Nanowires fabricated by Focused Ion Beam

This thesis reports research on nanowires fabricated by FIB lithography with experiments to understand their mechanical, electrical and hydrodynamic properties. Au nanowires fabricated on Si$_3$N$_4$ membranes with width below 50nm exhibit liquid like instabilities and below $\sim$20nm the instabilities grow destroying the nanowires due to the Rayleigh- Plateau instability. Stability is better in the case for Si substrates than for the insulators Si0$_2$ and Si$_3$N$_4$. A series of 4-terminal resistance measurements were carried out on a "platinum" nanowire grown by FIB-induced decomposition of an organometallic precursor. Such nanowires are found to be a two phase percolating system, containing up to 70% by volume carbon. They have unexpected temperature behaviour which is explained using a percolation model with Kirkpatrick conduction in the presence of temperature induced strain. Au nanowire bridges of very small diameter were probed using AFM to investigate their deformation and fracture strength. Below a diameter $\sim$50nm, the mechanical properties are consistent with liquid-like behaviour. After reaching the fracture, the gold molecules from the bridge retract towards the fixed ends; rebinding of the gold causing reforming of the nanowire bridge can occur. FIB fabrication was also used to form a thermal bimorph MEMS cantilever which was investigated by AFM during actuation

Estimation of Columbia River Virgin Flow: 1879 to 1928

The Columbia River has historically been a major source of economic activity for the Pacific Northwest, and is one of the more heavily modified rivers in the United States today. Understanding human and climate-induced changes in its hydrologic properties is, therefore, a topic of considerable interest. Long streamflow records are essential to determining how runoff has changed over time. Daily streamflow records of the Columbia River at The Dalles dates back to June 1978. However, the observed daily flow does not alone provide enough information to understand or separate anthropogenic and climate effects. It is necessary also to have an estimate of virgin flow of the river to provide a historical perspective of water resources development, separate anthropogenic and climate effects, and compare present water use scenarios with those of the past decades. The United State Geological Survey (USGS) has calculated a monthly averaged adjusted river flow at The Dalles for 1879-1999 that accounts for the effects of flow regulation. The Bonneville Power Administration (BPA) has estimated the monthly averaged virgin (or naturalized) flow at The Dalles, i.e., the flow in the absence of both flow regulation and irrigation depletion for 1929-89. We have estimated the monthly virgin flow of the Columbia River at The Dalles from records of irrigated area for the missing years, i.e., for the period 1879-1928. In addition, a filtered version of the daily observed flows were combined with monthly virgin flow corrections to obtain estimates of daily virgin flows with realistic higher moments and spectral properties. Examination of the virgin flow record shows that climate change since late 19th century has caused a decrease of \u3e7% in its annual average flow volume. The decrease in flow due to irrigation diversion during the same period is also ~7%. Broadly speaking, there are three periods of Columbia River flow management. Before 1900, mainstem dams were absent and flow diversions relatively small. Numerous dams were constructed between 1900 and 1970, and irrigation depletion increased 500%. Since about 1970, river flows have been managed on a system-wide basin, effecting significant interannual transfers of flows for the first time

Husband's Alcohol Use, Intimate Partner Violence, and Family Maltreatment of Low-Income Postpartum Women in Mumbai, India.

Husbands' alcohol use has been associated with family-level stress and intimate partner violence (IPV) against women in India. Joint family systems are common in India and IPV often co-occurs with non-violent family maltreatment of wives (e.g., nutritional deprivation, deprivation of sleep, blocking access to health care). Alcohol use increases for some parents following the birth of a child. This study examined 1,038 postpartum women's reports of their husbands' alcohol use and their own experiences of IPV (by husband) and non-violent maltreatment from husbands and/or in-laws. We analyzed cross-sectional, quantitative data collected in 2008, from women (ages 15-35) seeking immunizations for their infants <6 months at three large urban health centers in Mumbai, India. Crude and adjusted logistic regression models estimated associations between the independent variable (husbands' past month use of alcohol) and two dependent variables (postpartum IPV and maltreatment). Overall, 15% of husbands used alcohol, ranging from daily drinkers (10%) to those who drank one to two times per week (54%). Prevalence of postpartum IPV and family maltreatment was 18% and 42%, respectively. Prevalence of IPV among women married to alcohol users was 27%. Most abused women's husbands always (27%) or sometimes (37%) drank during violent episodes. Risk for IPV increased with a man's increasing frequency of consumption. Women who lived with a husband who drank alcohol, relative to non-drinkers, were more likely to report postpartum IPV, aOR = 2.0, 95% confidence interval (CI) = [1.3, 3.1]. Husbands' drinking was marginally associated with increased risk for family maltreatment, aOR = 1.4, 95% CI = [1.0, 2.1]. Our findings suggest that men's alcohol use is an important risk factor for postpartum IPV and maltreatment. Targeted services for Indian women contending with these issues are implicated. Postpartum care offers an ideal opportunity to screen for IPV, household maltreatment, and other health risks, such as husband's use of alcohol. There is need to scale up proven successful interventions for reducing men's alcohol use and design strategies that provide at-risk women protection from alcohol-related IPV

Liquid-like behaviour of gold nanowire bridges

A combination of Focused Ion Beam (FIB) and Reactive Ion Etch (RIE) was used to fabricate free standing gold nanowire bridges with radii of 30 nm and below. These were subjected to point loading to failure at their mid-points using an Atomic Force Microscope (AFM), providing strength and deformation data. The results demonstrate a dimensionally dependent transition from conventional solid metallic properties to liquid-like behaviour including the unexpected reformation of a fractured bridge. The work reveals mechanical and materials properties of nanowires which could have significant impact on nanofabrication processes and nanotechnology devices such as Nano Electro Mechanical Systems (NEMS)

Maternal morbidity associated with violence and maltreatment from husbands and in-laws: findings from Indian slum communities.

BackgroundIntimate partner violence (IPV) victimization is linked to a broad range of negative maternal health outcomes. However, it is unclear whether IPV is directly related to poor maternal outcomes or whether IPV is a marker for other forms of chronic, mundane maltreatment of women that stem from the culture of gender inequity that also gives rise to IPV. To determine the prevalence of non-violent forms of gender-based household maltreatment by husbands and in-laws (GBHM), and violence from in-laws (ILV) and husbands (IPV) against women during the peripregnancy period (during and in the year prior to pregnancy); to assess relative associations of GBHM, ILV and IPV with maternal health.MethodsCross-sectional data were collected from women <6 months postpartum (n = 1,039, ages 15-35 years) seeking child immunization in Mumbai, India. Associations of IPV, ILV and GBHM during the peripregnancy period with maternal health (prenatal care in first trimester, no weight gain, pain during intercourse, high blood pressure, vaginal bleeding, premature rupture of membranes, premature birth) were evaluated.ResultsOne in three women (34.0 %) reported IPV, 4.8 % reported ILV, and 48.5 % reported GBHM during the peripregnancy period. After adjusting for other forms of abuse, IPV related to pain during intercourse (AOR = 1.79); ILV related to not receiving first trimester antenatal care (AOR = 0.49), and GBHM remained associated with premature rupture of membranes (AOR = 2.28), pain during intercourse (AOR = 1.60), and vaginal bleeding (AOR = 1.80).ConclusionAfter adjusting for ILV and IPV, peripregnancy GBHM remained significantly associated with multiple forms of maternal morbidity, suggesting that GBHM is a prevalent and reliable indicator of maternal health risk

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses

Background: A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011. <p/>Methods: Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs). <p/>Results: 32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m2. MTD was 10 mg/m2; DLTs at 12 (2/4 patients) and 10 mg/m2 (3/12) included thrombocytopenia and febrile neutropenia; diarrhea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1--10 mg/m2. Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion. <p/>Conclusions: TP300 had predictable hematologic toxicity, and diarrhea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage

Advances in Tissue Engineering Approaches for Craniomaxillofacial Bone Reconstruction

Trauma, congenital abnormalities and pathologies such as cancer can cause significant defects in craniofacial bone. Regeneration of the bone in the craniofacial area presents a unique set of challenges due to its complexity and association with various other tissues. Bone grafts and bone cement are the traditional treatment options but pose their own issues with regards to integration and morbidity. This has driven the search for materials which mimic the natural bone and can act as scaffolds to guide bone growth. Novel technology and computer aided manufacturing have allowed us to control material parameters such as mechanical strength and pore geometry. In this chapter, we elaborate the current status of materials and techniques used in fabrication of scaffolds for craniomaxillofacial bone tissue engineering and discuss the future prospects for advancements

Skin microbiome prior to development of atopic dermatitis:early colonization with commensal staphylococci at 2 months is associated with a lower risk of atopic dermatitis at 1 year

Background: Disease flares of established atopic dermatitis (AD) are generally associated with a low-diversity skin microbiota and Staphylococcus aureus dominance. The temporal transition of the skin microbiome between early infancy and the dysbiosis of established AD is unknown. Methods: We randomly selected 50 children from the Cork Babies After SCOPE: Evaluating the Longitudinal Impact Using Neurological and Nutritional Endpoints (BASELINE) longitudinal birth cohort for microbiome sampling at 3 points in the first 6 months of life at 4 skin sites relevant to AD: the antecubital and popliteal fossae, nasal tip, and cheek. We identified 10 infants with AD and compared them with 10 randomly selected control infants with no AD. We performed bacterial 16S ribosomal RNA sequencing and analysis directly from clinical samples. Results: Bacterial community structures and diversity shifted over time, suggesting that age strongly affects the skin microbiome in infants. Unlike established AD, these patients with infantile AD did not have noticeably dysbiotic communities before or with disease and were not colonized by S aureus. In comparing patients and control subjects, infants who had affected skin at month 12 had statistically significant differences in bacterial communities on the antecubital fossa at month 2 compared with infants who were unaffected at month 12. In particular, commensal staphylococci were significantly less abundant in infants affected at month 12, suggesting that this genus might protect against the later development of AD. Conclusions: This study suggests that 12-month-old infants with AD were not colonized with S aureus before having AD. Additional studies are needed to confirm whether colonization with commensal staphylococci modulates skin immunity and attenuates development of AD