Hybrid laser metal deposition of a Fe–Cr–Mo–V–Mn tool steel for hot stamping applications

In this investigation, a novel Fe–Cr–Mo–V–Mn hot work tool steel powder was specifcally developed for laser-based additive manufacturing, targeting the possibility to create conformal cooling channels in hot stamping tools for improved cooling efciency during the forming of steel sheets for the automotive industry. Specimens of the proposed tool steel were printed via laser metal deposition and characterized to demonstrate its compatibility with hot work tool steels that are commonly used in the tooling industry. The applicability of the developed material was proved by fabricating cooling channels in a simple geometry demonstrator using a hybrid process combining milling and laser metal deposition. Finally, a hybridmanufactured hot stamping tool segment was tested in a pilot plant to evaluate the efect of the investigated material on the cooling performance when compared to a conventional tool machined from H13 hot work tool steel. The results showed that the Fe–Cr–Mo–V–Mn tool steel features thermophysical properties similar to the most popular H13 steel and it can be efficiently used to produce tools containing conformal cooling channels by hybrid laser metal deposition, without the need of intermediate structures to improve the compatibility between the substrate and the deposited volumes

Migraine and sleep apnea in the general population

Objective is to investigate the relationship between migraine and obstructive sleep apnea in the general population. A cross-sectional population-based study. A random age and gender stratified sample of 40,000 persons aged 20–80 years residing in Akershus, Hedmark or Oppland County, Norway, were drawn by the National Population Register. A postal questionnaire containing the Berlin Questionnaire was used to classify respondents to be of either high or low risk of obstructive sleep apnea. 376 persons with high risk and 157 persons with low risk of sleep apnea aged 30–65 years were included for further investigations. They underwent an extensive clinical interview, a physical and a neurological examination by physicians, and in-hospital polysomnography. Those with apnea hypopnoea index (AHI) ≥5 were classified with obstructive sleep apnea. Migraine without aura (MO) and migraine with aura (MA) was diagnosed according to the International Classification of Headache Disorders. MO and MA occurred in 12.5 and 6.8% of the participants with obstructive sleep apnea. The logistic regression analyses showed no relationship between the two types of migraine and obstructive sleep apnea, with adjusted odds ratios for MO 1.15 (0.65–2.06) and MA 1.15 (0.95–2.39). Further, estimates using cutoff of moderate (AHI ≥ 15) and severe (AHI ≥ 30) obstructive sleep apnea, did not reveal any significant relationship between migraine and the AHI. Migraine and obstructive sleep apnea are unrelated in the general population

Tension-type headache and sleep apnea in the general population

The main objective of this study is to investigate the relationship between tension-type headache and obstructive sleep apnea in the general population. The method involves a cross-sectional population-based study. A random age and gender stratified sample of 40,000 persons aged 20–80 years residing in Akershus, Hedmark or Oppland County, Norway were drawn by the National Population Register. A postal questionnaire containing the Berlin Questionnaire was used to classify respondents to be of either high or low risk of obstructive sleep apnea. Included in this study were 297 persons with high risk and 134 persons with low risk of sleep apnea, aged 30–65 years. They underwent an extensive clinical interview, a physical and a neurological examination by physicians, and in-hospital polysomnography. Those with apnea hypopnoea index (AHI) ≥5 were classified with obstructive sleep apnea. Tension-type headache was diagnosed according to the International Classification of Headache Disorders. Results showed the prevalence of frequent and chronic tension-type headache was 18.7 and 2.1% in the participants with obstructive sleep apnea. The logistic regression analyses showed no significant relationship between tension-type headache and obstructive sleep apnea, with adjusted odds ratios for frequent tension-type headache of 0.95 (0.55–1.62) and chronic tension-type headache of 1.91 (0.37–9.85). The results did not change when using cut-off of moderate (AHI ≥15) and severe (AHI ≥30) obstructive sleep apnea. Thus, we did not find any significant relationship between tension-type headache and the AHI. The presence and severity of sleep apneas seem not to influence presence and attack-frequency of tension-type headache in the general population

Armodafinil improves wakefulness and long-term episodic memory in nCPAP-adherent patients with excessive sleepiness associated with obstructive sleep apnea

Residual excessive sleepiness (ES) and impaired cognition can occur despite effective and regular nasal continuous positive airway pressure (nCPAP) therapy in some patients with obstructive sleep apnea (OSA). A pooled analysis of two 12-week, randomized, double-blind studies in nCPAP-adherent patients with ES associated with OSA evaluated the effect of armodafinil on wakefulness and cognition. Three hundred and ninety-one patients received armodafinil (150 or 250 mg) and 260 patients received placebo once daily for 12 weeks. Efficacy assessments included the Maintenance of Wakefulness Test (MWT), Cognitive Drug Research cognitive performance battery, Epworth Sleepiness Scale, and Brief Fatigue Inventory. Adverse events were monitored. Armodafinil increased mean MWT sleep latency from baseline to final visit by 2.0 min vs a decrease of 1.5 min with placebo (P < 0.0001). Compared with placebo, armodafinil significantly improved quality of episodic secondary memory (P < 0.05) and patients’ ability to engage in activities of daily living (P < 0.0001) and reduced fatigue (P < 0.01). The most common adverse events were headache, nausea, and insomnia. Armodafinil did not adversely affect desired nighttime sleep, and nCPAP use remained high (approximately 7 h/night). Adjunct treatment with armodafinil significantly improved wakefulness, long-term memory, and patients’ ability to engage in activities of daily living in nCPAP-adherent individuals with ES associated with OSA. Armodafinil also reduced patient-reported fatigue and was well tolerated

Breathe right nasal strips and the respiratory disturbance index in sleep related breathing disorders

This investigation assesses the effects of Breathe Right nasal strips on the respiratory disturbance index (RDI) measured by polysomnography in patients suffering from obstructive sleep apnea and snaring. The positive effect of these strips on nasal ventilation was shown in earlier studies. Twenty-six patients with art RDI higher than 10 in an initial measurement underwent a second preoperative polysomnography with Breathe Right nasal strips in place. Nineteen of these 26 patients showed reduction of RDI during the second night of polysomnography using the nasal strips, indicating that nasal obstruction seems to be a predominant factor in the etiology of snoring and apnea in these individuals. Demographic data, medical history, rhinoscopy, clinical assessment of pharyngeal obstruction (Mueller's maneuver), as well as anterior rhinomanometry and acoustic rhinometry were used to identify typical findings correlating with a positive effect of the Breathe Right nasal strips on the RDI: 1. Hyperplasia or hypertrophy of the lower turbinates, septal deviation, and/or allergic rhinitis. 2. None or only minor pharyngeal obstruction. 3. Age less than 55 years. if a positive effect is seen during polysomnography with the strips in place, patients will most likely profit from an improvement of nasal ventilation. This may help to target more effectively septal or turbinate surgery if applicable. In other cases, ifa significant RDI reduction is obtained by the use of the nasal strips, they could also offer a noninvasive modality of treatment, especially since the high degree of co-morbidity in this group of patients can sometimes make a surgical approach less favorable