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This paper proposes a random-effect spatial OD (origin-destination) dependence model to investigate varying trip distributions over time. By proposing a maximum likelihood estimation with spectral decomposition methods, the effects of spatial dependences and the unobservable zonal heterogeneity at the origin and destination can be estimated simultaneously. A series of numerical experiments and a real-world trip distribution study with cellular signaling data collected in Hangzhou, China, are conducted. This paper enriches the existing literature by developing (1) an innovative specification to allow for random effects in existing spatial OD dependence models; (2) an innovative estimation method to obtain the values of parameters and improve model fittings; and (3) a set of numerical experiments and an empirical trip distribution analysis that jointly captures spatial effects (spatial interaction and spatial OD dependences), and the unobservable zonal heterogeneity. This paper can equip policymakers with an effective tool for analyzing the OD travel flow over time which is a groundwork for making appropriate transportation policies.
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Modelos Teóricos , Viagem , Análise Espacial , ChinaRESUMO
Detection of early drug abuse has driven the use of mass spectrometry in clinical laboratories across North America. Mass spectrometry-based assays have been increasingly implemented in various clinical disciplines for their advantages in high analytical sensitivity, specificity and multiplexing capacity. Mass spectrometry is now routinely used for the clinical analysis of small molecule compounds, peptides, proteins, clinical toxicology and microbiology. Although more FDA-approved platforms and reagents need to be commercially available, there is no doubt that mass spectrometry technology has demonstrated rich clinical applications.
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Background@#and Purpose Recent studies suggested an increased incidence of cerebral venous thrombosis (CVT) during the coronavirus disease 2019 (COVID-19) pandemic. We evaluated the volume of CVT hospitalization and in-hospital mortality during the 1st year of the COVID-19 pandemic compared to the preceding year. @*Methods@#We conducted a cross-sectional retrospective study of 171 stroke centers from 49 countries. We recorded COVID-19 admission volumes, CVT hospitalization, and CVT in-hospital mortality from January 1, 2019, to May 31, 2021. CVT diagnoses were identified by International Classification of Disease-10 (ICD-10) codes or stroke databases. We additionally sought to compare the same metrics in the first 5 months of 2021 compared to the corresponding months in 2019 and 2020 (ClinicalTrials.gov Identifier: NCT04934020). @*Results@#There were 2,313 CVT admissions across the 1-year pre-pandemic (2019) and pandemic year (2020); no differences in CVT volume or CVT mortality were observed. During the first 5 months of 2021, there was an increase in CVT volumes compared to 2019 (27.5%; 95% confidence interval [CI], 24.2 to 32.0; P<0.0001) and 2020 (41.4%; 95% CI, 37.0 to 46.0; P<0.0001). A COVID-19 diagnosis was present in 7.6% (132/1,738) of CVT hospitalizations. CVT was present in 0.04% (103/292,080) of COVID-19 hospitalizations. During the first pandemic year, CVT mortality was higher in patients who were COVID positive compared to COVID negative patients (8/53 [15.0%] vs. 41/910 [4.5%], P=0.004). There was an increase in CVT mortality during the first 5 months of pandemic years 2020 and 2021 compared to the first 5 months of the pre-pandemic year 2019 (2019 vs. 2020: 2.26% vs. 4.74%, P=0.05; 2019 vs. 2021: 2.26% vs. 4.99%, P=0.03). In the first 5 months of 2021, there were 26 cases of vaccine-induced immune thrombotic thrombocytopenia (VITT), resulting in six deaths. @*Conclusions@#During the 1st year of the COVID-19 pandemic, CVT hospitalization volume and CVT in-hospital mortality did not change compared to the prior year. COVID-19 diagnosis was associated with higher CVT in-hospital mortality. During the first 5 months of 2021, there was an increase in CVT hospitalization volume and increase in CVT-related mortality, partially attributable to VITT.
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BackgroundFavipiravir is an oral, RNA-dependent RNA polymerase inhibitor with in vitro activity against SARS-CoV2. Despite limited data, favipiravir is administered to patients with COVID-19 in several countries. MethodsWe conducted a phase 2 double-blind randomized controlled outpatient trial of favipiravir in asymptomatic or mildly symptomatic adults with a positive SARS-CoV2 RT-PCR within 72 hours of enrollment. Participants were randomized 1:1 to receive placebo or favipiravir (1800 mg BID Day 1, 800mg BID Days 2-10). The primary outcome was SARS-CoV-2 shedding cessation in a modified intention-to-treat (mITT) cohort of participants with positive enrollment RT-PCRs. Using SARS-CoV-2 deep sequencing, we assessed favipiravirs impact on mutagenesis. ResultsFrom July 8, 2020 - March 23, 2021, we randomized 149 participants with 116 included in the mITT cohort. The participants mean age was 43 years (SD 12.5) and 57 (49%) were women. We found no difference in time to shedding cessation by treatment arm overall (HR 0.76 favoring placebo, 95% confidence interval [CI] 0.48 - 1.20) or in sub-group analyses (age, sex, high-risk comorbidities, seropositivity or symptom duration at enrollment). We observed no difference in time to symptom resolution (initial: HR 0.84, 95% CI 0.54 - 1.29; sustained: HR 0.87, 95% CI 0.52 - 1.45). We detected no difference in accumulation of transition mutations in the viral genome during treatment. ConclusionsOur data do not support favipiravir use at commonly used doses in outpatients with uncomplicated COVID-19. Further research is needed to ascertain if higher doses of favipiravir are effective and safe for patients with COVID-19. Trial registration numberNCT04346628 SummaryIn this phase 2 double-blind randomized controlled outpatient trial of favipiravir in asymptomatic or uncomplicated patients with COVID-19, we found no difference in time to shedding cessation or time to symptom resolution by treatment arm.
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Renal cell carcinoma (RCC) commonly metastasizes to the lung, liver, bones, and brain; however, cutaneous metastases remain rare with few reported cases. Since RCCs have the propensity to metastasize to highly vascular areas, the scalp and skin of the head and neck region are likely locations for cutaneous metastases. We report a rare case of a large, exophytic, cauliflower-like, hemorrhagic, metastatic mass of the posterior neck. This is the first reported case of a head and neck cutaneous RCC metastasis treated with endovascular embolization prior to surgical resection. Due to the increased vascularity of RCCs and risk of excessive hemorrhage during resection, adjunctive embolization of cutaneous head and neck metastasis may have a role. Essential characteristics to our treatment strategy are discussed with a review of pertinent literature.
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PURPOSE: The primary correlate to survival and preservation of neurologic function in patients suffering from an acute ischemic stroke is time from symptom onset to initiation of therapy and reperfusion. Communication and coordination among members of the stroke team are essential to maximizing efficiency and subsequently early reperfusion. In this work, we aim to describe our preliminary experience using the Join mobile application as a means to improve interdisciplinary team communication and efficiency. MATERIALS AND METHODS: We describe our pilot experience with the initiation of the Join mobile application between July 2015 and July 2016. With this application, a mobile beacon is transported with the patient on the ambulance. Transportation milestone timestamps and geographic coordinates are transmitted to the treating facility and instantly communicated to all treatment team members. The transport team / patient can be tracked en route to the treating facility. RESULTS: During our pilot study, 62 patients were triaged and managed using the Join application. Automated time-stamping of critical events, geographic tracking of patient transport and summary documents were obtained for all patients. Treatment team members had an overall favorable impression of the Join application and recommended its continued use. CONCLUSION: The Join application is one of several components of a multi-institutional, interdisciplinary effort to improve the treatment of patients with acute ischemic stroke. The ability of the treatment team to track patient transport and communicate with the transporting team may improve reperfusion time and, therefore, improve neurologic outcomes.
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Humanos , Ambulâncias , Aplicativos Móveis , Projetos Piloto , Reperfusão , Acidente Vascular Cerebral , Meios de TransporteRESUMO
PURPOSE: We investigated whether a 3D overlay roadmap using monoplane fluoroscopy offers advantages over a conventional 2D roadmap using biplane fluoroscopy during endovascular aneurysm treatment. MATERIALS AND METHODS: A retrospective chart review was conducted for 131 consecutive cerebral aneurysm embolizations by three neurointerventionalists at a single institution. Allowing for a transition period, the periods from January 2012 to August 2012 (Time Period 1) and February 2013 to July 2013 (Time Period 2) were analyzed for radiation exposure, contrast administration, fluoroscopy time, procedure time, angiographic results, and perioperative complications. Two neurointerventionalists (Group 1) used a conventional 2D roadmap for both Time Periods, and one neurointerventionalist (Group 2) transitioned from a 2D roadmap during Time Period 1 to a 3D overlay roadmap during Time Period 2. RESULTS: During Time Period 2, Group 2 demonstrated reduced fluoroscopy time (p<0.001), procedure time (P=0.023), total radiation dose (p=0.001), and fluoroscopy dose (P=0.017) relative to Group 1. During Time Period 2, there was no difference of immediate angiographic results and procedure complications between the two groups. Through the transition from Time Period 1 to Time Period 2, Group 2 demonstrated decreased fluoroscopy time (p<0.001), procedure time (p=0.022), and procedure complication rate (p=0.041) in Time Period 2 relative to Time Period 1. CONCLUSION: The monoplane 3D overlay roadmap technique reduced fluoroscopy dose and fluoroscopy time during neurointervention of cerebral aneurysms with similar angiographic occlusions and complications rate relative to biplane 2D roadmap, which implies possible compensation of limitations of monoplane fluoroscopy by 3D overlay technique.
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Aneurisma , Compensação e Reparação , Fluoroscopia , Aneurisma Intracraniano , Exposição à Radiação , Estudos RetrospectivosRESUMO
A 26-year-old male presented with delayed intracerebral hemorrhage from a ruptured distal middle cerebral artery pseudoaneurysm that followed a compound depressed skull fracture from years ago. The brain protrusion through the skull defect likely resulted in stretching and subsequent tearing of the arterial wall resulting in the pseudoaneurysm formation. No prior report of such a clinical occurrence exists in the literature. We highlight an unusual but treatable cause for intracerebral hemorrhage following surgery for traumatic brain injury.
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Adulto , Humanos , Masculino , Falso Aneurisma , Encéfalo , Lesões Encefálicas , Hemorragia Cerebral , Hemorragia , Artéria Cerebral Média , Crânio , Fratura do Crânio com Afundamento , LágrimasRESUMO
PURPOSE: An accurate determination of the natural history of a cerebral aneurysm has implications on management. Few risk factors other than female gender and cigarette smoking have been identified to be associated with cerebral aneurysm progression, particularly rapid progression. MATERIALS AND METHODS: This case series and literature review serves to illustrate a relationship between spontaneous carotid occlusion and rapid enlargement of cerebral aneurysms. RESULTS: In our case series, we demonstrated that increased hemodynamic stress on collateral vessels caused by a spontaneous carotid occlusion may contribute to unusually rapid aneurysm growth and/or rupture. CONCLUSION: Spontaneous carotid occlusive disease may be considered a risk factor for rapid cerebral aneurysm progression and/or rupture that may warrant more aggressive management options, including more frequent surveillance imaging in previously treated aneurysms.
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Feminino , Humanos , Aneurisma , Artéria Carótida Interna , Hemodinâmica , Aneurisma Intracraniano , História Natural , Fatores de Risco , Ruptura , FumarRESUMO
The current assortment of microcatheters widely used for aneurysm coil embolization may not be well suited for several anatomic variants, including excessive vascular tortuosity and small aneurysms less than 3 mm. Longer microcatheters designed with a smaller caliber that can accommodate and deliver coils may be of use in these situations. This case series and literature review illustrates the advantages and limitations of the Marathon microcatheter (Covidien, Irvine, CA, USA) when used for coil embolization of cerebral aneurysms. Despite some technical compromises including the distal marker, length, and the risk of buckling, the Marathon microcatheter was able to adequately deliver coils to achieve satisfactory occlusion of cerebral aneurysms. We found unique advantages with regards to length and smaller distal outer diameter (OD). These results may serve as a guide for the further development of a microcatheter used for coil embolization that has the features of a smaller distal OD and longer length.
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Aneurisma , Embolização Terapêutica , Procedimentos Endovasculares , Aneurisma IntracranianoRESUMO
Over the past two decades, scientists and researchers have successfully developed MEMS (Micro-Electro- Mechanical Systems) technology and its applications that provide a stepping stone for nanotechnology and nanostructure fabrication. Nanostructured devices, which have higher efficiency, less weight and lower power consumption, have been applied in the fields of electronics, chemistry, energy, environmental science and medicine. This patent review focuses on novel nanostructure fabrication methods and nanostructure devices applied in nanofluidics and nanomedicine. We can reasonably expect that the number of nanostructure patents will continue to grow, especially in the fields of biomedical science and energy.