Multicolour detection of every chromosome as a means of detecting mosaicism and nuclear organisation in human embryonic nuclei

Fluorescence in situ Hybridisation (FISH) revolutionised cytogenetics using fluorescently labelled probes with high affinity with target (nuclear) DNA. By the early 1990s FISH was adopted as a means of PGD sexing for couples at risk of transmitting X-linked disorders and later for detection of unbalanced translocations. Following a rise in popularity of PGD by FISH for sexing and the availability of multicolour probes (5-8 colour), the use of FISH was expanded to the detection of aneuploidy and selective implantation of embryos more likely to be euploid, the rationale being to increase pregnancy rates (referral categories were typically advanced maternal age, repeated IVF failure, repeated miscarriage or severe male factor infertility). Despite initial reports of an increase in implantation rates, reduction in trisomic offspring and spontaneous abortions criticism centred around experimental design (including lack of randomisation), inadequate control groups and lack of report on live births. Eleven randomised control trials (RCTs) (2004-2010) showed that PGS with FISH did not increase delivery rates with some demonstrating adverse outcomes. These RCTs, parallel improvements in culturing and cryopreservation and a shift to blastocyst biopsy essentially outdated FISH as a tool for PGS and it has now been replaced by newer technologies (array CGH, SNP arrays, qRT-PCR and NGS). Cell-by-cell follow up analysis of individual blastomeres in non-transferred embryos is however usually prohibitively expensive by these new approaches and thus FISH remains an invaluable resource for the study of mosaicosm and nuclear organization. We thus developed the approach described herein for the FISH detection of chromosome copy number of all 24 human chromosomes. This approach involves 4 sequential layers of hybridization, each with 6 spectrally distinct fluorochromes and a bespoke capturing system. Here we report previously published studies and hitherto unreported data indicating that 24 chromosome FISH is a useful tool for studying chromosome mosaicism, one of the most hotly debated topics currently in preimplantation genetics. Our results suggest that mosaic embryo aneuploidy is not highly significantly correlated to maternal age, probably due, in part, to the large preponderance of post-zygotic (mitotic) errors. Chromosome loss (anaphase lag) appears to be the most common mechanism, followed by chromosome gain (endoreduplication), however 3:1 mitotic non- disjunction of chromosomes appears to be rare. Nuclear organisation (i.e. the spatial and temporal topology of chromosomes or sub-chromosomal compartments) studies indicate that human morula or blastocyst embryos (day 4-5) appear to adopt a "chromocentric" pattern (i.e. almost all centromeric signals reside in the innermost regions of the nuclear volume). By the blastocyst stage however, a more ordered organisation with spatial and temporal cues important for embryo development appears. We have however found no association between aneuploidy and nuclear organization using this approach despite our earlier studies. In conclusion, while FISH is mostly "dead and buried" for mainstream PGS, it still has a place for basic biology studies; the development of a 24 chromosome protocol extends the power of this analysis

Small irrigation tanks as a source of malaria mosquito vectors: a study in north-central Sri Lanka

Watersheds / Tank irrigation / Rehabilitation / Malaria / Waterborne diseases / Disease vectors / Sri Lanka / Yan Oya

Treatment of colour industry wastewaters with concomitant bioelectricity production in a sequential stacked mono-chamber microbial fuel cells–aerobic system

The scalability of any microbial fuel cell (MFC)-based system is of vital importance if it is to be utilized for potential field applications. In this study, an integrated MFC–aerobic bioreactor system was investigated for its scalability with the purpose of treating a simulated dye wastewater and industrial wastewaters originated from textile dyebaths and leather tanning. The influent containing real wastewater was fed into the reactor in continuous mode at ambient temperature. Three MFC units were integrated to act in unison as a single module for wastewater treatment and a continuously stirred aerobic bioreactor operating downstream to the MFC module was installed in order to ensure more complete degradation of colouring agents found in the wastewater. Total colour removal in the final effluent exceeded 90% in all experiments where both synthetic (AO-7 containing) and real wastewater were used as the influent feed. The chemical oxygen demand reduction also exceeded 80% in all experiments under the same conditions. The MFC modules connected in parallel configuration allowed obtaining higher current densities than that can be obtained from a single MFC unit. The maximum current density of the MFC stack reached 1150 mA m−2 when connected in a parallel configuration. The outcome of this work implies that suitably up-scaled MFC–aerobic integrated bioprocesses could be used for colour industry wastewater treatment under industrially relevant conditions with possible prospects of bioelectricity generation

Incidence of some pathogenic organisms in cultured shrimp (penaeus monodon) collected from Chilaw

Samples offarm shrimp and pond water were collectedfrom Chi/aw. Totalbacterial counts of coliforms and Escherichia coli are reportedfor these samples.Pathogens Vibrio parahaemolyticus, and Salmonella along with qualitativemicroflora are also reported.The bacterial counts of water rangedfrom 5 x 102/gto 8.8 x 103/g whereasthat of shrimp rangedfrom 2.0 x IO"/g to 9.0 x lO'/g. E. coli. ranged from 3 toII/g for prawns 3/I00ml. to 49/I00ml. for pond water. Two shrimp sampleswere positive for v. parahaemolyticus bacterial counts, coliforms or E. colicounts did not show any correlation with water salinity, which rangedfrom 14-18ppt,Gram positive bacteria were predominant in shrimp and were representedby Micrococci (41.8%). Corynebacterium (19.3%) and Bacillus (14.2%).Common gram-negatives were Vibrios (19.2%) and Pseudomonas (5%)

Dose de-escalation of intrapleural tissue plasminogen activator therapy for pleural infection. The alteplase dose assessment for Pleural infection Therapy project

Rationale: Intrapleural therapy with a combination of tissue plasminogen activator (tPA) 10 mg and DNase 5 mg administered twice daily has been shown in randomized and open-label studies to successfully manage over 90% of patients with pleural infection without surgery. Potential bleeding risks associated with intrapleural tPA and its costs remain important concerns. The aim of the ongoing Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) project is to investigate the efficacy and safety of dose de-escalation for intrapleural tPA. The first of several planned studies is presented here. Objectives: To evaluate the efficacy and safety of a reduced starting dose regimen of 5 mg of tPA with 5 mg of DNase administered intrapleurally for pleural infection. Methods: Consecutive patients with pleural infection at four participating centers in Australia, the United Kingdom, and New Zealand were included in this observational, open-label study. Treatment was initiated with tPA 5 mg and DNase 5 mg twice daily. Subsequent dose escalation was permitted at the discretion of the attending physician. Data relating to treatment success, radiological and systemic inflammatory changes (blood C-reactive protein), volume of fluid drained, length of hospital stay, and treatment complications were extracted retrospectively from the medical records. Results: We evaluated 61 patients (41 males; age, 57 ± 16 yr). Most patients (n = 58 [93.4%]) were successfully treated without requiring surgery for pleural infection. Treatment success was corroborated by clearance of pleural opacities visualized by chest radiography (from 42% [interquartile range, 22–58] to 16% [8–31] of hemithorax; P < 0.001), increase in pleural fluid drainage (from 175 ml in the 24 h preceding treatment to 2,025 ml [interquartile range, 1,247–2,984] over 72 h of therapy; P <  0.05) and a reduction in blood C-reactive protein (P < 0.05). Seven patients (11.5%) had dose escalation of tPA to 10 mg. Three patients underwent surgery. Three patients (4.9%) received blood transfusions for gradual pleural blood loss; none were hemodynamically compromised. Pain requiring escalation of analgesia affected 36% of patients; none required cessation of therapy. Conclusions: These pilot data suggest that a starting dose of 5 mg of tPA administered intrapleurally twice daily in combination with 5 mg of DNase for the treatment of pl

Does Proximity to Conflict Zones Moderate Associations Between Girl Child Marriage, Intimate Partner Violence, and Contraception in Postconflict Sri Lanka?

Women’s primary contraceptive method type is impacted by the gender inequities of girl child marriage and intimate partner violence (IPV). Outside of South Asia, proximity to conflict zones has been found to impact contraceptive use, girl child marriage, and IPV, possibly moderating associations between these variables. We created multinomial regression models using the 2016 Demographic and Health Survey data from postconflict Sri Lanka to study associations between primary contraceptive method type (modern spacing methods, sterilization, and traditional methods compared to no method) and the gender inequities of girl child marriage and past year sexual, physical, and emotional IPV and to assess whether and how these associations were moderated by proximity to conflict. We found that proximity to conflict moderated the relationships between girl child marriage, past year physical and emotional IPV, and primary contraceptive method type. Girl child marriage was associated with increased relative risk (RR) of modern spacing methods (adjusted RR ratio/aRRR: 1.81–2.21) across all levels of proximity to conflict. In districts distal to conflict, past year physical IPV was associated with decreased RR of sterilization (aRRR: 0.67) and traditional methods (aRRR: 0.63), and past year emotional IPV was associated with decreased RR of traditional methods (aRRR: 0.71). In districts central to conflict, past year emotional IPV was associated with increased RR of modern spacing methods (aRRR: 1.50). Our findings suggest that policymakers and providers who seek to improve reproductive health in Sri Lanka must consider the moderating impact of proximity to conflict on the relationship between contraceptive use and the gender inequities of girl child marriage and IPV

Preferred growth direction of III-V nanowires on differently oriented Si substrates

One of the nanowire (NW) characteristics is its preferred elongation direction. Here, we investigated the impact of Si substrate crystal orientation on the growth direction of GaAs NWs. We first studied the self-catalyzed GaAs NW growth on Si (111) and Si (001) substrates. SEM observations show GaAs NWs on Si (001) are grown along four directions without preference on one or some of them. This non-preferential NW growth on Si (001) is morphologically in contrast to the extensively reported vertical preferred GaAs NW growth on Si (111) substrates. We propose a model based on the initial condition of an ideal Ga droplet formation on Si substrates and the surface free energy calculation which takes into account the dangling bond surface density for different facets. This model provides further understanding of the different preferences in the growth of GaAs NWs along selected directions depending on the Si substrate orientation. To verify the prevalence of the model, NWs were grown on Si (311) substrates. The results are in good agreement with the three-dimensional mapping of surface free energy by our model. This general model can also be applied to predictions of NW preferred growth directions by the vapor-liquid-solid growth mode on other group IV and III–V substrates

A mediation analysis of the role of girl child marriage in the relationship between proximity to conflict and past-year intimate partner violence in post-conflict Sri Lanka

Background Studies from many contexts indicate that proximity to conflict is associated with increased likelihood of intimate partner violence (IPV), and girl child marriage is associated with both proximity to conflict and increased IPV. In this study, we consider whether girl child marriage acts as a mediator of the association between proximity to conflict and IPV in the context of Sri Lanka, which sustained long-term conflict until 2009. Methods We analyzed responses of currently partnered women between ages 18 and 49 in the 2016 Sri Lankan Demographic and Health Survey (N = 13,691). Using logistic regression analyses, we measured associations between proximity to conflict (residence in districts which were central, proximal, or distal to the regions where the war occurred) and the outcomes of IPV and girl child marriage, and secondarily assessed girl child marriage as a possible mediator of the association between proximity to conflict and past year IPV. Results Women residing in districts central to conflict, as compared to districts distal to conflict, had increased odds of past year sexual, physical, and emotional IPV, with the odds of sexual IPV increasing the most (adjusted odds ratio/aOR 4.19, 95% confidence interval/CI 2.08–8.41). Residing in districts proximal to conflict compared to those distal to conflict was associated with lower odds of past year physical and emotional IPV, with the greatest decrease in emotional IPV (aOR 0.31, CI 0.18–0.54). Girl child marriage was more likely in districts central to conflict as opposed to those distal to conflict (aOR 1.89, CI 1.22–2.93), and partially mediated the relationship between centrality to conflict and IPV. Conclusions Our findings demonstrate that residing in districts central to conflict compared to those distal to conflict is associated with greater odds of IPV and girl child marriage in post-conflict Sri Lanka, with girl child marriage partially mediating the association between centrality to conflict and IPV. Residence in districts proximal to conflict appears protective against IPV. Future research should investigate what factors are responsible for decreased IPV in districts proximal to violence, and whether these factors can be reproduced to mitigate the increased prevalence of IPV in districts central to conflict

Preferred growth direction of III-V nanowires on differently oriented Si substrates

One of the nanowire characteristics is its preferred elongation direction. Here, we investigated the impact of Si substrate crystal orientation on the growth direction of GaAs nanowires. We first studied the self-catalyzed GaAs nanowire growth on Si (111) and Si (001) substrates. SEM observations show GaAs nanowires on Si (001) are grown along four directions without preference on one or some of them. This non-preferential nanowire growth on Si (001) is morphologically in contrast to the extensively reported vertical preferred GaAs nanowire growth on Si (111) substrates. We propose a model based on the initial condition of an ideal Ga droplet formation on Si substrates and the surface free energy calculation which takes into account the dangling bond surface density for different facets. This model provides further understanding of the different preferences in the growth of GaAs nanowires along selected directions depending on the Si substrate orientation. To verify the prevalence of the model, nanowires were grown on Si (311) substrates. The results are in good agreement with the three-dimensional mapping of surface free energy by our model. This general model can also be applied to predictions of nanowire preferred growth directions by the vapor-liquid-solid growth mode on other group IV and III-V substrates

Defect-Free Axially Stacked GaAs/GaAsP Nanowire Quantum Dots with Strong Carrier Confinement

Axially stacked quantum dots (QDs) in nanowires (NWs) have important applications in nanoscale quantum devices and lasers. However, there is lack of study of defect-free growth and structure optimization using the Au-free growth mode. We report a detailed study of self-catalyzed GaAsP NWs containing defect-free axial GaAs QDs (NWQDs). Sharp interfaces (1.8-3.6 nm) allow closely stack QDs with very similar structural properties. High structural quality is maintained when up to 50 GaAs QDs are placed in a single NW. The QDs maintain an emission line width of <10 meV at 140 K (comparable to the best III-V QDs, including nitrides) after having been stored in an ambient atmosphere for over 6 months and exhibit deep carrier confinement (∼90 meV) and the largest reported exciton-biexciton splitting (∼11 meV) for non-nitride III-V NWQDs. Our study provides a solid foundation to build high-performance axially stacked NWQD devices that are compatible with CMOS technologies