UV Spectra and Excitation Delocalization in DNA: Influence of the Spectral Width

The singlet excited states of the model DNA duplex (dA)10.(dT)10 are studied. Calculations are performed in the exciton theory framework. Molecular dynamics calculations provide the duplex geometry. The dipolar coupling is determined using atomic transition charges. The monomer transition energies are simulated by Gaussian functions resembling the absorption bands of nucleosides in aqueous solutions. Most of the excited states are found to be delocalized over at least two bases and result from the mixing of different monomer states. Their properties are only weakly affected by conformational changes of the double helix. On average, the highest oscillator strength is carried by the upper eigenstates. The duplex absorption spectra are shifted a few nanometers to higher energies with respect to the spectra of noninteracting monomers. The states with larger spatial extent are located close to the maximum of the absorption spectrum

A Comparative Analysis of Print-Of-View Modeling For Industrial and Technology Education Courses

(First paragraph): Enrollment in technology education at the college level has been declining (Isbell & Lovedahl, 1989; Volk, 1997; Daugherty, 1998; Hill, 1999; Ndahi & Ritz, 2003; Moye, 2009). It is essential for technology teacher educators to investigate ways to increase the enrollment in their programs, or the profession may fail to provide technology teachers in the future (Ndahi & Ritz, 2003). A solution that several institutions with technology education programs have adopted is the offering of the program via distance learning. Distance learning “allows participants to collapse time and space” (Cole, 2000, p. ix). According to Flowers (2003) technology education programs “with a history of hands-on learning at the undergraduate level” have been slow to implement distance learning techniques and strategies (p. 64). Therefore, it is important to explore the extent to which distance-learning technologies such as video modeling can be used by industrial and technical teacher education faculty. The intention of this study is to add to the body of knowledge on effective video modeling procedures and, in particular, the point of view used when recording instructional videos

A host–guest approach for determining drug–DNA interactions: an example using netropsin

Netropsin is a well-characterized DNA minor groove binding compound that serves as a model for the study of drug–DNA interactions. Our laboratory has developed a novel host–guest approach to study drug–DNA interactions in which the host, the N-terminal fragment of Moloney murine leukemia virus reverse transcriptase (MMLV RT) is co-crystallized with a DNA oligonucleotide guest in the presence and absence of drug. We have co-crystallized netropsin with the RT fragment bound to the symmetric 16mer d(CTTAATTCGAATTAAG)(2) and determined the structure of the complex at 1.85 Å. In contrast to previously reported netropsin–DNA structures, our oligonucleotide contains two AATT sites that bind netropsin with flanking 5′ and 3′ sequences that are not symmetric. The asymmetric unit of the RT fragment–DNA–netropsin crystals contains one protein molecule and one-half of the 16mer with one netropsin molecule bound. The guanidinium moiety of netropsin binds in a narrow part of the minor groove, while the amidinium is bound in the widest region within the site. We compare this structure to other Class I netropsin–DNA structures and find that the asymmetry of minor groove widths in the AATT site contributes to the orientation of netropsin within the groove while hydrogen bonding patterns vary in the different structures

Exciton States of Dynamic DNA Double Helices: Alternating dCdG Sequences

The present communication deals with the excited states of the alternating DNA oligomer (dCdG)5·(dCdG)5 which correspond to the UV absorption band around 260 nm. Their properties are studied in the frame of the exciton theory, combining molecular dynamics simulations and quantum chemistry data. It is shown that the dipolar coupling undergoes important variations with the site and the helix geometry. In contrast, the energy of the monomer transitions within the double helix is not sensitive to the local environment. It is thus considered to be distributed over Gaussian curves whose maximum and width are derived from the experimental absorption spectra of nucleosides in aqueous solution. The influence of the spectral width on the excited state delocalization and the absorption spectra is much stronger than that of the oligomer plasticity. About half of the excited states are delocalized over at least two bases. Many of them result from the mixing of different monomer states and extend on both strands. The trends found in the simulated spectra, when going from non-interacting monomers to the duplex, are in agreement with experimental observations. Conformational changes enhance the diversity of the states which can be populated upon excitation at a given energy. The states with larger spatial extent are located close to the maximum of the absorption spectrum

Hormonal Contraception Use is Common Among Patients with Inflammatory Bowel Diseases and an Elevated Risk of Deep Vein Thrombosis:

Persons with inflammatory bowel disease (IBD) have an increased risk of venous thromboembolism (VTE). We sought to examine whether self-report of hormonal contraception (HC), as a proxy for exposure to estrogen-based contraception, was less common for women with multiple risk factors for VTE

Cytomegalovirus viral load in the colon and risk of colectomy in hospitalized patients with inflammatory bowel diseases

To the Editor: We read with interest the article of Lee et al1 describing the risk factors for adverse outcomes in hospitalized patients with ulcerative colitis (UC) with concurrent cytomegalovirus (CMV) colitis. CMV reactivation and resolution can be spontaneous in patients with UC regardless of antiviral therapy; however, inconsistencies between CMV detection methods of various studies and criteria for defining CMV positivity may be leading to these disparate findings.2,3 In the study by Lee et al, CMV colitis was defined by the presence of 1 or more inclusion bodies on hematoxylin and eosin staining or CMV immunohistochemistry on colonic biopsies. The most accurate approach for detection of clinically significant CMV infection has not been firmly established and guidelines differ in their recommendations.3,4 A recent study using quantitative colonic PCR in consecutive patients with UC undergoing endoscopy in the setting of a moderate to severe flare demonstrated a correlation between higher viral load and resistance to immunosuppressive therapy with significant differences found when using a cutoff viral load of .250 per milligram tissue.

Prevalence of a Gluten-free Diet and Improvement of Clinical Symptoms in Patients with Inflammatory Bowel Diseases:

Background—Maintaining a gluten free diet (GFD) without an underlying diagnosis of celiac disease has enjoyed widespread acceptance in the USA. Methods—We performed a cross-sectional study utilizing a GFD questionnaire in 1647 patients with inflammatory bowel diseases (IBD) participating in the CCFA Partners longitudinal, Internet-based cohort. Results—A diagnosis of celiac disease (CD) and non-celiac gluten sensitivity (NCGS) were reported by 10 (0.6%) and 81 (4.9%) respondents, respectively. Three hundred fourteen (19.1%) participants reported having previously tried a GFD and 135 (8.2%) reported current use of GFD. Overall 65.6% of all patients, who attempted a GFD described an improvement of their GI-symptoms and 38.3% reported fewer or less severe IBD flares. In patients currently attempting a GFD, excellent adherence was associated with significant improvement of fatigue (p<0.03). Conclusion—In this large group of patients with IBD, a substantial number had attempted a GFD, of whom the majority had some form of improvement in GI-symptoms. Testing a GFD in clinical practice in patients with significant intestinal symptoms, which are not solely explained by the degree of intestinal inflammation, has the potential to be a safe and highly efficient therapeutic approach. Further prospective studies into mechanisms of gluten sensitivity in IBD are warranted

Avoidance of Fiber Is Associated With Greater Risk of Crohn’s Disease Flare in a 6-Month Period

Chronic inflammatory bowel diseases (IBDs) have been associated with an abnormal mucosal response to the gastrointestinal microbiota. Although dietary fiber affects the gastrointestinal microbiota, there is limited information on the role of fiber on IBD activity. We investigated factors associated with fiber consumption and whether it was associated with flares in patients with IBD

Role of Nonsteroidal Anti-Inflammatory Drugs in Exacerbations of Inflammatory Bowel Disease

To determine the role of NSAIDs in activation of IBD

Champion Teams: An Implementation Strategy to Drive Practice Improvement

Developing collaborative practice is an ongoing process requiring frequent upgrades as team members and processes are added. Recently, faculty in ETSU’s Department of Family Medicine have been experimenting with a mechanism for iterative upgrades to team care practice known as Champion Teams. Champion Teams are based on the Institute of Medicine’s learning health care system approach in which practitioners develop an internal strategy for implementing new evidence based practices on an ongoing basis. In this presentation, our interprofessional team will describe team-based education and practice at ETSU as it relates to the Champion Team concept including its origins, evidence-base, and the logistics of how it functions. We will provide examples of four Champion Team projects including: 1) integrating behavioral health, 2) increasing attendance at medical visits, 3) increasing vaccination rates, and 4) a transition to a new pharmacological regimen for congestive heart failure patients. The exemplars will demonstrate how quality improvement data informed progressive changes and confirmed implementation outcomes. During discussion, we will encourage participants to identify their own targets for champion teams