Analitical Method to Calculate the Unknown Geometry of Cylindrical Gears

A mathematical method of reverse engineering to determine the basic geometry for manufacturing of external parallel-axis cylindrical involute gears by means of workshop measurement tools is presented. This procedure proposes a practical method to obtain the fundamental gear parameters in order to have a reference for calculating the load capacity of cylindrical gears or when a “copy” of an external parallel-axis cylindrical involute gear is necessary for recreating other new gear according to ISO standards by generation cutting

Diagnóstico del estado de la Gestión de Lubricación en Grupos Electrógenos Fuel Oil

El objetiv o del artícul o es el diagnóstico de la gesti ón de la lubricación y los lubricantes de las centrales eléctricas fuel oíl del Oeste de La Habana. Se basó en la herramienta del Centr o de Estudi os de Ingeniería de Mantenimiento para evaluar el estado de dic ha gesti ón, y se modificó mediante el consenso de expertos. La herramienta permitió identificar las deficiencias en la gestión de la lubricación y concebir estrategias que contribuyan al au mento de la disponibilidad de los activ os físic os, así como , la disminución del con sum o de energía, lubricantes y piezas de repuesto. Esto permite obten er ahorros significativos en la organ ización y red ucir el impact o negati vo al medio ambiente. Se identificaron un grupo de defic iencias, entre las que se destacan por su impacto neg ativo, la falta de capacitación en los tem as de la gestión de la lubricación, y un inadecuado almacenamiento de aceites nuevos y la gestión de aceite usad

Prodromal symptoms and the duration of untreated psychosis in first episode of psychosis patients: what differences are there between early vs. adult onset and between schizophrenia vs. bipolar disorder?

To assess the role of age (early onset psychosis-EOP < 18 years vs. adult onset psychosis-AOP) and diagnosis (schizophrenia spectrum disorders-SSD vs. bipolar disorders-BD) on the duration of untreated psychosis (DUP) and prodromal symptoms in a sample of patients with a first episode of psychosis. 331 patients with a first episode of psychosis (7–35 years old) were recruited and 174 (52.6%) diagnosed with SSD or BD at one-year follow-up through a multicenter longitudinal study. The Symptom Onset in Schizophrenia (SOS) inventory, the Positive and Negative Syndrome Scale and the structured clinical interviews for DSM-IV diagnoses were administered. Generalized linear models compared the main effects and group interaction. 273 AOP (25.2 ± 5.1 years; 66.5% male) and 58 EOP patients (15.5 ± 1.8 years; 70.7% male) were included. EOP patients had significantly more prodromal symptoms with a higher frequency of trouble with thinking, avolition and hallucinations than AOP patients, and significantly different median DUP (91 [33–177] vs. 58 [21–140] days; Z = − 2.006, p = 0.045). This was also significantly longer in SSD vs. BD patients (90 [31–155] vs. 30 [7–66] days; Z = − 2.916, p = 0.004) who, moreover had different profiles of prodromal symptoms. When assessing the interaction between age at onset (EOP/AOP) and type of diagnosis (SSD/BD), avolition was significantly higher (Wald statistic = 3.945; p = 0.047), in AOP patients with SSD compared to AOP BD patients (p = 0.004). Awareness of differences in length of DUP and prodromal symptoms in EOP vs. AOP and SSD vs. BD patients could help improve the early detection of psychosis among minors

The polygenic basis of relapse after a first episode of schizophrenia

Little is known about genetic predisposition to relapse. Previous studies have linked cognitive and psychopathological (mainly schizophrenia and bipolar disorder) polygenic risk scores (PRS) with clinical manifestations of the disease. This study aims to explore the potential role of PRS from major mental disorders and cognition on schizophrenia relapse. 114 patients recruited in the 2EPs Project were included (56 patients who had not experienced relapse after 3 years of enrollment and 58 patients who relapsed during the 3-year follow-up). PRS for schizophrenia (PRS-SZ), bipolar disorder (PRS-BD), education attainment (PRS-EA) and cognitive performance (PRS-CP) were used to assess the genetic risk of schizophrenia relapse.Patients with higher PRS-EA, showed both a lower risk (OR=0.29, 95% CI [0.11–0.73]) and a later onset of relapse (30.96± 1.74 vs. 23.12± 1.14 months, p=0.007. Our study provides evidence that the genetic burden of neurocognitive function is a potentially predictors of relapse that could be incorporated into future risk prediction models. Moreover, appropriate treatments for cognitive symptoms appear to be important for improving the long-term clinical outcome of relapse

Simulation of Plain Bearings in Turbo-Generators Using the Stand ISO7902

The study of plain bearings is fundamental in guaranteeing the full running and maintenance of machines. Due to the fluctuations in working conditions, the simulation of plain bearing in turbines and generators has become increasingly necessary. The procedure used to obtain data is based on ISO Standards 7902:1998 which involves the calculation of the load capacity of plain bearings under hydrodynamic lubricant conditions. This method can be used to determine if the plain bearing under load and working conditions will be able to form and maintain a film of lubricant which is important to separate completely the shaft and bearing sliding surfaces in order to prevent friction between these two. Also, with this method it is possible to determine the ideal working conditions and limiting factors in the functioning of plain bearing. Some of these factors are: relative bearing clearance, shaft velocity, lubricant viscosity, diameter and width of bearing, average peak-to-valley height of sliding surfaces and nominal radial. Additionally, a calculation sample is presente

Effects of COVID-19 Lockdown on Tumour Burden of Melanoma and Cutaneous Squamous Cell Carcinoma.

The aim of this study was to compare tumour burden in patients who underwent surgery for melanoma and cutaneous squamous cell carcinoma during nationwide lockdown in Spain due to COVID-19 (for the period 14 March to 13 June 2020) and during the same dates in 2019 before the COVID-19 pandemic. In addition, associations between median tumour burden (Breslow thickness for melanoma and maximum clinical diameter for cutaneous squamous cell carcinoma) and demographic, clinical, and medical factors were analysed, building a multivariate linear regression model. During the 3 months of lockdown, there was a significant decrease in skin tumours operated on (41% decrease for melanoma (n = 352 vs n = 207) and 44% decrease for cutaneous squamous cell carcinoma (n = 770 vs n = 429)) compared with the previous year. The proportion of large skin tumours operated on increased. Fear of SARS-CoV-2 infection, with respect to family member/close contact, and detection of the lesion by the patient or doctor, were related to thicker melanomas; and fear of being diagnosed with cancer, and detection of the lesion by the patient or relatives, were related to larger size cutaneous squamous cell carcinoma. In conclusion, lockdown due to COVID-19 has resulted in a reduction in treatment of skin cancer

Risk factors and rate of recurrence after Mohs surgery in basal cell and squamous cell carcinomas: a nationwide prospective cohort (REGESMOHS, Spanish Registry of Mohs Surgery)

Randomized studies to assess the efficacy of Mohs micrographic surgery in basal cell and squamous cell carcinomas are limited by methodological and ethical issues and a lack of long follow-up periods. This study presents the "real-life" results of a nationwide 7-years cohort on basal cell carcinoma and squamous cell carcinoma treated with Mohs micrographic surgery. A prospective cohort was conducted in 22 Spanish centres (from July 2013 to February 2020) and a multivariate analysis, including characteristics of patients, tumours, surgeries and follow-up, was performed. A total of 4,402 patients followed up for 12,111 patient-years for basal cell carcinoma, and 371 patients with 915 patient-years of follow-up for squamous cell carcinoma were recruited. Risk factors for recurrence included age, non-primary tumours and more stages or unfinished surgeries for both tumours, and immunosuppression for squamous cell carcinoma. Incidence rates of recurrence were 1.3 per 100 person-years for basal cell carcinoma (95% confidence interval 1.1-1.5) and 4.5 for squamous cell carcinoma (95% confidence interval 3.3-6.1), being constant over time (0-5 years). In conclusion, follow-up strategies should be equally intense for at least the first 5 years, with special attention paid to squamous cell carcinoma (especially in immunosuppressed patients), elderly patients, non-primary tumours, and those procedures requiring more stages, or unfinished surgeries