Revealing the WEDM Process Parameters for the Machining of Pure and Heat-Treated Titanium (Ti-6Al-4V) Alloy

Ti-6Al-4V is an alloy that has a high strength-to-weight ratio. It is known as an alpha-beta titanium alloy with excellent corrosion resistance. This alloy has a wide range of applications, e.g., in the aerospace and biomedical industries. Examples of alpha stabilizers are aluminum, oxygen, nitrogen, and carbon, which are added to titanium. Examples of beta stabilizers are titanium–iron, titanium–chromium, and titanium–manganese. Despite the exceptional properties, the processing of this titanium alloy is challenging when using conventional methods as it is quite a hard and tough material. Nonconventional methods are required to create intricate and complex geometries, which are difficult with the traditional methods. The present study focused on machining Ti-6Al-4V using wire electrical discharge machining (WEDM) and conducting numerous experiments to establish the machining parameters. The optimal setting of the machining parameters was predicted using a multiresponse optimization technique. Experiments were planned using the response surface methodology (RSM) technique and analysis of variance (ANOVA) was used to determine the significance and contribution of the input parameters to changes in the output characteristics (cutting speed and surface roughness). The cutting speed obtained during the processing of the annealed titanium alloy using WEDM was quite large as compared to the cutting speed obtained in the case of processing the pure, quenched, and hardened titanium alloys using WEDM. The maximum cutting speed obtained while processing the annealed titanium alloy was 1.75 mm/min.     

An Experimental Investigation on the Cutting Quality of Three Different Rock Specimens Using High Power Multimode Fiber Laser

The laser cutting of rock has been popular recently because of its advantages over traditional rock cutting methods. Several types of research were performed to replace traditional rock cutting techniques with laser cutting. The purpose of this experiment is to observe cutting quality for intrusive igneous rocks using a high-power multimode fiber laser. The cutting quality, in terms of kerf width and penetration depth, resulted from different scanning speeds and was studied and compared. The specimens used in this study were gabbro, granite, and diorite, which are widely applied in the construction industry because of their high compressive strength and beautiful textures. Energy-dispersive X-ray Spectroscopy (EDX) analyses were conducted to observe the chemical content of three different areas, the melting area, the burnt area, and a non-processed area, for each rock specimen. The study of the compositional changes in each area will also go over the cutting quality of each rock specimen at different scanning speeds. According to the experimental results, the kerf widths of the specimens gradually decrease as the scanning speeds increase. The penetration depths into the specimens sharply decrease as scanning speeds increase. From a study of their compositional changes, it is found that the cutting quality for each rock depends on their silica content. This study summarizes that the cutting quality for a rock specimen greatly depends on the scanning speed of the laser cutting.     

The association of total cholesterol with processing speed is moderated by age in mid- to late-age healthy adults

Objectives: To investigate the nature of the association of normal levels of total cholesterol with cognitive function and the contribution of age to this association.

Methods: A sample of 61 senior executives, who were summoned for an annual medical examination with approximately four measurements of total cholesterol during 4 years, were examined with a computerized cognitive battery assessing mental processing speed as a sensitive measure of cognitive decline. We examined the association of total cholesterol with processing speed and the moderating effect of age on this association.

Results: A multiple regression analysis yielded a significant interaction between cholesterol and age for processing speed (p = .045). In order to examine the source of the interaction, simple slope analysis was performed. A significant negative high correlation was found for young subjects (p = .021), while no significant correlation was observed at middle (p = .286) or older (p = .584) age. The difference in slopes was robust to adjustment for potential confounding factors, including body mass index, and fasting glucose.

Conclusions: Within the normal range, higher total cholesterol levels were associated with better processing speed in younger ages and this association diminished with increasing age. Our findings highlight the important role of brain cholesterol in good cognitive functioning.     

应用高速涡轮手机分牙拔除阻生智齿124例临床体会

目的：为了进一步探讨应用高速涡轮手机拔除阻生智齿临床实际效果,并与传统的拔牙方法的临床效果进行对比,从而为相关研究提供借鉴和参考。方法：选取2010年12月-2012年12月本院收治的阻生智齿患者124例为研究对象进行了回顾性研究。将患者按随机随机数字表法将患者分为传统拔牙组（n=62）和高速涡轮手机组（n=62）,比较两组相关临床指标。结果：（1）在拔牙时间、肿胀度、张口受限度、拔牙窝完整性上,高速涡轮手机组均显著优于传统拔牙组（P〈0.05）;（2）高速涡轮手机组的心理畏惧情况显著优于传统拔牙组（P〈0.05）;（3）高速涡轮手机组的临床满意度显著高于传统拔牙组（P〈0.05）。结论：在临床拔除阻生智齿的实践过程中,采用高速涡轮手机的方法进行治疗的临床效果显著,是临床除阻生智齿的可靠选择。     

微创拔牙术在临床工作中的疗效分析

目的：通过比较微创拔牙法与传统拔牙法拔除下颌阻生智齿的临床应用效果,寻找更合理的阻生齿的拔除方案。方法：选择临床需要拔除下颌各种阻生齿的患者180例,按随机数字表法分为试验组和对照组,每组90例,分别采用高速涡轮机结合微创拔牙刀和传统拔牙器械拔除患牙。比较两组拔牙过程中畏惧发生率及术后张口度、疼痛、拔牙窝完整性等的差异。结果：试验组的牙科畏惧症发生率明显低于对照组,手术效果明显优于传统组,差异均具有统计学意义（P〈0.05）。结论：微创拔牙法拔除下颌阻生齿可达到无痛、安全、微创的目的,更适合临床推广应用。     

Public Health Perspectives on Hearing Loss and Aging Outcomes: The Association of Vision,Hearing, and Dual-Sensory Loss with Walking Speed and Incident Slow Walking: Longitudinal and Time to Event Analyses in the Health and Retirement Study

With the aging of the population, vision (VL), hearing (HL), and dual-sensory (DSL, concurrent VL and HL) loss will likely constitute important public health challenges. Walking speed is an indicator of functional status and is associated with mortality. Using the Health and Retirement Study, a nationally representative U.S. cohort, we analyzed the longitudinal relationship between sensory loss and walking speed. In multivariable mixed effects linear models, baseline walking speed was slower by 0.05 m/s (95% confidence interval [CI] = 0.04–0.07) for VL, 0.02 (95% CI = 0.003–0.03) for HL, and 0.07 (95% CI = 0.05–0.08) for DSL compared with those without sensory loss. Similar annual declines in walking speeds occurred in all groups. In time-to-event analyses, the risk of incident slow walking speed (walking speed < 0.6 m/s) was 43% (95% CI = 25–65%), 29% (95% CI = 13–48%), and 35% (95% CI = 13–61%) higher among those with VL, HL, and DSL respectively, relative to those without sensory loss. The risk of incident very slow walking speed (walking speed < 0.4 m/s) was significantly higher among those with HL and DSL relative to those without sensory loss, and significantly higher among those with DSL relative to those with VL or HL alone. Addressing sensory loss and teaching compensatory strategies may help mitigate the effect of sensory loss on walking speed.     

Comparing cognitive functioning in schizophrenia and autism using WAIS-III

The main goal of this study was to investigate differences and similarities in general cognitive functioning between adults with schizophrenia and autism, because this has not been systematically investigated. We used a cross-sectional design to compare adults with schizophrenia (n = 27), with autism (n = 114) and a healthy control group (n = 30). Schizophrenia diagnoses were based on the Structured Clinical Interview for the DSM-IV Axis I (SCID-I) and behavioral symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Autism was diagnosed with a DSM-IV questionnaire for autism spectrum disorders and the Autistic Diagnostic Interview, revised version. The Wechsler Adult Intelligence Scale, third version (WAIS-III) was used to assess cognitive functions. All participants were between 18 and 65 years of age and had a minimum full scale intelligence of 80. Results showed that patients with schizophrenia scored significantly lower on processing speed than patients with autism and the healthy control group. Differences on other index scales were not found. In participants with schizophrenia a correlation was found between processing speed impairment and negative symptoms. Diagnosis could be predicted correctly with WAIS-III profile in 70.4% of the cases with schizophrenia compared to 56.7% of the healthy control group and 22.8% of the autism group.     

The dynamic relationship between cognitive function and walking speed: the English Longitudinal Study of Ageing

Cognitive deficiency and oxidative stress have been well documented in aging and in neurodegenerative disorders such as Alzheimer’s disease. In this study, we assessed the therapeutic effect of polyprenols on d-galactose-induced cognitive impairment in mice by testing on of behavioral and cognitive performance. In order to explore the possible role of polyprenols against d-galactose-induced oxidative damages, we assessed various biochemical indicators. Chronic administration of d-galactose (150 mg/kg·d, s.c.) for 7 weeks significantly impaired cognitive performance (both in step-through passive and active avoidance tests) and locomotor activity (in open-field test) and the ability of spatial learning and memory (in Morris water maze test) compared with the control group. The results revealed that polyprenols treatment for 2 weeks significantly ameliorated model mice’s cognitive performance and oxidative defense. All groups of polyprenols enhanced the learning and memory ability in step-through passive and active avoidance tests, locomotor activity in open-field test, and the ability of spatial learning and memory in Morris water maze test. Furthermore, high and middle level of polyprenols significantly increased total antioxidative capacity (T-AOC), glutathione peroxidase (GSH-Px), super oxide dismutase (SOD) activity, neprilysin (NEP), and β-site AβPP cleaving enzyme 1 (BACE1) expression, while nitric oxide (NO), nitric oxide synthase (NOS) activity, malondialdehyde (MDA) concentration, and the level of Aβ1-42 and presenilin 1 (PS1) were decreased. Polyprenols have a significant relieving effect on learning, memory, and spontaneous activities in a d-galactose-induced mouse model and ameliorates cognitive impairment and biochemical dysfunction in mice. In summary, we have demonstrated that polyprenols may ameliorate memory and cognitive impairment via enhancing oxidative defense and affecting generation and dissimilation of Aβ-related enzymes, suggesting that polyprenols represent a novel drug for treating Alzheimer’s disease.