A dimensioning and tolerancing methodology for concurrent engineering applications I: problem representation

This paper is the first of two which present a methodology for determining the dimensional specifications of all the component parts and sub-assemblies of a product according to their dimensional requirements. To achieve this goal, two major steps are followed, each of which is described in a paper. In the first paper, all relationships necessary for finding the values of dimensions and tolerances are represented in a matrix form, known as a Dimensional Requirements/Dimensions (DR/D) matrix. In the second paper, the values of individual dimensions and tolerances are determined by applying a comprehensive solution strategy to satisfy all the relationships represented in the DR/D matrix. The methodology is interactive and suitable for use in a concurrent engineering (CE) environment. The graphical tool presented in this paper will assist a CE team in visualizing the overall D&T problem and foreseeing the ramifications of decisions regarding the selection of dimensions and tolerances. This will assist the CE team to systematically determine all the controllable variables, such as dimensions, tolerances, and manufacturing processes

Congenital anomalies in low- and middle-income countries: the unborn child of global surgery.

Surgically correctable congenital anomalies cause a substantial burden of global morbidity and mortality. These anomalies disproportionately affect children in low- and middle-income countries (LMICs) due to sociocultural, economic, and structural factors that limit the accessibility and quality of pediatric surgery. While data from LMICs are sparse, available evidence suggests that the true human and financial cost of congenital anomalies is grossly underestimated and that pediatric surgery is a cost-effective intervention with the potential to avert significant premature mortality and lifelong disability

Chirped pulse Raman amplification in warm plasma: towards controlling saturation

Stimulated Raman backscattering in plasma is potentially an efficient method of amplifying laser pulses to reach exawatt powers because plasma is fully broken down and withstands extremely high electric fields. Plasma also has unique nonlinear optical properties that allow simultaneous compression of optical pulses to ultra-short durations. However, current measured efficiencies are limited to several percent. Here we investigate Raman amplification of short duration seed pulses with different chirp rates using a chirped pump pulse in a preformed plasma waveguide. We identify electron trapping and wavebreaking as the main saturation mechanisms, which lead to spectral broadening and gain saturation when the seed reaches several millijoules for durations of 10's - 100's fs for 250 ps, 800 nm chirped pump pulses. We show that this prevents access to the nonlinear regime and limits the efficiency, and interpret the experimental results using slowly-varying-amplitude, current-averaged particle-in-cell simulations. We also propose methods for achieving higher efficiencies.close0

A dimensioning and tolerancing methodology for concurrent engineering applications II: comprehensive solution strategy

Dimensioning and tolerancing (D&T) is a multidisciplinary problem which requires the fulfillment of a large number of dimensional requirements. However, almost all of the currently available D&T tools are only intended for use by the designer. In addition, they typically provide solutions for the requirements one at time. This paper presents a methodology for determining the dimensional specifications of the component parts and sub-assemblies of a product by satisfying all of its requirements. The comprehensive solution strategy presented here includes: a strategy for separating D&T problems into groups, the determination of an optimum solution order for coupled functional equations, a generic tolerance allocation strategy, and strategies for solving different types of D&T problems. A number of commonly used cost minimization strategies, such as the use of standard parts, preferred sizes, preferred fits, and preferred tolerances, have also been incorporated into the proposed methodology. The methodology is interactive and intended for use in a concurrent engineering environment by members of a product development team

High TWIST1 mRNA expression is associated with poor prognosis in lymph node-negative and estrogen receptor-positive human breast cancer and is co-expressed with stromal as well as ECM related genes

Introduction: The TWIST homolog 1 (TWIST1) is a transcription factor that induces epithelial to mesenchymal transition (EMT), a key process in metastasis. The purpose of this study was to investigate whether TWIST1 expression predicts disease progression in a large breast cancer cohort with long-term clinical follow-up, and to reveal the biology related to TWIST1 mediated disease progression.Methods: TWIST1 mRNA expression level was analyzed by quantitative real-time reverse polymerase chain reaction (RT-PCR) in 1,427 primary breast cancers. In uni- and multivariate analysis using Cox regression, TWIST1 mRNA expression level was associated with metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS). Separate analyses in lymph node-negative patients (LNN, n = 778) who did not receive adjuvant systemic therapy, before and after stratification into estrogen receptor (ER)-positive (n = 552) and ER-negative (n = 226) disease, were also performed. The association of TWIST1 mRNA with survival endpoints was assessed using Kaplan-Meier analysis. Using gene expression arrays, genes showing a significant Spearman rank correlation with TWIST1 were used to identify overrepresented Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated biological pathways.Results: Increased mRNA expression level of TWIST1 analyzed as a continuous variable in both uni- and multivariate analysis was associated with shorter MFS in all patients (hazard ratio (HR): 1.17, 95% confidence interval, (95% CI):1.09 to 1.26; and HR: 1.17, 95% CI: 1.08 to 1.26; respectively), in LNN patients (HR: 1.22, 95% CI: 1.09 to 1.36; and HR: 1.21, 95% CI: 1.07 to 1.36; respectively) and in the ER-positive subgroup of LNN patients (HR: 1.34, 95% CI: 1.17 to 1.53; and HR: 1.32, 95% CI: 1.14 to 1.53; respectively). Similarly, high TWIST1 expression was associated with shorter DFS and OS in all patients and in the LNN/ER-positive subgroup. In contrast, no association of TWIST1 mRNA expression with MFS, DFS or OS was observed in ER-negative patients. Genes h

General Practitioners' opinions on their practice in mental health and their collaboration with mental health professionals

BACKGROUND: Common mental health problems are mainly treated in primary care settings and collaboration with mental health services is needed. Prior to re-organisation of the mental health care offer in a geographical area, a study was organized: 1) to evaluate GPs' opinions on their day-to-day practice with Patients with Mental Health Problems (PMHP) and on relationships with Mental Health Professionals (MHPro); 2) to identify factors associated with perceived need for collaboration with MHPro and with actual collaboration. METHODS: All GPs in the South Yvelines area in France (n = 492) were informed of the implementation of a local mental health program. GPs interested in taking part (n = 180) were invited to complete a satisfaction questionnaire on their practice in the field of Mental Health and to include prospectively all PMHP consultants over an 8-day period (n = 1519). For each PMHP, data was collected on demographic and clinical profile, and on needs (met v. unmet) for collaboration with MHPro. RESULTS: A majority of GPs rated PMHP as requiring more care (83.4%), more time (92.3%), more frequent consultations (64.0%) and as being more difficult to refer (87.7%) than other patients. A minority of GPs had a satisfactory relationship with private psychiatrists (49.5%), public psychiatrists (35%) and social workers (27.8%). 53.9% had a less satisfactory relationship with MHPro than with other physicians. Needs for collaboration with a MHPro were more often felt in caring for PMHP who were young, not in employment, with mental health problems lasting for more than one year, with a history of psychiatric hospitalization, and showing reluctance to talk of psychological problems and to consult a MHPro. Needs for collaboration were more often met among PMHP with past psychiatric consultation or hospitalization and when the patient was not reluctant to consult a MHPro. Where needs were not met, GP would opt for the classic procedure of mental health referral for only 31.3% of their PMHP. CONCLUSION: GPs need targeted collaboration with MHPro to support their management of PMHP, whom they are willing to care for without systematic referral to specialists as the major therapeutic option

Spectral morphometric characterization of breast carcinoma cells

The spectral morphometric characteristics of standard haematoxylin and eosin breast carcinoma specimens were evaluated by light microscopy combined with a spectral imaging system. Light intensity at each wavelength in the range of 450–800 nm was recorded for 104 pixels from each field and represented as transmitted light spectra. A library of six characteristic spectra served to scan the cells and reconstruct new images depicting the nuclear area occupied by each spectrum. Fifteen cases of infiltrating ductal carcinoma and six cases of lobular carcinoma were examined; nine of the infiltrating ductal carcinoma and three of the lobular carcinoma showed an in situ component. The spectral morphometric analysis revealed a correlation between specific patterns of spectra and different groups of breast carcinoma cells. The most consistent result was that lobular carcinoma cells of in situ and infiltrating components from all patients showed a similar spectral pattern, whereas ductal carcinoma cells displayed spectral variety. Comparison of the in situ and the infiltrating ductal solid, cribriform and comedo carcinoma cells from the same patient revealed a strong similarity of the spectral elements and their relative distribution in the nucleus. The spectrum designated as number 5 in the library incorporated more than 40% of the nuclear area in 74.08% of the infiltrating lobular cells and in 13.64% of the infiltrating ductal carcinoma cells (P < 0.001). Spectrum number 2 appeared in all infiltrating ductal cells examined and in none of the lobular cells. These results indicate that spectrum number 5 is related to infiltrating lobular carcinoma, whereas spectrum number 2 is characteristic for infiltrating ductal carcinoma cells. Spectral similarity mapping of central necrotic regions of comedo type in situ carcinoma revealed nuclear fragmentation into defined segments composed of highly condensed chromatin. We conclude that the spectral morphometric features found for lobular and ductal cell populations may serve future automated histological diagnostics. © 1999 Cancer Research Campaig