Self-adhesive, conductive, and multifunctional hybrid hydrogel for flexible/wearable electronics based on triboelectric and piezoresistive sensor.

Flexible electronics are highly developed nowadays in human-machine interfaces (HMI). However, challenges such as lack of flexibility, conductivity, and versatility always greatly hindered flexible electronics applications. In this work, a multifunctional hybrid hydrogel (H-hydrogel) was prepared by combining two kinds of 1D polymer chains (polyacrylamide and polydopamine) and two kinds of 2D nanosheets (Ti3C2Tx MXene and graphene oxide nanosheets) as quadruple crosslinkers. The introduced Ti3C2Tx MXene and graphene oxide nanosheets are bonded with the PAM and PDA polymer chains by hydrogen bonds. This unique crosslinking and stable structure endow the H-hydrogel with advantages such as good flexibility, electrical conductivity, self-adhesion, and mechanical robustness. The two kinds of nanosheets not only improved the mechanical strength and conductivity of the H-hydrogel, but also helped to form the double electric layers (DELs) between the nanosheets and the bulk-free water phase inside the H-hydrogel. When utilized as the electrode of a triboelectric nanogenerator (TENG), high electrical output performances were realized due to the dynamic balance of the DELs between the nanosheets and the H-hydrogel's inside water molecules. Moreover, flexible sensors, including triboelectric, and strain/pressure sensors, were achieved for human motion detection at low frequencies. This hydrogel is promising for HMI and e-skin.

Surgical treatment of popliteal cyst: a systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis of the clinical efficacy of different surgical methods in the therapy of popliteal cysts may provide evidence about effective surgical treatments. METHODS: PubMed, EMBASE, and OVID were searched with the following terms: (popliteal cyst* OR baker's cyst*) AND (arthroscopic OR excision OR operative OR treat* OR surgery). Inclusion criteria included the following: studies reported the efficacy of different surgical methods in popliteal cyst patients; patients were ≥ 16 years; and studies must have involved a minimum of 10 patients. Studies were grouped according to the surgical methods, and a meta-analysis was employed to identify the success rate based on the pooled data. RESULTS: A total of 11 studies were included: The communication between the cyst and the articular cavity was enlarged in 7 studies; this communication was closed in 3 studies; and only intra-articular lesions were managed in 1 study. After the data were pooled, the success rates were 96.7 and 84.6 % in the communication-enlargement group and communication-closure group, respectively. Studies with communication enlargement were subgrouped into the cyst wall resection group and the non-cyst wall resection group, for which the success rates were 98.2 and 94.7 %, respectively. CONCLUSIONS: Based on the current available evidence, at present, any how arthroscopic excision of the cyst wall, arthroscopic management of intra-articular lesions, and enlarging the communication between the cyst and the articular cavity is an ideal strategy for the popliteal cyst. The current literature on the treatment of popliteal cysts is limited to retrospective case series. Future prospective studies with high-quality methodology and uniform scoring system are required to directly compare communication-enlargement surgery and communication-closure surgery and determine the optimal treatment of popliteal cysts. Cyst wall resection may improve the therapeutic efficacy, to draw definitive conclusions, and high-level clinical researches with a large number of patients and long-term follow-up should be initiated.

Comparison of hamstring tendon autograft and tibialis anterior allograft in arthroscopic transtibial single-bundle posterior cruciate ligament reconstruction.

PURPOSE: To compare the outcomes between hamstring tendon autograft and tibialis anterior allograft in arthroscopic transtibial single-bundle posterior cruciate ligament (PCL) reconstruction. METHODS: Thirty-seven patients undergoing isolated single-bundle PCL reconstruction were enrolled in this study, and their data were retrospectively analyzed. They were divided into group A [4-strand hamstring tendon autograft (4SHG), n = 18] and group B [2-strand tibialis anterior allograft (2STAG), n = 19] and followed up for 2 years at least. Several parameters including the International Knee Documentation Committee score, Lysholm knee score, Tegner activity rating and knee laxity arthrometer were evaluated, and physical examination was performed preoperatively and postoperatively, and postoperative complications were also observed in all patients. Meanwhile, the postoperative posterior instability was compared between the affected knee and the contra-lateral knee. RESULTS: Compared with preoperative knee laxity and function, both groups had significant improvement postoperatively (P < 0.01). However, there were no significant differences in knee laxity and function between both groups (n.s.). Compared with contra-lateral knee, the posterior stability was worse in the affected knee (P < 0.01). CONCLUSIONS: The outcomes were similar between 4SHG or 2STAG in PCL reconstruction. Compared with contra-lateral knees, the affected knees have slight residual knee laxity in both groups. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

[The clinical research of the relation between the pain and the disc herniation type].

OBJECTIVE: To evaluate the preoperative pain degree of lumbar intervertebral disc herniation and analyzed its reason. METHODS: From January 2002 to December 2008,265 patients with lumbar intervertebral disc herniation were operated by single segment, of which site in L4,5 was 128 cases and in L5S1 was 137 cases. There were 162 males and 103 female, ranging in age from 21 to 78 years, with an average of 46.3 years. Oswestry index of all patients was observed before operation. The patients were divided into five groups based on Carragee system (according to degree of nucleus pulposus herniation and degree of fibrous ring cleavage to group, prolapse and liberation of nucleus pulposus with small ring cleavage was group I; prolapse and liberation with large ring cleavage was group II; contained fragment with integrated fibrous ring was group III; no contained fragment with integrated fibrous ring was group IV; calcified nucleus pulposus with degenerative fibrous ring was group V). The associativity between five types of lumbar intervertebral disc herniation and preoperative pain degree was analyzed. RESULTS: The preoperative pain in group I and group II was more severe than that of other groups (P<0.01). The preoperative pain in group II was more severe than that of group I (P<0.01). CONCLUSION: Nucleus pulposus can migrated into the spinal canal and will aggravate the nerve root pain if lumbar intervertebral disc herniation accompanies with fibrous ring cleavage; and freed materials can aggravate the nerve root pain by the chemical factor.