A Simple and Reliable Cooling Approach for the Cryopreservation of Hematopoietic Stem Cells: the Passive Cooling Rate-controlled Technique.

BACKGROUND: Cryopreservation of hematopoietic stem cells (HSCs) has widely been used in stem cell transplantation and cellular therapy treating various human diseases. However, the current conventional cooling approach for the cryopreservation of HSCs has the following potential problems: (1) requirement of a very expensive computer-programmed liquid nitrogen freezer (LNF) for the cooling rate control, (2) a large consumption of liquid nitrogen, (3) periodic breakdown of the LNF due to the mechanical failure of the liquid nitrogen valves (i.e., magnetic-solenoid valves) inside the LNF, and (4) constant monitoring of the LNF operation during the HSCs cooling process. OBJECTIVE: To test and evaluate a simple and reliable approach for the cryopreservation of HSCs using the passive cooling technique. MATERIALS AND METHODS: A passive cooling-rate-controlled device (PCD) was developed and used to cryopreserve HSCs. The PCD is inexpensive, simple, and user-friendly, which needs only the minimum maintenance and no consumption of liquid nitrogen. The PCD was compared to the LNF for the cryopreservation of HSCs in the present study through experiments. The cell viability and functionality were evaluated after cryopreservation. RESULTS: In comparison with the LNF method, the PCD approach enabled high cell viability/survival, recovery rate, and functionality after cryopreservation processes. CONCLUSION: The PCD offers a cost-effective, simple, and reliable approach for the optimal cryopreservation of HSCs.

A Low-cost Easy-to-Fabricate Sandwich-Structured Microdevice for Controllable Removal of Extracellular Cryoprotective Agents with High Efficiency.

　　BACKGROUND: Osmotic shock upon the addition and removal of cryoprotectant agent (CPA) is a major source of cell damage during cryopreservation. OBJECTIVE: Microfluidic device offers a new platform for CPA loading and unloading. The micro scale dimension makes possible to perform a detailed analysis and controllable removal of CPA with many advantages. MATERIALS AND METHODS: A microfluidic device was developed for extracting dimethyl sulfoxide (DMSO) from the sample streamline. The device has two parallel channels separated by a polytetrafluoroethylene (PTFE) membrane and serves as the stable environment for CPA removal. A diffusion-based simulation model was used to characterize the CPA extraction. To support the experimental design and device optimization we developed analogous scheme to simulate by COMSOL Multiphysics. RESULTS AND CONCUSION: The device can extract cryoprotectant in a mesoscale volume from cells and simplify the post-thaw sample handling. It has sufficient control on loading/unloading of CPAs by controlling the flow rate of cell stream/wash stream solutions via syringe pumps. Compared to other customary devices, this device is easy to fabricate and assemble, with features of high precision, reusability and low cost.

Shoulder instability in military personnel: diagnosis and outcomes of arthroscopic stabilisation.

INTRODUCTION: Shoulder instability is a common problem for military personnel due to the highly physical demands of work and training. This study assessed the pattern of glenoid labrum tears suffered by serving UK military personnel, the reliability of preoperative diagnostic methods (magnetic resonance arthrogram (MRA) vs clinical examination) and, finally, the outcomes of arthroscopic stabilisation in terms of satisfaction, pain, and return to sport and full deployment. METHODS: Retrospective demographic and clinical data were collected for all patients within our unit who underwent arthroscopic shoulder stabilisation between September 2016 and January 2019. Patients underwent clinical examination for instability and subsequent imaging with MRA. For service evaluation, patient-reported outcome measure data and occupational outcome data were gathered preoperatively and postoperatively. RESULTS: 41 military patients with shoulder instability were treated with arthroscopic stabilisation. 24.4% had an isolated anterior tear, and 41.5% had complex two-zone or pan-labral tears identified on arthroscopy. Clinical examination showed higher sensitivity, accuracy and negative predictive value for all labral tear patterns compared with MRA. Mean preoperative Oxford Shoulder Instability Score score was 18.58 (SE ±1.67) and mean postoperative score was 41.5 (SE ±1.13). 82.14% of the patients returned to full deployment during the study period and 85% had returned to sports. CONCLUSION: Complex labral tear patterns are common in military personnel with shoulder instability, and clinical examination appears to be more effective than imaging at predicting injury pattern. Patients respond well to arthroscopic stabilisation with good rates of return to work and sport, regardless of chronicity of injury.

The hydrodyanamics of gravity-driven vessel drainage of third order fluid using perturbation method.

In this work, tank drainage phenomena for in-compressible and isothermal fluid having unsteady fluid flow for third order fluid is studied. Analytical solution of the proposed problem is obtained using perturbation method subject to proper boundary conditions. No-slip condition is used because of fluid will have zero velocity relative to a solid boundary. Object of this work is to find out the velocity profile, flow rate, time required to empty a tank (time efflux) and mathematical relation of time and depth of the tank. Influence of different parameter over velocity profile, effect of radius of the tank over depth, effect of radius of piper over flow rate and effect of depth over flow rate are examined graphically using mathematica. Velocity profile of this model is compared with newtonian fluid's while assuming epsilon as a zero using graph and table from which it is clear that third order fluid posses greater velocity then Newtonian fluid.

Effectiveness of various Pseudomonas spp. and Burkholderia caryophylli containing ACC-deaminase for improving growth and yield of wheat (Triticum aestivum L.).

This study assessed the possible role of different traits in selected plant growth-promoting rhizobacteria (PGPR) for improving wheat growth and yield under natural conditions. Rhizobacteria exhibiting 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity were isolated and screened for their growth-promoting activity in wheat under axenic conditions. Five isolates belonging to Pseudomonas and one Burkholderia caryophylli isolate that showed promising performances under axenic conditions were selected and characterized for in vitro ACC-deaminase activity, chitinase activity, auxin production, P solubilization, and root colonization. These isolates were then used as inocula for wheat cultivated under natural conditions in pot and/or field trials. Significant increases in root elongation, root weight, tillers per pot, 1,000-grain weight, and grain and straw yields were observed in response to inoculation with PGPR in the pot trials. Inoculation with these PGPR was also effective under field conditions and increased the wheat growth and yield significantly. However, the efficacy of the strains was inconsistent under the axenic, pot, and field conditions. Pseudomonasfluorescens (ACC50), which exhibited a relatively high in vitro ACC-deaminase activity, chitinase activity, auxin production, and P solubilization and more intensive root colonization, was the most efficient isolate under the field conditions. Therefore, these results demonstrated that ACC-deaminase activity is an efficient parameter for the selection of promising PGPR under axenic conditions. However, additional traits of PGPR, including auxin production, chitinase activity, P solubilization, and root colonization, are also important for selecting PGPR as biofertilizers.