Effect of polysaccharides on the rheological behaviour of soy-wheat protein aggregation and conformational changes during high-moisture extrusion.

BACKGROUND: Due to the extrusion black box effect, polysaccharides determine the formation of meat-like fibrous structures by modulating the flow behaviour and structural changes of plant proteins under high-moisture extrusion conditions. However, there is limited knowledge on the mechanism of resolution. This study simulated the rheological properties of soy protein-wheat protein under 57% moisture conditions with addition of 4% sodium alginate (SA), 2% xanthan gum (XG), and 2% maltodextrin (MD). The effect of these polysaccharides on the aggregation behaviour and conformation of raw protein during high-moisture extrusion was investigated. RESULTS: It was revealed that the three polysaccharides were effective in increasing the interaction between proteins and between proteins and water. Among them, 4% SA elicited a significantly stronger storage modulus (gelation behaviour) compared to the control. Analysis of different zones of extrudates by protein electrophoresis, particle size, and turbidity showed that SA-4% was able to form more high molecular protein aggregates (> 245 kDa) and promoted crosslinking of low molecular subunits (< 48 kDa), resulting in moderately sized protein aggregated particles. Fluorescence and ultraviolet spectra showed the transformation of protein tertiary structures in different extrusion zones, confirming that the key extrusion zone for protein conformational transformation by polysaccharides is the die-cooling zone. Furthermore, stretching of polypeptide chains and accelerated protein rearrangement facilitated the formation of more fibrillar structures. CONCLUSION: Theoretical support for polysaccharide modulation of plant protein quality in high moisture extruded products is provided by this study. © 2023 Society of Chemical Industry.

[Automatic modeling of the knee joint based on artificial intelligence].

Objective: To investigate an artificial intelligence (AI) automatic segmentation and modeling method for knee joints, aiming to improve the efficiency of knee joint modeling. Methods: Knee CT images of 3 volunteers were randomly selected. AI automatic segmentation and manual segmentation of images and modeling were performed in Mimics software. The AI-automated modeling time was recorded. The anatomical landmarks of the distal femur and proximal tibia were selected with reference to previous literature, and the indexes related to the surgical design were calculated. Pearson correlation coefficient ( r) was used to judge the correlation of the modeling results of the two methods; the consistency of the modeling results of the two methods were analyzed by DICE coefficient. Results: The three-dimensional model of the knee joint was successfully constructed by both automatic modeling and manual modeling. The time required for AI to reconstruct each knee model was 10.45, 9.50, and 10.20 minutes, respectively, which was shorter than the manual modeling [(64.73±17.07) minutes] in the previous literature. Pearson correlation analysis showed that there was a strong correlation between the models generated by manual and automatic segmentation ( r=0.999, P<0.001). The DICE coefficients of the 3 knee models were 0.990, 0.996, and 0.944 for the femur and 0.943, 0.978, and 0.981 for the tibia, respectively, verifying a high degree of consistency between automatic modeling and manual modeling. Conclusion: The AI segmentation method in Mimics software can be used to quickly reconstruct a valid knee model.

Statistical modeling: Assessing the anatomic variability of knee joint space width.

Population-based knee joint space width (JSW) assessments are promising for the prevention and early diagnosis of osteoarthritis. This study aimed to establish the statistical shape and alignment model (SSAM) of knee joints for assessing anatomic variation in knee JSW in the healthy Chinese male population. CT scans of asymptomatic knee joints of healthy male participants (n = 107) were collected for manual segmentation to create mesh samples. The as-scanned positional error was reduced by a standard processing flow of deformable mesh registration. Principal component analysis (PCA) was performed to create a tibiofemoral SSAM that was trained on all mesh samples. The anatomic variability of the JSW in the healthy Chinese male population was then assessed using the SSAM with regression analysis and 3D analysis by color-coded mapping. Almost all PCA modes had a linear influence on the anatomic variation of the medial and lateral JSW. The JSW variability within the SSAM was mainly explained by mode 1 (45.1 % of variation), demonstrating that this mode had the greatest influence on JSW variation. 3D assessment of the JSW showed that the minimum medial JSW varied from 2.76 to 3.23 mm, and its site shifted a short distance on the medial tibial plateau. The root-mean-square fitting and generalization errors of the SSAM were below 1 mm. This study will benefit the design and optimization of prosthetic devices, and may be applicable to the prevention and early diagnosis of osteoarthritis.

Effect of high-pressure homogenization on Ca2+ -induced gel formation of soybean 11 S globulin.

BACKGROUND: High-pressure homogenization (HPH) is commonly used as a non-thermal processing technique for soybean and soy protein products, and the preparation of soy protein gel products often requires the synergistic effect of HPH and heat treatment. The dissociative association behavior of 11 S is the key to the protein gel formation state. In this study, therefore, 11 S thermal gels were prepared by high-pressure homogenization and co-induction (90 °C, 30 min) (adding Ca2+ to promote gel formation before heat treatment), and the effects of different high-pressure homogenization pressures (0-100 MPa) and co-treatment on the dissociative association behavior of 11 S protein, gel properties, and microstructure of 11 S gels were investigated. RESULTS: The results showed that HPH at higher pressures led to the breaking of disulfide bonds of aggregates and disrupted non-covalent interactions in protein aggregates, leading to collisions between protein aggregates and the reduction of large protein aggregates. High-pressure homogenization treatment at 60 MPa improved the gel properties of 11 S more. The HPH combined with heating changed the binary and tertiary structure of 11 S soy globulin and enhanced the hydrophobic interaction between 11 S molecules, thus improving the gel properties of 11 S. The change in intermolecular forces reflected the positive effect of HPH treatment on the formation of denser and more homogeneous protein gels. CONCLUSION: In conclusion, high-pressure homogenization combined with heating can improve the properties of 11 S gels by changing the structure of 11 S protein, providing data and theoretical support for soy protein processing and its further applications. © 2022 Society of Chemical Industry.

Structural Analysis and Study of Gel Properties of Thermally-Induced Soybean Isolate-Potato Protein Gel System.

Heat-induced composite gel systems consisting of different soybean protein isolate (SPI) and potato protein (PP) mixtures were studied to elucidate their "backbone" and property changes. This was achieved by comparing the ratio of non-network proteins, protein subunit composition, and aggregation of different gel samples. It was revealed that SPI was the "gel network backbone" and PP played the role of "filler" in the SPI-PP composite gel system. Compared with the composite gels at the same ratio, springiness and WHC decrease with PP addition. For hardness, PP addition showed a less linear trend. At the SPI-PP = 2/1 composite gel, hardness was more than doubled, while springiness and WHC did not decrease too much and increased the inter-protein binding. The hydrophobic interactions and electrostatic interactions and hydrogen bonding of the SPI gel system were enhanced. The scanning electron microscopy results showed that the SPI-based gel system was able to form a more compact and compatible gel network. This study demonstrates the use of PP as a potential filler that can effectively improve the gelling properties of SPI, thus providing a theoretical basis for the study of functional plant protein foods.

Roles of calcium signaling in cancer metastasis to bone.

Bone metastasis is a frequent complication for cancers and an important reason for the mortality in cancer patients. After surviving in bone, cancer cells can cause severe pain, life-threatening hypercalcemia, pathologic fractures, spinal cord compression, and even death. However, the underlying mechanisms of bone metastasis were not clear. The role of calcium (Ca2+) in cancer cell proliferation, migration, and invasion has been well established. Interestingly, emerging evidence indicates that Ca2+ signaling played a key role in bone metastasis, for it not only promotes cancer progression but also mediates osteoclasts and osteoblasts differentiation. Therefore, Ca2+ signaling has emerged as a novel therapeutical target for cancer bone metastasis treatments. Here, the role of Ca2+ channels and Ca2+-binding proteins including calmodulin and Ca2+-sensing receptor in bone metastasis, and the perspective of anti-cancer bone metastasis therapeutics via targeting the Ca2+ signaling pathway are summarized.

The design of a novel arthroscopy shaver.

Cases of arthroscopic surgery have increased over the past two decades, and arthroscopic shaver systems have become a commonly used orthopedic tool. Nevertheless, most shavers generally have problems such as the cutting edge is not sharp enough and easy to wear. This paper aims to discuss the structural characteristics of BJKMC's (Bojin◊ Kinetic Medical) novel arthroscopic shaver, the double serrated blade. The product's design and verification process are outlined. BJKMC's articular arthroscopy shaver has a "tube in a tube" structure, comprising a stainless steel outer sleeve and a rotating hollow inner tube. The outer sleeve and inner tube have corresponding suction and cutting windows, and there are serrated teeth on the inner and outer casing. To verify the design rationality, it was compared to Dyonics◊'s equivalent product, the Incisor◊ Plus Blade. The appearance, cutting tool hardness, metal pipe roughness, cutting tool wall thickness, tooth profile, and angle, overall structure, and the key dimensions were examined and compared. Compared with Dyonics◊'s Incisor◊ Plus Blade, BJKMC's Double Serrated Blade had a smoother working surface, harder and thinner blade head. Therefore, BJKMC's product may have satisfactory performance when it comes to surgery.

Rhein Protects Against Severe Acute Pancreatitis In vitro and In vivo by Regulating the JAK2/STAT3 Pathway.

Rhein is widely used in inflammation treatment in China, but its effects on severe acute pancreatitis (SAP) have not been studied closely. This study investigated rhein's protective effects against SAP using in vitro and in vivo models to determine whether its protective mechanism regulated the Janus kinase two and signal transducer and activator of transcription 3 (JAK2/STAT3) signalling pathway. Thirty-six male Sprague-Dawley rats were randomised into sham operation, SAP and rhein groups. The SAP model was induced by retrograde pancreatic bile duct injection of sodium taurocholate. Serum TNF-α and interleukin (IL)-6 levels were determined by ELISA, whereas serum amylase and lipase concentrations were measured using test kits. Western blot and/or immunohistochemistry quantified JAK2 and STAT3 expression. Furthermore, histopathological pancreatic changes were detected by haematoxylin and eosin staining. AR42J cells were randomly divided into the control, cerulein and rhein groups. Amylase activity was assessed using an amylase test kit; the tumour necrosis factor-α (TNF-α) expression was determined by enzyme-linked immunosorbent assay (ELISA). JAK2 and STAT3 protein expression were evaluated by western blot. SAP was concomitant with increased JAK2 and STAT3 expressions in vivo. Pre-treatment with rhein attenuated serum TNF-α and IL-6 levels effectively, and notably reduced p-JAK2, p-STAT3, JAK2 and STAT3 protein expression. Rhein significantly alleviated pancreatic histopathology. Compared to untreated groups, rhein significantly reduced amylase activity in supernatants of AR42J cells induced by cerulein in vitro. Furthermore, rhein altered JAK2 and STAT3 protein levels in AR42J cells after cerulein induction. Overall, rhein exerted protective effect on SAP in vitro and in vivo, possibly through the JAK2/STAT3 signalling pathway.

WITHDRAWN: Hydroxysafflor Yellow A Ameliorates Toll-like Receptor 4-Mediated Septic Cardiomyopathy

Since the authors are not responding to the editor's requests to fulfill the editorial requirement, therefore, the article has been withdrawn.Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused.The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.com/editorial-policies-main.php Bentham Science Disclaimer: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

Influence of geometric parameters on partial compressive force and pushing performance of flow diverter.

Research on flow diverter (FD) has progressed over the past decades; however, the relationships between parameters such as stent diameter, porosity, and number of wires and the properties of FDs, such as partial compressive force and push resistance, are not well understood. In this study, the partial compressive force and push resistance of braided FDs with varying porosity (61%-75%), diameter (2.5-5.0 mm), and number of wires (48 or 64) were evaluated using finite element analysis (FEA) and bench tests. At a small compression ratio, the 48-wire stents exhibited a larger partial compressive force than 64-wire stents of the same diameter. But when the compression ratio was 50%, the 64-wire stents had better resistance to pressure. The partial compressive force decreased as the stent diameter increased when all other parameters were equal. However, the influence of the diameter decreased as the stent porosity increased. The push resistance decreased as the porosity and diameter increased, and increased with the number of wires. These results provide useful information for FD design. Decreasing the number of wires can reduce the push resistance, while the push resistance is mainly influenced by the porosity and number of wires, and almost has no relationship with the partial compressive force. The FEA model proved very reliable, and corresponded well to the bench test results, which indicates that this model can be utilized to guide the design of FDs.

High-moisture extrusion cooking on soybean-wheat protein mixtures: Effect of sodium alginate/xanthan gum/maltodextrin on promoting a fibrous structure.

At present, the changes in fibrous structure of plant proteins improved by polysaccharides during high-moisture extrusion cooking (HMEC) are still unclear. In this study, different additions (1, 2, 3, 4, and 5%) of sodium alginate (SA), xanthan gum (XG), and maltodextrin (MD) were used in the preparation of organised protein products based on soybean protein and wheat protein under high moisture extrusion conditions. It was revealed that SA-4%, XG-2%, and MD-2% (w/w) significantly enhanced the structural and physical properties of the fibres. The polysaccharides increased the water distribution of extrudates by enhancing protein-water interactions through hydrogen bonding, with MD-2% having the strongest ability to trap free water. The mechanism by which the polysaccharides improved the fibrous structure of extrudates involved the reorganization of molten proteins from the die head region to the cooling region, formation of new molecular bonds and enhancement of thermal stability. XG-2% significantly increased the ß-sheet structure in the molten region (48.9 ± 1.35%) and showed the best thermal stability. Overall, SA-4% was able to better maintain the molecular bonding transformation and strong water absorption, which stabilised the protein conformation and formed the highest fibrous degree (2.1 ± 0.03). This suggests that the properties of the three polysaccharides can be used as modifiers of high water extruded plant proteins to improve the extruded materiality, functional and nutritional properties.

Development of a real-time blood damage monitoring device for cardiopulmonary bypass system using near-infrared spectroscopy.

The optical properties of hemoglobin could indicate the degree of hemolysis. We aimed to utilize this to develop a real-time blood damage monitoring device for cardiopulmonary bypass (CPB) systems. The real-time blood damage monitoring device comprised a near-infrared spectroscopy optical module with a fiber spectrometer and monitoring platform and computer software developed using LabVIEW 2017. The fiber spectrometer operated at wavelengths of 545, 660, and 940 nm and contained a detector fiber bundle (source-detector distance = 1.0-2.5 cm). CPB operation was simulated using an artificial heart-lung machine with a flow rate of 3, 4, or 5 L/min. Four hundred milliliter of anticoagulated porcine blood was continuously rotated for 4 h. The transmittance, reflectivity, and absorbance of the blood were measured using the optical device at a frequency of 25 Hz and then digitally averaged into 1-s interval. Samples of damaged blood were collected at regular intervals for in vitro hemolysis tests to calculate the normalized index of hemolysis (NIH). All experiments were repeated three times. We prepared 28 blood bags containing 400 ml of anticoagulant. Paired t test was used to examine the test-retest reliability of the differences between the three methods and control samples. Statistical tests revealed significant differences in the mean values between the test and control groups over time (P < 0.01). Relationship was established between the real-time monitoring results and the NIH values. An effective blood damage detection method that combined in vitro hemolysis tests and near-infrared spectroscopy was achieved. The results demonstrate the clinical potential of a real-time, low-cost, and reliable blood damage monitoring device to improve the safety of CPB operation.

Assessment of arthroscopic shavers: a comparison test of resection performance and quality.

BACKGROUND: Arthroscopic shavers play an indispensable role in arthroscopic debridement. They have exquisite structures and similar designs. The purpose of this study was to establish a reproducible testing protocol to compare the resection performance and the quality (tensile strength, torsional strength, and corrosion resistance) of different arthroscopic shavers with comparable designs. We hypothesized that there could be little difference in resection performance and quality between these shavers. METHODS: Incisor Plus Blade (IPB; Smith & Nephew, Andover, MA) and Double Serrated Plus Blade (DSPB; BJKMC, Shanghai, China) were selected for resection performance and quality test. For resection performance testing, the resection torque, which is the minimum torque required to cut off silicone blocks with the same cross-sectional area, was measured to evaluate the resection performance of shaver blades when the other factors remain the same. For quality testing, tensile and torsion tests of the shavers' joint part were performed, and ultimate failure load and maximum torque were measured and compared. The corrosion resistance of these blades was assessed by the boiling water test based on the ISO13402. RESULTS: No significant difference existed in the resection torque between the shaver blades of IPB and DSPB (P = 0.54). To the failure load of shavers' joint parts, IPB was significantly higher than DSPB, both in the outer and inner blades (P < 0.0001). The maximum torque of the joint part had no significant difference between IPB and DSPB (for inner blades P = 0.60 and outer blades P = 0.94). The failure load (for both IPB and DSPB P < 0.0001) and maximum torque (for IPB P = 0.0475 and DSPB P = 0.015) of the inner blades were higher than those of the outer blades. No blemishes were observed on the surface of the blades after corrosion resistance tests. CONCLUSIONS: This study provided some new methods to evaluate the resection performance and quality of different shavers. The resection performance, the torsional strength of the joint part, and the corrosion resistance of IPB and DSPB may show comparable properties, whereas the tensile strength of the shavers' joint part showed some level of difference.

[Effect of different root canal file tapers on fracture strength of root canal wall].

PURPOSE: To compare the effects of different nickel-titanium rotary tapers on fracture strength of root canal and the application value of finite element analysis in root canal therapy. METHODS: Twenty four mandibular premolars were selected and all crowns were removed. All samples were randomly divided into 4 groups: A, B, C and D. Group A and C were instrumented with Z-K3 nickel titanium file as 0.04 taper for root canal preparation. Group B and D were instrumented with Z-K3 nickel titanium file as 0.06 taper. Group C and D were sliced into 2 mm thick slices 3 times after root canal preparation. Two teeth were selected from group A and group B and scanned with micro-CT. The model was imported into different softwares to optimize. The assembly model was built and imported into ANSYS for finite element analysis. Universal testing machine and force bar were used to apply 100 N force to samples until fracture occurring at any place of tooth sample. The fracture load was recorded and comparative analysis was conducted. RESULTS: The results of finite element analysis showed that the maximum stress of 0.04, 0.06 taper models was 138.88 MPa and 78.812 MPa, respectively. The average fracture load of group A, B was 490.12 N and 501.83 N, respectively. In group C and D, the maximum average fracture load was 93.61 N and 141.53 N, respectively. From the neck to the middle and then to the tip, the average fracture load of root canal decreased in turn. CONCLUSIONS: For normal form mandibular premolars, the fracture strength of the root instrumented with 0.06 taper nickel titanium rotary file was significantly higher than that instrumented with 0.04 taper. Three dimensional finite element analysis could guide dentists to choose a suitable taper file in root canal treatment to reduce the incidence of root fracture.

Long noncoding RNA HCP5 suppresses skin cutaneous melanoma development by regulating RARRES3 gene expression via sponging miR-12.

OBJECTIVE: This research aimed to investigate the role and mechanism of long noncoding RNA (lncRNA) HCP5 in skin cutaneous melanoma (SKCM). MATERIALS AND METHODS: Survival analysis was performed using The Cancer Genome Atlas (TCGA)-SKCM data and SKCM patients' clinical data. Primary SKCM cells were derived from patients' pathologic tissue specimens. HCP5 overexpression was achieved by lentiviral transduction. Malignancy of SKCM cells was evaluated in vitro by cell proliferation, colony formation, apoptosis and transwell invasion assays. RARRES3 knockdown was achieved by siRNA transfection. DIANA microT-CDS algorithm was used to predict miRNAs that might interact with HCP5 and 3' untranslated region of RARRES3 mRNA. microRNA target luciferase reporter assay and AGO2-RNA immunoprecipitation were used to verify the interaction between HCP5, 3' UTR of RARRES3 mRNA and miR-1286. RESULTS: HCP5 level was decreased in SKCM tissue specimens compared to noncancerous counterparts. Low expression of HCP5 was associated with SKCM patients' poor overall survival and disease progression. HCP5 overexpression significantly reduced the malignancy of primary SKCM cells in vitro. RARRES3 was found as a HCP5-co-expressing gene in SKCM cells. HCP5 overexpression significantly increased RARRES3 expression in SKCM cells. RARRES3 knockdown partially abolished the anti-SKCM effect of HCP5 overexpression. MiR-1286 was found interacting with both HCP5 and 3' UTR of RARRES3 mRNA. CONCLUSION: HCP5 is a cancer-suppressive lncRNA in SKCM. HCP5 overexpression decreased SKCM cell malignancy in vitro by upregulating RARRES3, possibly via sponging miR-1286.

The Wall Apposition Evaluation for a Mechanical Embolus Retrieval Device.

A computational evaluation approach to the wall apposition of a cerebral mechanical emboli retrieval device (MERD) is presented. The typical enclosed multilattice structure, manufactured from the thin-walled Nitinol tube, consists of repeated "V"-shaped unit cells. During interventional thrombectomy, the MERD system is delivered inside an artery stenosis segment to capture emboli and restore cerebral blood flow. The wall apposition, which deteriorates during embolus capture, occurs during system migration along the tortuous intracranial vessel. The commercial finite element analysis (FEA) solver ABAQUS 6.10 Standard and user subroutine (UMAT/Nitinol) are utilized to study the ability to remain in close contact with the curved vessel wall during migration. In this numerical analysis, the influence of the contacting interference loadings on structure deformation and strain field distribution is obtained and analyzed. The results indicate that the middle segment of the MERD seriously contracts or collapses inside the curved vessel. In addition, the peak strain is in the apex flow-prone region and maintains at the safe range.

Improved synergetic therapy efficiency of cryoablation and nanoparticles for MCF-7 breast cancer.

AIM: Current cryoablation therapy easily induces a high tumor recurrence, it is therefore necessary to develop an effective method to enhance its antitumor efficacy. MATERIALS & METHODS: We solve the aforementioned problem by introducing doxorubicin (DOX) loading methoxy polyethylene glycol-polylactic-co-glycolic acid-poly-L-lysine-cyclic arginine-glycine-aspartic acid peptide nanoparticles (DOX nanoparticles) in the process of cryoablation. RESULTS: The combination of cryoablation and DOX nanoparticles greatly decreases the recurrence rate of breast cancer, which is owing to the specific targeting therapy of DOX nanoparticles for residuary breast cancer cells after cryoablation. Therefore, the survival time of MCF-7 breast cancer bearing mice significantly increases. CONCLUSION: The synergetic therapy of cryoablation and DOX nanoparticles is an effective therapy means for breast cancer. This strategy provides new means for treating breast cancer.

The Role of Simulation in the Design of a Semi-Enclosed Tubular Embolus Retrieval.

A numerical analysis of a semi-enclosed tubular mechanical embolus retrieval device (MERD) for the treatment of acute ischemic stroke (AIS) is presented. In this research, the finite element analysis (FEA) methodology is used to evaluate mechanical performance and provide suggestions for optimizing the geometric design. A MERD fabricated from nickel-titanium alloy (Nitinol) tubing is simulated and analyzed under complex in vivo loading conditions involving shape-setting, crimping, deployment, and embolus retrieval. As a result, the peak strain of the shape-setting procedure is proved to be safe for the device pattern. However, the MERD shows poor mechanical behavior after crimping into a catheter, because the peak crimping strain obtains a value of 12.1%. The delivery and deployment step demonstrates that the artery wall has little risk of serious injuries or rupture. In addition, the process of simulation of embolus retrieval and device system migration inside the cerebral artery lumen provides useful information during the design process.

[Experimental study of temperature sensor in temperature-guided radiofrequency catheter ablation].

In order to optimize temperature monitoring, the mean of temperature measured by Copper-CuNi thermocouple (TC) was compared with the actual temperature. By the use of the temperature response curve of TC, the data from monitoring temperature were analyzed in regard to the depth of installation, the diameter of TC hole and the material of ablation electrode. The accuracy and real-time of TC with a depth of 3.5 mm were better than those of 2.5 mm or 3 mm, when TC was installed in the ablation electrode TC hole. However, the difference of real-time performance was not obvious. When TC was installed in different TC holes with diameter of 0.44 mm, 0.42 mm, 0.33 mm respectively, TC with the diameter of 0.33 mm TC hole was noted to be of higher accuracy and better real-time to response temperature, compared with others. In terms of material quality, the slope of platinum temperature response curve was greater than that of stainless steel, while the accuracy of sensor temperature changed inconspicuously. As a result, the monitoring device of temperature should be put to the heat source as nearly as possible. Also, platinum ablation electrode with better thermal conductivity should be chosen.

Morphology study of freeze-drying mononuclear cells of human cord blood.

The research on haematopoietic stem cells of human cord blood has become more important recently. At present, cord blood is mainly preserved at ultra-low temperatures. In the former study, we compared the effects of preserving mononuclear cells (MNC) and whole human cord blood by freeze-drying. This time, a further study was conducted on freeze-drying mononuclear cells. Samples in the presence of PVP, sucrose, mannitol and FBS were firstly frozen to -38 degrees C. Afterwards, they were vacuum-dried at a selected shelf temperature of -30 degrees C for the main drying stage, and then vacuum-dried at 15 degrees C for the second drying stage. The entire time of freeze-drying process was 41 hours. Samples were stored at room temperature for 7 days prior to evaluation. Subsequently, the dried samples were resuspended in an isotonic phosphate-buffered saline solution. The residual moisture content was 6.5 +/- 0.87%. The recovery of the cells was tested by a haemacytometer, and the numerical cell count recovery of rehydrated MNC increased by 8%. Morphology of the fresh and rehydrated MNC was analyzed respectively using standard light microscopy, scanning electron microscope and transmission electron microscope. The results showed that karyons changed and cytoplasm decreased after rehydration, but it is still unknown that whether these changes will influence the proliferative ability of the stem cells.