Trajectory Tracking Control Design for Dual-Arm Robots Using Dynamic Surface Controller

This paper presents a dynamic surface controller (DSC) for dual-arm robots (DAR) tracking desired trajectories. The DSC algorithm is based on backstepping technique and multiple sliding surface control principle, but with an important addition. In the design of DSC, low-pass filters are included which prevent the complexity in computing due to the “explosion of terms”, i.e. the number of terms in the control law rapidly gets out of hand. Therefore, a controller constructed from this algorithm is simulated on a four degrees of freedom (DOF) dual-arm robot with a complex kinetic dynamic model. Moreover, the stability of the control system is proved by using Lyapunov theory. The simulation results show the effectiveness of the controller which provide precise tracking performance of the manipulator

Ho Chi Minh's Thoughts On Control Of The State's Power And Lessons For Vietnam

In Vietnam, the State’s power is unified, agencies shall assign, coordinate and control each other in the exercises of the legislative, executive, and judicial powers. This is necessary to prevent abuse of power and ensure the state’s power. The Constitution 1946 was written by Ho Chi Minh (1890 -1969) and created a mechanism and foundation to control the state’s power in Vietnam. Nearly, in the Constitution 2013, the issue of controlling state power is recorded. The assignment and control are reflected in the assignment of the scope of power to each state agency. From the approach of philosophical, social philosophy, and political philosophy, through research and analysis documents in Ho Chi Minh Complete Collection; of previous researchers and policies, legal of Vietnam’s Government on control of the state's power and lessons for Vietnam today. The result shows that Ho Chi Minh’s thought on controlling power has shown the basic contents related to asserting that the power owner belongs to the people and focusing on supervision; use the Constitution to limit state power. The article also gives experiences when studying Ho Chi Minh's thoughts on state power control over Vietnam today

Complete revascularization in coronary artery bypass grafting with coronary artery endarterectomy: updated findings from Vietnam

We examined the technique and early outcomes of coronary artery bypass graft surgery (CABG) with endarterectomy. In 2023, the single-center database identified 24 severe coronary disease patients undergoing CABG with coronary artery endarterectomy. The patients were in a selected cohort with a minimum of three grafts for the three main vessels. Patients’ mean age was 63.8 years. The mean number of grafts was 4.3. A coronary endarterectomy (CE) was performed on the right coronary artery in 45.8% of patients, the left anterior descending artery in 29.1%, the circumflex artery in 16.6%, and the diagonal artery in 29.1%. Aortic cross-clamp took 147.2 minutes, perfusion 180.9 minutes, mechanical ventilation 18.9 hours, and intensive care unit stay 4.8 days. Our in-hospital mortality rate was 8.3% with no technical complications. To achieve complete revascularization in patients with extensive coronary artery disease, CE should be considered an acceptable adjunct to CABG

Diagnosis and Treatment for Pediatric Supracondylar Humerus Fractures with Brachial Artery Injuries

(1) Background: This study aims to describe the clinical and paraclinical characteristics of and the diagnostic approach to brachial artery injuries in pediatric supracondylar humerus fractures, as well as to evaluate intraoperative vascular anatomical lesions and early postoperative results. (2) Methods: A retrospective, hospital-based analysis of medical records at Viet Duc University Hospital (Vietnam), using a sample of children under 16 years who met the diagnostic criteria for supracondylar humerus fractures with brachial artery injuries between January 2016 and December 2020, was performed. A total of 50 patients were included in the analysis. (3) Results: Out of 50 pediatric patients, 36 patients were male (72%) and the mean age was 5.85 years (range, 1.5–14 years). Before treatment, there were 46 patients with severely displaced fractures which were classified as Gartland type III (92%). Following casting, the percentage of those with severely displaced fractures was reduced significantly to 12%, while there were no patients with Gartland type III fractures after percutaneous pinning. Doppler sonography failed to assess vascular lesions at the fracture site before and after casting in most patients. Two-thirds of surgical cases had only vasospasm, without physical damage to the vessel wall or intravascular thrombosis. Preoperative Doppler spectrum analysis was not consistent with the severity of intraoperative brachial artery injury. Out of 24 patients with vasospasm, we performed vascular blockade using papaverin in 11 cases and intraoperative balloon angioplasty of the brachial artery using the Fogarty catheter in 13 cases. Brachial artery graft was performed with 12 patients who had anatomical damage to the vascular wall. A complication of embolism occurred in one patient immediately after surgery, and two patients had superficial infections. One month following surgery, 2 out of 36 patients had a temporary loss of sensation in the area of incision. (4) Conclusions: Most pediatric patients did not present with symptoms of critical limb ischemia similar to those associated with lower extremity vascular injuries. The diagnosis and treatment of pediatric supracondylar humerus fractures with vascular injury is difficult and time-consuming, especially in cases of transverse fractures

Detection of placental lactogens in swamp buffalo by radioimmunoassay technique.

editorial reviewe

Estrus synchronization, artificial insemination, and pregnancy diagnosis in water buffaloes (Bubalus bubalis)

One of the big obstacles in management of reproductive activity in water buffaloes is their silent estrus. This characteristic prevents the determination of time for artificial insemination (AI), resulting in lengthening of the calving interval (Nguyen et al. 1990 Proc. FAO Workshop, Bulgaria, 210–216). Pregnancy-associated glycoprotein (PAG) measurement in maternal blood is an effective method of early pregnancy diagnosis in ruminant species (Zoli et al. 1992 Biol. Reprod. 46, 83–92). The present study describes a preliminary attempt to improve buffalo reproductive performance by association of three different approaches: synchronization of estrus by hormonal treatment, followed by two AI, and finally pregnancy diagnosis based on PAG measurements. A total of 33 buffalo females (4 to 15 years old), with no apparent estrus during a period of 9 to 36 months after last calving, were used. Each female received 2 injections of 5 mL of PGF2α (Intervet, France) 10 days apart (Day -12 and Day -2), one injection of 500 IU of PMSG (SABC, Vietnam) at Day -5, and 1000 IU of hCG (Intervet, France) on the day of AI (Day 0). A second AI was performed 8 h after hCG injection. Blood samples (9 mL) were collected from each female at Days 20, 25, 40, and 45 after AI. Blood samples were withdrawn by jugular venipuncture (heparinized Vacutainer tubes) and kept in a cool box until centrifugation (500g, 10 min). Plasma samples were stored at -20°C until assayed for PAG. Pregnancy diagnosis was considered negative, doubtful, or positive according to the PAG concentrations (0.8 ng mL-1, respectively). Clinical observation of females after insemination showed that the total rate of animals that exhibited signs of estrus until Day 45 was 9.1% (3/33). These 3 females were not considered for pregnancy diagnosis. Table 1 shows the results of pregnancy diagnosis in 30 water buffalo females. These results show that fertilization is easily obtained after estrus synchronization in buffaloes and that measurement of PAG concentrations in maternal plasma can be used for pregnancy diagnosis from Day 40 after AI

Estrus synchronization, artificial insemination and pregnancy diagnosis in water buffaloes (Bubalus bubalis).

editorial reviewe

Detection of placental lactogens in swamp buffalo by radioimmunoassay technique

peer reviewedRuminant placental lactogens (PL) are members of the growth factor/prolactin (GH/PRL) family. They are synthesized by trophectodermal binucleate cells. There is evidence to suggest that PL is involved in control of fetal growth, through actions in both the maternal and fetal compartments, as well as in influencing mammary growth during pregnancy (Byatt JC et al. 1992 J. Anim. Sci. 70, 2911–2923). The structure and biology of PL have been studied in the cow, sheep, goat, human, and mice. The maternal concentration of PL is 100- to 1 000-fold greater in pregnant sheep and goats than in cows but no information exists about PL concentration in buffalo. The aim of the present study was to evaluate the ability to detect PL in buffalo fluids by using bovine PL antibody. Samples were collected in the slaughterhouse immediately after animal slaughter. The fetuses were measured after heart blood collection. A bPL RIA system was used to determine the bPL concentrations in the buffalo samples (Alvarez-Oxiley AV et al. 2007 Reprod. Fertil. Dev. 19, 877–885). The rbPL molecules were radio-iodinated with [125]I-Na by using the lactoperoxidase method (Thorell JI and Johansson BG 1971 Biochim. Biophys. Acta 251, 363–369). Concentrations of buffalo PL are presented in Table 1. In this RIA system, the minimum detected value was 0.068 ng mL–1, and the binding competition curves of bovine PL standard and buffalo fluids dilution using bovine PL antibody were paralleled in all kinds of samples. The lowest concentration was detected in allantoid fluid and the greatest concentration in fetal plasma (P < 0.05). Study of the biology of PL in buffalo has proved difficult because the concentration of PL in all buffalo fluids is very low. Furthermore, the research concerning buffalo PL function required in vivo experiments. Existing data suggest that at least the concentration of buffalo PL is different from cattle and other smaller domestic ruminants. In conclusion, our results provide preliminary information about concentrations of PL in buffalo fluids