Supplementation of Clostridium butyricum Alleviates Vascular Inflammation in Diabetic Mice.

BACKGRUOUND: Gut microbiota is closely related to the occurrence and development of diabetes and affects the prognosis of diabetic complications, and the underlying mechanisms are only partially understood. We aimed to explore the possible link between the gut microbiota and vascular inflammation of diabetic mice. METHODS: The db/db diabetic and wild-type (WT) mice were used in this study. We profiled gut microbiota and examined the and vascular function in both db/db group and WT group. Gut microbiota was analyzed by 16s rRNA sequencing. Vascular function was examined by ultrasonographic hemodynamics and histological staining. Clostridium butyricum (CB) was orally administered to diabetic mice by intragastric gavage every 2 days for 2 consecutive months. Reactive oxygen species (ROS) and expression of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were detected by fluorescence microscopy. The mRNA expression of inflammatory cytokines was tested by quantitative polymerase chain reaction. RESULTS: Compared with WT mice, CB abundance was significantly decreased in the gut of db/db mice, together with compromised vascular function and activated inflammation in the arterial tissue. Meanwhile, ROS in the vascular tissue of db/db mice was also significantly increased. Oral administration of CB restored the protective microbiota, and protected the vascular function in the db/db mice via activating the Nrf2/HO-1 pathway. CONCLUSION: This study identified the potential link between decreased CB abundance in gut microbiota and vascular inflammation in diabetes. Therapeutic delivery of CB by gut transplantation alleviates the vascular lesions of diabetes mellitus by activating the Nrf2/HO-1 pathway.

Design and Development of a Continuum Robot with Switching-Stiffness.

Continuum robots have the advantages of agility and adaptability. However, existing continuum robots have limitations of low stiffness and complex motion modes, and the existing variable stiffness methods cannot achieve a wide range of stiffness changes and fast switching stiffness simultaneously. A continuum robot structure, switching stiffness method, and motion principle are proposed in this article. The continuum robot is made up of three segments connected in series. Each segment comprises multiple spherical joints connected in series, and the joints can be locked by their respective airbag. A valve controls each airbag, quickly switching the segment between rigidity and flexibility. The motion of the segments is driven by three cables that run through the robot. The segment steers only when it is unlocked. When a segment becomes locked, it acts as a rigid body. As a result, by locking and unlocking each segment in sequence, the cables can alternately drive all the segments. The stiffness variation and movement of the continuum robot were tested. The segment's stiffness varies from 36.89 to 1300.95 N/m and the stiffness switching time is 0.25-0.48 s. The time-sharing control mode of segment stiffness and motion is validated by establishing a specific test platform and a mathematical model. The continuum robot's flexibility is demonstrated by controlling the fast bending of different segments sequentially.

Application of imaging techniques in pancreaticobiliary maljunction.

Imaging techniques are useful tools in the diagnosis and treatment of pancreaticobiliary maljunction (PBM). PBM is a precancerous lesion often relative to the disease of the pancreas and biliary tract, for example, cholecystolithiasis, protein plugs, and pancreatitis. For patients with PBM, early diagnosis and timely treatment are highly important, which is largely dependent on imaging techniques. The continuous development of imaging techniques, including endoscopic retrograde cholangiopancreatography, magnetic resonance cholangiopancreatography, computed tomography, ultrasound, and intraoperative cholangiography, has provided appropriate diagnostic and therapeutic tools for PBM. Imaging techniques, including non-invasive and invasive, have distinct advantages and disadvantages. The purpose of this paper is to review the application of various imaging techniques in the diagnosis and treatment of PBM.

Design of an Ankle Exoskeleton That Recycles Energy to Assist Propulsion During Human Walking.

OBJECTIVE: Active exoskeletons can handle different walking conditions, but require bulky components (e.g., motors) that need a significant source of power to do so. Purely passive exoskeletons are lightweight and energy-neutral, containing energy-recycling mechanisms that capture energy loss during negative power phases and return it as walking assistance. However, they are usually designed for stereotyped gaits (e.g., walking at fixed speed) and thus show poor adaptivity for variable conditions. This study is aimed to overcome these issues. METHODS: A quasi-passive ankle exoskeleton is designed to integrate the merits of both active and passive exoskeletons, which captures the heel-strike energy loss and recycles it into propulsion. A novel, lightweight, energy-saving clutch and a heel-strike energy-storage mechanism are developed. They are coupled by a series spring that assists user's calf muscles. Six healthy subjects walked with the device on level ground and inclined surfaces to validate its functionality. RESULTS: Level ground studies indicate that the energy-storage mechanism enhances the assistance by increasing the output torque of the exoskeleton. Reductions in metabolic cost (6.4 ± 1.3%, p < 0.05) were observed. During uphill walking, the assistance torque decreased compared with that on level ground, but it still reduced overall metabolic cost compared with baseline walking. During downhill walking, the assistance torque increased, but metabolic cost also slightly increased. CONCLUSION: These results demonstrate the functionality of the prototype on level ground and its limitations on inclined surfaces. SIGNIFICANCE: The proposed device highlights the possibility of widening the potential applications of exoskeletons.

Sinistral portal hypertension associated with pancreatic pseudocysts - ultrasonography findings: A case report.

BACKGROUND: Sinistral portal hypertension associated with pancreatic pseudocysts is rare, often caused by extrinsic compression of splenic vein, the follow-up examinations by ultrasonography for early diagnosis are quietly necessary since haematemesis, a life-threatening condition. Few studies have reported the ultrasonography findings of sinistral portal hypertension. CASE SUMMARY: A 52-year-old man presented with acute abdominal pain after drinking, steatorrhea, weight loss and accidentally melena in the past 2 mo. He underwent ultrasound-guided fine needle aspiration in other hospital and diagnosed with pancreatic pseudocysts. Ultrasonography imaging, in our department, appeared as cystic heterogeneous hypoechoic area with the size of 4.7 cm × 3.8 cm that located posterior to the body and tail of pancreas, adjacent to splenic vein associated with thrombosis resulted from compression. Spleen incrassated to approximately 7.3 cm, but no dilation of main portal vein was presented. Color Doppler Flow Imaging demonstrated the formation of splenic venous collateral, nevertheless no significantly flow signals was observed in splenic vein. Pulsed Doppler revealed that the peak velocity of splenic venous collateral was 18.4 cm/s with continuous waveform. Laparotomy confirmed sinistral portal hypertension associated with pancreatic pseudocysts, subsequently distal pancreatectomy combined with splenectomy and partial gastrectomy was performed. CONCLUSION: It's important clinically to know the ultrasound appearance of sinistral portal hypertension associated with pancreatic pseudocysts for sonographer and physician.

Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness.

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. This paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. The results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. The results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. The maximum average values of torque also decrease from 41.2 to 24.2 N·mm (bovine), 37.0 to 21.6 N·mm (porcine), and 13.6 to 6.7 N·mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. The variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

A lariat-based dilatation device for hysteroscopy: an in vitro study.

BACKGROUND: Hysteroscopy is regarded as the golden standard for the therapeutic and diagnostic methods of many uterine diseases. Carbon dioxide, normal saline and pharmaceuticals are generally used to dilate the uterus to obtain enough operating space and clear vision during the surgery. However, these methods often cause various syndromes. METHODS: In this study, we designed a novel mechanical dilator and operating system. The dilator contains a structure with a diameter of 9 mm in its initial status to pass through the narrow cervix after initial cervical dilation by cervical dilator and then its diameter can be expanded up to 60 mm in the working status to achieve a favorable operating space. The operating system is composed of an endoscope and the surgical instrument driving tube. The endoscope was motioned by pre-bent hyperelastic wires and the surgical instrument was driven by a pre-bent driving tube. To obtain the parameters for successful expansion and operation, the relationships between the tension, the diameter of the dilator and the visual and operating space of the operating system were analyzed in detail. On the basis of the obtained parameters, the surgical experiment was performed and the experimental results demonstrated the ability of this dilator to expand and the ability of the operator to operate in small spaces for hysteroscopy. RESULTS: According to the achieved results, the dilator could support the inner wall of the simulated organ to act like a cage, so that the space in the cage was large enough. The operating system can thrust into the intracavity of the simulated uterus through the channel (with a diameter of 6 mm) of the dilator to search for and excise the raised polyp. CONCLUSIONS: It can be concluded that the proposed dilator and operating system can be efficiently applied in organ expansion and operation in hysteroscopy.