The Otterbein Miscellany - May 1969

https://digitalcommons.otterbein.edu/miscellany/1009/thumbnail.jp

Medieval menarche: changes in pubertal timing in the aftermath of the Black Death

OBJECTIVES: Bioarchaeological evidence suggests stature increased in males but decreased in females after the Black Death (1348-1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague. MATERIALS AND METHODS: Our sample comprises 74 adolescent females from St Mary Spital, London (1120-1540 CE) within the age range during which menarche occurs (10-25 years). They were assessed as being pre- or post-menarcheal and divided into three groups: Early Pre-Black Death (n=13), Late Pre-Black Death (n=38), and Post-Black Death (n=23). Changes in the ages of pre- and post-menarcheal females were assessed using Mann-Whitney tests. RESULTS: The average age of post-menarcheal females increased from the Early- to Late Pre-Black Death periods and declined after the Black Death. CONCLUSIONS: Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre- and post-menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology

Application of Pulsed Field Gel Electrophoresis to Determine γ-ray-induced Double-strand Breaks in Yeast Chromosomal Molecules

The frequency of DNA double-strand breaks (dsb) was determined in yeast cells exposed to γ-rays under anoxic conditions. Genomic DNA of treated cells was separated by pulsed field gel electrophoresis, and two different approaches for the evaluation of the gels were employed: (1) The DNA mass distribution profile obtained by electrophoresis was compared to computed profiles, and the number of DSB per unit length was then derived in terms of a fitting procedure; (2) hybridization of selected chromosomes was performed, and a comparison of the hybridization signals in treated and untreated samples was then used to derive the frequency of dsb

The Xpc gene markedly affects cell survival in mouse bone marrow

The XPC protein (encoded by the xeroderma pigmentosum Xpc gene) is a key DNA damage recognition factor that is required for global genomic nucleotide excision repair (G-NER). In contrast to transcription-coupled nucleotide excision repair (TC-NER), XPC and G-NER have been reported to contribute only modestly to cell survival after DNA damage. Previous studies were conducted using fibroblasts of human or mouse origin. Since the advent of Xpc−/− mice, no study has focused on the bone marrow of these mice. We used carboplatin to induce DNA damage in Xpc−/− and strain-matched wild-type mice. Using several independent methods, Xpc−/− bone marrow was ∼10-fold more sensitive to carboplatin than the wild type. Importantly, 12/20 Xpc−/− mice died while 0/20 wild-type mice died. We conclude that G-NER, and XPC specifically, can contribute substantially to cell survival. The data are important in the context of cancer chemotherapy, where Xpc gene status and G-NER may be determinants of response to DNA-damaging agents including carboplatin. Additionally, altered cell cycles and altered DNA damage signalling may contribute to the cell survival end point

Toward a Theory of Child Well-Being

Assuring the well-being of children has emerged over the past several decades as an important goal for health and social policymakers. Although the concept of child well-being has been operationalized and measured in different ways by different child-serving entities, there are few unifying theories that could undergird and inform these various conceptual and measurement efforts. In this paper, we attempt to construct a theory of child well-being. We first review the social and policy history of the concept of child well-being, and briefly review its measurement based on these conceptualizations. We then examine three types of theories of well-being extant in philosophy - mental states theories, desire-based theories and needs-based theories - and investigate their suitability to serve as prototypes of a theory of child well-being. We develop a constraint that child well-being is important in and of itself and not merely as a way station to future adult well-being (we call this a non-reduction constraint). Using this constraint, we identify the limitations of each of the three sets of theories to serve as a basis for a theory of child well-being. Based on a developmentalist approach, we then articulate a theory of child well-being that contains two conditions. First, a child's stage-appropriate capacities that equip her for successful adulthood, given her environment; and, second, an engagement with the world in child-appropriate ways. We conclude by reviewing seven implications of this theoretical approach for the measurement of child well-being. Key Words Child well-being, philosophy, social policy, child developmentNoneThis is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s11205-014-0665-

Low-fidelity DNA synthesis by human DNA polymerase theta

Human DNA polymerase theta (pol θ or POLQ) is a proofreading-deficient family A enzyme implicated in translesion synthesis (TLS) and perhaps in somatic hypermutation (SHM) of immunoglobulin genes. These proposed functions and kinetic studies imply that pol θ may synthesize DNA with low fidelity. Here, we show that when copying undamaged DNA, pol θ generates single base errors at rates 10- to more than 100-fold higher than for other family A members. Pol θ adds single nucleotides to homopolymeric runs at particularly high rates, exceeding 1% in certain sequence contexts, and generates single base substitutions at an average rate of 2.4 × 10−3, comparable to inaccurate family Y human pol κ (5.8 × 10−3) also implicated in TLS. Like pol κ, pol θ is processive, implying that it may be tightly regulated to avoid deleterious mutagenesis. Pol θ also generates certain base substitutions at high rates within sequence contexts similar to those inferred to be copied by pol θ during SHM of immunoglobulin genes in mice. Thus, pol θ is an exception among family A polymerases, and its low fidelity is consistent with its proposed roles in TLS and SHM

Study on crystallization phenomenon and thermal stability of binary Ni–Nb amorphous alloy

In this paper, a ribbon of binary Ni–Nb amorphous alloy was prepared by the melt spinning technique. Glass transition and crystallization phenomenon of the alloy were investigated by differential scanning calorimetry. Thermal properties of the ribbon of binary Ni–Nb upon heating and cooling were analysed by DTA at a heating/ cooling rate of 0.5 K s-1 under the purified argon atmosphere. The thermal stability of Ni–Nb amorphous alloy was studied by using an X-ray diffractometer equipped with an in situ heating system. The structure and fracture morphology of the ribbons were examined by X-ray diffraction and scanning electron microscopy methods

The ERCC6 Gene and Age-Related Macular Degeneration

Background: Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the developed countries and is caused by both environmental and genetic factors. A recent study (Tuo et al., PNAS) reported an association between AMD and a single nucleotide polymorphism (SNP) (rs3793784) in the ERCC6 (NM_000124) gene. The risk allele also increased ERCC6 expression. ERCC6 is involved in DNA repair and mutations in ERCC6 cause Cockayne syndrome (CS). Amongst others, photosensitivity and pigmentary retinopathy are hallmarks of CS. Methodology/Principal Findings: Separate and combined data from three large AMD case-control studies and a prospective population-based study (The Rotterdam Study) were used to analyse the genetic association between ERCC6 and AMD (2682 AMD cases and 3152 controls). We also measured ERCC6 mRNA levels in retinal pigment epithelium (RPE) cells of healthy and early AMD affected human donor eyes. Rs3793784 conferred a small increase in risk for late AMD in the Dutch population (The Rotterdam and AMRO-NL study), but this was not replicated in two non-European studies (AREDS, Columbia University). In addition, the AMRO-NL study revealed no significant association for 9 other variants spanning ERCC6. Finally, we determined that ERCC6 expression in the human RPE did not depend on rs3793784 genotype, but, interestingly, on AMD status: Early AMD-affected donor eyes had a 50% lower ERCC6 expression than healthy donor eyes (P = 0.018). Conclusions/Significance: Our meta analysis of four Caucasian cohorts does not replicate the reported association between SNPs in ERCC6 and AMD. Nevertheless, our findings on ERCC6 expression in the RPE suggest that ERCC6 may be functionally involved in AMD. Combining our data with those of the literature, we hypothesize that the AMD-related reduced transcriptional activity of ERCC6 may be caused by diverse, small and heterogeneous genetic and/or environmental determinants

Bone histomorphometric measures of physical activity in children from Medieval England

Objectives: Histomorphometric studies show consistent links between physical activity patterns and the microstructure underlying the size and shape of bone. Here we adopt a combined bone approach to explore variation in microstructure of ribs and humeri related to physical activity and historical records of manual labor in skeletal samples of children (n=175) from medieval England. The humerus reflects greater biomechanically induced microstructural variation than the rib which is used here as a control. Variation in microstructure is sought between regions in England (Canterbury, York, Newcastle), and between high- and low-status children from Canterbury. Materials and Methods: Thin-sections were prepared from the humerus or rib and features of bone remodeling were recorded using high-resolution microscopy and image analysis software. Results: The density and size of secondary osteons in the humerus differed significantly in children from Canterbury when compared to those from York and Newcastle. Amongst the older children, secondary osteon circularity and diameter differed significantly between higher and lower status children. Discussion: By applying bone remodeling principles to the histomorphometric data we infer that medieval children in Canterbury engaged in less physically demanding activities than children from York or Newcastle. Within Canterbury, high-status and low-status children experienced similar biomechanical loading until around seven years of age. After this age low-status children performed activities that resulted in more habitual loading on their arm bones than the high-status children. This inferred change in physical activity is consistent with historical textual evidence that describes children entering the work force at this age

Calculated phase diagrams, iron tolerance limits, and corrosion of Mg-Al alloys

The factors determining corrosion are reviewed in this paper, with an emphasis on iron tolerance limit and the production of high-purity castings. To understand the iron impurity tolerance limit, magnesium phase diagrams were calculated using the Pandat software package. Calculated phase diagrams can explain the iron tolerance limit and the production of high-purity castings by means of control of melt conditions; this is significant for the production of quality castings from recycled magnesium. Based on the new insight, the influence of the microstructure on corrosion of magnesium alloys is reviewed