Effect of Hydrothermal Aging on the Tribological Performance of Nitrile Butadiene Rubber Seals.

High temperature and humidity affect the tribological performance of nitrile butadiene rubber (NBR) seals, which affects the precise positioning of cylinder systems. Therefore, it is crucial to study the effect of hydrothermal aging on the tribological performance of the NBR seals. In this study, the changes in the tribological performance of the NBR seals under hydrothermal aging conditions were investigated. The results show that the volatilization of additives and the increase in crosslink density of the NBR seals occurs in the hydrothermal aging environment, leading to the deterioration of their surface quality, elastic deformability, and tribological performance. The formation of surface micropores due to additive volatilization is the main factor in the degradation of tribological performance.

Characteristics of human papillomaviruses infection in men with genital warts in Shanghai.

Human papillomaviruses (HPV) infected men causes continued transmission of HPV to women. The prevalence of 15 high-risk HPV strains (HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66 and 68) and 6 low-risk HPV strains (HPV6, 11, 42, 43, 44 and CP8304) were evaluated in 935 males with genital warts. Of the 447 (447/935, 47.8%) HPV DNA positive subjects, 230 (24.6%), 356 (38.1%) and 139 (14.9%) were infected by high-risk, low-risk and both high and low-risk HPV respectively. Of the 356 low-risk HPV infected subjects, 333(93.5%) were infected by single HPV strain; 203 (57.0%), 147 (41.3%), 24 (6.7%) and 5 (1.4%) were infected with HPV genotype 6, 11, CP8304 and 44 respectively; population with age ≤ 20 showed the highest infection rate. High-risk HPV are also highly prevalent in our patients, genotype 16, 58, 51, 39, 52 and 53 are the top five prevalent genotypes with infection rates of 27.4%, 18.7%, 14.3%, 13.9%, 12.6% and 12.6% respectively; only 68.3% subjects were sole infection; subjects with 41 ≤ age ≤ 50 showed the highest infection rate. Both high and low-risk HPV are highly prevalent in men with genital warts, its impact on women HPV control and prevention need further evaluation.

Ingenol Mebutate Signals via PKC/MEK/ERK in Keratinocytes and Induces Interleukin Decoy Receptors IL1R2 and IL13RA2.

Squamous cell carcinoma (SCC) is the second most common human skin cancer and the second leading cause of skin cancer-related death. Recently, a new compound, ingenol mebutate, was approved for treatment of actinic keratosis, a precursor of SCC. As the mechanism of action is poorly understood, we have further investigated the mechanism of ingenol mebutate-induced cell death. We elucidate direct effects of ingenol mebutate on primary keratinocytes, patient-derived SCC cells, and a SCC cell line. Transcriptional profiling followed by pathway analysis was performed on ingenol mebutate-treated primary keratinocytes and patient-derived SCC cells to find key mediators and identify the mechanism of action. Activation of the resulting pathways was confirmed in cells and human skin explants and supported by a phosphorylation screen of treated primary cells. The necessity of these pathways was demonstrated by inhibition of certain pathway components. Ingenol mebutate inhibited viability and proliferation of all keratinocyte-derived cells in a biphasic manner. Transcriptional profiling identified the involvement of PKC/MEK/ERK signaling in the mechanism of action and inhibition of this signaling pathway rescued ingenol mebutate-induced cell death after treatment with 100 nmol/L ingenol mebutate, the optimal concentration for the first peak of response. We found the interleukin decoy receptors IL1R2 and IL13RA2 induced by ingenol mebutate in a PKC/MEK/ERK-dependent manner. Furthermore, siRNA knockdown of IL1R2 and IL13RA2 partially rescued ingenol mebutate-treated cells. In conclusion, we have shown that ingenol mebutate-induced cell death is mediated through the PKCδ/MEK/ERK pathway, and we have functionally linked the downstream induction of IL1R2 and IL13RA2 expression to the reduced viability of ingenol mebutate-treated cells.

Preservation of canine composite facial flaps using UW solution.

OBJECTIVE: To evaluate the effect of University of Wisconsin (UW) solution on composite facial flaps in dogs to offer a preservation time limit for clinical application. METHODS: The experiment included 2 parts. In part 1, 32 half facial flaps were cold stored for 12, 24, 36, and 48 hours in UW solution (experimental group) or normal saline (control group). In part 2, 8 flaps that had been cold stored in UW solution for 24 (group A, n = 3), 36 (group B, n = 3), and 48(group C, n = 2) hours were autotransplanted. RESULTS: After preservation in part 1, the viability of each tissue type (skin, mucosa, muscle, blood vessel, nerve, and gland) in the experimental groups was better than that in the control group. Muscle viability decreased more quickly than did the viability of other tissue. In the experimental groups, the viability of all tissue preserved for 12 and 24 hours was better than that of tissue preserved for 36 and 48 hours. After 48 hours of preservation, tissue had good structure and integrity in the experimental group but showed degeneration in the control group. In part 2, the flap survival percentages were 100%, 100%, and 99.7% in group A; 93.2%, 95.7%, and 94.1% in group B; and 87.2% and 86.1% in group C. Six months after surgery, the dogs in group A showed contraction potential and corneal reflex. CONCLUSION: Twenty-four hours could be considered a reference time for clinical application of UW solution flap preservation.

[Anatomic study of supratrochlear artery and its application in nasal reconstruction].

OBJECTIVE: To study the anatomy of the cutaneous branch (CB) of supratrochlear artery and its relevance to the design of frontal flap in nasal reconstruction. METHODS: 10 fresh cadavers were dissected to study the position and course of the CB of supratrochlear artery (supraorbital rim and facial midline as landmark). The communication between the CB and supraorbital artery was also studied. 5 cases of ultra-thin frontal flaps and 11 cases of bi-flap( cutaneous flap and muscular flap) were designed on anatomic basis. The survival rate of flap, the stability and aesthetic appearance of the reconstructed nose were followed up. RESULTS: The supratrochlear artery gave off constant CB (1.18 +/- 0.36) cm from upper orbital rim and (1.35 +/- 0.34) cm from the midline of face. The CB passed in a subcutaneous plane and communicated with the bilateral muscular branch, CB of the opposite side and bilateral supraorbital artery. The supratrochlear artery only had CB with no muscular branch in 3 cases. All the flaps survived completely except one with blister on the nose tip which healed spontaneously. The postoperative aesthetic appearance was very satisfactory. CONCLUSIONS: The supratrochlear artery has constant CB. The frontal ultra-thin flap pedicled with the CB can improve the therapeutic effect of nasal reconstruction.

[Research of the preservation of the composite facial allograft].

OBJECTIVE: To investigate the effective method of preserving composite facial allograft so as to attenuate ischemic injury. METHODS: The composite facial allografts were harvested from dog, perfused and preserved with 4 degrees C physiological sodium chloride and UW solution respectively. Immediately after the removal of the flap, after 12, 24, 48 h of preservation, MTT assay was used to determine the viability of several kinds of tissue, including skin, mucosa, muscle, bleed vessel, nerve and gland. The results of the two groups were compared in term of viability percentage. The pathology of several tissues were observed after 24 and 48 h of storage. RESULTS: The viability percentage of every tissue conserved in UW solution for 48 hours was more than 75%. There was significant difference between physiological sodium chloride group and UW group (P < 0.05). Some changes, including Porous arrangement of fibers in connective tissue of skin and mucosa, hyalinization of tissue around the hair follicle and edema of cell in hair follicle, enlargement of space between muscle bundles and unclearness of boundary of acinus could be seen in physiological sodium chloride group while no significant change in UW group. CONCLUSIONS: UW solution could be considered as preservation solution for composite facial allograft.

[Establishment of composite facial and scalp allograft transplantation model in canine].

OBJECTIVE: To develop an experimental model of composite facial and scalp allograft in canine in order to investigate technical and immunological aspects and functional recovery of facial muscles of this new approach to facial reconstruction. METHODS: (1) Anatomic study: Four mongrel dogs were used for anatomical dissection of the head and neck region and for harvesting flap experiment. (2) Autologous transplantation (group I): Three types composite facial and scalp autologous transplantation were performed in five mongrel dogs. Type I composite tissue flap (group I a n = 2) included bilateral external ear and orbicularis oculi muscle. Type II (group I b n = 1) included single-lateral external ear, orbicularis oculi muscle, external nose upper and lower lip. Type III (group I c n = 2) included single - lateral external ear and orbicularis oculi muscle. (3) Allograft transplantation (group II): In group II a (n = 2), two allograft transplantation were performed with type III composite facial and scalp . In group II b (n = 4), four allograft transplantation were performed with the modified type III composite facial and scalp which included single - lateral external ear, orbicularis oculi muscle and one third of inferior tarsal plate and palpebral conjunctiva. To prevent allograft rejection, Cyclosporin A (CsA) and Methylprednisolone (MP) or Prednisone (PS ) were combined used as immunosuppressive protocol . Dose of CsA was adjusted depending on its blood drug level. Electromyogram (EMG) of orbicularis oculi muscle was carried out at 4 weeks, 6 weeks, 12 weeks and 6 months postoperation. RESULTS: (1) The facial anatomic characteristic of dog is similar to that of human being, external carotid artery and external jugular vein afford good blood supply to composite facial and scalp. (2) The dogs in group I c were long-term surviving with leakage of salivary juice. (3) In group II a (n = 2), one dog presented rejection reaction at 28th day postoperation, the reversal of rejection was achieved by increasing the dose of CsA and prednisone and with topical clobetasol for 2 weeks, the dog survived indefinitely( > 309 days). In group II b (n = 4), there were three dogs survived indefinitely ( > 159 days, > 129 days, > 108 days) without complication, EMG showed the function of orbicularis oculi muscle was gradually improving. CONCLUSION: The modified type III composite facial and scalp allograft transplantation model is an ideal model for facial allograft transplantation study.