Assessing Methods for Evaluating the Number of Components in Non-Negative Matrix Factorization.

Non-negative matrix factorization is a relatively new method of matrix decomposition which factors an m×n data matrix X into an m×k matrix W and a k×n matrix H, so that X≈W×H. Importantly, all values in X, W, and H are constrained to be non-negative. NMF can be used for dimensionality reduction, since the k columns of W can be considered components into which X has been decomposed.

Diabetes, medical comorbidities and couple fecundity.

Study Question: What is the relationship between couple's health and fecundity in a preconception cohort?

Summary Answer: Somatic health may impact fecundity in men and women as couples whose male partner had diabetes or whose female partner had two or more medical conditions had a longer time-to-pregnancy (TTP).

What Is Already Known: The impact of somatic health on human fecundity is hypothesized given the reported declines in spermatogenesis and ovulation among individuals with certain medical comorbidities.

Study Design, Size, Duration: A population-based prospective cohort study recruiting couples from 16 counties in Michigan and Texas (2005-2009) using sampling frameworks allowing for identification of couples planning pregnancy in the near future.

Urinary paracetamol and time-to-pregnancy.

Study Question: Is preconception urinary paracetamol (acetaminophen) associated with time-to-pregnancy (TTP)?

Summary Answer: Higher urinary paracetamol concentrations among male partners were associated with a longer TTP.

What Is Known Already: Paracetamol is a commonly used analgesic among women and men of all ages. As metabolites of select chemicals used in the manufacturing of polyurethane foam, dyes and various industrial products, as well as a common medicinal product, paracetamol and its primary metabolite p-aminophenol, are ubiquitous in the environment.

Time-to-Pregnancy Associated With Couples' Use of Tobacco Products.

Introduction: Previous studies suggest female smoking increases time-to-pregnancy (TTP), a couple-dependent reproductive outcome, while associations with male smoking are more ambiguous. Furthermore, despite small increases in smokeless tobacco use in the United States, no prior study has evaluated TTP among smokeless tobacco users.

Methods: Using population-based sampling in 16 counties in Michigan and Texas, 501 couples discontinuing contraception to become pregnant were followed until positive pregnancy test or 12 months of trying.

Lifestyle and pregnancy loss in a contemporary cohort of women recruited before conception: The LIFE Study.

Objective: To estimate pregnancy loss incidence in a contemporary cohort of couples whose lifestyles were measured during sensitive windows of reproduction to identify factors associated with pregnancy loss for the continual refinement of preconception guidance.

Design: Prospective cohort with preconception enrollment.

Setting: Sixteen counties in Michigan and Texas.

Persistent organic pollutants and pregnancy complications.

We sought to investigate the relationship between maternal preconception exposures to persistent organic pollutants (POPs) and pregnancy complications, gestational diabetes (GDM) and gestational hypertension. Data from 258 (51%) women with human chorionic gonadotropin (hCG) confirmed pregnancies reaching ≥24weeks gestation, from a prospective cohort of 501 couples who discontinued contraception to attempt pregnancy, were analyzed. Preconception concentrations of 9 organochlorine pesticides (OCPs) and 10 polybrominated diphenyl ethers (PBDEs) were quantified in serum.

Pre-pregnancy maternal exposure to polybrominated and polychlorinated biphenyls and gestational diabetes: a prospective cohort study.

Background: While several studies have shown an association between environmental pollutants and diabetes among non-pregnant adults, few studies have prospectively assessed the association among pregnant women. We estimated the association between maternal pre-pregnancy levels of a polybrominated biphenyl (PBB 153) and 36 polychlorinated biphenyls (PCBs) with gestational diabetes (GDM).

Methods: Data are from women (18-40 years) participating in a prospective cohort who achieved pregnancy lasting ≥24 weeks gestation and completed monthly pregnancy journals (n = 258).

Parental urinary biomarkers of preconception exposure to bisphenol A and phthalates in relation to birth outcomes.

Background: Bisphenol A (BPA) and phthalates are ubiquitous non-persistent endocrine disrupting chemicals whose relation with infant birth size is not clearly understood.

Methods: We examined associations between maternal and paternal preconception urinary concentrations of total BPA and 14 phthalate metabolites and birth size for 233 infants. Multiple linear regression models were used to estimate parental quartiles of BPA and phthalates in relation to birth weight, length, head circumference, and ponderal index with separate models run for each parent adjusting for age, smoking, body mass index, education, alcohol, parity, and creatinine.

Clustering of retrospectively reported and prospectively observed time-to-pregnancy.

Purpose: Given reportedly high clustering but limited validity of retrospectively reported time-to-pregnancy (TTP), we assessed within-woman clustering for retrospectively reported TTPs alone and including gold-standard prospectively observed TTPs among women with 2 or more retrospectively reported and 1 or more prospectively observed TTPs. We further investigated whether past trying times inform future trying time among women with 1 or more retrospectively reported and 1 or more prospectively observed TTPs.

Methods: Five hundred one couples attempting pregnancy were prospectively observed until human chorionic gonadotropin pregnancy or 12 months of trying.

Birth outcomes and background exposures to select elements, the Longitudinal Investigation of Fertility and the Environment (LIFE).

Evidence suggests that trace exposures to select elements may increase the risk for adverse birth outcomes. To investigate further, we used multiple regression to assess associations between preconception parental exposures to Pb, Cd, and total Hg in blood, and 21 elements in urine, with n=235 singleton birth outcomes, adjusted for confounders and partner's exposure. Earlier gestational age at delivery (GA) was associated with higher tertiles of urine maternal W (-1.

A prospective study of prepregnancy serum concentrations of perfluorochemicals and the risk of gestational diabetes.

Objective: To examine preconception serum concentrations of perfluorooctanoic acid (PFOA) and six other PFCs in relation to gestational diabetes (GDM) risk.

Design: Prospective cohort with longitudinal follow-up.

Setting: Not applicable.

Urinary concentrations of benzophenone-type ultraviolet radiation filters and couples' fecundity.

Concern has arisen about benzophenone (BP) ultraviolet (UV) radiation filters, given their use in sunscreen and personal-care products and their reported estrogenic and antiandrogenic activity. We recruited 501 couples who were discontinuing use of contraceptives in order to become pregnant for the Longitudinal Investigation of Fertility and the Environment (LIFE) Study (Michigan and Texas, 2005-2009). Couples provided urine specimens and completed daily journals until they either achieved pregnancy or had tried for 12 months.

Preconception maternal and paternal exposure to persistent organic pollutants and birth size: the LIFE study.

Background: Persistent organic pollutants (POPs) are developmental toxicants, but the impact of both maternal and paternal exposures on offspring birth size is largely unexplored.

Objective: We examined associations between maternal and paternal serum concentrations of 63 POPs, comprising five major classes of pollutants, with birth size measures.

Methods: Parental serum concentrations of 9 organochlorine pesticides, 1 polybrominated biphenyl (PBB), 7 perfluoroalkyl chemicals (PFCs), 10 polybrominated diphenyl ethers (PBDEs), and 36 polychlorinated biphenyls (PCBs) were measured before conception for 234 couples.

Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study.

Objective: To assess the relationship between environmental chemicals and couple fecundity or time to pregnancy (TTP).

Design: Prospective cohort.

Setting: Communities of targeted populations with reported exposure.

Higher urinary lignan concentrations in women but not men are positively associated with shorter time to pregnancy.

Phytoestrogens have been associated with subtle hormonal changes, although effects on fecundity are unknown. Our objective was to evaluate the association between male and female urinary phytoestrogen (isoflavone and lignan) concentrations and time to pregnancy (TTP) in a population-based cohort of 501 couples desiring pregnancy and discontinuing contraception. Couples were followed for 12 mo or until pregnancy.

Semen quality and time to pregnancy: the Longitudinal Investigation of Fertility and the Environment Study.

Objective: To assess semen parameters and couple fecundity as measured by time to pregnancy (TTP).

Design: Observational prospective cohort with longitudinal measurement of TTP.

Setting: Sixteen Michigan/Texas counties.

Persistent environmental pollutants and couple fecundity: the LIFE study.

Background: Evidence suggesting that persistent environmental pollutants may be reproductive toxicants underscores the need for prospective studies of couples for whom exposures are measured.

Objectives: We examined the relationship between selected persistent pollutants and couple fecundity as measured by time to pregnancy.

Methods: A cohort of 501 couples who discontinued contraception to become pregnant was prospectively followed for 12 months of trying to conceive or until a human chorionic gonadotrophin (hCG) test confirmed pregnancy.

Strength of default mode resting-state connectivity relates to white matter integrity in children.

A default mode network of brain regions is known to demonstrate coordinated activity during the resting state. While the default mode network is well characterized in adults, few investigations have focused upon its development. We scanned 9-13-year-old children with diffusion tensor imaging and resting-state functional magnetic resonance imaging.

Document classification for mining host pathogen protein-protein interactions.

Objective: Scientific findings regarding human pathogens and their host responses are buried in the growing volume of biomedical literature and there is an urgent need to mine information pertaining to pathogenesis-related proteins especially host pathogen protein-protein interactions (HP-PPIs) from literature.

Methods: In this paper, we report our exploration of developing an automated system to identify MEDLINE abstracts referring to HP-PPIs. An annotated corpus consisting of 1360 MEDLINE abstracts was generated.

A meta-analysis of functional neuroimaging studies of dyslexia.

Reading and phonological processing deficits have been the primary focus of neuroimaging studies addressing the neurologic basis of developmental dyslexia, but to date there has been no objective assessment of the consistency of these findings. To address this issue, spatial coordinates reported in the literature were submitted to two parallel activation likelihood estimate (ALE) meta-analyses. First, a meta-analysis including 96 foci from nine publications identified regions where typical readers are likely to show greater activation than dyslexics: two left extrastriate areas within BA 37, precuneus, inferior parietal cortex, superior temporal gyrus, thalamus, and left inferior frontal gyrus.