Strand-specific ChIP-sequencing reveals nucleosome dynamics at DNA double-strand breaks

DNA double-strand breaks (DSBs) are highly toxic lesions that, if not correctly repaired, can have detrimental consequences on genome integrity and cell survival. During the course of evolution, different mechanisms developed to repair DSBs including nonhomologous end-joining (NHEJ) and homologous recombination (HR). A pivotal step of the cellular repair pathway decision is the processing of DSB ends during DNA end resection, which, through the degradation of 5’-terminated strands, generates a long stretch of single-stranded DNA (ssDNA) that prevents re-ligation by NHEJ factors and guides repair towards HR. At the same time, resection divides the chromatin surrounding a DSB in distinct ssDNA and dsDNA domains. Establishment of these domains is crucial for HR repair as well as for DNA damage signaling and checkpoint activation, but the protein composition and the interactions between these compartments were not fully understood. Specifically, it was unclear whether nucleosomes, the fundamental unit of chromatin, could be found in the ssDNA domain as well. This would have considerable implications for the recruitment of repair factors to DSBs and for the maintenance of the epigenetic information during repair. However, previously used techniques were inadequate to address this question. Here, we combined site-specific induction of DSBs with chromatin immunoprecipitation, followed by strand-specific library preparation and next-generation sequencing to analyze the in vivo DNA binding mode of key DSB repair proteins as well as nucleosomes. In proof-of-principle experiments, strand-specific ChIP-sequencing recapitulated the characteristic binding pattern of RPA and Rad51 to ssDNA at resected DSBs. Using this technique, we were also able to detect Rad51 binding to dsDNA during homology search. The 9-1-1 signaling platform was suggested to bind at the ss-dsDNA junction at resected DSBs. We showed that, in vivo, 9-1-1 associates with the dsDNA compartment and locates at the leading edge of resection. Furthermore, we did not find evidence of the presence of nucleosomes on ssDNA and, therefore, they do not represent a major species at resected DSBs. In contrast, we found that nucleosomes become fully evicted in concomitance with resection and that the chromatin remodelers RSC and SWI/SNF act redundantly to promote such nucleosome eviction. Taken together, our study revealed that nucleosome eviction is intrinsically coupled with resection and that the ssDNA and dsDNA domains generated by resection are characterized by distinct properties

FACTORS RELATING TO HPV BEHAVIORS OF FEMALE COLLEGE STUDENTS

This study examined the knowledge, sources of information, reasons for and against Gardasil® uptake, and possible relationships between unhealthy behaviors and vaccination for undergraduate college females at a public university. Utilizing an online survey, 2400 random students were emailed as well as recruited through online classes. The final sample size was 516 females. The study determined how many participants had been vaccinated and their rationale for or against vaccination. The majority of study participants were knowledgeable about HPV and Gardasil®. The primary sources of information about HPV and Gardasil® were doctors and television; however parents and friends were also common sources of information. Predictors for HPV inoculation included race, the belief that the vaccine would protect against HPV, alcohol use, and engagement in anal intercourse. Over 50% of participants had received at least one dose of Gardasil®, and 82% had completed the series. The most common rationale for not getting the vaccine, or not completing the vaccination series, was concern about side effects. The most common rationale for completing the vaccination or intending to complete the series was protection from cervical cancer. In conclusion, there is a continued need provide health education about HPV and HPV vaccination for college females

COMMUNICATING SOCIAL SUPPORT: UNDERSTANDING COMPLEXITIES OF BREASTFEEDING COMMUNICATION AMONG AFRICAN AMERICAN MOTHERS

Breast milk is the best choice for meeting the nutritional needs for an infant whenever possible. Despite the knowledge that this nutritional choice is the best choice for an infant, data demonstrates that there is a sharp decline in the rates of breastfeeding mothers. Among African Americans, breastfeeding rates are significantly lower than the national averages. Despite many of the applications of social support in communication research, there is a gap in knowledge on the social support systems in the context of breastfeeding, especially for African Americans. With the social ecological model as a framework, social support theory provides understanding of the exchange between the mothers and their interpersonal relationships and community resources in the provision of emotional, tangible, and informational support. Study 1 consisted of focus group interviews with mothers and grandmothers. Mothers (n=16) discussed their experiences in receiving social support and grandmothers (n=12) discussed their experience giving social support to the mothers. The findings revealed the different communication and actions that mothers received from healthcare providers, peers, loved ones, strangers, and the grandmother of the child. Healthcare providers and peers seemed to have the largest positive communication in regards to a mother’s initiation and sustainment of breastfeeding; strangers had both positive and negative supportive interactions, and family members and grandmothers were reported to provide negative support. Further exploration into the mother/ grandmother communication detailed the dissonance between the giver of support (the grandmother) and the receiver (the mother). Study 2 explored how breastfeeding champions (community level support) reported providing social support to breastfeeding mothers. Breastfeeding champions (n= 13) provided positive emotional, tangible, and informational support to mothers. The findings from these studies are discussed in terms of family relationship dynamics, the types of community level support, and future directions for communication research

A systematic approach to the design of effective chip breakers

An investigation into chip breaker designs which will result in the proper chip control is presented in this thesis. The investigation of the premise that chip breakers placed roughly normal to the direction of chip flow would have the greatest likelihood of breaking the chip, was simplified by the use of chip flow angle equations. After the accuracy of these equations was verified, it was possible to construct the chip breaker face at a ninety degree angle to the chip flow direction

Geteilte Verantwortung? : der nationalsozialistische Völkermord an den Sinti und Roma in der deutschen Erinnerungspolitik und in Ausstellungen zum Holocaust

[no abstract

The organizational model of the Interregional Transplant Agency Organizzazione Centro-Sud Trapianti

In Italy, all donation and transplant activities were officially disciplined in 1999 by the law 91 of April 1, 1999. This law enacted a coordinator-based model of transplantation, instituted the National Center for Transplantation (Centro Nazionale Trapianti-CNT), and endorsed the existing interregional transplant agencies (ITA), such as the Nord Italia Transplant program (NITp), the Associazione InterRegionale Trapianti (AIRT), and the Organizzazione Centro-Sud Trapianti (OCST). Within its borders each ITA has adopted its own organizational model; there is no overt centralized control exerted by the CNT according to the law 91/1999. The aim of the current work is to report on the organizational model adopted by OCST, the ITA gathering the Italian regions of Abruzzo, Basilicata, Calabria, Campania, Latium, Molise, Sardinia, Sicily, and Umbria