Trajectory Planning Algorithms in Two-Dimensional Environment with Obstacles

This article proposes algorithms for planning and controlling the movement of a mobile robot in a two-dimensional stationary environment with obstacles. The task is to reduce the length of the planned path, take into account the dynamic constraints of the robot and obtain a smooth trajectory. To take into account the dynamic constraints of the mobile robot, virtual obstacles are added to the map to cover the unfeasible sectors of the movement. This way of accounting for dynamic constraints allows the use of map-oriented methods without increasing their complexity. An improved version of the rapidly exploring random tree algorithm (multi-parent nodes RRT – MPN-RRT) is proposed as a global planning algorithm. Several parent nodes decrease the length of the planned path in comprise with the original one-node version of RRT. The shortest path on the constructed graph is found using the ant colony optimization algorithm. It is shown that the use of two-parent nodes can reduce the average path length for an urban environment with a low building density. To solve the problem of slow convergence of algorithms based on random search and path smoothing, the RRT algorithm is supplemented with a local optimization algorithm. The RRT algorithm searches for a global path, which is smoothed and optimized by an iterative local algorithm. The lower-level control algorithms developed in this article automatically decrease the robot’s velocity when approaching obstacles or turning. The overall efficiency of the developed algorithms is demonstrated by numerical simulation methods using a large number of experiments

Enhanced setup for wired continuous long-term EEG monitoring in juvenile and adult rats: application for epilepsy and other disorders

Abstract Background The electroencephalogram (EEG) is a widely used laboratory technique in rodent models of epilepsy, traumatic brain injury (TBI), and other neurological diseases accompanied by seizures. Obtaining prolonged continuous EEG tracings over weeks to months is essential to adequately answer research questions related to the chronobiology of seizure emergence, and to the effect of potential novel treatment strategies. Current EEG recording methods include wired and the more recent but very costly wireless technologies. Wired continuous long-term EEG in rodents remains the mainstay approach but is often technically challenging due to the notorious frequent EEG cable disconnections from the rodent’s head, and to poor signal-to-noise ratio especially when simultaneously monitoring multiple animals. Premature EEG cable disconnections and cable movement-related artifacts result from the animal’s natural mobility, and subsequent tension on the EEG wires, as well as from potential vigorous and frequent seizures. These challenges are often accompanied by injuries to the scalp, and result in early terminations of costly experiments. Results Here we describe an enhanced customized swivel-balance EEG-cage system that allows tension-free rat mobility. The cage setup markedly improves the safety and longevity of current existing wired continuous long-term EEG. Prevention of EEG cable detachments is further enhanced by a special attention to surgical electrode anchoring to the skull. In addition to mechanically preventing premature disconnections, the detailed stepwise approach to the electrical shielding, wiring and grounding required for artifact-free high signal-to-noise ratio recordings is also included. The successful application of our EEG cage system in various rat models of brain insults and epilepsy is described with illustrative high quality tracings of seizures and electrographic patterns obtained during continuous and simultaneous monitoring of multiple rats early and up to 3 months post-brain insult. Conclusion Our simple-to-implement key modifications to the EEG cage setup allow the safe acquisition of substantial high quality wired EEG data without resorting to the still costly wireless technologies

Lestaurtinib (CEP-701) reduces the duration of limbic status epilepticus in periadolescent rats

Background: The timely abortion of status epilepticus (SE) is essential to avoid brain damage and long-term neurodevelopmental sequalae. However, available anti-seizure treatments fail to abort SE in 30% of children. Given the role of the tropomyosin-related kinase B (TrkB) receptor in hyperexcitability, we investigated if TrkB blockade with lestaurtinib (CEP-701) enhances the response of SE to a standard treatment protocol and reduces SE-related brain injury. Methods: SE was induced with intra-amygdalar kainic acid in postnatal day 45 rats under continuous electroencephalogram (EEG). Fifteen min post-SE onset, rats received intraperitoneal (i.p.) CEP-701 (KCEP group) or its vehicle (KV group). Controls received CEP-701 or its vehicle following intra-amygdalar saline. All groups received two i.p. doses of diazepam, followed by i.p. levetiracetam at 15 min intervals post-SE onset. Hippocampal TrkB dimer to monomer ratios were assessed by immunoblot 24 hr post-SE, along with neuronal densities and glial fibrillary acid protein (GFAP) levels. Results: SE duration was 50% shorter in the KCEP group compared to KV (p 0.05). The KCEP group had lower GFAP levels than KV (p 0.05), and both were lower than controls (p < 0.05). Conclusions: Given its established human safety, CEP-701 is a promising adjuvant drug for the timely abortion of SE and the attenuation of SE-related brain injury.This research project was funded by the Medical Practice Plan Fund ( 320150 ) to MO at the American University of Beirut, Beirut, Lebanon, and by Indiana University to MO, Indianapolis, IN, US.Scopu

Phytochemicals as Micronutrients: What Is their Therapeutic Promise in the Management of Alzheimer’s Disease?

Alzheimer’s disease (AD) is a debilitating neurodegenerative disease with devastating outcomes to patients and exhaustive burdens to healthcare systems. Alzheimer’s disease has always been the focus of extensive research since its discovery in the early 1900s; however, AD continues to wreak havoc among the elderly population. Unfortunately, until now AD is still without any defined treatment that can curb its otherwise insidious progression. In the wake of this crisis and in the absence of a restorative cure, alternative approaches to AD management have been sought. In this regard, phytochemicals—a class of micronutrients composed of herbal or plant secondary metabolites— have shown potential as novel agents in the management of several diseases including cancer, hyperlipidemia, cardiovascular diseases, hyperglycemia, and neurodegenerative disorders including AD. Phytochemicals therapeutic abilities can be attributed to their ability to protect against several AD pathologic events such as inflammation, oxidative stress, protein misfolding, aggregation, and several more. In this chapter, we overview AD and its progression to pathology. Next, we highlight the available conventional treatments currently used to mitigate symptoms of AD. Then, we expose phytochemicals and their known therapeutic potential in several diseases including neurodegenerative disorders. Lastly, we explore the available literature concerning the use of phytochemicals in the management of AD. Specifically, light is shed on the possible curative capacity of certain plant phytochemicals—namely those of Ginkgo biloba, Piper nigrum, Withania somnifera, Lavandula angustifolia, Olea europaea, Nigella sativa, Ficus carica, and Panax ginseng—in the management of AD. Mechanisms by which extracts of these plants exert their neuroprotective effects are discussed alongside other aspects pertaining to the efficacy, safety, and druggability of some of these phytochemicals. We conclude that phytochemicals have shown promise in the management of AD. However, clinical trials remain lacking in this area and extensive efforts need to be exerted to determine the safety, efficacy, and exact modes of action of phytochemicals in human AD patients

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research