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Objective: To design new and effective polyphenol oxidase （PPO） inhibitors and expand their application in the field of aquatic product preservation. Methods: The synthesized H8[P2Mo17Ni（OH2）O61] （P2Mo17Ni） structure was characterized by ultraviolet and infrared spectrum. The inhibitory effect, type and mechanism of P2Mo17Ni on the relative activity of mushroom PPO in vitro was clarified. Then, the preservation effects of P2Mo17Ni on Litopenaeus vannamei Boone were evaluated through studying the index change of shrimps treated with P2Mo17Ni stored at 4 ℃, in which included the sensory score, the value of chromatic aberration L*, the value of total chromatic aberration （ΔE）, the total number of colonies, the value of pH and the value of total volatile basic nitrogen （TVB-N）. Results: The results showed that P2Mo17Ni was synthesized successfully. P2Mo17Ni inhibited the activity of PPO from mushroom in vitro with semi-inhibitory concentration （IC50） of （0.377±0.004） mmol/L. P2Mo17Ni inhibited mushroom PPO in a competitive reversible manner, and the inhibition constant KI was 0.185 mmol/L. Under the cold storage condition of 4 ℃, compared with the control group, P2Mo17Ni could effectively delay the decline of sensory score and the increase of L* and ΔE value in shrimps treated with P2Mo17Ni, and the inhibitory effect was significant. P2Mo17Ni could significantly inhibit the increase of total number of colonies, pH value and TVB-N value. P2Mo17Ni could extend the shelf life of shrimps for 4~5 days. Conclusion: P2Mo17Ni can slow down the blackening of shrimps and prevent its spoilage. P2Mo17Ni possesses a good preservation effect on L. vannamei and can be used in the preservation industry of aquatic products.

As an important part of the International Health Regulations, risk communication plays a significant role in the response and management of public health emergencies. Recommended by World Health Organization (WHO), the five principles for risk communication practice include building trust，releasing information timely，information transparency，paying attention to the public, and formulating preplan. In the study, we analyze and summarize the application of WHO′s five principles of risk communication in the management process of a health emergency response after a strong earthquake occurred in Maduo County, Guoluo Tibetan Autonomous Prefecture, Qinghai Province in May 2021 for providing a reference to prospective practice in future.

In order to study the influence of multiple clutches on the transmission efficiency of a hydro-mechanical continuously variable transmission （HMCVT），the structure characteristics of a closed loop consisting of multiple wet friction clutches in the transmission are investigated. The influence of clutch drag torque on the efficiency characteristics of hydro-mechanical CVT is analyzed. By analysis and calculation of the drag torque generated in the clutch disengagement stage，which affects the transmission efficiency，a calculation model for power transmission in the clutch disengagement stage in a closed loop is established，a calculation formula for power loss caused by clutch drag torque in closed transmission is deduced and a calculation method for the total efficiency of the transmission system is further derived. The calculation results show that the band and row loss of multiple friction clutches in HMCVT has a great influence on its transmission efficiency.

In order to investigate the influence of cutwater on the hydraulic performance of the pump as a turbine (PAT) and improve the performance of the pump operated in reverse as a turbine, a single-stage single-suction centrifugal pump with a specific speed of 69 was selected as the research object. Nine schemes, including the original model, with variations in cutwater placement angle and cutwater radius, were designed. Using the SST k-ω model, numerical simulations of the entire flow passage were conducted for each scheme. Entropy production diagnostic analysis was introduced to analyze the variations in head, efficiency, and internal flow field of the PAT under different schemes. The research results show that within a certain range, increasing the cutwater placement angle leads to a significant reduction in head of the hydraulic PAT in the larger flow rate range. In this PAT, when the cutwater radius is 1.5 mm, the entropy production loss inside the impeller and volute is reduced, resulting in an increase in PAT efficiency. [ABSTRACT FROM AUTHOR]

The thermal oxidative degradation behavior and process of vulcanized styrene-butadiene rubber (SBR) at high temperature was studied by the sol-gel analysis, equilibrium swelling method, Fourier transform infrared spectroscopy coupled with mass spectrometry (FTIR-MS) and in-situ Fourier transform infrared spectroscopy.The chemical structure changes of degradation process of the SBR vulcanizate at 210 ℃ were compared with those of 150 ℃.The results showed that the sol content of the SBR vulcanizate at 210 ℃ gradually increased in the initial stage of the reaction, reached a maximum value of 28.1% at 10 min, and then a significant decline occurred.The trend of the reaction at 150 ℃ was similar to that at 210 ℃, but the reaction rate was relatively slower.The vulcanized SBR produced a small amount of sulfur dioxide gas at 7 min and a relatively large amount of other oxidation products containing carboxyl group and thioheterocyclic group at 12 min were observed by FTIR-MS.The cross-linking bonds of the vulcanized SBR were initially converted from polysulfur bonds to monosulfur bonds, part of which were then oxidized to sulfoxide groups and further to sulfonyl groups or sulfates.The backbone oxidation of the SBR vulcanizate was an autocatalytic oxidation, and the carbonyl group content remained stable during the late stage of oxidation.

Focusing on the problems of poor scalability,the random selection of primary nodes,and high network overhead in the practical-Byzantine-fault-tolerant consensus algorithm,this paper proposes a Byzantine-fault-tolerant consensus algorithm based on credit evaluation mechanism.First of all,the system sets different roles for the nodes in the cluster and assigns different permissions to the nodes according to different roles,so that the nodes with different permissions can enter and exit the network dynamically.Secondly,the voting mechanism and follow-the-satoshi algorithm based on credibility are designed to ensure the security and fairness of the election.Finally,in the aspect of the consensus process,an optimized two-stage Byzantine-fault-tolerant consensus is proposed to reduce the network overhead in the PBFT consensus process.Experiments show that the consensus algorithm based on the credit evaluation mechanism proposed in this paper has the characteristics of high dynamic,election security,and low cost compared with the PBFT algorithm which is suitable for the alliance chain.

In order to solve the privacy and data integrity problems of shared electronic medical records,this paper proposes a red-black tree-based shared electronic medical records data integrity verification scheme based on the parallel blockchain architecture.First,the doctor-patient integrity verification information is stored on the patient chain and the doctor chain with different attri-bute-based encryption,and the doctor-patient data specific information is stored on the CSP off-chain server.Then,the red-black tree-based data integrity verification scheme and dynamic data update scheme are constructed.Security analysis shows that the proposed scheme not only has public verifiability,can effectively resist the cloud server forgery attack,but also can protect the privacy of user and patient information,with high efficiency of integrity verification and data update.

In order to solve the scheduling problem of aircraft moving assembly line in uncertainty environment, this paper proposes a perceptron-dependent fruit fly optimization algorithm(PDFOA) to generate the assembly scheduling template with strong robustness. The proposed PDFOA, taking the fruit fly optimization algorithm as the basis, designs narrow-field osphresis-search operation and narrow-field vision-search operation which is helpful for searching and choosing neighborhood solutions. Simultaneously, the PDFOA sets up a memory library to enhance the global search ability. Finally, simulation experiments are conducted using different testing samples on different job scales. The proposed PDFOA is compared with tabu search, the genetic algorithm and the immune particle swarm optimization algorithm. The results demonstrate the effectiveness of the PDFOA.

Objective To investigate the stability of IgE in postmortem plasma and hemolyzed samples under different storage conditions and freezing-thawing. Methods Thirty nine cardiac blood samples were collected from non-frozen corpses with the postmortem interval of less than 48 hours, including 20 plasma samples and 19 hemolyzed samples taken from whole blood. The samples were stored at -20 ℃, 4 ℃ and 25 ℃ for 28 d and at -80 ℃ for 1 year to evaluate the stability of IgE under different storage conditions. Repeated freezing-thawing treatment was conducted for 5 times to explore the stability of IgE in postmortem plasma and hemolyzed samples. IgE concentration in plasma and hemolyzed samples was detected by electroluminescence before and after treatment. Results The degradation rates of IgE in plasma samples under the three storage conditions, -20 ℃, 4 ℃ and 25 ℃ were close. After 28 d, the mean value was about 15%, the degradation speed of IgE in hemolyzed samples was faster than that of plasma under the same condition （P0.05）, while the concentration of hemolyzed samples was degraded after freezing at -80 ℃ for 1 year（P0.05）. Conclusion IgE has good freezing-thawing stability in postmortem plasma and hemolyzed samples. Stability of IgE is better in postmortem plasma samples than hemolyzed samples, thus it is recommended to separate plasma from postmortem blood samples as soon as possible in forensic practice.

Root canal therapy of mandibular first premolar is challenging for there are some variations in mandibu⁃ lar first premolar root canal. And it is easy to fail when there are some tiny missing root canals. This article reported a mandibular first premolar with apical furcation which was found by the combined application of X⁃ray and CBCT. This article also focuses on root canal exploration and instrumentation, in order to provide evidence for treatment of mandibu⁃ lar first premolar.

Using mesophase pitch based carbon fibers (CFMP) as reinforcement and pyrolytic carbon (PyC) and resin carbon as matrix, high thermal conductivity carbon fiber modified carbon/carbon (C/C) composites were prepared by chemical vapor deposition and liquid phase impregnation process. The micro-structure, mechanical and thermal conductivity properties of the modified C/C composites that heat treated at different temperature (2 000 and 3 000 °C) were investigated. The results show that the structure of CFMP and PyC is not changed obviously after 2 000 °C heat treatment, and the interface between PyC and carbon fiber is tightly bonded, with fewer micro-cracks observed at the interface. However, after 3 000 °C heat treatment, the graphitization degree of CFMP and PyC increases significantly, meanwhile, obvious micro-cracks are formed at the interface between CFMP and PyC. With 2 000 °C heat treatment, the average flexural strength and thermal conductivity of the modified C/C composites are 101.81 MPa and14.739 W/m·K, respectively. However, after 3 000 °C heat treatment, the average flexural strength is declined to 49.35 MPa, whereas the thermal conductivity is enhanced to 63.568 W/m·K. The declined flexural strength and enhanced thermal conductivity are mainly associated with the increased graphitization degree of different carbon phases after 3 000 °C heat treatment. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of using cone-beam computed tomography (CBCT) and dental operating microscope (DOM) in treating maxillary molars containing bifurcative canals buccally. Methods 304 endodontically treated maxillary molars (159 maxillary first molars and 145 maxillary second molars) were included. After preparing access to pulp chamber, the number of canal orifices and location in the pulp chamber floor of each tooth were recorded. For those teeth with bifurcative canals buccally confirmed by preoperative radiographs, the root canals were negotiated by naked eyes firstly, then under DOM according CBCT results. Following working length determination, the root canals were prepared by step-down technique and obturated with cold lateral condensation technique. The efficiency was evaluated with radiographs before, during and after operation. Results In 304 maxillary molars, 51 molars were found to have two canal orifices (buccal one and palatal one) in the pulp floor, 30 bifurcative canals buccally (8 upper first molars and 22 upper second molars) were found. CBCT information indicated the level of bifurcation in buccal canals were 3 - 8 mm under the pulp chamber floors. In 30 maxillary molars, 7 teeth treated by X-rays and eyes could be negotiated, 22 teeth treated by CBCT and DOM could be negotiated and were well instrumented and filled by evaluating with radiographs during and after operation, 8 teeth with deep divergent MB2 canals or calcified canal could not be negotiated. Conclusion Operative field can be located precisely by CBCT and dental operating microscope that could be effective method in treating these sort of canals. [ABSTRACT FROM AUTHOR]

Questionnaire survey has been a very important way for empirical research. Social media provides a new platform for implementing web surveys. Nowadays investigators can use mixed survey modes to collect data based on the social media to make up for the problem of low sample coverage in a single survey mode. By using the CFA, this paper studied the measurement equivalence among the pen-and-pencil survey, web survey, BBS survey, micro blog survey and SNS survey. The results show that these five survey methods have the same basic structure and factor loading matrix. Except for pen-and-pencil survey, the rest four survey methods meet the equivalence of factor covariance matrix. Furthermore, the micro blog survey and SNS survey have equivalence in the intercepts. [ABSTRACT FROM AUTHOR]

This paper summarizes the latest progress for vegetable oil-based polyurethanes mainly from the view of thermoset and thermoplastic. Firstly, the modification methods for traditional thermoset polyurethane are introduced, including physical modification methods (filling and alloying) and chemical modification methods (copolymerization grafting, crosslinking and interpenetrating polymer network). Materials used for physical modification mainly contain inorganic materials such as SiO2 and organic substances such as cellulose. Grafting copolymerization of styrene, acrylate and other monomers with polyurethane is the main method of chemical modification. The characteristics, preparations and application fields of thermoplastic polyurethane are reviewed, and the preparations, performances and applications of oleic acid-based thermoplastic polyurethane are chiefly presented. The development prospects of vegetable oil-based polyurethane are put forward. Surface-initiated living polymerization and other methods are used to controllable chemical modification of the traditional thermoset polyurethane and click chemistry method is uesd to promote multi-functionalization of the thermoplastic polyurethane.

In order to explore the characteristics and sources of heavy metals in farmland soil and their risks to human health and to provide an important scientific basis for farmland pollution control, 133 surface soils (0-20 cm) were collected from typical agricultural production areas in Zhejiang Province, and the contents of soil Cd, Pb, Cr, Cu, Zn, Ni, As, and Hg were determined. Various methods were applied to evaluate the degree of heavy metal pollution in farmland and its ecological risks in the study area. The method of combining Kriging interpolation and positive definite matrix factor analysis (PMF) was applied to analyze the pollution sources and quantify the contribution of each pollution source. Combined with the health risk assessment model, the risk to human health of each pollution source was evaluated from the perspective of source exposure. The results showed that the average ω (Cd), ω (Pb), ω (Cr), ω (Cu), ω (Zn), ω (Ni), ω (As), and ω (Hg) were 0.76, 65.22, 92.02, 103.92, 198.49, 36.65, 5.97, and 0.20 mg·kg -1 , respectively. The average contents of Cd and Cu were higher than the risk screening values of soil contamination of agricultural land, and 85.71% and 96.24% of soil was contaminated by heavy metals. The average contents of Pb, Cr, Zn, and Ni exceeded the soil background values of the Wenhuang Plain in Zhejiang Province, and the As and Hg contents were within the limit values. The potential soil ecological risks were mainly light-moderate, accounting for 90.98%, and both high and higher risk accounted for 4.51%; Cd was the main potential ecological risk element. The main sources of heavy metal pollution in the study area were the sources of the electronic waste dismantling process (26.82%), the mixed sources of coal combustion and traffic emissions (34.50%), mixed sources of natural parent materials and agricultural inputs (25.59%), and e-waste pickling runoff and solid waste leaching sources (13.09%). The health risk of heavy metal exposure to children was significantly greater than that in adults. Mixed sources of natural parent materials and agricultural inputs contributed the most to human health risks, and Cr was the element with the greatest contribution to human health risks.

Objective: This study aims to examine the biomechanical effects of different reconstruction methods, including single-bundle, double-bundle anatomical reconstruction, and double-bundle truly anatomical reconstruction of the coracoclavicular ligament on the acromioclavicular joint using finite element analysis, to provide a theoretical basis for the clinical application of truly anatomical coracoclavicular ligament reconstruction., Methods: One volunteer, aged 27 years old, with a height of 178 cm and a weight of 75 kg, was selected for CT scanning of the shoulder joint. Three-dimensional finite element models of single-bundle reconstruction, double-bundle anatomical reconstruction, and double-bundle truly anatomical reconstruction of coracoclavicular ligament were established by using Mimics17.0, Geomagic studio 2012, UG NX 10.0, HyperMesh 14.0 and ABAQUS 6.14 software. The maximum displacement of the middle point of the distal clavicle in the main loading direction and the maximum equivalent stress of the reconstruction device under different loading conditions were recorded and compared., Results: The maximum forward displacement and the maximum backward displacement of the middle point of the distal clavicle in the double-bundle truly anatomic reconstruction were the lowest, which were 7.76 mm and 7.27 mm respectively. When an upward load was applied, the maximum displacement of the distal clavicle midpoint in the double-beam anatomic reconstruction was the lowest, which was 5.12 mm. Applying three different loads forward, backward, and upward, the maximum equivalent stress of the reconstruction devices in the double-beam reconstruction was lower than that in the single-beam reconstruction. The maximum equivalent stress of the trapezoid ligament reconstruction device in the double-bundle truly anatomical reconstruction was lower than that in the double-bundle anatomical reconstruction, which was 73.29 MPa, but the maximum equivalent stress of the conoid ligament reconstruction device was higher than that of the double-bundle anatomical reconstruction., Conclusion: The truly anatomical reconstruction of coracoclavicular ligament can improve the horizontal stability of acromioclavicular joint and reduce the stress of the trapezoid ligament reconstruction device. It can be a good method for the treatment of acromioclavicular joint dislocation.

Objective: To evaluate the effect of the York-Mason procedure (posterior sagittal approach) in the treatment of urethrorectal fistula., Methods: Ten 15－80 (mean 54) years old male patients with urethrorectal fistula were treated by the York-Mason procedure, 3 by anoplasty for congenital anal atresia, 5 by laparoscopic radical prostatectomy, and the other 2 by radical rectal cancer resection. All the cases were single fistula with a history of 3 months to 18 years. Enterostomy was performed in 6 of the cases before the York-Mason procedure., Results: The York-Mason procedure lasted 90－130 (mean 104) minutes, with no perioperative complications. Nine of the cases were successfully repaired in the first surgery and 1 in the second. The patients were discharged after an average of 7 hospital days postoperatively and followed up for 6－90 months without recurrence., Conclusions: The York-Mason procedure is a reliable and effective option for the treatment of urethrorectal fistula, with the advantages low morbidity, short operation time and fast recovery.

To reveal the distribution characteristics of carbon, nitrogen and phosphorus in the sediments of Zhushan Bay at Taihu Lake, sedimentary columns were collected and sliced by 2 cm vertically from ten sampling points in three sections of Zhushan Bay. The content of total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) were determined for each slice to reveal their horizontal and vertical distribution. The results showed that:spatially, the content of TN, TP, and TOC increased in the surface sediments of Zhushan Bay from the open lake area to the bay, and inside the bay these indexes were significantly higher than in the open lake area ( P <0.01). The content of TN, TP, and TOC in the surface sediments in the bay (section A) were 1.53 mg·g -1 , 1.55 mg·g -1 , and 11.31 mg·g -1 , respectively, while in the surface sediments near the open lake (section C) they were only 0.75 mg·g -1 , 0.57 mg·g -1 , and 6.70 mg·g -1 , respectively. Vertically, a feature of surficial enrichment was shown, and the contents of carbon, nitrogen and phosphorus in all three sections showed a decreasing trend with increase of depth. The contents of TN, TP and TOC in the surface sediments are 2-3 times, 2-5 times, and 2-3 times those in the bottom sediments, respectively. Generally, the average TP content in the sediment of Zhushan Bay is 0.93 mg·g -1 , suggesting an apparent heavy pollution, while the average TN content is 1.11 mg·g -1 as slight pollution. According to the organic nitrogen index and comprehensive pollution index, the northern part of Zhushan Bay is suffering from heavy pollution, where the organic pollution is relatively strong. The TP pollution index is between 1.03 and 3.87, indicating heavy pollution in Zhushan Bay.

In shallow eutrophic lakes, benthic bioclastic deposits accumulate abundant organic carbon derived from macrophyte detritus. Taking the typical macrophyte-dominated Xukou Bay as the study area, field investigations were performed using sediment cores to evaluate benthic phytodetritus accumulation. Specifically, nutrient contents, TOC/TN ratios, pigmentation, and biodegradable compounds were measured as descriptive parameters. The results show that the benthic bioclastic deposit had accumulated abundant pigments, nutrients, and biodegradable compounds derived from macrophytes detritus. These were mainly localized in the top 15 cm of sediments. Nitrogen loading in the sediments was significantly higher than phosphorous loading, with a distinct spatial difference; the total nitrogen content ranged from 127.2-2092.8 mg·kg -1 and total phosphorous content ranged from 222.1-528.4 mg·kg -1 . Moreover, nitrogen loading (1033.6 mg·kg -1 ) in the vegetated zones were higher than in the unvegetated zones (325.2 mg·kg -1 ). In addition, carbohydrate (3.7 mg·g -1 ) was the dominant component of sedimentary bioclastic material, with lipids (2.8 mg·g -1 ) being the second most abundant of the biodegradable compounds. The major sources of nutrients and biodegradable compounds in the sediment were massive aggregates of macrophyte detritus. The pigment, nutrient, and biodegradable compound contents in the vegetated zones were significantly higher than in unvegetated zones ( P <0.01). The benthic eutrophic state showed a trend from mesotrophic to eutrophic in Xukou Bay, which should be given more attention in the future management of freshwater lake ecosystems.

Objective: To investigate the expression of long non-coding RNA-HOTAIR in prostate cancer cells and its effects on the growth and metastasis of the cells., Methods: Using quantitative reverse-transcription PCR (qRT-PCR), we determined the relative expression of HOTAIR in the normal human prostate epithelial cell line RWPE-I and prostate cancer cell lines PC-3 and DU145. We detected the effects of HOTAIR on the cell cycle and invasiveness of prostate cancer cells by RNA interference, flow cytometry, and Transwell mitration assay., Results: The expressions of HOTAIR in the PC3 and DU145 cells were increased 3.2 and 5.7 times, respectively, as compared with that in the normal RWPE-1 cells. After si-HOTAIR interference, the prostate cancer cells were arrested in the G2 phase and downregulated in the G1 phase. The invasive ability of the prostate cancer cells was evidently inhibited, with the inhibition rates of 32% and 44% of the PC3 cells and 43% and 34% of the DU145 cells for si-HOTAIR1 and si-HOTAIR2, respectively., Conclusion: IncRNA HOTAIR is highly expressed in prostate cancer, which is associated with the growth and invasiveness of prostate cancer cells. HOTAIR is potentially a novel marker for the diagnosis and prognosis of prostate cancer.

Objective: To investigate the pathogenesis and treatment of penile necrosis resulting from microwave diathermy following circumcision., Methods: We retrospectively analyzed the clinical data about 9 cases of penile necrosis resulting from postoperative microwave diathermy following circumcision. The 9 males, aged 20 - 39 (mean 26) years, underwent traditional circumcision for redundant prepuce or phimosis in other hospitals, followed by microwave diathermy for 30 - 60 minutes daily, which resulted in penile necrosis. With no response to conservative therapy, the patients were referred to our hospital at 3 -30 days postoperatively. Of the 9 patients, 5 presented with dry gangrene and 4 with moist gangrene. Six of the patients underwent partial penectomy, including 1 that received penis lengthening.3 months later, while the other 3 underwent total penectomy for total penile necrosis followed by penile reconstruction 3 months later, with deep inferior epigastric perforator (DIEP) flaps and by implantation of the 12th costal cartilage in 2 cases and with epigastric groin island flaps and by urethroplasty in the other., Results: The patients were followed up for 2 - 8 years, and all could urinate smoothly in the standing position. Of the 6 men treated by partial penectomy, 1 received penis lengthening and achieved a penile length of 7 cm and 5 had the remaining penile length of 3 -5 cm, 4 with erectile function and the other 2 capable of sexual intercourse. The 3 men treated by total penectomy achieved nearly normal external appearance of the penis, with a finalized length of (11.7 ± 1.3) cm, a circumference of (11.4 ± 2.1) cm, and a normal feel of the skin. Of the 3 cases of penile reconstruction, 2 achieved sufficient erectile hardness of the penis (grade 3) for sexual intercourse, while the other 1 remained impotent., Conclusion: Post-circumcision microwave diathermy may result in penile necrosis, for the management of which, early debridement is necessitated and penile lengthening or reconstruction can be performed according to the severity of the lesion and needs of the patient.

Objective: To investigate the safety and feasibility of laparoscopy-assisted combined radical resection for synchronous rectal and gastric cancer in elderly patients., Methods: Clinical data of two elderly patients undergoing laparoscopy-assisted combined radical resection for synchronous rectal and gastric cancer were analyzed retrospectively., Results: The two cases were 78 and 75 years old respectively. Both were complicated with many medical conditions. One case suffered from stage II cancer in the gastric body and stage IB rectal cancer, and the other suffered from stage IIIA gastric cancer and stage IB rectal cancer. Both cases had received laparoscopy-assisted combined radical resection for synchronous rectal and gastric cancer, with 5 cm of incision. The operative time was 260 and 255 min and the intraoperative bleeding was 60 and 80 ml respectively. No complication occurred intraoperatively. Time to resume oral intake was 4 and 5 days and length of postoperative hospital stay was 13 and 14 days respectively. No postoperative complication occurred. The patients were followed up for 13 and 12 months and no postoperative recurrence or metastasis was noticed., Conclusion: Laparoscopy-assisted combined radical resection for elderly synchronous rectal and gastric cancer is safe and feasible when performed by surgeons with plentiful experience in laparoscopic technology, and associated with less injury and faster recovery.

Objective: To evaluate the efficacy and safety of long-term on-demand use of vardenafil in the treatment of erectile dysfunction (ED)., Methods: We conducted a questionnaire investigation among 891 ED patients treated by on-demand use of oral vardenafil at 20 mg every 3 days from March 2007 to January 2010, covering the general information of the patients, their need for and attitudes towards the treatment, clinical efficacy and adverse events of the drug, and satisfaction of the patients and their partners after 12 weeks of treatment., Results: Treatment and follow-up were completed in 700 patients, of whom 504 (72%) achieved sufficient hardness and duration of penile erection and overall sexual satisfaction, 84 (12%) admitted to improvement of erectile hardness and duration but not adequate satisfaction, and the other 112 (16%) experienced no significant changes. Significant differences were found in IIEF-5 scores, Rigiscan test results and partners TSS scores before and after the treatment (P < 0.05). Most frequent adverse events included flushing (15%), dizziness and headache (10%), dyspepsia (3%), and nasal congestion (1%)., Conclusion: Long-term on-demand use of oral vardenafil, in addition to its safety and good tolerance, can effectively improve the erectile function of ED patients, their success rate of sexual intercourse, and overall quality of sexual life.

Objective: To investigate the effects of sodium alginate gels on marrow mesenchymal stem cell transplantation for repair of spinal cord injury (SCI) in mice., Methods: In the present study, effects of different sterilization methods and concentrations of sodium alginate gels were examined. Marrow mesenchymal stem cells (mMSCs) were isolated from mice and cultured. Cells were cultured with sodium alginate gels and MTT assay was applied to determine the cell viability. Mice spinal cord injury was induced by spinal cord transection. mMSCs were transplanted into the cavity of injured spinal cord with sodium alginate gels. The effects of sodium alginate gel were assessed by BMS scales and immunofluorescence staining for NF-200., Results: Compared with liquid form, solid form sodium alginate gel prepared with high pressure vapor sterilization had a better effect on cell viability. SCI mice treated with 10 % sodium alginate gel and mMSCs achieved higher score in BMS scale as well as higher expression of NF-200 compared with the untreated SCI group., Conclusion: Sodium alginate gel prepared with solid form sterilization induces mMSCs proliferation and thus can be used as the carrier of stem cell in treatment of SCI.

Objective: To evaluate the effect of using cone-beam computed tomography (CBCT) and dental operating microscope (DOM) in treating maxillary molars containing bifurcative canals buccally., Methods: 304 endodontically treated maxillary molars (159 maxillary first molars and 145 maxillary second molars) were included. After preparing access to pulp chamber, the number of canal orifices and location in the pulp chamber floor of each tooth were recorded. For those teeth with bifurcative canals buccally confirmed by preoperative radiographs, the root canals were negotiated by naked eyes firstly, then under DOM according CBCT results. Following working length determination, the root canals were prepared by step-down technique and obturated with cold lateral condensation technique. The efficiency was evaluated with radiographs before, during and after operation., Results: In 304 maxillary molars, 51 molars were found to have two canal orifices (buccal one and palatal one) in the pulp floor, 30 bifurcative canals buccally (8 upper first molars and 22 upper second molars) were found. CBCT information indicated the level of bifurcation in buccal canals were 3-8 mm under the pulp chamber floors. In 30 maxillary molars, 7 teeth treated by X-rays and eyes could be negotiated, 22 teeth treated by CBCT and DOM could be negotiated and were well instrumented and filled by evaluating with radiographs during and after operation, 8 teeth with deep divergent MB2 canals or calcified canal could not be negotiated., Conclusion: Operative field can be located precisely by CBCT and dental operating microscope that could be effective method in treating these sort of canals.

Objective: To analyze the clinical characteristics and the surgical treatment strategy of cervical kyphosis., Methods: From March 2006 to October 2009, 31 cases of cervical kyphosis were treated. According to the clinical features and imaging findings, different treatment methods were used. There were 9 patients in operation group, including 4 male and 5 female patients, aged from 17 to 72 years (average age of 35 years). Among them, 5 cases were idiopathic kyphosis and 4 cases were caused by laminectomy or other reasons. There were 22 patients in conservative treatment group, including 11 male and 11 female patients, aged from 14 to 40 years (average age of 29 years), who were all idiopathic cervical kyphosis. Before and 1 week after operation, clinical assessment were taken for the patients in operation group using Spinal Cord Injuries Classification Standard of American Spinal Injury Association (AISA). During the periodic review, the anteroposterior, normal sagittal films of cervical spine were taken. At 1 week and every 6 months after operation, MRI films were also taken. These films were studied to evaluate the effects of the operations. In the conservative group, assessment of treatment results by studying anteroposterior and normal lateral views of cervical spine were were taken every month. The clinical characteristics and the surgical treatment strategies of these patients were analyzed., Results: In operation group, 9 cases were followed up for 6 to 18 months, all patients did not failed in internal fixation and fusion. AISA neurological score and neurological function significantly improved. Three days after operation the average Cobb angle was -1.29 ° (preoperative 54.24 °). In conservative group, the average Cobb angle was -5.41 ° (before treatment 11.20 °) 4 months after the treatment. The symptoms of neck shoulder and back pain disappeared, and all patients were followed up for 3 to 24 months, with no recurrence of symptoms., Conclusions: In the early period of cervical kyphosis, adopt postural therapy, plaster braces to correct an imbalance in cervical spine biomechanics can prevent deformity development. According to patients' clinical characteristics, choosing individual treatment programs can correct the severe cervical kyphosis and achieve good outcome.

Objective: To summarize the clinical characteristics of severe adolescent idiopathic cervical kyphosis and the operation method., Methods: A retrospective study was performed in 12 adolescent patients with severe cervical kyphosis treated from July 2003 to January 2007. Preoperative the Cobb angle of kyphosis range from 55 degrees to 73 degrees (average 61 degrees ). According to the angles between the posterior vertebral body tangents at every involved level on lateral cervical radiograph in extension, the osteotomy angles and range of lamina and facet were decided. The anterior release and posterior osteotomy were performed firstly. Then skull traction was maintained in order to correct the deformity as long as possible, fusion and internal fixation was completed after 7-10 days. The cervical coronal and sagittal planes X-rays and the MR were hold after operation 3 days, 3 months, 6 months, 1 year and 2 years. At the same time the treatment result, bone fusion and the instrumentation were followed up, and the symptoms were compared between pre-operation and post-operation., Results: The defect appearance of the patients was improved significantly, with the total disappearance of neck pain and improvement of nerve function. Post-operational cervical spine MR showed that the physiological curve of cervical spine was restored, cerebral spinal fluid line was clear in the kyphosis area and no spinal cord compression was found. X-ray imaging of post-operation 3 d showed that Cobb angle ranged from -12.3 degrees to 11.2 degrees with an average of -2.0 degrees . Beside one patient's AISA score was D, other patient's AISA score was E., Conclusions: The severe adolescent idiopathic cervical kyphosis has its own clinical manifestation. It is an ideal treatment to completely assess the deformity, have staging operation and skull traction between two operations.

Objective: To investigate the expression and its significance of retinoic acid receptor-beta (RAR-beta) in colorectal cancer., Methods: RAR-beta was detected by immunohistochemistry methods and carcino-embryonic antigen (CEA) was tested by chemiluminescence immunoassay methods in normal tissues, paracancerous tissues and colorectal cancer tissues of 60 patients with colorectal cancer treated from January 2006 to January 2007. Above-mentioned data, together with the clinicopathological data of these 60 patients, were analyzed to figure out the expression and its significance of RAR-beta in colorectal cancer., Results: The expression rate of RAR-beta in tumor tissues (48%) was significantly lower than those in both normal tissues (87%) and paracancerous tissues (87%) (P < 0.05). And its expression was also significant lower in patients with lymph node metastasis (32%) and patients with advanced cancer (TNM stage III and IV) (29%) than in those without lymph nodes metastasis (60%) and those with early stage cancer (stage I and II) (69%). There was no significant differences among well, mildly and poorly differentiated cancer tissues. The CEA level rose in 20 patients, and its rising rate was remarkably higher in patients with lymph node metastasis (48%) and in patients with advanced cancer (52%) than those without lymph node metastasis (23%) and in early stage(14%)., Conclusions: The expression of RAR-beta decreases significantly in cancer tissues in patients with colorectal cancer, which may be related to the carcinogenesis of colorectal cancer; and its decreasing degree is correlated negatively with the lymph node metastasis and advanced clinicopathological stage. The expression level of RAR-beta may be a new prognostic indication of patients with colorectal cancer.

Retinoid resistance has limited clinical activity of retinoids as differentiation-inducing and apoptosis-inducing drugs. The present study was designed to investigate whether celecoxib (selective COX-2 inhibitor) has effects on cellular retinoid sensitivity of human colon cancer cell lines and its possible mechanism. Cell viability was measured by MTT assay. Apoptosis was detected by Annexin-V/PI staining and flow cytometry assay. PGE2 production was measured by ELISA assay. Expression of RARbeta was assayed by Western blotting. The results showed that celecoxib enhanced the inhibitory effect of ATRA in both COX-2 high-expressing HT-29 and COX-2 low-expressing SW480 cell lines. Further study showed the ATRA and celecoxib combination induced greater apoptosis, and the addition of PGE2 did not affect the number of apoptotic cells induced by the combination. Moreover, NS398 (another selective COX-2 inhibitor) did not affect the inhibitory effects of ATRA on both cell lines. Western blotting showed that the expression of RARbeta in HT-29 cell lines increased in celecoxib group and combination group. And the addition of PGE2 did not affect the expression of RARbeta induced by celecoxib either. In conclusion, celecoxib increased expression of RARbeta and cellular ATRA sensitivity through COX-2-independent mechanisms, which may provide a potential strategy for combination therapy.

Objective: To evaluate the safety of living related donors in short term after transplantation., Methods: Two hundred and fifty-one cases of living related donor kidney transplantation from May 2000 to July 2007 were analysed retrospectively. There were 117 male and 134 female aged from 22 to 72 years old, with a mean of 46.6 years old. The indexes were compared including serum creatinine (SCr), creatinine clearance (CCr), glomerular filtration rate (GFR) and quality of life before and after donation. Surgical complications were followed-up., Results: Donors' SCr was (75.9 +/- 17.2) micromol/L before donation, (107.4 +/- 21.2) micromol/L on 7 d after donation, (130.4 +/- 58.2) micromol/L at the 1(st) month and (116.1 +/- 24.1) micromol/L at the 3(rd) month. There were significant difference between any 2 time points (P < 0.01). CCr was (94.4 +/- 17.5) ml/min before donation and (63.5 +/- 17.8) ml/min on 10 d after donation (P < 0.01). In 62 donors, total GFR was (82.4 +/- 21.8) ml/min before donation. On 10 d after donation, GFR of remaining kidney was (57.4 +/- 14.1) ml/min which was 34.7% higher than GFR of this kidney before donation (42.6 +/- 11.8) ml/min. There was no significant difference in quality of life before living related donors and non-donor populations (P = 0.116). Surgical complications included splenic rupture in 1 case, descending colon rupture in 1 case and wound infection in 5 cases., Conclusion: Living donor kidney transplantation is safe for donors, although part of indexes would vary within normal range during the early time after donation.

Aim: To investigate the expression of BMP-2 protein and mRNA in glioma, and evaluate its clinical significance in clinicopathological status of patients with glioma., Methods: BMP-2 protein and mRNA expression in 88 patients with glioma were examined by SABC immunohistochemistry and RT-PCR, respectively., Results: The positive expression rate of BMP-2 protein in glioma tissues were 78.40% (69/88), which was significantly higher (P<0.01) than that in normal brain tissues [3% (6/20)]. The expression of BMP-2 protein and mRNA in gliomas of grade III-IV was also significantly higher than that in gliomas of grade I-II., Conclusion: BMP-2 expression in cancerous tissues may play an important role in the progression of glioma, which may help to predict patients' prognosis as a tumor marker.

Objective: To offer normal reference of diameter of the cervical spinal cord and available diameter of cervical spinal canal and to screen scientific radiographic criteria to define and quantify cervical spinal cord disease., Methods: The magnetic resonance images of 120 normal people had been measured. The data of diameters of cervical spinal cord, CSF, M, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M had been collected and statistical analysis was made. And the relationships between the data above and each of gender, the length of C-spine and age were evaluated. In addition, the ratio of diameters of cord and CSF, and the ratio of diameters of cord and M was evaluated., Results: The study showed that in healthy people, the diameters of cervical spinal cord, CSF and M was larger in the males than in the females, decreased with age, and increased with the length of C-spine but the diameter of CSF. And the ratio of diameters of cord and CSF increased with age and not affected by the length of C-spine. However, the ratio of diameters of cord and M was not affected by age and the length of C-spine., Conclusion: The ratio of diameters of cord and M is not affected by individual variation and can be used to evaluate cervical spinal cord atrophy, compression and impaired in patients with cervical myelopathy and can be important information in looking for clinically critical points.

Objective: To discuss Clinic feature and turnover of delayed hyperextension injury concomitance spinal cord injury of cervical spine., Methods: The clinic data of 30 patients delayed hyperextension injury of cervical spine were reviewed and analyzed. Course of disease was from 3 months to 8 years. Thirty patients were divided into three groups according to course of disease. The first group, 3 - 6 months, 17 cases; the second group, 6 - 12 months, 8 cases; the third group, 12 months-8 years, 5 cases. Neurological function improvement rates were evaluated according to the JOA scores at preoperative, 3 months and 1 year post operation, and complications were observed in three groups. Twenty-six cases were treated with anterior decompression, bone graft and plate fixation. Four cases were treated with posterior decompression, bone graft and plate fixation., Results: The patient number of the three group exist with statistical significance. Thirty patients were followed up for 18 - 39 months, 23 months on average. Neurological function recovery rates were 23.8% in the first group, 53.9% in the second group and 54.3% in the third group at 1 year post operation. JOA scores of the first group and the second group with statistical significance at 3 months and 1 year post operation. JOA scores of the first group and the third group with statistical significance at 3 months and 1 year post operation. JOA scores of the second group and the third group without statistical significance at 3 months and 1 year post operation., Conclusions: Incidence of hyperextension injury associated with spinal cord injury of cervical spine would degrade along with course of disease prolong. If delayed spinal cord injury occurred earlier, the patient's condition was severer and badly improvement rate.

Objective: To investigate the curative effect of electrocorticography (ECoG) monitoring in the microsurgical treatment of cavernous angiomas., Methods: Clinical data of 71 patients with epileptogenic cavernous angiomas,who had been performed ECoG monitoring during the operation,were analyzed retrospectively., Results: The foci of cavernous angiomas and epilepsy of the 71 patients were resected during the operation. In the 58 patients who were followed up,42 had not epileptic seizure,and 16 still had epileptic seizure,while the frequencies of 13 patients reduced to below 10%,and 3 patients over 10%., Conclusion: The drug treatment of epileptogenic cavernous angiomas can not control epileptic seizure,and the patients should receive the microsurgical treatment early. Electrocorticography monitoring can direct the surgical procedure,and control the postoperative epileptic seizure.

Objective: To evaluate the type V phosphodiesterase (PDE-5) inhibitor erection-provoking test with audio-visual sexual stimulation in the diagnosis of erectile dysfunction., Methods: A total of 853 out-patients diagnosed with erectile dysfunction were divided into an injury and a non-injury group. After scored on IIEF-5 questionnaires, all the patients received oral administration of PDE-5 inhibitors and, 30 minutes later, audio-visual sexual stimulation. The data on penile erection were recorded with Rigiscan Plus., Results: The patients with mild, moderate and severe ED accounted for 18.8, 31.9 and 49.3% in the injury group, and 50.6, 39.8 and 9.6% in the non-injury group, with statistic differences between the two groups in the mild and severe parts (P < 0.05). The rates of conspicuous effectiveness, effectiveness, ineffectiveness and total effectiveness of the combined method were 13.0, 14.5, 72.5 and 27.5% in the injury group, but 55.7, 20.7, 23.6 and 76.4% in the non-injury group, with significant differences (P < 0.05)., Conclusion: The PDE-5 inhibitor erection-provoking test with audio-visual sexual stimulation is a simple, practical, safe and effective method for the differentiation of organic from psychological erectile dysfunction.

Objective: To explore the effect of the cerebral thrombin preconditioning on the thrombin-induced brain edema, to detect the expression of tumor necrosis factor-alpha (TNF-alpha), and to analyse the relationship between TNF-alpha and the thrombin-induced brain edema., Methods: Forty SD rats were randomly divided into a ST group and a TT group. The rats received 50 L saline (ST group) or 1 U thrombin infusion (TT group), and received the second infusion (10 U thrombin) 24 h later. The rats were sacrificed at 24 and 72 h after the second infusion in order to examine the changes of brain water and sodium contents as well as the expression of TNF-alpha in the brain., Results: The brain water and sodium contents in the ST group were significantly higher than those on the TT group, and those on the 1st day were higher than those on the 3 th day. The positive expression of TNF-alpha and in the change of water content were identical in the TT group and the ST group., Conclusion: Thrombin preconditioning can alleviate the thrombin-induced brain edema. The increase of TNF-alpha expression after thrombin treatment may be related to the thrombin-induced brain edema.

Objective: To investigate the clinical characteristics, diagnosis, treatment and prognosis of deep sarcoma of the penis., Methods: The pathological and clinical data of 2 cases of deep sarcoma of the penis were analyzed retrospectively and the literature reviewed., Results: Both of the cases were treated by total penectomy. Epithelioid angiosarcoma of the penis was confirmed by postoperative pathology in one patient, who died of pulmonary metastasis in the eighth month after the operation; and epithelioid sarcoma of the penis was confirmed in the other, who died of brain metastasis in the second month after the operation., Conclusion: Deep sarcoma of the penis is rare but can be diagnosed pathologically. Total penectomy is the main option for its treatment. Node dissection, with poor prognosis, is not recommended unless adenopathy is palpable.

Objective: To explore the multidrug resistance (MDR) mechanism of ABC superfamily transporters in the tumor stem cells(TSC) from human brain glioma tissues., Methods: Samples of glioma were obtained from 30 patients undergoing microsurgical tumor resection. The CD133(+) cells and CD133(-) cells from these tumor specimens were isolated by magnetic activated cell sorting(MACS). These cells were cultured, proliferated and passaged. The protein and activity expression of multidrug-resistance protein 1(MDR1) and multidrug-resistance associated protein 1(MRP1) were analyzed between CD133(+) and CD133(-) cells by immunocytochemistry and RT-PCR respectively., Results: CD133(+) cells generated free floating neurosphere like brain tumor spheres(BTS) and abnormal proliferating capacity in the serum-free medium(SFM) in vitro. Three cases from glioblastoma stem cells could form BTS in the complete medium, and could be cultured for 1-3 passages. The range of positive cell proportion for MDR1 and MRP1 expression in CD133(+) cells was 18%-67% and 23%-73% respectively. The expression levels of MDR1 and MRP1 mRNA were higher in CD133(+) glioma stem cells than those in the differentiated tumor cells(TC), the protein activity was increased to 16.1 and 19.6 times respectively compared with that of TC. The protein and activity expression were positively related to the pathological grades of tumors. MDR1 or MRP1 drug resistance was not expressed in all the tumors and there was obvious correlation between MDR1 and MRP1., Conclusion: Only a small proportion of cells in the heterogeneous glioma is CD133(+) brain tumor stem cells which display the strong capacity of self-renewing, abnormal proliferation and intrinsic multidrug resistance to traditional chemotherapy. The high expression of MDR1 and MRP1 by the CD133(+) brain tumor stem cells is one of the main mechanisms in the chemoresistance of tumors. CD133(+) brain tumor stem cells can be served as the root of multidrug resistance and key therapeutic target for glioma chemotherapy.

We have investigated the degradation of pure Polycaprolactone (PurePCL) and chitin short fiber reinforced Polycaprolactone composite (SFRP) in vitro in order to provide useful scientific basis for clinical application. PurePCL, SFRP and DL-PLA were immersed in 0.9% NaCL solution for periods of 2, 4, 8, 12, 16 and 24 weeks. Then pH values in immersing solution, weight loss and mechanical properties of tested materials were measured and SEM was used to study the change of the materials in the process of degradation. It was shown that the initial strength of SFRP was much higher than that of PurePCL. In the process of degradation of SFRP, the pH values maintained weak acid or remianed neutral. The rate of weight loss of SFRP was faster than that of PurePCL, but slower than that of DL-PLA. The strength and modulus of SFRP did not change much in 24 weeks, compared with the initial ones. In conclusion, the composites have excellent properties and may be optimal for clinical use in reconstruction of chest wall defects as well as in internal fixation of bone fracture.

Objective: To establish a simplified culture system for the isolation of brain tumor stem cells (BTSCs) from the tumors of human neuroepithelial tissue, to observe the growth and differentiation pattern of BTSCs, and to investigate their expression of the specific markers., Methods: Twenty-six patients with brain neuroepithelial tumors underwent tumor resection. Two pieces of tumor tissues were taken from each tumor to be dissociated, triturated into single cells in sterile DMEM-F12 medium, and then filtered. The tumor cells were seeded at a concentration of 200,000 viable cells per mL into serum-free DMEM-F12 medium simply supplemented with B27, human basic fibroblast growth factor (20 microg/L), human epidermal growth factor (20 microg /L), insulin (4 U/L), L-glutamine, penicillin and streptomycin. After the primary brain tumor spheres (BTSs) were generated, they were triturated again and passed in fresh medium. Limiting dilution assay was performed to observe the monoclone formation. 5-bromodeoxyuridine (BrdU) incorporation test was performed to observe the proliferation of the BTS. The BTSCs were cultured in mitogen-free DMEM-F12 medium supplemented with 10% fetal bovine serum to observe their differentiation. Immunocytochemistry was used to examine the expression of CD133 and nestin, specific markers of BTSC, and the rate of CD133 positive cells., Results: Only a minority of subsets of cells from the tumors of neuroepithelial tissue had the capacity to survive, proliferate, and generate free-floating neurosphere-like BTSs in the simplified serum-free medium. These cells attached to the poly-L-lysine coated coverslips in the serum-supplemented medium and differentiated. The BTSCs were CD133 and nestin positive. The rate of CD133 positive cells in the tumor specimens was (21 +/- 6.2)% - (38 +/- 7.0)%., Conclusion: A new simplified culture system for the isolation of BTSCs is established. The tumors of human neuroepithelial tissue contain CD133 and nestin positive tumor stem cells which can be isolated, proliferate and differentiate in vitro and give rise to brain tumor spheres. This tumorigenic subset may provide both a platform for brain tumor research and a target for clinical treatment.

Since Nature published the first report in 2002 on using immunodeficient mice as recipients and allogeneous or heterogeneous testes as donor tissues to study the ectopic development of spermatogenic cells, the technique has been widely applied in various species (including human). In comparison with other in vitro maturation methods for male germ cells, testicular allografting or xenografting technique has such advantages as similar environment for the development of germ cells in physiological conditions, and better reproducibility. Up to now, sperm has been successfully produced by this technique from the testicular tisues of the immature mouse, hamster, cat, rabbit, pig, goat, bovine and rhesus monkey, and their offspring have even been generated by ICSI technique using the mouse and rabbit sperm derived from testis grafts. This article comprehensively reviews the development of the technique by discussing the influencing factors on the germ cell development in grafts including the variety and age of donors, the sex, integrity and immunity of recipients, the graft location and grafting time. And the applications of the technique and the existing problems are discussed as well.

Objective: To study the genetic susceptibility of HLA-DQB1 alleles to duodenal ulcer in Chinese Hans from Guangdong area around., Methods: Hundred and five patients with duodenal ulcer and hundred and five healthy controls were examined for HLA-DQB1 genotypes. HLA-DQB1 allele typing was carried out by polymerase chain reaction with sequence specific primers (PCR-SSP)., Results: The allele frequency of HLA-DQB1*0602 in patients with duodenal ulcer (64.8%) was significantly higher than that in healthy controls (14.3%)., Conclusion: These findings suggest that HLA-DQB1*0602 is a susceptible gene to duodenal ulcer in Guangdong Hans of China. And at HLA-DQB1 site, there are immunogenetic differences between duodenal ulcer patients and healthy controls.

Chitin short fiber reinforced polycaprolactone composite was prepared by melting blending method. The cytotoxicity and biocompatibility of pure polycaprolactone and of chitin short fiber reinforced polycaprolactone composite were investigated in order to provide useful scientific basis for clinical application. The biocompatibility of pure polycaprolactone and that of chitin short fiber reinforced polycaprolactone composite were evaluated by a series of tests, including cytotoxicity test in vitro, acute systemic toxicity test, hemolysis test, pyrogen test and sensitivity test. The results showed that the cytotoxicity scores of the two materials were grade 0 and the growth and proliferation of the cultured cells were not significantly inhibited by the two materials. There were no potential allergic materials in the composites and the maceration extract showed no hemolytic reaction, no acute systemic toxicity and no pyrogen reaction. We conclude that the composites have fine biocompatibility and are safe for clinical use in the reconstruction treatment for chest wall defect.

Objective: To investigate the application of a novel degradable biomaterial as a chest wall prosthesis and provide valuable scientific basis for clinical application., Methods: Preparation of chitin long fiber reinforced polycaprolactone (PCL) by means of melt blending and modeling. Full-thickness chest wall defects of 10 cm x 8 cm was created in 10 dogs and then repaired with long chitin fiber reinforced PCL artificial rib in 8 dogs (tested group) and Marlex mesh in 2 dogs (control group). It was dynamically observed that the situation of the implanted chest wall prosthesis and the progress of the regeneration of the chest wall tissue postoperatively., Results: No operative and perioperative deaths were observed in all experimental dogs. In tested group, slight paradoxical respiration occurred in 2 dogs and could not be seen in 2 weeks. No chest wall subsidence and infection occurred. New bone tissue obviously regenerated around both resection ends of the ribs and integrated tightly with artificial ribs. In control group, there were evidently paradoxical respiration and chest wall subsidence. Marlex mesh folded and was enveloped by fibrous tissue., Conclusion: Degradable chitin long fiber reinforced PCL can provide effective support to chest walls and is a practicable material for chest wall reconstruction.