Demonstration of tantalum as a structural material for MEMS thermal actuators.

This work demonstrates the processing, modeling, and characterization of nanocrystalline refractory metal tantalum (Ta) as a new structural material for microelectromechanical system (MEMS) thermal actuators (TAs). Nanocrystalline Ta films have a coefficient of thermal expansion (CTE) and Young's modulus comparable to bulk Ta but an approximately ten times greater yield strength. The mechanical properties and grain size remain stable after annealing at temperatures as high as 1000 °C. Ta has a high melting temperature (T m = 3017 °C) and a low resistivity (ρ = 20 µΩ cm). Compared to TAs made from the dominant MEMS material, polycrystalline silicon (polysilicon, T m = 1414 °C, ρ = 2000 µΩ cm), Ta TAs theoretically require less than half the power input for the same force and displacement, and their temperature change is half that of polysilicon. Ta TAs operate at a voltage 16 times lower than that of other TAs, making them compatible with complementary metal oxide semiconductors (CMOS). We select α-phase Ta and etch 2.5-µm-thick sputter-deposited films with a 1 µm width while maintaining a vertical sidewall profile to ensure in-plane movement of TA legs. This is 25 times thicker than the thickest reactive-ion-etched α-Ta reported in the technical literature. Residual stress sensitivities to sputter parameters and to hydrogen incorporation are investigated and controlled. Subsequently, a V-shaped TA is fabricated and tested in air. Both conventional actuation by Joule heating and passive self-actuation are as predicted by models.

Mechanochemical Effects of Adsorbates at Nanoelectromechanical Switch Contacts.

Herein, classical molecular dynamics simulations are used to examine nanoscale adsorbate reactions during the cyclic opening and closing of nanoelectromechanical system (NEMS) switches. We focus upon how reactions change metal/metal conductive contact area, asperity morphology, and plastic deformation. We specifically consider Pt, which is often used as an electrode material for NEMS switches. The structural evolution of asperity contacts in gaseous environments with molecules which can potentially form tribopolymers is determined by various factors, for example, contact forces, partial pressure and molecular weight of gas, and the fundamental reaction rates of surface adsorption and adsorbate linkages. The modeled systems exhibit significant changes during the first few cycles, but as the number of contact cycles increases, the system finds a steady-state where the morphologies, Pt/Pt contact area, oligomer chain lengths, amount of Pt transfer between opposing surfaces, and deformation rate stabilize. The stress generated during asperity contact increases the rate of reactions among the adsorbates in the contact region. This makes the size of the adsorbate molecules increase and thus more exposed metal, which implies higher electrical conductance in the closed contact, but more plastic deformation, metal-metal transfer, and mechanical work expended in each contact cycle.

Risk of chronic ankle instability: A reliability study on radiographic assessment of the ankle joint geometry.

BACKGROUND: Chronic ankle instability (CAI) is a multifactorial disabling condition. Ideally all factors contributing to CAI are identified and implemented in a risk assessment model. However, they need to meet strict reliability requirements. To assess usability of radiographic factors for this risk assessment model and future clinical practice, the objective of the current study was to assess the intra and inter observer reliability of three radiographic measurements. METHODS AND METHODS: The radiographs of 39 consecutive patients, at least 16years, who visited the Emergency Department after sustaining a lateral ankle sprain (LAS), were assessed by four observers. The radiographic measurements included absolute and relative ankle alignment, sagittal fibular position and ankle joint congruency (talar radius and height, and tibiotalar sector), performed twice by all observers independently. Reliability was assessed by calculating the Intraclass Correlation Coefficient (ICC) which was considered good when ICC>0.70. RESULTS: The intra observer reliability of the absolute and relative fibular position, and talar height were good to excellent, (ICC 0.84-0.98, 0.85-0.98, and 0.79-0.93, respectively). The talar radius (ICC 0.69-0.89) was moderate to good. The overall inter observer reliability was good for the absolute and relative fibular position, and talar radius (ICC 0.84, 0.86, and 0.79, respectively). Other measurements had ICC values of <0.70. CONCLUSIONS: In an effort to identify the multifactorial nature of CAI, both the fibular position and the talar radius measurements showed good observer reliability, and will be implemented in a future risk assessment models. The other measurements are too prone for measurement errors, for future reference. LEVEL OF EVIDENCE: IV Case Series.

Communication of prognosis in head and neck cancer patients; a descriptive qualitative analysis.

OBJECTIVES: In shared decision making it is important to adequately, timely and actively involve patients in treatment decisions. Sharing prognostic information can be of key importance. This study describes whether and how prognostic information on life expectancy is included during communication on diagnosis and treatment plans between physicians and head and neck (H&N) oncologic patients in different phases of disease. METHODS: A descriptive, qualitative study was performed of n = 23 audiotaped physician-patient conversations in which both palliative and curative treatment options were discussed and questions on prognosis were expected. Verbatim transcribed consultations were systematically analyzed. A distinction was made between prognostic information that was provided (a) quantitatively: by giving numerical probability estimates, such as percentages or years or (b) qualitatively: through the use of words such as 'most likely' or 'highly improbable'. RESULTS: In all consultations, H&N surgeons provided some prognostic information. In 5.9% of the provided prognostic information, a quantitative method was used. In 94.1% prognostic information was provided qualitatively, using six identified approaches. H&N surgeons possibly affect patients' perception of prognostic content with two identified communication styles: directive (more physician-centered) and affective (more patient-centered). CONCLUSION: This study is first in providing examples of how H&N surgeons communicate with their patients regarding prognosis in all stages of disease. They often exclude specific prognostic information. The study outcomes can be used as a first step in developing a guideline for sharing prognostic information in H&N oncologic patients, in order enable the process of shared decision making.

Crystalline polymer nanofibers with ultra-high strength and thermal conductivity.

Polymers are widely used in daily life, but exhibit low strength and low thermal conductivity as compared to most structural materials. In this work, we develop crystalline polymer nanofibers that exhibit a superb combination of ultra-high strength (11 GPa) and thermal conductivity, exceeding any existing soft materials. Specifically, we demonstrate unique low-dimensionality phonon physics for thermal transport in the nanofibers by measuring their thermal conductivity in a broad temperature range from 20 to 320 K, where the thermal conductivity increases with increasing temperature following an unusual ~T1 trend below 100 K and eventually peaks around 130-150 K reaching a metal-like value of 90 W m-1 K-1, and then decays as 1/T. The polymer nanofibers are purely electrically insulating and bio-compatible. Combined with their remarkable lightweight-thermal-mechanical concurrent functionality, unique applications in electronics and biology emerge.

Capillary-induced crack healing between surfaces of nanoscale roughness.

Capillary forces are important in nature (granular materials, insect locomotion) and in technology (disk drives, adhesion). Although well studied in equilibrium state, the dynamics of capillary formation merit further investigation. Here, we show that microcantilever crack healing experiments are a viable experimental technique for investigating the influence of capillary nucleation on crack healing between rough surfaces. The average crack healing velocity, v̅, between clean hydrophilic polycrystalline silicon surfaces of nanoscale roughness is measured. A plot of v̅ versus energy release rate, G, reveals log-linear behavior, while the slope |d[log(v̅)]/dG| decreases with increasing relative humidity. A simplified interface model that accounts for the nucleation time of water bridges by an activated process is developed to gain insight into the crack healing trends. This methodology enables us to gain insight into capillary bridge dynamics, with a goal of attaining a predictive capability for this important microelectromechanical systems (MEMS) reliability failure mechanism.

Experience of palliative care for patients with head and neck cancer through the eyes of next of kin: impact of an Expert Center.

BACKGROUND: Literature is scarce on the palliative care experiences of patients with head and neck cancer. We report our experience in this patient population after the establishment of our Expert Center. METHODS: We administered a questionnaire to 40 surviving relatives of patients with head and neck cancer after the establishment of our Expert Center and compared the results to a similar group of patients with head and neck cancer before the establishment of our Expert Center. RESULTS: Since the establishment of our Expert Center, we found: an improved evaluation of the psychosocial support offered; better contact between head and neck surgeons, the patients, and families; and improvement in the quantity of information in the palliative phase. Some relatives, however, reported that patients received treatment against their wishes and life was not made as comfortable as possible. CONCLUSION: Important aspects of palliative care, such as psychosocial support and contact between patient and surgeon, have been improved since the establishment of our Expert Center.

Photocatalytic degradation of bacteriophages evidenced by atomic force microscopy.

Methods to supply fresh water are becoming increasingly critical as the world population continues to grow. Small-diameter hazardous microbes such as viruses (20-100 nm diameter) can be filtered by size exclusion, but in this approach the filters are fouled. Thus, in our research, we are investigating an approach in which filters will be reusable. When exposed to ultraviolet (UV) illumination, titanate materials photocatalytically evolve (•)OH and O2(•-) radicals, which attack biological materials. In the proposed approach, titanate nanosheets are deposited on a substrate. Viruses adsorb on these nanosheets and degrade when exposed to UV light. Using atomic force microscopy (AFM), we image adsorbed viruses and demonstrate that they are removed by UV illumination in the presence of the nanosheets, but not in their absence.

Symptoms of patients with incurable head and neck cancer: prevalence and impact on daily functioning.

BACKGROUND: There is lack of research on symptoms in patients with head and neck cancer in the palliative phase. The aim of this study was to explore symptom prevalence and the impact of these symptoms on daily functioning in patients with incurable head and neck cancer. Also, discrepancies between patients and family caregivers are described. METHODS: Questionnaires were used to collect data about symptom prevalence (n = 124) and symptom impact (n = 24). RESULTS: We discovered that the symptoms with a high prevalence were fatigue, pain, weakness, trouble with short walks outside, and dysphagia. The symptoms with the greatest impact on daily functioning were dyspnea, voice changes, trouble with short walks outside, anger, and weakness. CONCLUSIONS: Patients with incurable head and neck cancer experience a great number of different symptoms. Focus on these symptoms by health care professionals could further optimize symptom management. In future research, we recommend further validation of the used questionnaires.

Recordings of consultations are beneficial in the transition from curative to palliative cancer care: a pilot-study in patients with oesophageal or head and neck cancer.

PURPOSE: There is reluctance in providing incurable cancer patients with recordings of their consultation. In this pilot-study, we explored the feasibility and utility of providing consultation recordings when patients are told a new diagnosis of non-curable cancer, and the impact of the recordings on quality of life and the openness to discuss cancer-related issues in the family. METHOD: Seventeen patients with a new diagnosis of incurable oesophageal or head and neck cancer were randomized to receive a CD (n = 10) or no CD (n = 7) of their consultation in which the diagnosis was told and the decision to provide only palliative care was discussed. Data were collected before consultation and 1 week and 1 month afterwards. After 1 month, patients allocated to the control group were offered to receiving the CD of their consultation as well. RESULTS: No major technical or procedural problems were encountered. Three-quarters of the patients appreciated receiving the CD, which was listened to by 8/10 patients and by 10/10 others in the CD group. After 1 month, two-thirds of the patients in the control group also asked to receive the CD. We found a trend towards a poorer quality of life but an improved openness to discuss cancer-related issues, in the CD group. CONCLUSION: The provision of a CD recording on the consultation in which the transition from a curative to a palliative care stage was communicated is feasible and was well-received by most cancer patients and their family. These findings require however verification in a study with a larger sample size.

Brief report: a phase IIa, randomized, double-blind, placebo-controlled trial of apilimod mesylate, an interleukin-12/interleukin-23 inhibitor, in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the safety, tolerability, pharmacokinetics, and efficacy of apilimod mesylate, an oral interleukin-12 (IL-12)/IL-23 inhibitor, in patients with rheumatoid arthritis (RA). METHODS: We performed a phase IIa, randomized, double-blind, placebo-controlled proof-of-concept study of apilimod, in combination with methotrexate, in 29 patients with active RA (3:1 ratio of apilimod-treated to placebo-treated patients) in 3 stages. Patients received apilimod 100 mg/day or placebo for 4 weeks (stage 1) or 8 weeks (stage 2). In stage 3, patients received apilimod 100 mg twice a day or placebo for 8 weeks, with an optional extension of 4 weeks. Clinical response (Disease Activity Score in 28 joints [DAS28] and American College of Rheumatology [ACR] criteria) was assessed throughout; synovial tissue samples collected at baseline and on day 29 (stages 1 and 2) or day 57 (stage 3) were stained for cellular markers and cytokines for immunohistochemistry analysis. RESULTS: While only mild adverse events were observed in stages 1 and 2, in stage 3, all patients experienced headache and/or nausea. Among apilimod-treated patients (100 mg/day), there was a small, but significant, reduction in the DAS28 on day 29 and day 57 compared with baseline. ACR20 response was reached in only 6% of patients on day 29 and 25% of patients on day 57, similar to the percentage of responders in the placebo group. Increasing the dosage (100 mg twice a day) did not improve clinical efficacy. Consistent with clinical results, apilimod did not have an effect on expression of synovial biomarkers. Of importance, we also did not observe an effect of apilimod on synovial IL-12 and IL-23 expression. CONCLUSION: Our results do not support the notion that IL-12/IL-23 inhibition by apilimod is able to induce robust clinical improvement in RA.

Survival of patients with palliative head and neck cancer.

BACKGROUND: The purpose of this study was to describe patient characteristics and prognostic factors for survival in the palliative stage of patients with head and neck cancer. METHODS: Since November 2003, all patients with palliative head and neck cancer treated in our hospital have been recorded in a central database. In total, 262 deceased patients were included in this retrospective study. RESULTS: The reasons for palliation were inoperability, distant metastases, refusal of curative treatment, or poor condition. The mean palliative phase lasted 5.3 months for patients with squamous cell carcinomas. Involvement of a specialized nurse was significantly related with the number of admissions and place of dying. Multivariate analysis showed comorbidity and treatment to be independent predictors of survival in the palliative phase. CONCLUSION: Comorbidity and palliative interventions are possible prognostic factors for survival. The involvement of a specialized nurse might be associated with an improved quality of life.

Goal processes & self-efficacy related to psychological distress in head & neck cancer patients and their partners.

UNLABELLED: PURPOSE AND OBJECTIVE OF THE RESEARCH: In this cross-sectional study we used a self-regulation perspective to better understand the experience of psychological distress in head & neck (H&N) cancer patients and their partners. We examined which goals they valued and the extent to which patients and partners experience goal disturbance. Furthermore, associations were explored between goal disturbance, goal re-engagement, (goal)self-efficacy, and psychological distress. METHODS AND SAMPLE: H&N cancer patients and their partners, recruited from the Erasmus Medical Center Rotterdam (N = 40), were interviewed and completed questionnaires, assessing the above aspects of the self-regulation theory. KEY RESULTS: H&N cancer patients and their partners experienced goal disturbance from the disease. Such disturbances were in patients significantly related to more psychological distress. Higher levels of goal re-engagement were related to less psychological distress, again only significantly in patients. More self-efficacy was significantly associated with less psychological distress in both patients and partners. CONCLUSIONS: Self-regulation abilities as goal re-engagement and self-efficacy may be screened and used as target in future psychological interventions, given their potential to decrease perceived psychological distress. In view of elevated levels of goal disturbances in partners, psychological support for caring relatives in such interventions is recommended.

Early hyperbaric oxygen therapy for reducing radiotherapy side effects: early results of a randomized trial in oropharyngeal and nasopharyngeal cancer.

PURPOSE: Comparison of quality of life (QoL) and side effects in a randomized trial for early hyperbaric oxygen therapy (HBOT) after radiotherapy (RT). METHODS AND MATERIALS: From 2006, 19 patients with tumor originating from the tonsillar fossa and/or soft palate (15), base of tongue (1), and nasopharynx (3) were randomized to receive HBOT or not. HBOT consisted of 30 sessions at 2.5 ATA (15 msw) with oxygen breathing for 90 min daily, 5 days per week, applied shortly after the RT treatment was completed. As of 2005, all patients received validated questionnaires (i.e., the European Organization for Research and Treatment of Cancer [EORTC] QLQ-C30, EORTC QLQ Head and Neck Cancer Module (H&N35), Performance Status Scale): before treatment; at the start of RT treatment; after 46 Gy; at the end of RT treatment; and 2, 4, and 6 weeks and 3, 6, 12, and 18 months after follow-up. RESULTS: On all QoL items, better scores were obtained in patients treated with hyperbaric oxygen. The difference between HBOT vs. non-HBOT was significant for all parameters: EORTC H&N35 Swallowing (p = 0.011), EORTC H&N35 Dry Mouth (p = 0.009), EORTC H&N35, Sticky Saliva (p = 0.01), PSS Eating in Public (p = 0.027), and Pain in Mouth (visual analogue scale; p < 0.0001). CONCLUSIONS: Patients randomized for receiving hyperbaric oxygen after the RT had better QoL scores for swallowing, sticky saliva, xerostomia, and pain in mouth.

Effect of 5 weeks horizontal bed rest on human muscle thickness and architecture of weight bearing and non-weight bearing muscles.

The aim of the present study was to investigate the changes in thickness, fascicle length (L (f)) and pennation angle (theta) of the antigravity gastrocnemius medialis (GM) and vastus lateralis (VL) muscles, and the non-antigravity tibialis anterior (TA) and biceps brachii (BB) muscles measured by ultrasonography in ten healthy males (aged 22.3 +/- 2.2 years) in response to 5 weeks of horizontal bed rest (BR). After BR, muscle thickness decreased by 12.2 +/- 8.8% (P < 0.05) and 8.0 +/- 9.1% (P < 0.005) in the GM and VL, respectively. No changes were observed in the TA and BB muscles. L (f) and theta decreased by 4.8 +/- 5.0% (P < 0.05) and 14.3 +/- 6.8% (P < 0.005) in the GM and by 5.9 +/- 5.3% (P < 0.05) and 13.5 +/- 16.2% (P < 0.005) in the VL, again without any changes in the TA and BB muscles. The finding that amongst the antigravity muscles of the lower limbs, the GM deteriorated to a greater extent than the VL is possibly related to the differences in relative load that this muscle normally experiences during daily loading. The dissimilar response in antigravity and non-antigravity muscles to unloading likely reflects differences in loading under normal conditions. The significant structural alterations of the GM and VL muscles highlight the rapid remodelling of muscle architecture occurring with disuse.

Whole muscle contractile parameters and thickness loss during 35-day bed rest.

Extended exposure to microgravity leads to significant musculoskeletal adaptations. Contractile parameters of four skeletal muscles (biceps brachii-BB, vastus medialis-VM, biceps femoris-BF and gastrocnemius medialis-GM) were measured in ten healthy males (aged 22.3 +/- 2.2 years) during 35 days of horizontal bed rest by a mechanomyography-based method termed 'tensiomyography' (TMG). Two contractile parameters: contraction time (Tc) and maximal displacement (Dm) were individually measured from electrically evoked maximal single twitch TMG response of all four muscles before and after bed rest. Significant changes in Tc were found after bed rest, as shown by an increase in GM muscle Tc by 18% (p < 0.01). Dm values significantly increased (p < 0.01) after bed rest, by 24, 26 and 30% in the VM, BF and GM muscles, respectively. In the GM, the change in Dm significantly correlated with the decrease in muscle thickness (r = -0.70, p < 0.01). In conclusion, bed rest induced changes in both Dm and Tc of the TMG signal; changes in Dm being inversely related to those of muscle thickness. Amongst the investigated muscles, most affected, in terms of atrophy and mechanical alterations, were those of the lower limbs. The observed increase in Dm may be attributed to a decrease in muscle, as well as tendon stiffness, causing larger muscle fibre and non-contractile tissue oscillations following contraction.

Experience of palliative care for patients with head and neck cancer through the eyes of next of kin.

BACKGROUND: Little is known about how palliative care is experienced by patients with head and neck cancer and their relatives. The aim of this retrospective study was to analyze this care from the point of view of surviving relatives. METHODS: Fifty-five surviving relatives of patients with head and neck cancer treated at our department were enrolled in this study. Forty-five returned a completed questionnaire. RESULTS: Medical treatment during the palliative stage was judged as sufficient in most cases, but was often felt to be intrusive. The majority of patients had more need for psychosocial and physical support. Contact between head and neck surgeon and patient was sufficient. Many relatives found information about the terminal stage unsatisfactory. CONCLUSION: Not all aspects of palliative care for head and neck patients are sufficient, and improvements are, in our setting, necessary, specifically within the psychosocial field. This supports the initiation of our Expert Center to improve quality of life in the palliative stage.

Changes in antagonist muscles' coactivation in response to strength training in older women.

BACKGROUND: The purpose of this study was to assess changes in neuromuscular function of the plantarflexor and dorsiflexor muscles after 1 year of strength training of these muscles in elderly women. Twelve participants were assigned to a training (74.2 +/- 3.1 years) group and eight to a nontraining group (73.6 +/- 4.3 years). METHODS: Isometric maximum voluntary contractions (MVC) and muscle activation based on surface electromyography (EMG) were recorded before and after the 12-month training program at six different joint angles. RESULTS: After training (in the training group), (a) plantarflexion (PF) MVC increased on average by 14.4% (p <.05) across ankle joint angles from -20 degrees dorsiflexion (DF) to +30 degrees PF, (b) DF MVC decreased by 5.7% (p <.05), (c) PF EMG root mean square increased on average by 22.3% (p <.05), and (d) PF antagonists' coactivation increased on average by 7.5% across the tested joint angles. No changes were observed in the nontraining group. CONCLUSIONS: The present results show a significant increase in antagonist muscle coactivation with strength training in older women. The hypothesis is put forward that with a training-induced gain in agonist muscles' torque, stabilization of the ankle joint by increasing antagonist coactivation is needed because of a changed ratio of maximal PF torque to maximal DF torque.

The temporal responses of protein synthesis, gene expression and cell signalling in human quadriceps muscle and patellar tendon to disuse.

We hypothesized that rates of myofibrillar and patellar tendon collagen synthesis would fall over time during disuse, the changes being accompanied in muscle by decreases in focal adhesion kinase (FAK) phosphorylation and in gene expression for proteolytic enzymes. We studied nine men (22 +/- 4 years, BMI 24 +/- 3 kg m(-2) (means +/- s.d.) who underwent unilateral lower leg suspension for 23 days; five were studied between 0 and 10 days and four between 10 and 21 days. Muscle and tendon biopsies were taken in the postabsorptive state at days 0, 10 and 21 for measurement of protein synthesis, gene expression and protein phosphorylation. Muscle cross-sectional area decreased by 5.2% at 14 days and 10.0% (both P < 0.001), at 23 days, i.e. 0.5% day(-1), whereas tendon dimensions were constant. Rates of myofibrillar protein synthesis fell (P < 0.01) from 0.047% h(-1) at day 0 to 0.022% h(-1) at 10 days without further changes. Tendon collagen synthetic rates also fell (P < 0.01), from 0.052 to 0.023% h(-1) at 10 days and then to 0.010% h(-1) at 21 days. FAK phosphorylation decreased 30% (P < 0.01) at 10 days. No changes occurred in the amounts/phosphorylation of PKB-P70s6k-mTOR pathway components. Expression of mRNA for MuRF-1 increased approximately 3-fold at 10 days without changes in MAFbx or tripeptidyl peptidase II mRNA, but all decreased between 10 and 21 days. Thus, both myofibrillar and tendon protein synthetic rates show progressive decreases during 21 days of disuse; in muscle, this is accompanied by decreased phosphorylation of FAK, with no marked increases in genes for proteolytic enzymes.