Fractal signatures of the COVID-19 spread.

Recent quantitative approaches for studying several aspects of urban life and infrastructure have shown that scale properties allow the understanding of many features of urban infrastructure and of human activity in cities. In this paper, we show that COVID-19 virus contamination follows a similar pattern in different regions of the world. The superlinear power-law behavior for the number of contamination cases as a function of the city population, with exponent ß of the order of 1.15 is always obtained. Due to the strong indication that scaling is a determinant feature of covid-19 spread, we propose an epidemiological model that embodies a fractal structure, allowing a more detailed description of the observed data about the virus spread in different countries and regions. The hypothesis that fractal structures can be formed in cities as well as in larger networks is tested, indicating that indeed self-similarity may be found in networks connecting several cities.

Effectiveness of photo-ozone therapy against equine Pythium insidiosum.

Cutaneous pythiosis is a life-threatening infectious disease. Low-level laser therapy (LLLT) and ozone (O3) have been used individually in the treatment of infected wounds. The goals of the study were a) to characterize the antimicrobial action of the photo-ozone therapy (LLLT-O3) against equine Pythium insidiosum, and b) to assess the cytotoxic potential of the LLLT-O3 in keratinocytes. Specimens of pathogen were isolated from 10 horses. After culturing, 120 hyphae plugs were distributed among four groups (n=30 hyphae plugs/group): LLLT (laser irradiation for 160 sec;), O3 (exposition to O3 for 15 min;), LLLT-O3 (LLLT and O3 treatments in sequence) and control (untreated plugs). The hyphae growth was measured during the first 14 days post-treatment. Where there was an absence of hyphae growth, the plug was recultured for an additional 7 days. The cytotoxic potential of the treatments against HaCaT keratinocytes was assessed by colorimetric assays. The LLLT-O3 and O3 treatments inactivated, respectively, 92.3% (28/30) and 30% (9/30) of the samples. No growth was detected after 7 days reculture of inactivated hyphae plugs on new media. Hyphae growth was visualized in 100% of the control and LLLT hyphae plugs. The viability of HaCaT cells was not affected by the isolated treatments (LLLT and O3), while the LLLT-O3 showed slight cytotoxic effect (20%) when compared to the control group (P<0.05). Photo-ozone therapy inactivated equine P. insidiosum hyphae with minimal cytotoxicity in skin cells in vitro.

Dose-related ethanol-like effects of the NMDA antagonist, ketamine, in recently detoxified alcoholics.

BACKGROUND: This study evaluated the dose-related ethanol-like subjective effects of the N-methyl-D-aspartate (NMDA) glutamate receptor antagonist ketamine hydrochloride in recently detoxified alcoholics. METHODS: Twenty male inpatients meeting DSM-III-R criteria for alcohol dependence and who had not consumed alcohol for 10 to 27 days prior to the study completed 3 test days that involved the intravenous infusion of ketamine hydrochloride (0.1 mg/kg or 0.5 mg/kg) or saline solution under randomized double-blind conditions. Ethanol-like subjective effects were assessed using the Sensation Scale; the Biphasic Alcohol Effects Scale; visual analog scales to measure "high" and degree of similarity to ethanol, cocaine, and marijuana; a scale assessing the number of standard alcohol drinks producing similar subjective effects; and visual analog scales measuring ethanol craving. RESULTS: Ketamine produced dose-related ethanol-like effects on each scale measuring its similarity to ethanol. Its effects were more similar to the sedative or descending limb effects of ethanol than to the stimulant or ascending limb effects. Ketamine effects also were more like ethanol than marijuana or cocaine. Ethanol-like effects were more prominent at the higher ketamine dose, a dose rated as similar to greater levels of ethanol intoxication. However, ketamine did not increase craving for ethanol. CONCLUSION: The production of ethanol-like subjective effects by ketamine supports the potential clinical importance of NMDA receptor antagonism among the mechanisms underlying the subjective effects of ethanol in humans.

Complications of alcohol withdrawal: pathophysiological insights.

Disease processes or events that accompany acute alcohol withdrawal (AW) can cause significant illness and death. Some patients experience seizures, which may increase in severity with subsequent AW episodes. Another potential AW complication is delirium tremens, characterized by hallucinations, mental confusion, and disorientation. Cognitive impairment and delirium may lead to a chronic memory disorder (i.e., Wernicke-Korsakoff syndrome). Psychiatric problems associated with withdrawal include anxiety, depression, and sleep disturbance. In addition, alterations in physiology, mood, and behavior may persist after acute withdrawal has subsided, motivating relapse to heavy drinking. Recent advances in neurobiology may support the development of improved medications to decrease the risk of AW complications and support long-term sobriety.