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Brazilian federalism was important in the political game of combating the pandemic for three reasons. First, Brazil's public health system depends heavily on intergovernmental relations between Union, states, and municipalities because there is a policy portfolio based on federative cooperation. Second, the subnational governments' autonomy to act against COVID-19 was constantly questioned by the Federal Government – the conflict between the President and governors was a key piece in all health policy. Finally, states and local governments were primarily responsible for policies to fight against pandemic, but the absence and/or wrong measures taken by the Federal Government (such as the delay in purchasing vaccines) generated intergovernmental incoordination, increased territorial inequality, and reduced the effectiveness of subnational public policies, especially those linked to social isolation. In this context, Brazilian federalism played a dual role in the pandemic. On the one hand, the federative structure partially succeeded in averting an even worse scenario, mitigating the impact of mistaken presidential decisions. The role of subnational governments, especially of the states, was critical as a counterweight to federal decisions. On the other hand, the President actively acted against governors and mayors and, above all, sought to weaken intergovernmental articulations within the Unified Health System (SUS), the federative model designed three decades ago. One could say that the federative actors, such as the Supreme Court (Supremo Tribunal Federal – STF) and subnational governments, were the main obstacles for the Bolsonarist antiscientific agenda. The success of this reaction to President Bolsonaro's negationist populism was partial, but the results of the fight against COVID-19 would have been much worse without these federalist barriers.

In South Africa, many illicit drugs have only recently been introduced and drug-related complications are often new to treating physicians. Heroin-induced leukoencephalopathy has been reported elsewhere in patients who inhale heated heroin vapors, a method known as “chasing the dragon.” The purpose of this paper is to present two patients, known to have inhaled heroin a few weeks prior to presenting with progressive neurological deficits.

Case presentations: two young males presented independently within eight weeks of one another with progressive slurring of speech, incoordination and weakness of the limbs over a period of two to three weeks. Both were known heroin addicts, and were known to one another, and both had inhaled heroin prior to the onset of symptoms.

The patients presented with a pancerebellar syndrome with marked bilateral upper motor neuron signs. CT scans showed diffuse symmetrical hypodense lesions involving the cerebral and cerebellar white matter with normal CSF. Both patients deteriorated neurologically, became cardiovascularly unstable and demised. Postmortem in one of the patients showed a prominent spongiform leukoencephalopathy consistent with reports of heroin-inhalation injury to the brain.

Toxic leukoencephalopathy due to heroin vapor inhalation was first described in the Netherlands in 1982. It has not been reported to occur with other modes of heroin use; an unknown toxin contained in heroin pyrolysate which forms when heroin is heated, may be causative. Brain MRI typically shows diffuse, symmetrical white matter hyperintensities on T2 and fluid-attenuated inversion recovery sequences in the cerebellum, posterior cerebrum and posterior limbs of the internal capsule with a posterior-anterior gradient. Pathologically, spongiform degeneration with relative sparing of subcortical U-fibers is seen. No treatment has been proven effective, but antioxidants and Vitamin E may be beneficial. Mortality is high at 23-48 percent.

This report emphasizes that spongiform leukoencephalopathy as a rare consequence of inhaling heroin vapors does occur in South Africa and clinicians should consider this disorder in their differential diagnosis of acutely developing leukoencephalopathy.

An awareness program regarding this grave condition is planned.

The cardiovascular complications of patients inhaling heroin vapor has not been highlighted previously. These are the first patients from Africa described with this condition. A toxic component appears likely.

Most current lower extremity exoskeletons emphasize assistance for walking rather than stability. The purpose of this paper is to propose a rehabilitation gait based on the transfer of gravity center to improve the balance of exoskeleton rehabilitation training of the hemiplegic patients in the frontal plane, reducing the dependence on crutches/walking frames.

The real-time and predictable instability factors of human and exoskeleton system (HES) are analyzed. Inspired by the walking balance strategy of the blind, a rehabilitation gait based on the transfer of gravity center is proposed and studied by modeling and experimental test and is finally applied to the prototype – Zhejiang University lower extremity exoskeleton (ZJULEEX) – to verify its feasibility.

At least three real-time and predictable factors cause the instability of HES, and the factor of lateral tilt caused by gravity should be focused in the balance control of frontal plane. With the proposed gait, the hip height of stepping leg of HES does not reduce obviously even when the crutches do not work, which can improve the balance of HES.

However, the rehabilitation gait control needs to be more complete and intelligent to response to other types of perturbations to further improve the balance of HES. In addition, more clinical trials should be conducted to evaluate the effect of the proposed gait.

May bring happiness to the rehabilitation of patients with hemiplegia.

The rehabilitation gait based on the transfer of gravity center to improve the balance of HES is first proposed and applied to HES.

Land policy plays an important role in urban development planning. The value of land use depends on the nature and scale of urban land use. Based on this, in the study and analysis, the adaptation between regional land finance and urban planning and construction was discussed. First of all, the current incoordination between the land policy and the urban planning and construction in the development of urbanization was elaborated, and the status quo of the research was analyzed; then, the coordination of the layout of the urban planning space under the land finance was analyzed; taking a small-town project as an example, the actual planning of towns was concretely analyzed, and the waterfront landscape was planned and designed, the functional utilization of the land was promoted. Regression analysis of adaptation confirmed the success of urban planning and construction.

The venture capital syndication brings in various resources for the portfolio firms, which positively affects those firms’ performance, while conflicts within syndicates also have negative impact on the portfolio firms’ performance. This study aims to explore the two opposite effects of the venture capital syndication on the portfolio firms’ operations. Drawing on Ma et al.’s (2013) power source match perspective, the authors examine the effect of (mis)match of power source between ownership and status on the portfolio firms’ performance.

The study uses panel data from two professional databases containing information about the venture capital-backed firms in China. The fixed effect model is applied to analyze the data.

This study found that power source match in the venture capital syndicates works positively on the portfolio firms’ performance. This positive relationship is weakened when there is ownership-dominated power source mismatch present.

This study suggests that when new ventures search for venture capital, it is better to allocate greater ownership to the venture capital providers with high-status power, so that ownership power and status power can have a proper match to increase the coordination among venture capital providers, thereby helping portfolio firms perform better.

This study looks into the performance of a portfolio firm when there is power a (mis)match in a venture capital syndication, extending the current literature in this area where only the performance of the venture syndications is examined.

This study aims to minimize the risk of costly failures of flight tests during the path tracking control design, and a noble approach has been proposed in this study to put the whole vehicle-in-the simulation loop. Working with the real system is essential for developing intelligent and data-driven controllers for multirotor drones which needs learning the drones' nonlinear complicated dynamics. The vehicle-in-the-loop (VIL) platform developed in this paper is a safe and effective solution to deal with this problem.

To avoid risky flight test during controller design, the multirotor is hinged to a shaft that allows the multirotor's angular motion but restricts translational motion. The test-bed includes the real system attitude dynamics and the simulation of the position dynamics to model the complete flight based on real-time reactions of the vehicle. For the authors' case study, a hexacopter angular motion provides the real-time attitude data in translational motion simulation loop. To test the set-up, a proportional-integral-derivative (PID) and a brain emotional learning-based intelligent controller (BELBIC) is implemented for tracking of circle and 8-shape flight trajectories.

The results show that the platform helps the intelligent controller to learn the system dynamics without worrying about the failure in the early stages of the design and in the real-world flight test. Although the hexacopter translational dynamics is modeled in simulation, the authors still have highly accurate attitude dynamics matching the requirement of the control loop design. The comparison of the two controllers also shows that the performance of BELBIC is better than PID in this test.

The research background is reviewed in the introduction section. The other sections are originally developed in this paper.

Lower extremity exoskeletons have drawn much attention recently due to their potential ability to help the stroke and spinal cord injury patients to regain the ability of walking. However, the balance of the human-exoskeleton system (HES) remains a big challenge. Usually, patients use crutches to keep balance when they wear exoskeleton. However, the balance depends greatly on the patient's balance ability and will be inevitably poor occasionally, which often causes the landing in advance of HES. The purpose of this paper is to propose a real-time stepping gait trajectory planning method based on the hip height variation of the swing leg to solve the problem.

The hip height of the swing leg was analyzed and measured. The simulation with MATLAB and the experimental test with the prototype of the proposed gait were conducted to verify its feasibility.

With the proposed method, HES can achieve successful step even when the balance kept by crutches is poor.

Instead of actively avoiding the poor balance due to the instability caused by gravity, the method just modifies the stepping gait passively to avoid the landing in advance when the poor balance appears. In addition, it may not work well when the balance is too poor. Moreover, the proposed gait is just used in the initial stage of rehabilitation training. Besides, the step length of the gait must be limited for comfort.

A real-time stepping gait trajectory planning method based on the hip height variation of the swing leg is first proposed and its feasibility to avoid the landing in advance when the balance kept by the crutches is poor has been preliminary verified.

Robot-assisted system for minimally invasive surgery (MIS) has been attracting more and more attentions. Compared with a traditional MIS, the robot-assisted system for MIS is able to overcome or reduce defects, such as poor hand-eye coordination, heavy labour intensity and limited motion of the instrument. The purpose of this paper is to design a novel robotic system for MIS applications.

A robotic system with three separate slave arms for MIS has been designed. In the proposed robot, a new mechanism was designed as the remote centre motion (RCM) mechanism to restrain the movement of instrument or laparoscope around the incision. Moreover, an improved instrument without coupling motion between wrist and grippers was developed to enhance its manipulability. A control system architecture was also developed, and an intuitive control method was applied to realize hand-eye coordination of the operator.

For the RCM mechanism, the workspace was analyzed and the positioning accuracy of the remote centre point was tested. The results show that the RCM mechanism can be applied to MIS. Furthermore, the master-slave trajectory tracking experiments reveal that slave robots are able to follow the movement of the master manipulators well. Finally, the feasibility of the robot-assisted system for MIS is proved by performing animal experiments successfully.

This paper offers a novel robotic system for MIS. It can accomplish the anticipated results.