiloxane (PDMS) successively along the fiber axis. The as-fabricated sensor can be used not only for magnetic field strength and direction sensing, but also for temperature detection. The achieved magnetic field intensity sensitivities are 1720 pm/mT (90° direction) and -710 pm/mT (0° direction), and the temperature sensitivity is -2070 pm/°C. On top of its temperature compensation ability, the easy fabrication and very high sensitivity of the proposed sensor are attractive features for vector magnetic field sensing applications.

Grip strength is an important predictor for nutritional risk and early postoperative ambulation in gastrointestinal tumors undergoing laparoscopic surgery: a prospective multicenter clinical study.

BACKGROUND: Using grip strength as a predictor of nutritional risk and early ambulation for gastrointestinal tumor surgery and determining its critical value have not been reported. This study was designed to explore the influencing factors of early postoperative ambulation ability for patients with gastrointestinal tumors who underwent laparoscopic surgery. METHODS: Four-hundred twenty-seven patients with gastrointestinal tumors who underwent laparoscopic surgery at three tertiary A hospitals in Beijing were prospectively enrolled. Subsequently, logistic regression analysis was conducted to determine the independent predictors of early postoperative ambulation. Logistic regression analyses for the different gender were also performed. In addition, the effectiveness of preoperative grip strength measurement in nutritional risk assessment was analyzed by using nutritional risk score 2002 (NRS 2002) as a control. RESULTS: The included cases were comprised of 283 male and 144 female patients, with an age of 59.35 ± 11.70 years. Gender, preoperative grip strength, operative time, and number of indwelling tubes were independent predictors of early postoperative ambulation. In the male group, lower preoperative grip strength and more indwelling tubes were independent risk factors for early postoperative ambulation. In the female group, lower preoperative grip strength and extended operating time were independent risk factors. Moreover, preoperative grip strength (male < 32 kg, female < 21 kg) can be used as a risk predictor for both preoperative nutritional risk and early postoperative ambulation. CONCLUSIONS: As a simple and objective measure of muscle strength, grip strength measurement is expected to be an effective predictor for both early postoperative ambulation ability and nutritional status of patients.

Revealing the interaction mechanism of pulsed laser processing with the application of acoustic emission.

The mechanisms of interaction between pulsed laser and materials are complex and indistinct, severely influencing the stability and quality of laser processing. This paper proposes an intelligent method based on the acoustic emission (AE) technique to monitor laser processing and explore the interaction mechanisms. The validation experiment is designed to perform nanosecond laser dotting on float glass. Processing parameters are set differently to generate various outcomes: ablated pits and irregular-shaped cracks. In the signal processing stage, we divide the AE signals into two bands, main and tail bands, according to the laser processing duration, to study the laser ablation and crack behavior, respectively. Characteristic parameters extracted by a method that combines framework and frame energy calculation of AE signals can effectively reveal the mechanisms of pulsed laser processing. The main band features evaluate the degree of laser ablation from the time and intensity scales, and the tail band characteristics demonstrate that the cracks occur after laser dotting. In addition, from the analysis of the parameters of the tail band very large cracks can be efficiently distinguished. The intelligent AE monitoring method was successfully applied in exploring the interaction mechanism of nanosecond laser dotting float glass and can be used in other pulsed laser processing fields.

Spontaneous migration of peripherally inserted central catheter into the azygos vein during postoperative gastrointestinal dysmotility: A case report.

RATIONALE: The spontaneous migration of the peripherally inserted central catheter (PICC) is the displacement of the PICC tip from a satisfactory documented position in the superior vena cava (SVC) into its adjacent veins after several days or months of PICC insertion, and most frequently occurs in the ipsilateral internal jugular vein. However, it is rarely reported to detect migration of PICC tip into the azygos vein in patients who suffered from gastrointestinal dysmotility after abdominal surgery. We report 2 cases of spontaneous malposition of PICC into the azygos vein here and discuss the predisposing factors and processing procedures of this condition. PATIENT CONCERNS: Two female patients with pancreatic disease were inserted PICCs on the left limbs before the abdominal surgery. After the surgery, 1 patient suffered from gastroparesis, and the other suffered from constipation. The nurses found that blood could not be aspirated from the PICCs while normal saline could be injected through the PICCs smoothly. DIAGNOSES: We identified the position of the PICC tip step-by-step, using ultrasound, intracavitary electrocardiogram, and chest X-ray, and confirmed that the tip of the PICC migrated into the azygos vein. INTERVENTIONS: The patients were placed in the semi-reclining position from the supine position, and blood could be easily aspirated from the PICC after flushing with the push-pause flush technique. Intracavitary electrocardiogram displayed the elevated P, indicating that the PICC tip reentered the SVC and was at the lower 1/3 of SVC. OUTCOMES: The PICCs of the 2 patients functioned well afterward and were removed after the parenteral nutrition support was completed. LESSONS: It is critical to assess the function of the PICC before every time of infusion. For patients who undergo abdominal surgery with PICC on the left side, when they had gastrointestinal dysmotility combined with PICC dysfunction, the possibility of spontaneous migration of PICC tip into the azygos vein should be considered.

Crack growth analysis of ultraviolet nanosecond laser scanning glass with acoustic emission.

Undesirable crossing crack defects are prone to occur in the laser processing of glass, but a comprehensive analysis of the crack mechanism is absent. We apply an acoustic emission (AE) monitoring technique in the glass's laser scanning to reveal the crack phenomenon. A two-step experiment (single-line and multi-line scanning) is designed to present the crossing crack's occurrence and growth, and the corresponding AE signals are collected and analyzed in different domains. The time-domain AE feature (root mean square) correlates strongly with the laser ablation intensity in the single-line scanning experiment, and the frequency content of 150 âˆ¼ 200 kHz is extracted as the crack characteristic in the multi-line experiment. The crossing crack growth is proved to be generated by the rapid release of thermal stress in the overlapped heat-affected zone by a brief mechanism discussion. This paper interprets the crack behavior in glass's laser scanning and provides a basis for other monitoring research on laser processing.

Photonic Crystal Enhanced Fluorescence: A Review on Design Strategies and Applications.

Nanoscale fluorescence emitters are efficient for measuring biomolecular interactions, but their utility for applications requiring single-unit observations is constrained by the need for large numerical aperture objectives, fluorescence intermittency, and poor photon collection efficiency resulting from omnidirectional emission. Photonic crystal (PC) structures hold promise to address the aforementioned challenges in fluorescence enhancement. In this review, we provide a broad overview of PCs by explaining their structures, design strategies, fabrication techniques, and sensing principles. Furthermore, we discuss recent applications of PC-enhanced fluorescence-based biosensors incorporated with emerging technologies, including nucleic acids sensing, protein detection, and steroid monitoring. Finally, we discuss current challenges associated with PC-enhanced fluorescence and provide an outlook for fluorescence enhancement with photonic-plasmonics coupling and their promise for point-of-care biosensing as well monitoring analytes of biological and environmental relevance. The review presents the transdisciplinary applications of PCs in the broad arena of fluorescence spectroscopy with broad applications in photo-plasmonics, life science research, materials chemistry, cancer diagnostics, and internet of things.

Dual-channel-in-one temperature-compensated all-fiber-optic vector magnetic field sensor based on surface plasmon resonance.

All-fiber-optic magnetic field sensor integrated with magnetic fluid has been investigated for decades, accompanied by the commitment to vectorization, miniaturization, integration and solving the temperature cross-sensitivity caused by thermo-optic effect of magnetic fluid. A kind of dual-channel-in-one temperature-compensated all-fiber-optic vector magnetic field sensor was proposed and investigated theoretically in this work. Three optical surfaces, including two sensing surfaces (plated with gold film of 40 nm thickness and then coated with magnetic fluid and polydimethylsiloxane, respectively, referred as CH1 and CH2) and one reflective surface, were integrated on a single-mode fiber tip to facilitate the dual-channel-in-one design. The Kretschmann configurations were formed by the waveguide fiber, gold film and functional materials at the sensing surfaces (CH1 and CH2). Surface plasmon resonance was excited in different wavelength bands corresponding to CH1 and CH2. Attenuation wavelengths corresponding to CH1 and CH2 depend on the magneto-induced and temperature-induced refractive index change of functional materials, respectively, which makes the temperature-compensated magnetic field sensing possible. The non-centrosymmetric evanescent field generated by micro-fiber-tip-prism enables the vector magnetic field sensing. Especially, the length of the sensing area is only 115.5 µm, which achieves ultra-integration and miniaturization. The current work provides a novel scheme for designing all-fiber-optic vector magnetic field sensing based on magnetic fluid and demonstrates the realization of lab-on-a-fiber and then promotes the industrial application of all-fiber-optic vector magnetic field sensing devices.

Effects of enhanced hygiene measures on severe diarrhea and anastomotic leak after colorectal cancer surgery: the experience of a tertiary referral hospital in China.

Background: The 2019 novel coronavirus (COVID-19) global pandemic has greatly changed the mode of hospital admissions. This study summarized and analyzed the incidence of severe diarrhea and anastomotic leakage during different periods for colorectal cancer surgery. Methods: From January 2017 to September 2020, 2,619 colorectal operations were performed in Peking Union Medical College Hospital. In contrast with previous years, enhanced hand hygiene training, more frequent ventilation of the wards, and separate bed treatments for patients were implemented in 2020. Data on incidence of severe diarrhea and anastomotic leakage were retrieved and collected. Results: The number of cases of severe diarrhea after colorectal surgery was 32 (4.60%), 24 (3.33%), 32 (3.83%), and 11 (2.99%) in 2017, 2018, 2019, and 2020 respectively, while the incidence of anastomotic leakage was 3.30% (23/696), 3.75% (27/720), 2.87% (24/835), and 2.17% (8/368), respectively. There was no significant difference in the incidence of postoperative severe diarrhea or anastomotic leakage across the various years. Conclusions: The number of colorectal surgeries in 2020 was significantly decreased due to the COVID-19 pandemic. Among the different years, no difference was observed regarding the incidence of postoperative flora disorder or anastomosis leakage. Enhanced hygiene measures during the COVID-19 epidemic partially contributed to the decrease of severe diarrhea and anastomotic leakage.

Dual-channel temperature-compensated vector magnetic field sensor based on lab-on-a-fiber-tip.

Fiber-optic magnetic field sensors based on magnetic fluid (MF) is encountering with thermal effects and demand for vectorization for several years. A common solution is to use axially processed fiber cascaded with fiber Bragg grating (FBG). However, the length of such sensors is usually in centimeter-level, which restricts the sensing applications in narrow space and gradient field cases. In this work, we present an ultracompact reflection-type dual-channel sensor for vector magnetic field (Channel 1, referred as CH1) and temperature (Channel 2, referred as CH2) monitoring, which is composed of a pair of gold-plated wedge-shaped multimode fiber (MMF) tip and gold-plated multimode-no-core fiber (MNF) tip. The surface plasmon resonance (SPR) effect was adopted. The two sensor probes are coated with magnetic-field-sensitive MF and temperature-sensitive polydimethylsiloxane (PDMS), respectively. The issue of vector magnetic field and temperature cross-sensitivity is tactfully resolved. Importantly, the proposed sensing probes are ultracompact and the spatial resolution is extremely small (615 µm for CH1 based on wedge-shaped fiber tip and 2 mm for CH2 based on MNF), which is very helpful for narrow space and gradient magnetic field detection. The obtained magnetic field intensity sensitivities are 1.10 nm/mT (90° direction) and -0.26 nm/mT (0° direction), and temperature sensitivity is -3.12 nm/°C.

Fiber-Optic Vector-Magnetic-Field Sensor Based on Gold-Clad Bent Multimode Fiber and Magnetic Fluid Materials.

A kind of bent multimode fiber (MMF) vector magnetic sensor based on surface plasmon resonance (SPR) was proposed. By plating gold film on the curved part of the bent multimode fiber, the surface plasmon mode (SPM) was excited via a whispering gallery mode (WGM). Fabricating the structure only required bending the fiber and plating it with gold, which perfectly ensured the integrity of the fiber and made it more robust compared with other structures. The sensor used magnetic fluid (MF) as the magnetically sensitive material. Through monitoring the shift of the surface plasmon resonance dip, the as-fabricated sensor not only had a high magnetic field intensity sensitivity of 9749 pm/mT but could also measure the direction of a magnetic field with a high sensitivity of 546.5 pm/°. The additional advantages of the proposed sensor lay in its easy fabrication and good integrity, which make it attractive in the field of vector-magnetic-field sensing.