Investigating the Age of Becoming a Smoker and Its Related Factors Among Student Population: a Web-based Study

Background: Preventing smoking at an early age is one of the primary solutions to reduce the likelihood of becoming a smoker in adulthood. This study aimed to investigate the age of becoming a smoker and its related factors and to assess the change in the age trend of becoming a smoker among students in Iran.Methods: A cross-sectional web-based survey was performed from July to August 2019 in Tabriz, Iran. A proportional cluster sampling in all universities of the city was implemented, according to the number of students in each university. The data were collected from 3640 students via an online survey questionnaire. Data analyses were performed by using Stata (version 16). The statistical level of significance was set at 0.05. Results: The average (±SD) age of becoming a smoker in the students was 18.8 (6 2.6) years. The age of becoming a smoker has decreased over time. A linear regression model showed that male and undergraduate students become smokers 0.77 and 0.50 years earlier than other students, respectively (P <0.001). Older age, being single, and later smoking initiation increase the average age of becoming a smoker by 0.2 years, 0.77 years, and 0.54 years, respectively (P <0.001).Conclusion: The age of becoming a smoker has decreased over time. Prevention programs should target males and undergraduate students. Furthermore, since students have become smokers earlier than their peers in the past, there is a direct relationship between smoking initiation and the age of becoming a smoker.

Yishen Huazhuo Decoction Induces Autophagy to Promote the Clearance of Aβ1-42 in SAMP8 Mice: Mechanism Research of a Traditional Chinese Formula Against Alzheimer’s Disease

Background: Studies have found that autophagy could promote the clearance of Aβ. To promote and maintain the occurrence of autophagy in Alzheimer's disease (AD) might be a potential way to reduce neuronal loss and improve the learning and memory of AD. Objective: To investigate the possible mechanisms of Yishen Huazhuo Decoction (YHD) against AD model. Methods: Forty 7-month-old male SAMP8 mice were randomly divided into model (P8) group and YHD group, 20 in each group, with 20 SAMR1 mice as control (R1) group. All mice were intragastrically administered for 4 weeks, YHD at the dosage of 6.24g/kg for YHD group, and distilled water for P8 group and R1 group. Morris water maze (MWM) test, Nissl’s staining, TEM, TUNEL staining, immunofluorescence double staining, and western blot analysis were applied to learning and memory, structure and ultrastructure of neurons, autophagosome, apoptosis index, Aβ, LAMP1, and autophagy related proteins. Results: The escape latency time of YHD group was significantly shorter on the 4th and 5th day during MWM test than those in P8 group (P=0.011, 0.008<0.05), and the number of crossing platform in YHD group increased significantly (P=0.02<0.05). Nissl’s staining showed that the number of neurons in YHD group increased significantly (P<0.0001). TEM showed in YHD group, the nucleus of neurons was slightly irregular, with slightly reduced organelles, partially fused and blurred cristae and membrane of mitochondria. The apoptosis index of YHD group showed a decreasing trend, without statistically significant difference (P=0.093>0.05), while Caspase3 expression in YHD group was significantly lower (P=0.044<0.05). YHD could promote the clearance of Aβ1-42 protein, improve the expression of Beclin-1 and p-Bcl2 proteins, reduce mTOR and p62 proteins. Conclusions: YHD could induce autophagy initiation, increase the formation of autophagosomes and autolysosome, promote the degradation of autophagy substrates, thereby to regulate autophagy, thereby to promote the clearance of Aβ1-42 to improve memory impairment in SAMP8 mice.

Barriers and explanatory mechanisms in diagnostic delay in four cancers – A health-care disparity?

Introduction: Most cancer disparities research has traditionally focused on two key outcomes, access to appropriate treatment and survival, but they do not encompass important aspects of patient-centered care such as the timeliness of diagnosis and treatment. Prolonged time intervals between symptom onset and treatment initiation increase the risk of poorer clinical outcomes and are associated with worse patient experience of subsequent cancer care. This study aims to assess the delay from symptom onset to the start of definitive treatment and to identify the possible contributory factors and its impact on response in cancers of head and neck, breast, cervix, and lung. Materials and Methods: This was a retrospective study of patients enrolled between 2015 and 2017. A questionnaire was filled in about socioeconomic aspects, patient history, tumor data, professionals who evaluated the patients, and the respective time delays. Statistical test included Mann–Whitney U test, univariate and multivariate test, and one-way ANOVA to evaluate the correlations. Results: Stage migration was significant with patient delay (P < 0.01). In head and neck squamous cell carcinoma (HNSCC) and Carcinoma lung, a significant correlation was found between referral delay and residence (P < 0.01) and treatment delay and reason for referral (HNSCC only) (P = 0.04). Referral delay and treatment delay were correlated to response in breast and cervix, respectively (P < 0.01). Conclusion: Social awareness, regularly updating primary care physicians about alarming symptoms of cancer, developing guidelines to identify these symptoms, promoting continuity of care, and enabling access to specialist expertise through prompt referral should all help prevent delays in cancer diagnosis.

Effect of Notch Radius on the Thermal Fatigue Property of a New Guide Vane Materials

Thermal fatigue property of a directionally solidified nickel-base superalloy with different notch radius was studied. The results show that cycle numbers of crack initiation increase and resistance of thermal fatigue decreases with the rise of notch radius at the upper temperature of 1050°C. Thermal fatigue crack initiates at carbide or oxidized cavity. The join of oxidized cavity makes crack propagate. The propagation rate lowers with the increasing notch radius. Crack propagation direction is along <110> direction in {111} plane. The stress concentration drops and thermal fatigue property improves with the increase of notched radius.

Multiple Sites of Action Potential Initiation Increase Neuronal Firing Rate

Sensory input to an individual interneuron or motoneuron typically evokes activity at a single site, the initial segment, so that firing rate reflects the balance of excitation and inhibition there. In a network of cells that are electrically coupled, a sensory input produced by appropriate, localized stimulation can cause impulses to be initiated in several places. An example in the leech is the chain of S cells, which are critical for sensitization of reflex responses to mechanosensory stimulation. S cells, one per segment, form an electrically coupled chain extending the entire length of the CNS. Each S cell receives input from mechanosensory neurons in that segment. Because impulses can arise in any S cell and can reliably propagate throughout the chain, all the S cells behave like a single neuron with multiple initiation sites. In the present experiments, well-defined stimuli applied to a small area of skin evoked mechanosensory action potentials that propagated centrally to several segments, producing S cell impulses in those segments. Following pressure to the skin, impulses arose first in the S cell of the same segment as the stimulus, followed by impulses in S cells in other segments. Often four or five separate initiation sites were observed. This timing of impulse initiation played an important role in increasing the frequency of firing. Impulses arising at different sites did not usually collide but added to the total firing rate of the chain. A computational model is presented to illustrate how mechanosensory neurons distribute the effects of a single sensory stimulus into spatially and temporally separated synaptic input. The model predicts that changes in impulse propagation in mechanosensory neurons can alter S cell frequency of firing by changing the number of initiation sites.