Novel mixed integer optimization sparse regression approach in chemometrics.

Sparse mathematical modelling plays an increasingly important role in chemometrics due to its interpretability and prediction power. While many sparse techniques used in chemometrics rely on L1 penalization to create sparser models, Mixed Integer Optimization (MIO) achieves sparsity by imposing constraints directly in the model. In this paper, we develop an intuitive and flexible robust sparse regression framework using MIO. We use constraints and penalization to achieve sparsity and robustness respectively. We test and compare results with those obtained using other techniques generating sparser models such as LASSO and sparse PLS. We also use PLS as a baseline to compare predictive performance. We use a LIBS data set of certified reference materials (CRM) of various mineral ores to illustrate the framework using different objective functions. The MIO framework proposed improves accuracy, sparsity and robustness vs. LASSO and SPLS. MIO achieves an average R2 higher than other methods on average by at least 10.6%. Robust MIO approach also improves interpretability. It also uses 4.3 variables on average while LASSO and SPLS use 16.1 and 805.8 respectively. We also illustrate how interpretability can help build better models through examples derived from the data sets used. When adding noise to the signal, MIO achieves an R2 of 0.69 on average when all models have negative R2 values. The MIO framework proposed is versatile and could be used in other chemometrics applications.

Synthesis of high-purity precipitated calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. <90 mass% as CaCO3). In this study, we used the insight gained from our previous work and developed an indirect aqueous CaS carbonation process for the production of high-grade CaCO3 (i.e. >99 mass% as CaCO3) or precipitated calcium carbonate (PCC). The process used an acid gas (H2S) to improve the aqueous dissolution of CaS, which is otherwise poorly soluble. The carbonate product was primarily calcite (99.5%) with traces of quartz (0.5%). Calcite was the only CaCO3 polymorph obtained; no vaterite or aragonite was detected. The product was made up of micron-size particles, which were further characterised by XRD, TGA, SEM, BET and true density. Results showed that about 0.37 ton of high-grade PCC can be produced from 1.0 ton of gypsum waste, and generates about 0.19 ton of residue, a reduction of 80% from original waste gypsum mass to mass of residue that needs to be discarded off. The use of gypsum waste as primary material in replacement of mined limestone for the production of PPC could alleviate waste disposal problems, along with converting significant volumes of waste materials into marketable commodities.

Conversion of calcium sulphide to calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

The production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste can be achieved by thermally reducing the waste into calcium sulphide (CaS), which is then subjected to a direct aqueous carbonation step for the generation of hydrogen sulphide (H2S) and CaCO3. H2S can subsequently be converted to elemental sulphur via the commercially available chemical catalytic Claus process. This study investigated the carbonation of CaS by examining both the solution chemistry of the process and the properties of the formed carbonated product. CaS was successfully converted into CaCO3; however, the reaction yielded low-grade carbonate products (i.e. <90 mass% as CaCO3) which comprised a mixture of two CaCO3 polymorphs (calcite and vaterite), as well as trace minerals originating from the starting material. These products could replace the Sappi Enstra CaCO3 (69 mass% CaCO3), a by-product from the paper industry which is used in many full-scale AMD neutralisation plants but is becoming insufficient. The insight gained is now also being used to develop and optimize an indirect aqueous CaS carbonation process for the production of high-grade CaCO3 (i.e. >99 mass% as CaCO3) or precipitated calcium carbonate (PCC).

[Screening strategy and diagnostic criteria for gestational diabetes. Proposals of the GGOLFB]. / Stratégie de dépistage et critères diagnostiques du diabète gestationnel. Propositions du GGOLFB.

For nearly 50 years, the strategy of screening and the diagnostic criteria for gestational diabetes have been the subject of endless controversies. They differ between countries and from one center to another, mainly because of the lack of hard data allowing to define glycemic thresholds at which a therapeutic management is needed. Recently, a large observational study has demonstrated the existence of a robust relationship between maternal blood sugar and several fetomaternal perinatal complications. This relationship is linear, with no clear threshold that would define gestational diabetes unambiguously. Meanwhile, two randomized intervention trials have shown that the therapeutic management of mild gestational diabetes was associated with improved perinatal outcomes. Based on these data, the " International Association of Diabetes and Pregnancy Study Group "(IADPSG) released new recommendations on screening methods and diagnostic criteria for gestational diabetes. Although already endorsed by several international associations and implemented in some countries, these recommendations still raise questions and criticisms. This is why the "Groupement des Gynécologues Obstétriciens de Langue Française de Belgique " (GGOLFB) organized a meeting between diabetologists and gynecologists which allowed to reach a consensus on the strategy that we intend to implement in our respective centers. The purpose of this paper is to briefly overview the recent advances in gestational diabetes and more particularly to make our key conclusions known to the medical community. This will enable the standardization of the management of gestational diabetes in the French-speaking part of Belgium.

[Screening strategy and diagnostic criteria for gestational diabetes. Proposals of the GGOLFB]. / Stratégie de dépistage et critères diagnostiques du diabète gestationnel. Propositions du GGOLFB.

For nearly 50 years, the strategy of screening and the diagnostic criteria for gestational diabetes have been the subject of endless controversies. They differ between countries and from one center to another, mainly because of the lack of hard data allowing to define glycemic thresholds at which a therapeutic management is needed. Recently, a large observational study has demonstrated the existence of a robust relationship between maternal blood sugar and several fetomaternal perinatal complications. This relationship is linear, with no clear threshold that would define gestational diabetes unambiguously. Meanwhile, two randomized intervention trials have shown that the therapeutic management of mild gestational diabetes was associated with improved perinatal outcomes. Based on these data, the "International Association of Diabetes and Pregnancy Study Group" (IADPSG) released new recommendations on screening methods and diagnostic criteria for gestational diabetes. Although already endorsed by several international associations and implemented in some countries, these recommendations still raise questions and criticisms. This is why the "Groupement des Gynécologues Obstétriciens de Langue Française de Belgique" (GGOLFB) organized a meeting between diabetologists and gynecologists which allowed to reach a consensus on the strategy that we intend to implement in our respective centers. The purpose of this paper is to briefly overview the recent advances in gestational diabetes and more particularly to make our key conclusions known to the medical community. This will enable the standardization of the management of gestational diabetes in the French-speaking part of Belgium.

Physicochemical properties and nutritional quality of raw cereals for newly weaned piglets.

The digestibility of the starch component of raw cereals in newly weaned piglets is highly variable. Reasons for this must be elucidated if the most suitable cereals are to be used. A novel approach was employed, which consisted of assessing the physicochemical properties (rapid visco analysis, water absorption and solubility indices, particle size distribution and in vitro amylolytic digestion) of eight raw cereals contained within piglet diets and subsequently relating this in vitro data to the biological responses of weaned piglets. Trial 1 examined soft and hard wheat, trial 2 - soft wheat, barley, rye and triticale, and trial 3 - soft wheat, naked oats, whole oats and maize. The initial observation was that in vitro testing prior to animal trials is recommended in nutritional evaluation since it indicated fundamental differences between raw cereals, such as for example the levels of endogenous amylase in wheat. Starch and nitrogen digestibility differed between cereals (apparent digestibility coefficients at the 0.5 site of the small intestine ranged from 0.10 to 0.69 for starch and from 0.17 to 0.68 for nitrogen). There is also a probable relationship between the coefficients of ileal apparent starch digestibility, at approximately halfway from the gastric pylorus to the ileocaecal valve, and the presence of endogenous amylase (mean values of 0.53 and 0.62 in trials 2 and 3, respectively, for the higher amylase wheat; 0.38 for the low-amylase wheat used in trial 1). This additional variable (i.e. the unforeseen presence of endogenous amylase) in wheat made it more difficult to draw a firm conclusion about the nutritional suitability of the different cereals. All raw-cereal diets caused atrophy of the villi during the initial week following weaning, but the soft wheat was associated with the highest comparative villi height and might therefore be considered the best of all raw cereals in minimising the post-weaning growth check. For wheat, this might also suggest a possible interaction between villus architecture and endosperm texture in the immediate post-weaning period.

Physicochemical changes to starch granules during micronisation and extrusion processing of wheat, and their implications for starch digestibility in the newly weaned piglet.

Two trials were performed to assess changes in the physicochemical properties of precisely processed (micronised v. extruded) wheats, prior to inclusion in piglet diets. The in vitro data obtained were subsequently related to biological responses of newly weaned piglets over 14 days. The effects of the severity of micronisation (Trial 1) or extrusion (Trial 2) on the nutritional value of two wheats (varying in endosperm texture) were examined. Extrusion, in contrast to micronisation, drastically disrupted the structural properties of wheat starch granules through melting of crystallites and macromolecular degradation of starch polysaccharides. These structural changes strongly improved the hydration characteristics of starch and its digestibility. The amount of starch digested in vitro was approximately 0.20, 0.70 and 0.90 for the unprocessed, micronised and extruded samples, respectively. This enhanced in vitro digestibility correlated well with, and helped to explain, the significant improvement in the apparent digestibility of starch at both the 0.5 region (mean coefficients for extruded wheat were 0.869 and 0.959 v. raw 0.392; P = 0.017) and 0.75 region (extruded 0.973 v. raw 0.809; P = 0.009) of the small intestine, when compared with piglets fed an unprocessed wheat diet. Extrusion and, to a lesser extent, micronisation lessened the reduction in apparent starch digestibility on day 4 post-weaning, typically seen at the 0.5 intestinal region in piglets fed an unprocessed wheat diet. Processing variables influenced both in vitro and in vivo data, with for instance, a positive relationship between specific mechanical energy (SME) input during extrusion and starch digestibility at the 0.5 region. The higher digestibility coefficient observed at the 0.5 region for the high SME diet suggests enhanced digestion and more rapid release of starch. However, it remains to be seen whether a diet containing rapidly digestible, as opposed to slowly digestible, starch is more beneficial for piglets. This rate of starch breakdown in the piglet is an important finding, which may have implications in helping to alleviate the post-weaning growth check, particularly in the absence of in-feed antibiotic growth promoters. Processing did not appear to offer any benefit over unprocessed wheat with regard to daily live-weight gain or the apparent digestibility of nitrogen in the small intestine over the 14-day period. Based on the enhanced in vivo starch digestibility, performance might be improved over a longer period, although future studies are required to confirm this. Precise processing variables for raw materials must be stated in all animal trials.

Direct and indirect identification of the formation of hydroxyaluminosilicates in acidic solutions.

Morin-aluminium fluorescence and membrane filtration were successfully applied to the indirect identification of the formation of hydroxyaluminosilicates (HAS) in acidic solutions of varying pH and of known concentrations of aluminium (Al) and silicic acid (Si(OH)(4)). It was proven to be especially useful in providing evidence of the strong competition between Si(OH)(4) and Al(OH)(3) to condense with hydroxyaluminium templates to form HAS in preference to Al(OH)(3(s)). The aggregation and stability of HAS and Al(OH)(3(s)) were dependent upon both the pH and the [Al] of the solution. The applicability of these indirect techniques was confirmed using the direct observation of HAS in solution by atomic force microscopy (AFM). AFM was also a powerful tool in providing valuable information on the morphology of colloidal HAS of various structures and stoichiometries. The results have provided further confirmation of both the mechanism of HAS formation and the form and stability of HAS in solution. This information is essential to our understanding of the biological availability and hence toxicity of Al in biota, including man.

In vitro cellular responses from sheep draining lymph node cells after subcutaneous inoculation with Salmonella abortusovis.

Salmonella abortusovis infection leads to ovine abortion. The basis for immunity against this infection is unknown. Immune responses were studied from prescapular lymph node (PSLN) cells of sheep infected with either a subcutaneous inoculation of virulent (15/5) or a vaccine (Rv6) strain and compared with those of uninfected sheep. PSLN cell phenotypes were characterized by immunofluorescence staining associated with flow cytometry. The in vitro responses were analysed using the PSLN cell proliferative response to several antigens, their secreted IL-2-like activities and their level of nitric oxide (NO) release. The phenotype analyses showed that the CD4(+)-T cell percentages decreased whereas B and MHC-II+ cell percentages increased in the infected sheep. This phenomenon occurred earlier for the virulent strain. The PSLN enlargement was greater and in vitro proliferation more frequent for the sheep infected with the virulent strain compared with the vaccine-infected ones. Proliferation occurred as a result of cell exposure to whole killed bacteria or to the cell wall fraction from S abortusovis but not to the homologous lipopolysaccharide. The secreted IL-2-like activities increased in parallel. The mitogenic response to concanavalin A decreased for infected sheep. For infected sheep, the level of NO release was maximal at the beginning of the infection. It was downregulated by in vitro exposure to S abortusovis antigens but remained unchanged for concanavalin A. NO release was not detected in uninfected sheep. This preliminary investigation provided some keys to the understanding of ovine response to S abortusovis infection and suggested that it shared common features with the mouse immune response.

Detection of illegal clenbuterol use in calves using hair analysis. Application in meat quality control.

This study describes a real-life situation involving nine calves, 106 days old, which received oral doses of clenbuterol administered through their milk. Powdered skim milk containing 6.7 mg of clenbuterol was given daily for fifteen days under supervision (i.e. 100 mg per calf for the whole study) to seven calves, and two calves did not receive the drug. Hair samples and urine were taken and subjected to analysis by gas chromatography-mass spectrometry. Hairs were pulverized in a ball mill and 100 mg were incubated in a mildly acidic medium. The sample clean-up procedure involved solid-phase extraction on C18 cartridges. Metoprolol was used as the internal standard for quantitation, after formation of methylboronate derivatives. The calibration curve for clenbuterol in hair was linear in the range 20-5000 pg/mg. The limit of detection of clenbuterol was 16 pg/mg in hair and 0.14 ng/ml in urine. Hair testing was effective after 7-10 days of treatment, and concentrations were in the range of 20 to 4372 pg/mg. Urinalysis can detect clenbuterol for up to two weeks after discontinuation of the drug. Conveniently, this is around the time when the hair samples attain greatest sensitivity. Therefore, the combination of the two matrices appears to be the method of choice for testing for the illegal use of drugs in meat-producing animals.

Flow cytometric analysis of the reactivity of workshop monoclonal antibodies on sheep lymph node cells, after infection with Salmonella abortusovis.

Of the 302 monoclonal antibodies included in the Third Workshop on Ruminant Leukocyte Antigens, 167 have been tested for their reactivity on uninfected and Salmonella-infected sheep lymph node leukocytes using FACS analysis. Only 47 of them showed specificities which could be related to those of some control monoclonal antibodies, such as the anti-CD5, anti-Ig light chain and anti-MHC Class II monoclonal antibodies.

[Clinical development of acute noise-induced acoustic trauma. An evaluation of a study of 250 cases]. / Evolution clinique des traumatismes sonores aigus. Bilan d'une étude de 250 cas.

Traumatic damage on Cochlea (250 cases) induced by assault gun (F.A.M.A.S.) consists in tinitus and hearing impairement on 6000 Hz. Noise's effects are specific to one Cochlea. Dissociated developments of both tinitus and hearing loss show that their anatomical sites are different. Acoustic injury entails definitive haire cells lesions, cellular biochemical and vascular changes. The treatment that reestablishes or raises cochlear blood flow entails recovery in 80% of cases provided that it is given within 48 hours after the trauma.

[Otorhinolaryngologic manifestation of chronic atrophic polychondritis. Apropos of a case]. / Les manifestations ORL de la polychondrite chronique atrophiante. A propos d'une observation.

Approximately 300 cases of relapsing polychondritis have been reported. The etiology of the disease is still unknown. The pathologist finds a fibrous degeneration of the cartilage of the body. A case relapsing polychondritis is presented and the otolaryngological disorders of the disease are reviewed.

Immunoglobulin-bound lipoproteins (Ig-Lp) as markers of familial hypercholesterolemia, xanthomatosis and atherosclerosis.

In autoimmune hyper- or dislipidemia secondary to a monoclonal antilipoprotein gammapathy, immunoglobulin-lipoprotein (Ig-Lp) complexes are found in the circulating blood. In order to determine their possible significance in common types of hyperlipidemia we compared the Ig-Lp content of sera from 98 healthy blood donors and 155 outpatients from a Lipid Clinic, including 91 cases of hypercholesterolemia (55 familial and 36 non-familial), 15 cases of hypertriglyceridemia, 20 cases of mixed hyperlipidemia and 29 miscellaneous cases. Detection of the Ig-Lp was performed by an ELISA technique with polyclonal affinity purified anti-LDL + HDL as capture antibodies and peroxidase-labeled anti-Ig antibodies specific for IgA, IgG, IgM heavy chains as indicators. Two cases of monoclonal gammapathy (one IgA K and one IgG L) with dislipidemia served as positive controls for the test. IgG, IgA and IgM Lp were found in the sera of the blood donors, in very small quantities when compared with the monoclonal gammapathy cases. All three types of Ig-Lp were also found in the different hyperlipidemic populations studied. When blood donors were compared to hyperlipidemic patients, no difference was observed for IgG Lp. A significant increase in IgM Lp was found in patients with familial hypercholesterolemia (P less than 0.01). An increase in IgA Lp was also found in hypercholesterolemia, familial or not (P less than 0.01), and in patients with corneal arcus (P less than 0.0001), ischaemic disease (P less than 0.01), tendon xanthomas (P less than 0.05) or xanthelasma (P less than 0.05). Furthermore, in a group of 18 paired parents from 9 different families, positive interparent correlations were found for IgM Lp (r = 0.78; P = 0.013) and IgG Lp (r = 0.69; P = 0.038). Therefore IgM Lp may be markers for subpopulations of familial hypercholesterolemia, and IgA Lp markers for the risk of atherosclerotic ischemic disease and deposition of lipids in the cornea. It may be (1) that natural clones of autoanti-lipoprotein antibodies are responsible for the minute quantities of Ig-Lp found in normal people; (2) that the marked development of one of these clones is the cause of autoimmune hyper- or dyslipidemia and xanthomatosis associated with monoclonal gammapathy; (3) that the limited development of a clone produces the Ig-Lp particles found in hypercholesterolemic patients; (4) that there are types of Ig-Lp particles (IgA Lp) that may be harmful for tissues independently of hypercholesterolemia.

[ORL selection of French astronauts]. / La sélection O.R.L. des spationautes français.

Strict criteria were used, under the control of the Centre National d'Etudes Spatiales (CNES) to select seven French spationautes for future participation in human cargo space flights to take place between 1987-1991 within the framework of the scientific missions of the USA and USSR. Data and results of the clinical O.R.L. examinations and vestibular tests conducted during medical operations of this selection procedure are presented.

Residual vascular risk of discontinued oral contraception. Role of antibodies to synthetic sex hormones.

Recent epidemiological data indicate that the risk of thromboembolic disease associated with oral contraception (OC) may persist after discontinuation of the drug. It was demonstrated on the other hand that antibodies to sex steroid hormones which develop in OC users, were significantly correlated with the incidence of thrombosis. It is well known that antibodies may persist years after the antigenic stimulation. So it was of interest to see if the eventual occurrence of thrombosis in ex-users might be correlated with the presence of anti-sex steroid antibodies remaining after stopping OC. Thirty-eight women with thrombosis on OC and positive antibody levels, who were required to stop the pill, were followed for periods ranging from 1 to 10 years. No disappearance of anti-ethinyl-estradiol antibodies (anti-EE ab) was observed except for 2 cases. On the other hand, 109 patients with thrombosis either current- (50), past- (29), or never-users (30) of OC were compared to 102 controls of similar groups. Results indicate that the levels of anti-EE ab, and the percentage of women who had anti-EE ab, were similar in those who experienced thrombosis either in the course of OC or after discontinuation. A significant difference was observed between both cases who were current- or ex-users and their controls.

Quantitative determination of free cholesterol and cholesteryl esters in skin biopsies.

A new technique is described for the determination of cholesterol in skin biopsies which is sensitive, practical and reproducible. The determination of cutaneous cholesterol is of clinical interest, because of its correlation with the degree of atherosclerosis. There was no correlation found between the blood total cholesterol and total triglycerides, and cholesterol and triglycerides determined in the skin biopsies. Determinations were carried out on several normal subjects, 7 long-distance runners, 34 hyperlipidemic patients. There was a significant increase with age of total skin cholesterol in the normal subjects, the values obtained with the long-distance runners had a tendency to be somewhat lower. All the patients investigated had higher cholesterol values than the normal controls or the sportsmen. This technique can be used therefore as a diagnostic tool to detect pathologies of skin lipids, or of tissue lipid metabolism, as for example in normolipidemic patients presenting corneal arcus or xanthelasmas.