Adielectrophoresis-basedmicrofluidicchipappliedtocellspatterningisdesignedandfabricated, and it demonstrates non-contact and batch manipulation of cells. The microfluidic chip employs a PDMS microchannel and two ITO electrodes, which are designed as astep shape. The distribution of electric field caused by the microelectrodes is simulated by finite element simulation software, COMSOL. The position of the maximum intensity of electric field is also determined. The ITO microelectrodes and the PDMS microchannel are fabricated using MEMS fabrication process. After oxygen plasma surface treatment, the PDMS microchannel and glass substrate with the ITO microelectrodes are aligned and bonded to form experimental microfluidic chip. Through DEP experiment with the varying frequencies, DEP response of yeast cells is examined, and the electric field frequency of the both positive and negative DEP responses are confirmed. The results showed that yeast cells in solution conductivity of 60 μS/cm had negative DEP movement at the frequency of 1 kHz to 10 kHz, positive DEP movement at the 500 kHz to 10 MHz, and no DEP movement at the 50 kHz. Under the condition of the sinusoidal potential of 8Vp-p and the electric field frequency of 5 MHz, the yeast cells were aligned into chains along the step edge of microelectrodes.

Malnutrition and dehydration are prevalent in the elderly poplulation, and obesity is also a growing problem, which pose a serious challenge to the nutritional management in geriatrics. In order to better guide clinical practice, the European Society for Clinical Nutrition and Metabolism (ESPEN) published the practical guideline on clinical nutrition and hydration in geria-trics on March 5, 2022. This guideline provides 82 recommendations on clinical nutrition and hydration in geriatrics based on clinical practicability, covering basic problems and general prin-ciples, prevention and treatment of malnutrition/nutri-tional risk, prevention and treatment of specific diseases, as well as prevention and treatment of obesity, along with flow-charts, hoping to be convenient for doctors, nutritionists and nurses to use in clinical practice.

Objective:To systematically evaluate the safety and efficacy of laparoscopic versus open surgery for palliative resection of the primary tumor in stage IV colorectal cancer.Methods:The databases of CNKI, Wanfang, VIP, PubMed, EMBASE and Cochrane Library were searched to retrieve randomized controlled trials (RCT) or clinical controlled trials (CCT) comparing laparoscopic surgery with open surgery for palliative resection of the primary tumor in stage IV colorectal cancer published from January 1991 to May 2019. Chinese search terms included "colorectum/colon/rectum" , "cancer/malignant tumor" , "laparoscopy" , "metastasis" , " IV" ; English search terms included "laparoscop*" , "colo*" , "rect*" , "cancer/tumor/carcinoma/neoplasm" , " IV" , "metasta*" . Inclusion criteria: (1) RCT or CCT, with or without allocation concealment or blinding; (2) patients with stage IV colorectal cancer that was diagnosed preoperatively and would receive resection of the primary tumor; (3) the primary tumor that was palliatively resected by laparoscopic or open procedure. Exclusion criteria: (1) no valid data available in the literature; (2) single study sample size ≤20; (3) subjects with colorectal benign disease; (4) metastatic resection or lymph node dissection was performed intraoperatively in an attempt to perform radical surgery; (5) duplicate publication of the literature. Two researchers independently evaluated the quality of the included studies. In case of disagreement, the evaluation was performed by discussion or a third researcher was invited to participate. The data were extracted from the included studies, and the Cochrane Collaboration RevMan 5.1.0 version software was used for this meta-analysis.Results:Four CCTs with a total of 864 patients were included in this study, including 216 patients in the laparoscopic group and 648 patients in the open group. Compared with the open group, except for longer operation time (WMD=37.60, 95% CI: 26.11 to 49.08, P<0.05), laparoscopic group had less intraoperative blood loss (WMD=-74.89, 95% CI: -144.78 to -5.00, P<0.05), earlier first flatus and food intake after surgery (WMD=-1.00, 95% CI: -1.12 to -0.87, P<0.05; WMD=-1.61, 95%CI: -2.16 to -1.06, P<0.05), shorter hospital stay (WMD=-2.01, 95% CI: -2.21 to -1.80, P<0.05) and lower morbidity of postoperative complication (OR=0.52, 95% CI: 0.35 to 0.77, P<0.05). However, no significant differences were found in time to start postoperative chemotherapy, postoperative chemotherapy rate, and mortality ( P > all 0.05). Conclusion:Laparoscopic surgery for palliative resection of the primary tumor is safe and feasible to enhance recovery after surgery by promoting postoperative bowel function recovery, shortening hospital stay and reducing postoperative complication in stage IV colorectal cancer.

Objective:To systematically evaluate the safety and efficacy of laparoscopic versus open surgery for palliative resection of the primary tumor in stage IV colorectal cancer.Methods:The databases of CNKI, Wanfang, VIP, PubMed, EMBASE and Cochrane Library were searched to retrieve randomized controlled trials (RCT) or clinical controlled trials (CCT) comparing laparoscopic surgery with open surgery for palliative resection of the primary tumor in stage IV colorectal cancer published from January 1991 to May 2019. Chinese search terms included "colorectum/colon/rectum" , "cancer/malignant tumor" , "laparoscopy" , "metastasis" , " IV" ; English search terms included "laparoscop*" , "colo*" , "rect*" , "cancer/tumor/carcinoma/neoplasm" , " IV" , "metasta*" . Inclusion criteria: (1) RCT or CCT, with or without allocation concealment or blinding; (2) patients with stage IV colorectal cancer that was diagnosed preoperatively and would receive resection of the primary tumor; (3) the primary tumor that was palliatively resected by laparoscopic or open procedure. Exclusion criteria: (1) no valid data available in the literature; (2) single study sample size ≤20; (3) subjects with colorectal benign disease; (4) metastatic resection or lymph node dissection was performed intraoperatively in an attempt to perform radical surgery; (5) duplicate publication of the literature. Two researchers independently evaluated the quality of the included studies. In case of disagreement, the evaluation was performed by discussion or a third researcher was invited to participate. The data were extracted from the included studies, and the Cochrane Collaboration RevMan 5.1.0 version software was used for this meta-analysis.Results:Four CCTs with a total of 864 patients were included in this study, including 216 patients in the laparoscopic group and 648 patients in the open group. Compared with the open group, except for longer operation time (WMD=37.60, 95% CI: 26.11 to 49.08, P<0.05), laparoscopic group had less intraoperative blood loss (WMD=-74.89, 95% CI: -144.78 to -5.00, P<0.05), earlier first flatus and food intake after surgery (WMD=-1.00, 95% CI: -1.12 to -0.87, P<0.05; WMD=-1.61, 95%CI: -2.16 to -1.06, P<0.05), shorter hospital stay (WMD=-2.01, 95% CI: -2.21 to -1.80, P<0.05) and lower morbidity of postoperative complication (OR=0.52, 95% CI: 0.35 to 0.77, P<0.05). However, no significant differences were found in time to start postoperative chemotherapy, postoperative chemotherapy rate, and mortality ( P > all 0.05). Conclusion:Laparoscopic surgery for palliative resection of the primary tumor is safe and feasible to enhance recovery after surgery by promoting postoperative bowel function recovery, shortening hospital stay and reducing postoperative complication in stage IV colorectal cancer.