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ABSTRACT In order to provide the basis for the design and control of a citrus picking robot clamp and cutter, and find the optimal combination of cutting parameters, this study used a self-made citrus stem cutting test-bed to study the effects of the citrus stem diameter, blade cutting speed, blade cutting clearance, and tool sliding cutting angle on the peak cutting force of citrus stems through a single-factor experiment. Based on the single-factor test, the blade cutting speed, blade cutting clearance, and tool sliding angle are selected as the influencing factors, and a multi-factor test is carried out with the target of the peak cutting force, and the regression model is established. The results showed that the peak cutting force increased linearly with the diameter of the fruit stalk, decreased with the increase of the blade cutting speed and sliding cutting angle, and first decreased and then increased with the increase of the blade cutting clearance. Through the optimisation analysis of the regression model, it is found that the optimal cutting parameter combination is the blade cutting speed of 40 mm/min, blade cutting gap of 1 mm, tool sliding cutting angle of 20°, and the peak cutting force under this combination is 168.23 N. The deviation between the predicted value of the peak cutting force and the measured value is less than 2%, and the optimisation result of the cutting parameters is reliable. This study provides a theoretical basis for the optimal design and control of the clamping and cutting mechanism of the citrus picking robot.

OBJETIVO: A cirurgia torácica vídeo-assistida (CTVA) tem sido uma intervenção de escolha para o tratamento de pneumotórax espontâneo (PS) com bolha pulmonar. Nosso objetivo foi apresentar uma abordagem de CTVA uniportal unilateral para bulectomia bilateral e avaliar sua eficácia terapêutica. MÉTODOS: Entre maio de 2011 e janeiro de 2012, cinco pacientes foram submetidos a bulectomia bilateral por essa abordagem. Todos apresentavam PS bilateral. A TCAR pré-operatória mostrou que todos os pacientes tinham bolhas bilaterais no pulmão apical. As indicações cirúrgicas, os procedimentos de operação e os desfechos foram revisados. RESULTADOS: Todos os pacientes foram submetidos com sucesso a essa abordagem para bulectomia bilateral, sem complicações intraoperatórias. A mediana de tempo para a retirada do dreno torácico foi de 4,2 dias, e a mediana do tempo de hospitalização no pós-operatório foi de 5,2 dias. A mediana de seguimento pós-operatório foi de 11,2 meses. Um paciente teve recidiva de PE do lado esquerdo três semanas após a cirurgia e foi submetido a abrasão pleural. CONCLUSÕES: A bulectomia bilateral utilizando CTVA uniportal combinada com acesso contralateral ao mediastino anterior é tecnicamente confiável e promove desfechos favoráveis para pacientes com PS que desenvolvem bolhas bilaterais no pulmão apical. Entretanto, para a realização desse procedimento cirúrgico, são necessários cirurgiões com experiência em CTVA, instrumentos toracoscópicos longos, entre outras exigências.OBJECTIVE: Video-assisted thoracoscopic surgery (VATS) has been a surgical intervention of choice for the treatment of spontaneous pneumothorax (SP) with lung bulla. Our objective was to introduce a uniportal VATS approach for simultaneous bilateral bullectomy and to evaluate its therapeutic efficacy. METHODS: Between May of 2011 and January of 2012, five patients underwent bilateral bullectomy conducted using this approach. All of the patients presented with bilateral SP. Preoperative HRCT revealed that all of the patients had bilateral apical bullae. We reviewed the surgical indications, surgical procedures, and outcomes. RESULTS: All of the patients were successfully submitted to this approach for bilateral bullectomy, and there were no intraoperative complications. The median time to chest tube removal was 4.2 days, and the median length of the postoperative hospital stay was 5.2 days. The median postoperative follow-up period was 11.2 months. One patient experienced recurrence of left SP three weeks after the surgery and underwent pleural abrasion. CONCLUSIONS: Bilateral bullectomy through uniportal VATS combined with contralateral access to the anterior mediastinum is technically reliable and provides favorable surgical outcomes for patients with bilateral SP who develop bilateral apical bullae. However, among other requirements, this surgical procedure demands that surgeons be experienced in VATS and that the appropriate thoracoscopic instruments are available.

Based on the work of A.Van Daele, E.G.Effros and Z.J.Ruan on multiplier Hopf algerba and discrete quantum group, this paper states that discrete quantum group (A, Delta) is exactly the set {(omega otimes imath)Delta(a)| a in A; omega in A^{ast}}, where A^{ast} is the space of all reduced functionals on A. Furthermore, this paper characterizes(A, Delta) as an algebraic quantum group with a standard *-operation and a special element z in A such that (1 otimes­ a)Delta(z) = Delta(z)(a otimes­ 1) (forall a in A).