Phytoplankton composition of Sazlidere Dam lake, Istanbul, Turkey

The phytoplankton composition of Sazlidere Dam lake was studied at 5 sampling sites between December 2003 - November 2005. A total of 67 taxa were recorded, representing Bacillariophyta (31), Chlorophyta (18), Cyanophyta (9), Chrysophyta (1), Cryptophyta (1), Dinophyta (3) and Euglenophyta (4). Bacillariophyta members constituted the dominant phytoplankton group in terms of species number. Nygaard’s compound index value and composition of phytoplankton indicate that the trophic state of Sazlidere Dam lake was changing from oligotrophic to mesotrophic

The Impact of Festival Participation on Social Well-Being and Subjective Well-Being: A Study of the International Orange Blossom Carnival Visitors in Turkey

Festivals provide numerous benefits for societies. For instance, they enhance destinations’ images in visitors’ mind, therefore they are very useful marketing tools to promote the destinations and their attractions (Fredline & Faulkner, 2000; Yolal et al., 2016). They also have a great impact on boosting local economy through tax revenues, increased employment and business opportunities through increased visitor arrivals, expanded tourist season, and extended length of stay and expenditures (Yolal et al., 2009). Moreover, they have positive social impacts on local communities such as increasing the community attachment of residents (Lau & Li, 2015) and strengthening community ties with past or existing culture which help to preserve local culture (Bagiran & Kurgun, 2013). Beyond generating all the economic and social benefits and opportunities, festivals are likely to create positive significant impacts on both the residents’ and visitors’ subjective well-being (SWB) (Jepson & Stadler, 2017; Packer & Ballantyne, 2011; Yolal et al., 2016). Despite the substantial literature on the association between leisure, recreation, tourism, travel and subjective well-being (SWB), until recently, there are only few studies concerning festivals’ positive impacts on SWB (Jepson & Stadler, 2017; Yolal, Gursoy, & Uysal, 2016). Therefore, this study aimed to contribute to the limited understanding of the possible impacts of festival participation on SBW of festival participants. Moreover, the study investigated the relationships between the following main constructs: festival motivations, festival satisfaction, perceived social impacts of festival, social well-being, subjective wellbeing (positive affect, negative affect and life satisfaction), revisit intention and word of mouth. The study used a face to face survey to obtain quantitative data. The data was collected from the attendees of the 6th International Orange Blossom Carnival, 2018 in Adana, Turkey. A total of 652 festival visitors were approached and invited to participate in the survey. Of the 652 visitors, 550 accepted to be in the study and filled out the survey (response rate: %84). The data was analyzed using SPSS 25 and EQS 6.3 with advanced Confirmatory Factor Analyses (CFA). To test the hypothetical relationships, the structural equation modeling (SEM) method was adopted. Based on the results of final structural model, some hypotheses were rejected while most of the hypotheses failed to be rejected. While no significant relationship was found between festival motivation and wellbeing factors (positive affect, negative affect, life satisfaction and social wellbeing), significant association was found between festival satisfaction and wellbeing factors. The results also indicate that there is a significant relationship between the perceived social impacts of the festival and wellbeing of the festival attendees. Furthermore, the study also found that positive affect has a positive link to revisit intention and word of mouth, while negative affect has negative associations with both revisit intention and word of mouth. The findings suggest that moods during the festival impacts the participants intention to revisit the festival next year. Similar to affect, life satisfaction has also significant relationship with both revisit intention and word of mouth. This finding suggest that individuals who has higher life satisfaction has higher intention to revisit the festival. Finally, the study found a significant association link from social wellbeing to both revisit intention and word of mouth recommendations. The study provided important practical implications for festival organizers and community leaders to maximize the positive social benefits of festivals and gain more support for their organizations. Identifying the factors affecting subjective well-being of attendees and understanding the relationships among the factors can help organizers to develop strategies to monitor and better manage these factors

The Influence of Hotel Managers’ Intentions for Green Marketing Practices: An Application of the Theory of Planned Behavior in Turkey

What drives hotel managers to adapt green practices in their hotel especially in developing countries with less policy and control of environmental impacts? In seeking to answer this question, the developing country of Turkey was selected as an ideal context given the lack of sustainable development throughout its hospitality industry. Applying Theory of Planned Behavior (TPB) as the main theoretical framework, this research studied how hotel managers’ behavioral intentions are related to determinants within the TPB, and how managerial intentions predict their green marketing behavior. In addition to the existing constructs within the TPB model, environmental attitude (as measured through the NEP Scale) was added as a modification. Ultimately, the framework aimed to assess how marketing intentions translates to actual green marketing behavior among hotel managers throughout Turkey. Based on previous studies, an online survey was designed to measure the above constructs. A census was taken of all one-to five-star hotels and boutique hotels registered to Republic of Turkey Tourism and Culture Ministry. To potentially increase the response rate of participation, the researcher offered hotel managers an incentive of planting a tree for every completed questionnaire through TEMA (The Turkish Foundation for Combating Soil Erosion, for Reforestation and the Protection of Natural Habitats). Overall, 160 hotel managers completed questionnaires (i.e., a response rate of 8.3%). The result of the study indicates that environmental attitude, attitude toward green marketing, subjective norms and perceived behavior control each significantly predict managers’ intention to practice green marketing. Furthermore, the study found a strong relationship between managers’ intention to practice green marketing and green marketing behavior. Finally, theoretical relations and several implications associated with hotel managers and green marketing were presented. Additionally, the limitations of the study followed by suggestions for improvements and possible directions for future research were discussed. This study contributes to the organizational greening and green marketing literature by increasing the understanding of how managers’ attitudes and intentions toward green marketing are associated with green marketing practices at hotels in a developing country. Although managers should seriously pay attention to environmental issues and act responsibly, they do not always behave accordingly, because their behavior is directed by some constraints. Thus, financial aid seems to be especially important in developing countries. Governments should support hospitality sector by providing economic incentives for the industry to adopt environmentally sound practices. This may include certain creating environmental requirements in the hotel environmental standardization procedures and monitoring the process throughout time. Collaboration with stakeholders in regards to green marketing will also aid in alleviating problems with the hospitality tourism sector

Deciphering complex mechanisms of resistance and loss of potency through coupled molecular dynamics and machine learning [preprint]

Drug resistance threatens many critical therapeutics through mutations in the drug target. The molecular mechanisms by which combinations of mutations, especially involving those distal from the active site, alter drug binding to confer resistance are poorly understood and thus difficult to counteract. A strategy coupling parallel molecular dynamics simulations and machine learning to identify conserved mechanisms underlying resistance was developed. A series of 28 HIV-1 protease variants with up to 24 varied substitutions were used as a rigorous model of this strategy. Many of the mutations were distal from the active site and the potency to darunavir varied from low pM to near μM. With features extracted from molecular dynamics simulations, elastic network machine learning was applied to correlate physical interactions at the molecular level with potency loss. This fit to within 1 kcal/mol of experimental potency for both the training and test sets, outperforming MM/GBSA calculations. Feature reduction resulted in a model with 4 specific features that correspond to interactions critical for potency regardless of enzyme variant. These predictive features throughout the enzyme would not have been identified without dynamics and machine learning and specifically varied with potency. This approach enables capturing the conserved dynamic molecular mechanisms by which complex combinations of mutations confer resistance and identifying critical interactions which serve as bellwethers over a wide range of inhibitor potency. Machine learning models leveraging molecular dynamics can thus elucidate mechanisms that confer loss of affinity due to variations distal from the active site, such as in drug resistance

HIV-1 protease-substrate coevolution in nelfinavir resistance

Resistance to various human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. The virus accumulates mutations within the protease (PR) that render the PIs less potent. Occasionally, Gag sequences also coevolve with mutations at PR cleavage sites contributing to drug resistance. In this study, we investigated the structural basis of coevolution of the p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations by determining crystal structures of wild-type and NFV-resistant HIV-1 protease in complex with p1-p6 substrate peptide variants with L449F and/or S451N. Alterations of residue 30\u27s interaction with the substrate are compensated by the coevolving L449F and S451N cleavage site mutations. This interdependency in the PR-p1-p6 interactions enhances intermolecular contacts and reinforces the overall fit of the substrate within the substrate envelope, likely enabling coevolution to sustain substrate recognition and cleavage in the presence of PR resistance mutations. IMPORTANCE: Resistance to human immunodeficiency virus type 1 (HIV-1) protease inhibitors challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. Mutations in HIV-1 protease selected under the pressure of protease inhibitors render the inhibitors less potent. Occasionally, Gag sequences also mutate and coevolve with protease, contributing to maintenance of viral fitness and to drug resistance. In this study, we investigated the structural basis of coevolution at the Gag p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations. Our structural analysis reveals the interdependency of protease-substrate interactions and how coevolution may restore substrate recognition and cleavage in the presence of protease drug resistance mutations

Interdependence of Inhibitor Recognition in HIV-1 Protease

Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1\u27 and S2\u27 subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. All-atom molecular dynamics simulations starting from these structures were performed and systematically analyzed in terms of atomic fluctuations, intermolecular interactions, and water structure. These analyses reveal that the S1\u27 subsite highly influences other subsites: the extension of the hydrophobic P1\u27 moiety results in 1) reduced van der Waals contacts in the P2\u27 subsite, 2) more variability in the hydrogen bond frequencies with catalytic residues and the flap water, and 3) changes in the occupancy of conserved water sites both proximal and distal to the active site. In addition, one of the monomers in this homodimeric enzyme has atomic fluctuations more highly correlated with DRV than the other monomer. These relationships intricately link the HIV-1 protease subsites and are critical to understanding molecular recognition and inhibitor binding. More broadly, the interdependency of subsite recognition within an active site requires consideration in the selection of chemical moieties in drug design; this strategy is in contrast to what is traditionally done with independent optimization of chemical moieties of an inhibitor

The Levels of Ghrelin, TNF-α, and IL-6 in Children with Cyanotic and Acyanotic Congenital Heart Disease

Background/Aim. Ghrelin has effects on nutrient intake and growth. The cause of growth retardation in congenital heart disease is multifactorial. The aim of the present study is to investigate the ghrelin in congenital heart disease and the association of ghrelin with TNF-α and IL-6. Materials and methods. We measured serum ghrelin, TNF-α, and IL-6 levels using spesific immunoassay in 68 patients (47 acyanotic, 21 cyanotic with congenital heart disease) and in 25 control subjects. Results. In comparison to controls, serum ghrelin, TNF-α levels were significantly higher in acyanotic patients and cyanotic patients with congenital heart disease (P<.0001). In acyanotic and cyanotic patients with congenital heart disease, there was a positive correlation between ghrelin and TNF-α (r=.485, P<.05 and r=.573, P<.01, resp.). Conclusion. Serum ghrelin levels is elevated in acyanotic and cyanotic patients with congenital heart disease. Increased ghrelin levels represents malnutrition and growth retardation in these patients. The relation of ghrelin with cytokines may be explained by the possible effect of chronic congestive heart failure and chronic shunt hypoxemia

Does Hypothyroidism Affect Gastrointestinal Motility?

Background. Gastrointestinal motility and serum thyroid hormone levels are closely related. Our aim was to analyze whether there is a disorder in esophagogastric motor functions as a result of hypothyroidism. Materials and Methods. The study group included 30 females (mean age ± SE 45.17 ± 2.07 years) with primary hypothyroidism and 10 healthy females (mean age ± SE 39.40 ± 3.95 years). All cases underwent esophagogastric endoscopy and scintigraphy. For esophageal scintigraphy, dynamic imaging of esophagus motility protocol, and for gastric emptying scintigraphy, anterior static gastric images were acquired. Results. The mean esophageal transit time (52.56 ± 4.07 sec for patients; 24.30 ± 5.88 sec for controls; P = .02) and gastric emptying time (49.06 ± 4.29 min for the hypothyroid group; 30.4 ± 4.74 min for the control group; P = .01) were markedly increased in cases of hypothyroidism. Conclusion. Hypothyroidism prominently reduces esophageal and gastric motor activity and can cause gastrointestinal dysfunction

Serum Endothelin-1 and Transforming Growth Factor-β Levels in the Newborns With Respiratory Distress

The purpose of this present study was to evaluate the serum levels of ET-1 and TGF-β in the newborns with respiratory distress. In this study, newborns with respiratory distress hospitalized into the Newborn Intensive Care Unit were included. The highest values of ET-1 and TGF-β were obtained from newborns with diagnosis as meconium aspiration syndrome (5.70 ± 5.87 pg/mL and 3.75 ± 1.94 pg/mL, resp) in the sample obtained in the first six hours after birth, and these are statistically different from control group (P < .05). Also, same results were obtained for newborns with respiratory distress syndrome (3.37 ± 1.59 pg/mL and 2.05 ± 0.98 pg/mL, resp). After oxygen treatment, ET-1 values obtained in the first six hours of life were decreased regularly in the following days (P < .05). In the differentiating diagnosis of the respiratory distress of newborns, the investigation of ET-1 and TGF-β levels is meaningful. The ET-1 levels investigated in the first six hours is more useful in determining the prognosis, and repeating ET-1 levels in the following days is more meaningful to determine clinical response

Serum IL-1β, IL-6, IL-8, and TNF-α Levels in Early Diagnosis and Management of Neonatal Sepsis

Aim. To determine serum IL-1β, IL-6, IL-8, and TNF-α levels in neonatal sepsis at the time of diagnosis and after therapy, and to show the meaningful on the follow up. Methods. This prospective study was performed on newborns who were hospitalized for neonatal sepsis and who were classified as culture-proven sepsis (n=12), as culture-negative sepsis (n=21), and as healthy newborns (n=17). Results. At the time of diagnosis, serum IL-1β, IL-6, IL-8, and TNF-α levels of culture-proven sepsis were significantly higher than those of the control groups (P<.05). At the time of diagnosis, IL-1β, IL-6, IL-8, and TNF-α levels of culture-proven sepsis and culture-negative sepsis were significantly higher than levels at the seventh day after antibiotic treatment. Conclusion. Serum IL-1β, IL-6, IL-8, and TNF-α are mediators of inflammation and can be used at the diagnosis and at the evaluation of the therapeutic efficiency in neonatal sepsis