Competing interests: In March and early April, the authors developed a prototype of a geolocation-based contact tracing app. They do not report having, and have never had, any commercial interest in developing the app (and are no longer working on the project). The authors will freely share their work with any public health agency. Colin Merkel reports that he is a software engineer who worked at Google until June 2019. Google's parent company, Alphabet, makes the Android phone operating system, and Google produces mapping services. Colin Merkel now works for an unrelated education start-up company. He did not receive any compensation for this work. No other competing interests were declared. This article has been peer reviewed.

ethadone is a US Food and Drug Administration (FDA)-approved treatment for opioid use disorder (OUD) that is associated with reduced overdose and all-cause mortality. 1 In the US, methadone maintenance treatment of OUD is primarily dispensed through opioid treatment programs (OTPs). 2 There are fewer than 1700 OTP locations across the US where patients can access methadone maintenance treatment, 3 and many rural counties have shortages of OTPs. 4 Although office-based prescribing of buprenorphine for OUD has increased in recent years, methadone remains an important component of OUD treatment, with guidelines recommending methadone maintenance for patients with unsuccessful buprenorphine treatment trials. 5 More than 380 000 people in the US received methadone maintenance treatment in 2017 despite regulations restricting its use and shortages of OTPs. 6 Methadone is dosed daily, and federal regulations require patients to travel to dispensing facilities up to daily for medication dispensing. 2 Regional samples suggest that driving times to OTPs are longer in rural areas than urban areas, 7-9 and patients with longer driving distances have shorter duration in methadone maintenance treatment. 10 In Australia, Canada, and the UK, patients can obtain daily dispensed methadone at community pharmacies. 11 In the US, pharmacies can dispense methadone prescribed for analgesia, but only pharmacies registered as medication units under the auspices of an OTP can dispense methadone for OUD. 12,13 Given that widespread pharmacy-based dispensing of methadone maintenance is an alternative model of care that has the potential to enhance access to methadone maintenance treatment, this study compared driving access to OTPs and pharmacies in the US. The a priori hypothesis was that the population-weighted IMPORTANCE Methadone maintenance is an effective treatment of opioid use disorder, but federal regulations in the US restrict methadone dispensing to opioid treatment programs (OTPs). In Australia, Canada, and the UK, patients can obtain methadone maintenance from community pharmacies.OBJECTIVE To compare driving access to methadone maintenance treatment between OTP and pharmacy dispensing models. DESIGN, SETTING, AND PARTICIPANTSThis descriptive cross-sectional study assessed driving times from census tract mean centers of population to OTPs and pharmacies. Census tracts from the 50 US states and the District of Columbia (based on the 2010 US Census) were included if their population was greater than 0, if their mean center of population (MCP) was within 3 miles of the road network, and if the 1-way driving times from the census tract MCP to both an OTP and a pharmacy were 12 hours or less. Data analyses were performed from November 15, 2019, to April 18, 2020. MAIN OUTCOMES AND MEASURESThe primary outcome was the population-weighted mean driving time from census tract MCPs to OTPs and pharmacies in the US. Census tract MCPs are population-weighted geographic centroids of residents living in each census tract. Driving times were e...

The histopathological changes associated with ultrasonic heating of normal cat brain have been correlated with thermal distributions. Ultrasound energy was applied for 50 min at different intensities to generate tissue temperatures from 42 to 48 degrees C. Animals were sacrificed at various intervals from 1 to 56 days. The organization and resolution of thermal damage was characterized by three stages of histopathological changes within the nervous tissue. The acute stage (Days 1-3) was defined by (1) extensive coagulation necrosis, (2) pyknosis of neuronal elements in the gray matter, (3) edema and vacuolation in the white matter, and (4) polymorphonuclear leukocytes. The subacute stage (Days 3-21) was characterized by (1) the appearance of lipid-laden macrophages, (2) liquefaction of the necrotic regions, (3) fibroblastic proliferation, and (4) vascular proliferation with some perivascular inflammatory infiltration (lymphocytes). Lastly, the chronic stage (Days 21-56) was defined by (1) fibrosis (reticulin and collagen formation) and (2) gliosis (reactive astrocytic proliferation) occurring around the fluid-filled necrotic center. Analysis of these data has also included a study of the lesion size versus the dose (temperature for 50 min) of heating. The results demonstrate a significant linear dose-response correlation. The results of this study indicate that the histological appearance and time course of repair of thermal injury in the normal brain tissue are analogous to acute brain necrosis resulting from cerebral infarction, except the thermal damage does not result in significant hemorrhage.

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