Stress minimization for lattice structures. Part I: Micro-structure design.

Lattice structures are periodic porous bodies which are becoming popular since they are a good compromise between rigidity and weight and can be built by additive manufacturing techniques. Their optimization has recently attracted some attention, based on the homogenization method, mostly for compliance minimization. The goal of our two-part work is to extend lattice optimization to stress minimization problems two-dimensionally. The present first part is devoted to the choice of a parametrized periodicity cell that will be used for structural optimization in the second part of our work. In order to avoid stress concentration, we propose a square cell microstructure with a super-ellipsoidal hole instead of the standard rectangular hole often used for compliance minimization. This type of cell is parametrized two-dimensionally by one orientation angle, two semi-axis and a corner smoothing parameter. We first analyse their influence on the stress amplification factor by performing some numerical experiments. Second, we compute the optimal corner smoothing parameter for each possible microstructure and macroscopic stress. Then, we average (with specific weights) the optimal smoothing exponent with respect to the macroscopic stress. Finally, to validate the results, we compare our optimal super-ellipsoidal hole with the Vigdergauz microstructure which is known to be optimal for stress minimization in some special cases. This article is part of the theme issue 'Topics in mathematical design of complex materials'.

Assessing multiple goods and services derived from livestock farming on a nation-wide gradient.

Livestock farming is an essential activity in many rural areas, where it contributes to the maintenance of soil fertility and farmland biodiversity, as well as to a set of social public goods including food security, rural vitality and culture. However, livestock sustainability assessments tend to focus primarily on environmental and economic dimensions; therefore, these valuations might be limited because they do not consider the complete set of associated goods and services (GS). Hence, a need exists to recognise the multiple contributions provided by livestock to human well-being and society. The objective of this study was to analyse the provision of multiple GS derived from livestock across regions in France and empirically demonstrate sets of GS that repeatedly appeared together. We designated these multiple GS provided by livestock as contributions to productive, environmental, rural vitality and cultural benefits that human populations derive directly or indirectly from livestock agroecosystems. First, we combined expert knowledge with results of a literature review to define a bundle of GS provided by livestock. We then described indicators that quantified each good or service and screened national databases to determine the availability of supporting data. Finally, we assessed the GS and their relationships (synergies or trade-offs) on a nation-wide gradient in France at the department level (Nomenclature of Territorial Units for Statistics 3). Four main categories of GS were considered: provisioning (e.g. food quantity and quality), environmental quality (e.g. biodiversity, landscape heterogeneity, water quality), rural vitality (e.g. employment, rural dynamism) and culture (e.g. gastronomy and landscape heritage). Four major types of GS bundles were identified, which suggested strong contrasts among French rural areas in terms of the nature of the GS that occurred together and their levels of provision. GS bundles in France had a non-random spatial distribution. This study represents an initial step towards developing a methodology to consider GS bundles provided by livestock. Nonetheless, further research is needed to understand socio-economic, environmental, political and geographic determinants of the composition of GS bundles.

Factors influencing dairy calf and replacement heifer mortality in France.

Herd-level risk factors for dairy calf and heifer mortality in France were identified by calculating herd-level variables (including mortality risk or rate) using the National Bovine Identification Database (2005 and 2006). Eleven dairy production areas representing different livestock systems were also included. Statistical analyses were based on a probit model (mortality risk or rate=0 or >0) and a linear model (mortality risk or rate >0) corrected by the sample bias Heckman method. The same associations were reported for 2005 and 2006. The mortality risks or rates for calves and heifers were positively associated with the proportion of purchased cows or being a Milk Control Program member and negatively associated with adhering to the Good Breeding Practices charter and having an autumn calving peak. The associations between mortality and the breeds or the production areas were positive or negative, depending on the classes of animal. Mortality and having a beef herd in addition to the dairy herd were negatively associated for noncrossed birth to 2-d-old calves, noncrossed 3-d- to 1-mo-old calves, and 3-d- to 1-mo-old heifers. Having a beef herd probably provides specific know-how related to newborn and young calf management that makes it easier to attain low mortality in pure-breed dairy calves. The proportion of males born was positively associated with mortality for the birth to 2-d-old calves (all classes) and for the 3-d- to 1-mo-old beef-crossed calves, but negatively for all classes of heifers. This indicates that heifer management was improved when the availability of newborn heifers decreased, resulting in low mortality. This lower mortality is apparent for all classes of heifers present on the farm during the year when the proportion of males was low, and demonstrates an anticipatory effect. In conclusion, this study shows that the presence of a beef herd in addition to the dairy herd within a farm is associated with decreased dairy calf mortality. It also shows that heifer mortality decreases when the proportion of heifers born decreased. These determinants of dairy calf and heifer mortality are of great importance for farmer advisors, the dairy industry, and the political decision makers.

Perinatal, neonatal, and rearing period mortality of dairy calves and replacement heifers in France.

Dairy calf and replacement heifer mortality in France was assessed by calculating mortality rates at 0 to 2d (calves), 3d to 1 mo (calves and heifers), 1 to 6 mo of age, and 6 mo of age to first calving (heifers) using the national identification database. Between birth and 2-d-old, 261,000 and 251,000 of the 3.56 and 3.43 million calves born in 2005 and 2006, respectively, died. The overall 0- to 2-d-old calf mortality rate was around 6.7%, which is similar to the low range of values reported in the literature. Among the 2.38 and 2.39 million calf-month, 139,000 and 133,000 died between 3d and 1 mo of age in 2005 and 2006, respectively. Among the 3d to 1 m of age group, dairy calf mortality rate was around 5.7%. Such a rate has not been reported previously because of the great differences in age classes between studies. For the 0- to 2-d-old and 3-d- to 1-mo-old calves, annual mortality was zero on 26 and 44% of the farms, respectively. Calf mortality during the first month of life increased in winter (to 12-17%) and decreased in summer (to 8-12%), with a small peak in June or July. Mortality during the first month of life is higher in males than in females, with a mortality odds ratio of 1.20 (and 95% confidence interval of 1.19-1.21). Such a difference is also found within the noncrossed or beef-crossed calf subpopulations. Disregarding the sex, the mortality of beef-crossed calves is slightly less than that of noncrossed dairy calves, with a mortality odds ratio of 0.98 (and 95% confidence interval of 0.98-0.99) before 1 mo of age. In heifers, around 51,000, 35,000, and 40,900 out of the 1.2 million 3-d- to 1-mo-old, 1.1 million 1- to 6-mo-old, and 950,000 6-mo-old to first calving heifers died, respectively. The respective mortality rates were 4.5, 3.1, and 4.1%; these rates are similar to the low range of values previously published. The proportions of farms with no heifer mortality during a year were higher than for calves, between 60 and 70%. The mortality probability for heifers was very high for the first day of life (95% survival between 2-30 d of age), then decreased during the first year of life and became constant up to around 3 yr of age (88% survival at 36 mo of age). The risk of mortality is higher in Montbéliarde and Normande heifers compared with Holstein. In conclusion, and beyond the average mortality rates, farmers and farm advisors should keep in mind the broad range of mortality values, which shows that very low mortality (1-2%) can be achieved, even in animals with a known high risk of mortality, such as beef-crossed dairy calves.

Herd-level and contextual factors influencing dairy cow mortality in France in 2005 and 2006.

Dairy cow mortality causes financial loss and is increasing over time; it indicates suboptimal herd health or welfare. To describe the herd-level and contextual factors affecting cow mortality, the French National Bovine Dataset Identification was used to create dairy, beef, or fattening units within farms, for 2005 and 2006. Mortality rate (MO-RA, outcome variable) and most variables were calculated at the unit level, whereas contextual variables were defined at the municipality level [cattle density, inhabitant density, agricultural land always with grass on overall agricultural land (ALWG/OAL)]. The localization (11 dairy production areas, representative of the farming systems) was also included. The statistical analysis was performed with a probit regression model (MO-RA=0 or>0) and with a linear model corrected by the Heckman method for bias sample selection. For 2005 and 2006, 3.8 and 3.7 million dairy cow-years, 101,445 and 96,954 dairy units, and 141,677 and 143,424 deaths were recorded, respectively. Over one-third of the units had no dairy cow mortality in 2005 or 2006. Overall MO-RA was 3.7 and 3.8% for 2005 and 2006, respectively. Restricted MO-RA (farms without death excluded) was 5.8% for 2005 and 2006. The correlation of MO-RA among units between the 2 yr was 0.25. The same effects and close estimate values were reported for 2005 and 2006 with both models. Mortality rate was positively associated with the number of cow-years, having a beef unit in addition to a dairy unit, the proportion of purchased cows, the proportion of first-calving cows, the average calving interval, being a Milk Control Program member, inhabitant density, not being in dairy production area Grand-Ouest, and ALWG/OAL. Negative associations were reported for breed other than Holstein, being a Good Breeding Practices member, having a calving peak in autumn, culling rate, and municipal cattle density. This study reports an average mortality rate for the French dairy cows. It suggests that the farmer's management style highly influences mortality. In addition, farming system has an effect on the mortality. A possible association between municipal intensification of production and decreased mortality was also reported.

Bone metastasis from a granulosa cell tumor of the ovary.

BACKGROUND: Granulosa cell tumors (GCT) of the ovary generally have a good prognosis. Recurrences tend to be late and are usually abdominopelvic. Bone metastases are extremely rare. CASE: A case of recurrent GCT with vertebral metastasis is presented. Radiologic studies were helpful in documenting the presence of an invasive tumor destroying the vertebral body of T7. Bone scintigraphy excluded other metastatic sites. Diagnosis could not be established by CT-scan-directed fine-needle aspiration cytology or trocar biopsies. Since the lesion was isolated and resectable, aggressive surgery with complete tumoral excision was performed followed by local radiation therapy. Megestrol acetate was given as systemic treatment. CONCLUSION: Multiple treatments of GCT may alter the pattern of recurrence. Every symptom should be thoroughly evaluated. Bone metastases may be treated aggressively.

Malignant fibrous histiocytoma of the conjunctiva.

We report the clinical and pathological findings in a case of malignant fibrous histiocytoma in the conjunctiva of a 60-year-old man. The patient initially had an atypical limbal lesion, resembling a pterygium, which was excised. Two local recurrences, noted during the following year, were treated by surgical excision followed by cryotherapy. Histopathologic examination of the conjunctival lesions showed a stromal neoplastic infiltrate composed of atypical spindle cells and histiocytelike cells. The immunohistochemical and ultrastructural studies suggested that the tumor was composed of various cellular elements: fibroblasts, myofibroblasts, and histiocytes.

Persistent hyperplastic primary vitreous with retinal tumor in tuberous sclerosis: report of a case including tumoral immunohistochemistry and cytogenetic analyses.

OBJECTIVE: The authors describe an ocular lesion combining the characteristics of persistent hyperplastic primary vitreous (PHPV) and a retinal tumor in an infant with tuberous sclerosis complex (TSC). STUDY DESIGN: Case report. METHODS: Immunohistochemistry and cytogenetic studies were performed on TSC cells from an intraocular tumor in a 6-week-old infant. RESULTS: Histopathologic examination showed a thick fibrovascular membrane between the aspect of the lens and the astrocytic component of the mass. Glial fibrillary acidic protein (GFAP) showed a variable intracytoplasmic reaction in the astrocytic proliferation, involving approximately 50% of the cells. Tissue culture studies showed a fairly rapid proliferation of fusiform cells, consistent with bipolar astrocytic cells. Cytogenetic studies showed one abnormal clone consisting of three hyperdiploid cells with a loss of chromosome 9 and a gain of chromosomes 6 and 12. CONCLUSION: The atypical localization of the retinal tumor could be explained by the fact that it was trapped during its proliferation by the retinal detachment associated with the PHPV.

Human immunodeficiency virus infection is a major risk factor for detection of human papillomavirus DNA in esophageal brushings.

The presence of human papillomavirus (HPV) DNA in esophageal brushings from human immunodeficiency virus (HIV)-seropositive hosts was investigated in a cross-sectional study. Oral and esophageal brushings from individuals scheduled for esophagogastroscopy (53 HIV-positive and 61 age-matched HIV-negative patients) were tested for the presence of HPV DNA by a consensus L1 polymerase chain reaction assay. HPV DNA was detected in esophageal brushings of 9 (17%) of the 53 HIV-seropositive patients and 0 of the 61 HIV-negative individuals. HPV-16 DNA was the most frequently detected. No proliferative mucosal lesion was noted in individuals with HPV-positive esophageal brushings. Cytological smears were done for 6 of the 9 patients with HPV-positive esophageal brushings, and epithelial atypia was recorded for 1. HIV infection and a history of genital herpes were strong independent predictors of HPV, suggesting that HPV is transmitted sexually in the esophagus.

Risk factors for oral human papillomavirus in adults infected and not infected with human immunodeficiency virus.

BACKGROUND AND OBJECTIVES: To investigate in a cross-sectional study the determinants of oral human papillomavirus infection in 287 individuals who are sexually active. GOAL: To assess prevalence as well as risk factors for oral human papillomavirus infection. STUDY DESIGN: One hundred seventy-eight human immunodeficiency virus-seropositive (158 men and 20 women) and 109 human immunodeficiency virus-negative (73 men and 36 women) individuals were recruited consecutively from sexually transmitted disease-human immunodeficiency virus clinics and gastrointestinal endoscopy clinics. Oral brushings were tested with the L1 consensus polymerase chain reaction assay for human papillomavirus detection. RESULTS: Human papillomavirus DNA was detected in 32 (11.2%) of 287 individuals. Associated with oral human papillomavirus infection on univariate analyses were human immunodeficiency virus infection (odds ratio, 6.9; 95% confidence interval, 2.0-23.2), homosexuality (odds ratio, 3.7; 95% confidence interval, 1.5-9.4), unprotected oral sex (odds ratio, 5.5; 95% confidence interval, 1.6-18.4), syphilis (odds ratio, 2.5; 95% confidence interval, 1.1-6.3), gonorrhea (odds ratio, 4.2; 95% confidence interval, 1.9-9.1), Chlamydia trachomatis (odds ratio, 4.4; 95% confidence interval, 1.8-10.6), and genital herpes (odds ratio, 2.9; 95% confidence interval, 1.3-6.5). Human immunodeficiency virus infection and C. trachomatis were independently predictive of human papillomavirus infection in multivariate stepwise logistic regression.

Insular (poorly differentiated) carcinoma of the thyroid: an ultrastructural and immunocytochemical study of two cases.

Two cases of pure insular (poorly differentiated) carcinoma of the thyroid are reported, with emphasis on their ultrastructure. Notwithstanding their solid/primitive histologic character, a high degree of structural organization and differentiation was present at the submicroscopic level, namely a highly developed cytosecretory apparatus and numerous abortive/rudimentary follicles. A prominent inclusion/dot-like pattern (often paranuclear) of thyroglobulin immunoreactivity was observed, ultrastructurally corresponding to the following features: a) abortive/rudimentary follicular lumina with abundant periluminal dense bodies, and with varying amounts of colloid and microvilli, both at the intercellular and intracellular level; b) large inclusions of fibrillar/lamellar or finely granular material within dilated cisternae of endoplasmic reticulum and possibly of lysosomal nature as well, likely reflecting altered production and/or storage of thyroglobulin substrate. One tumor had many cytophenotypical attributes ascribed to differentiated papillary carcinoma (PC), whereas the other tumor was more analogous to differentiated follicular carcinoma (FC). The present study supports the concept that the insular pattern is a common pathway of dedifferentiation for follicular cell neoplasia of both PC and FC types, yet with maintenance of most of their respective cytophenotypical features, and with evidence of a high level of differentiation/maturation at the submicroscopic level.

Metastasis to the optic nerve: clinicopathological correlations.

OBJECTIVE: To describe the clinical, radiologic and histopathological features of two cases of carcinoma metastatic to the optic nerve with different pathways of spread. DESIGN: Chart review. SETTING: Oncology clinic in Montreal. PATIENTS: One patient previously treated for breast carcinoma and one patient previously treated for small-cell carcinoma of the lung. RESULTS: The patient with breast carcinoma was found to have an elevated mass involving her right optic nerve head. This finding was confirmed by B-scan ultrasonography. The other patient initially presented with left retinal metastasis and subsequently manifested massive secondary involvement of the ipsilateral optic nerve, documented by computed tomography. Both patients were initially treated with radiotherapy to the eye and orbit, but postmortem histopathological study showed that this treatment had little effect on the tumour. CONCLUSIONS: The histopathological observations suggest that if radiotherapy is to be used in the treatment of metastasis to the optic nerve, the dosage of radiation should be higher than that recommended for the treatment of choroidal metastasis.

Liver angiomyolipoma: classic and unusual presentations.

Two cases of liver angiomyolipoma (AML) are presented. The first case has the classical imaging findings previously reported. The second case has no fat content on the various imaging modalities. AML should probably be included in the differential diagnosis of any hypervascular lesion of the liver. Preoperative diagnosis with core biopsy is possible.