Design and Development of a Deep Acoustic Lining for the 40-by 80-Foot Wind Tunnel Test Section

The work described in this report has made effective use of design teams to build a state-of-the-art anechoic wind-tunnel facility. Many potential design solutions were evaluated using engineering analysis, and computational tools. Design alternatives were then evaluated using specially developed testing techniques, Large-scale coupon testing was then performed to develop confidence that the preferred design would meet the acoustic, aerodynamic, and structural objectives of the project. Finally, designs were frozen and the final product was installed in the wind tunnel. The result of this technically ambitious project has been the creation of a unique acoustic wind tunnel. Its large test section (39 ft x 79 ft x SO ft), potentially near-anechoic environment, and medium subsonic speed capability (M = 0.45) will support a full range of aeroacoustic testing-from rotorcraft and other vertical takeoff and landing aircraft to the take-off/landing configurations of both subsonic and supersonic transports

Population-Based Rates of Revision of Primary Total Hip Arthroplasty: A Systematic Review

Background: Most research on failure leading to revision total hip arthroplasty (THA) is reported from single centers. We searched PubMed between January 2000 and August 2010 to identify population- or community-based studies evaluating ten-year revision risks. We report ten-year revision risk using the Kaplan-Meier method, stratifying by age and fixation technique. Results: Thirteen papers met the inclusion criteria. Cemented prostheses had Kaplan-Meier estimates of revision-free implant survival of ten years ranging from 88 % to 95%; uncemented prostheses had Kaplan-Meier estimates from 80 % to 85%. Estimates ranged from 72 % to 86 % in patients less than 60 years old and from 90 to 96 % in older patients. Conclusion: Data reported from national registries suggest revision risks of 5 to 20 % ten years following primary THA. Revision risks are lower in older THA recipients. Uncemented implants may have higher ten-year rates of revision, regardless of age

The Harris hip score: Do ceiling effects limit its usefulness in orthopedics?: A systematic review

The Harris hip score (HHS), a disease-specific health status scale that is frequently used to measure the outcome of total hip arthroplasty, has never been validated properly. A questionnaire is suitable only when all 5 psychometric properties are of sufficient quality. We questioned the usefulness of the HHS by investigating its content validity. We performed a systematic review based on a literature search in PubMed, Embase, and the Cochrane Library for descriptive studies published in 2007. 54 studies (59 patient groups) met our criteria and were included in the data analysis. To determine the content validity, we calculated the ceiling effect (percentage) for each separate study and we pooled data to measure the weighted mean. A subanalysis of indications for THA was performed to differentiate the populations for which the HHS would be suitable and for which it would not. A ceiling effect of 15% or less was considered to be acceptable. Over half the studies (31/59) revealed unacceptable ceiling effects. Pooled data across the studies included (n = 6,667 patients) suggested ceiling effects of 20% (95%CI: 18-22). Ceiling effects were greater (32%, 95%CI:12-52) in those patients undergoing hip resurfacing arthroplasty. Although the Harris hip score is widely used in arthroplasty research on outcomes, ceiling effects are common and these severely limit its validity in this field of researc

Does parallel item content on WOMAC's Pain and Function Subscales limit its ability to detect change in functional status?

BACKGROUND: Although the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) is considered the leading outcome measure for patients with osteoarthritis of the lower extremity, recent work has challenged its factorial validity and the physical function subscale's ability to detect valid change when pain and function display different profiles of change. This study examined the etiology of the WOMAC's physical function subscale's limited ability to detect change in the presence of discordant changes for pain and function. We hypothesized that the duplication of some items on the WOMAC's pain and function subscales contributed to this shortcoming. METHODS: Two eight-item physical function scales were abstracted from the WOMAC's 17-item physical function subscale: one contained activities and themes that were duplicated on the pain subscale (SIMILAR-8); the other version avoided overlapping activities (DISSIMILAR-8). Factorial validity of the shortened measures was assessed on 310 patients awaiting hip or knee arthroplasty. The shortened measures' abilities to detect change were examined on a sample of 104 patients following primary hip or knee arthroplasty. The WOMAC and three performance measures that included activity specific pain assessments – 40 m walk test, stair test, and timed-up-and-go test – were administered preoperatively, within 16 days of hip or knee arthroplasty, and at an interval of greater than 20 days following the first post-surgical assessment. Standardized response means were used to quantify change. RESULTS: The SIMILAR-8 did not demonstrate factorial validity; however, the factorial structure of the DISSIMILAR-8 was supported. The time to complete the performance measures more than doubled between the preoperative and first postoperative assessments supporting the theory that lower extremity functional status diminished over this interval. The DISSIMILAR-8 detected this deterioration in functional status; however, no significant change was noted for the SIMILAR-8. The WOMAC pain scale demonstrated a slight reduction in pain and the performance specific pain measures did not reflect a change in pain. All measures showed substantial improvement over the second assessment interval. CONCLUSIONS: These findings support the hypothesis that activity overlap on the pain and function subscales plays a causal role in limiting the WOMAC physical function subscale's ability to detect change

Risk factors of anterior cruciate ligament tears: Neuromuscular status

Peer reviewe

Psychometric properties of the Vertigo symptom scale – Short form

<p>Abstract</p> <p>Background</p> <p>The aim of the study was to examine the psychometric properties of the Vertigo symptom scale – short form (VSS-SF), a condition-specific measure of dizziness, following translation of the scale into Norwegian.</p> <p>Methods</p> <p>A cross-sectional survey design was used to examine the factor structure, internal consistency and discriminative ability (sample I, n = 503). A cross-sectional pre-intervention design was used to examine the construct validity (sample II, n = 36) of the measure and a test-retest design was used to examine reliability (sub-sample of sample II, n = 28).</p> <p>Results</p> <p>The scree plot indicated a two factor structure accounting respectively for 41% and 12% of the variance prior to rotation. The factors were related to vertigo-balance (VSS-V) and autonomic-anxiety (VSS-A). Twelve of the items loaded clearly on either of the two dimensions, while three items cross-loaded. Internal consistency of the VSS-SF was high (alpha = 0.90). Construct validity was indicated by correlation between path length registered by platform posturography and the VSS-V (r = 0.52), but not with the VSS-A. The ability to discriminate between dizzy and not dizzy patients was excellent for the VSS-SF and sub-dimension VSS-V (area under the curve 0.87 and 0.91, respectively), and acceptable for the sub-dimension VSS-A (area under the curve 0.77). High test-retest reliability was demonstrated (ICC VSS-SF: 0.88, VSS-V: 0.90, VSS-A: 0.90) and no systematic change was observed in the scores from test to retest after 2 days.</p> <p>Conclusion</p> <p>Using a Norwegian translated version of the VSS-SF, this is the first study to provide evidence of the construct validity of this instrument demonstrating a stable two factor structure of the scale, and the identified sub-dimensions of dizziness were related to vertigo-balance and autonomic-anxiety, respectively. Evidence regarding a physical construct underlying the vertigo-balance sub-scale was provided. Satisfactory internal consistency was indicated, and the discriminative ability of the instruments was demonstrated. The instrument showed satisfactory test-retest reliability.</p

Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape

The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit

Systematic Analysis of Sequences and Expression Patterns of Drought-Responsive Members of the HD-Zip Gene Family in Maize

Background: Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings: In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related ciselements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution

Long-term symptoms in dizzy patients examined in a university clinic

Background: The long-term course of dizziness was investigated combining medical chart and survey data. The survey was undertaken median (interquartile range (IQR)) 4.6 (4.3) years after the initial medical examination. Methods: Chart data comprised sex, age, diagnosis, symptom duration, postural sway and neck pain. Survey data comprised symptom severity assessed by the Vertigo Symptom Scale – Short Form (VSS-SF), and data regarding current state of dizziness, medication, neck pain and other chronic conditions. Results: The sample consisted of 503 patients, the mean (standard deviation (SD)) age was 50.0 (11.6) years, women being slightly overrepresented (60%). Severe problems with dizziness (VSS-SF mean (SD) 13.9, (10.8)) were indicated in the total group and in 5 of 6 diagnostic sub-groups. Vertigo/balance- and autonomic/anxiety-related symptoms were present in all groups. Current dizziness was confirmed by 73% who had significantly more severe problems than the non-dizzy (VSS-SF mean (SD): 17.2 (10.1) versus 5.0 (7.3)). Symptoms were related to vertigo/balance more than to autonomic/anxiety (test of interaction p < 0.001). Based on simple logistic regression analysis, sex, symptom duration, neck pain, sway and diagnoses predicted dizziness. Symptom duration and neck pain remained predictors in the adjusted analysis. Age, symptom duration, neck pain, sway and diagnoses predicted vertigo/balance-related dizziness in both regression analyses. Sex, neck pain and sway predicted development of autonomic/anxiety-related dizziness according to simple regression analysis, while only neck pain remained a significant predictor in the adjusted analysis. With respect to diagnosis, simple regression analysis showed significant reduced likelihood for development of dizziness in all vestibular sub-groups when compared to the non-otogenic dizziness group. With respect to vertigo/balance- and autonomic/anxiety-related symptoms, the implication of diagnostic belonging varied. No effect of diagnoses was seen in adjusted analyses. Conclusion: The majority of patients had persistent and severe problems with dizziness. The wait-and-see attitude before referral to specialist institutions may be questioned. Early, active movements seem necessary, and attention should be paid to the presence of neck pain. Diagnoses had limited prognostic value. Questionnaire-based evaluations could assist in classification and identification of type of dizziness and thereby provide a better basis for specific rehabilitation