Cardio-metabolic risk factors in polycystic ovary syndrome

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Nova Science Publishers in Cardiometabolic Diseases and Risk Factors in July 2020.Available online: https://novapublishers.com/shop/cardiometabolic-diseases-and-risk-factors/acceptedVersio

Vitamin D and Human Reproduction

Vitamin D is one of the steroid hormones. The precursor of vitamin D, 7-dehydrocholesterol, which is an intermediary for cholesterol pathway, is available in the skin. Ultraviolet B (UVB) radiation makes the transformation of 7-dehydrocholesterol to provitamin D3, which automatically isomerizes to cholecalciferol (vitamin D3). Vitamin D3 is secreted into blood circulation and carried by the vitamin D–binding protein (VDBP). Around 80–90% of vitamin D is from sunlight-derived production in the skin. A little amount of vitamin D is also extracted from foods and/or additional supplementation. Vitamin D has been well known for its function in maintaining calcium and phosphorus homeostasis and promoting bone mineralization. Accumulating evidence from animal and human studies suggests that vitamin D also modulates reproductive processes in women and men and is involved in many functions of the reproductive system. Vitamin D receptor (VDR) and vitamin D–metabolizing enzymes are found in reproductive tissues of women and men. This chapter presents an up-to-date review for describing the function of vitamin D in female reproduction throughout reproductive ages from menarche to menopause, during pregnancy and lactation, and some disorders affecting women and also the role of vitamin D applied to male fertility

Switching Focus in New Business Enterprise:From a Survival to a Profit Orientation

What objective should an entrepreneur focus on when starting a new business enterprise? Both a survival orientation and a profit one are important for the continuity of the new venture, but a survival focus is key in the hazardous early months or even years. In this thesis, I identify the conditions under which an entrepreneur should switch from a survival orientation, where the venture’s likelihood of survival is more critical, to a profit orientation where the venture’s profit instead is more critical. I accomplish this task by determining the optimal time to switch from a survival to a profit orientation based on maximizing the entrepreneur’s accumulated utility over a given time horizon. At each time period, the utility is positively associated with the amount of added value to the business venture that entrepreneur owns and manages, and the time horizon is determined by the time at which the entrepreneur’s venture exit – for instance, it is being sold. That added value contains a planned portion (e.g., due to what the entrepreneur can control) and an unplanned portion. The portion of a firm’s added value that is unplanned depends on the entrepreneur’s orientation, whereby, at any time period, the expected added value and its variation are considered to be low under a survival orientation, but they are considered to be high under a profit orientation. I use an approach from the economics literature, known as the LEN model, where the use of an exponential utility function (E), a linear relationship between the utility and random effects (L), and normality of those random effects (N) allow me to transfer the probabilistic objective function into a certainty equivalent that makes the problem tractable. The decision framework and its resulting findings suggest two environmental and two entrepreneurial characteristics that influence the existence of a time at which to switch orientation from survival to profit. Based on these characteristics, I derive sixteen scenarios and discussed some of the necessary conditions for the existence of a switching time. I find that it is not straightforward to determine whether the orientation switch should be delayed or expedited as business environments (or entrepreneurial types) are compared. I thus further develop my analysis by adding more structure to the functional forms that underline the behavior of how the mean of and variation in the firm’s added value are regulated over time, as well as for the risk propensity of the firm’s owner. This exercise allow me to study the conditions under which the switching time should be delayed or expedited, and to numerically investigate the behavior of a firm’s total valuation as changes occur in key model parameters. I use franchising as an application of the sensitivity analysis I perform to identify whether a change in a model parameter (everything else being equal) should delay or expedite the orientation switch. Based on this application, I would advise entrepreneurs to switch their orientation later if they go into entrepreneurship as a franchisee rather than as a franchisor. A simulation analysis allows me to further propose a positive relationship between a firm’s total valuation and the planned added value by the entrepreneur to that firm. That analysis also suggests a positive relationship between a firm’s total valuation and the expected unplanned-added-value growth under a profit orientation, but a negative relationship under a survival orientation. Further, I find a positive relationship between total valuation and the variation in unplanned-added-value growth under a survival orientation, but a negative relationship under a profit orientation. One of the key challenges that have been raised for future entrepreneurship research is how to define an entrepreneur’s objective function. My thesis contributes to this debate by suggesting that, in the early years, there should be an orientation switch, that is, sequentially as opposed to simultaneously consider both survival and profit maximization. My thesis also contributes to the literature on firm growth because using risk-return tradeoffs to characterize the two orientations is unique in the entrepreneurial context, and so is the consideration of a sequential use of these orientations to study firm added value over time and the resulting accumulated total valuation. Characterizing each of the two orientations – survival and profit – based on risk-return tradeoffs and linking these orientations to firm growth open up new avenues for research in entrepreneurial decision making

The prevalence of idiopathic hirsutism and polycystic ovary syndrome in the Tehran Lipid and Glucose Study

<p>Abstract</p> <p>Background</p> <p>There is no clear and contemporaneous method for screening of idiopathic hirsutism (IH) and polycystic ovary syndrome (PCOS) at the community level and current estimates regarding their prevalence are limited. We aimed to ascertain the prevalence of IH and PCOS in a randomly selected sample of reproductive aged female participants of the Tehran Lipid and Glucose Study (TLGS).</p> <p>Methods</p> <p>One thousand and two women, aged 18-45 years, were randomly selected from among reproductive aged women who participated in the TLGS. Those women with either hirsutism or menstrual dysfunction were assessed for biochemical hyperandrogenemia; whereas those participants with hirsutism per se were further assessed for subclinical menstrual dysfunction. PCOS were diagnosed using the National Institute of Health (NIH) criteria. IH was defined as hirsutism without clinical or sub clinical menstrual dysfunction or biochemical hyperandrogenemia (BH).</p> <p>Results</p> <p>The mean ± SD of age of study population was 29.2 ± 8.7 years. Estimated prevalences of idiopathic hirsutism and pure menstrual dysfunction were 13.0% (95% CI: 10.9%-15.1%) and 1.5%(95% CI: 1.1%-1.9%), respectively. The prevalence of PCOS was 8.5% (95% CI: 6.8% - 10.2%); more than one third of these cases would possibly have remained undiagnosed or misdiagnosed, had we not assessed them for subclinical menstrual dysfunction or biochemical hyperandrogenemia.</p> <p>Conclusions</p> <p>These data from a large representative and non selected population of women confirm the concept that IH and PCOS are the two most common gynecological endocrinopathies among reproductive aged women. The estimated prevalence of these conditions is highly influenced by their screening methods at the community level.</p

Isolated Maternal Hypothyroxinemia and adverse pregnancy outcomes : A systematic review

acceptedVersio

Investigating the clinical utility of the Anti-Mullerian Hormone Testing for the prediction of age at menopause and assessment of functional ovarian reserve : A practical approach and Recent Updates

publishedVersio

Maternal hyperandrogenism is associated with a higher risk of type 2 diabetes mellitus and overweight in adolescent and adult female offspring : a long‑term population‑based follow‑up study

Author’s accepted manuscript (postprint).This is an Accepted Manuscript of an article published by Springer in Journal of Endocrinological Investigation on 19/01/2022.Available online: https://link.springer.com/article/10.1007/s40618-021-01721-2acceptedVersio

Is There any Association between Age at Menarche and Risk of Metabolic Syndrome? The Tehran Lipid & Glucose Study

publishedVersio

Metformin therapy before conception versus throughout the pregnancy and risk of gestational diabetes mellitus in women with polycystic ovary syndrome : a systemic review, meta-analysis and meta-regression

publishedVersio