Dynamic modeling of nitrogen losses in river networks unravels the coupled effects of hydrological and biogeochemical processes

The importance of lotic systems as sinks for nitrogen inputs is well recognized. A fraction of nitrogen in streamflow is removed to the atmosphere via denitrification with the remainder exported in streamflow as nitrogen loads. At the watershed scale, there is a keen interest in understanding the factors that control the fate of nitrogen throughout the stream channel network, with particular attention to the processes that deliver large nitrogen loads to sensitive coastal ecosystems. We use a dynamic stream transport model to assess biogeochemical (nitrate loadings, concentration, temperature) and hydrological (discharge, depth, velocity) effects on reach-scale denitrification and nitrate removal in the river networks of two watersheds having widely differing levels of nitrate enrichment but nearly identical discharges. Stream denitrification is estimated by regression as a nonlinear function of nitrate concentration, streamflow, and temperature, using more than 300 published measurements from a variety of US streams. These relations are used in the stream transport model to characterize nitrate dynamics related to denitrification at a monthly time scale in the stream reaches of the two watersheds. Results indicate that the nitrate removal efficiency of streams, as measured by the percentage of the stream nitrate flux removed via denitrification per unit length of channel, is appreciably reduced during months with high discharge and nitrate flux and increases during months of low-discharge and flux. Biogeochemical factors, including land use, nitrate inputs, and stream concentrations, are a major control on reach-scale denitrification, evidenced by the disproportionately lower nitrate removal efficiency in streams of the highly nitrate-enriched watershed as compared with that in similarly sized streams in the less nitrate-enriched watershed. Sensitivity analyses reveal that these important biogeochemical factors and physical hydrological factors contribute nearly equally to seasonal and stream-size related variations in the percentage of the stream nitrate flux removed in each watershed

Site-selective modification of proteins for the synthesis of structurally defined multivalent scaffolds

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A combination of classical site-directed mutagenesis, genetic code engineering and bioorthogonal reactions delivered a chemically modified barstar protein with one or four carbohydrates installed at specific residues. These protein conjugates were employed in multivalent binding studies, which support the use of proteins as structurally defined scaffolds for the presentation of multivalent ligands.DFG, SFB 765, Multivalenz als chemisches Organisations- und Wirkprinzip: Neue Architekturen, Funktionen und Anwendunge

Management of Dyspnea in Advanced Cancer: ASCO Guideline.

PURPOSE To provide guidance on the clinical management of dyspnea in adult patients with advanced cancer. METHODS ASCO convened an Expert Panel to review the evidence and formulate recommendations. An Agency for Healthcare Research and Quality (AHRQ) systematic review provided the evidence base for nonpharmacologic and pharmacologic interventions to alleviate dyspnea. The review included randomized controlled trials (RCTs) and observational studies with a concurrent comparison group published through early May 2020. The ASCO Expert Panel also wished to address dyspnea assessment, management of underlying conditions, and palliative care referrals, and for these questions, an additional systematic review identified RCTs, systematic reviews, and guidelines published through July 2020. RESULTS The AHRQ systematic review included 48 RCTs and two retrospective cohort studies. Lung cancer and mesothelioma were the most commonly addressed types of cancer. Nonpharmacologic interventions such as fans provided some relief from breathlessness. Support for pharmacologic interventions was limited. A meta-analysis of specialty breathlessness services reported improvements in distress because of dyspnea. RECOMMENDATIONS A hierarchical approach to dyspnea management is recommended, beginning with dyspnea assessment, ascertainment and management of potentially reversible causes, and referral to an interdisciplinary palliative care team. Nonpharmacologic interventions that may be offered to relieve dyspnea include airflow interventions (eg, a fan directed at the cheek), standard supplemental oxygen for patients with hypoxemia, and other psychoeducational, self-management, or complementary approaches. For patients who derive inadequate relief from nonpharmacologic interventions, systemic opioids should be offered. Other pharmacologic interventions, such as corticosteroids and benzodiazepines, are also discussed

Heat flow of the Earth and resonant capture of solar 57-Fe axions

In a very conservative approach, supposing that total heat flow of the Earth is exclusively due to resonant capture inside the Earth of axions, emitted by 57-Fe nuclei on Sun, we obtain limit on mass of hadronic axion: m_a<1.8 keV. Taking into account release of heat from decays of 40-K, 232-Th, 238-U inside the Earth, this estimation could be improved to the value: m_a<1.6 keV. Both the values are less restrictive than limits set in devoted experiments to search for 57-Fe axions (m_a<216-745 eV), but are much better than limits obtained in experiments with 83-Kr (m_a<5.5 keV) and 7-Li (m_a<13.9-32 keV).Comment: 8 page

ZnMoO4: a promising bolometer for neutrinoless double beta decay searches

We investigate the performances of two ZnMoO4 scintillating crystals operated as bolometers, in view of a next generation experiment to search the neutrinoless double beta decay of Mo-100. We present the results of the alpha vs beta/gamma discrimination, obtained through the scintillation light as well as through the study of the shape of the thermal signal alone. The discrimination capability obtained at the 2615 keV line of Tl-208 is 8 sigma, using the heat-light scatter plot, while it exceeds 20 sigma using the shape of the thermal pulse alone. The achieved FWHM energy resolution ranges from 2.4 keV (at 238 keV) to 5.7 keV (at 2615 keV). The internal radioactive contaminations of the ZnMoO4 crystals were evaluated through a 407 hours background measurement. The obtained limit is < 32 microBq/kg for Th-228 and Ra-226. These values were used for a Monte Carlo simulation aimed at evaluating the achievable background level of a possible, future array of enriched ZnMoO4 crystals.Comment: 9 pages, 8 figure

Sleep disorders, depressive symptoms and health-related quality of life-a cross-sectional comparison between kidney transplant recipients and waitlisted patients on maintenance dialysis

BACKGROUND: Kidney transplantation is believed to improve health-related quality of life (HRQoL) of patients requiring renal replacement therapy (RRT). Recent studies suggested that the observed difference in HRQoL between kidney transplant recipients (Tx) vs patients treated with dialysis may reflect differences in patient characteristics. We tested if Tx patients have better HRQoL compared to waitlisted (WL) patients treated with dialysis after extensive adjustment for covariables. METHODS: Eight hundred and eighty-eight prevalent Tx patients followed at a single outpatient transplant clinic and 187 WL patients treated with maintenance dialysis in nine dialysis centres were enrolled in this observational cross-sectional study. Data about socio-demographic and clinical parameters, self-reported depressive symptoms and the most frequent sleep disorders assessed by self-reported questionnaires were collected at enrollment. HRQoL was assessed by the Kidney Disease Quality of Life Questionnaire. RESULTS: Patient characteristics were similar in the Tx vs WL groups: the proportion of males (58 vs 60%), mean +/- SD age (49 +/- 13 vs 49 +/- 12) and proportion of diabetics (17 vs 18%), respectively, were all similar. Tx patients had significantly better HRQoL scores compared to the WL group both in generic (Physical function, General health perceptions, Energy/fatigue, Emotional well-being) and in kidney disease-specific domains (Symptoms/problems, Effect- and Burden of kidney disease and Sleep). In multivariate regression models adjusting for clinical and socio-demographic characteristics, sleep disorders and depressive symptoms, the modality of RRT (WL vs Tx) remained independently associated with three (General health perceptions, Effect- and Burden of kidney disease) out of the eight HRQoL dimensions analysed. CONCLUSIONS: Kidney Tx recipients have significantly better HRQoL compared to WL dialysis patients in some, but not all, dimensions of quality of life after accounting for differences in patient characteristics. Utilizing multidimensional disease-specific questionnaires will allow better understanding of treatment, disease and patient-related factors potentially affecting quality of life in patients with chronic medical conditions

IGF1 genotype, mean plasma level and breast cancer risk in the Hawaii/Los Angeles multiethnic cohort

The insulin-like growth factor 1 gene (IGF1) is a strong candidate gene for a breast cancer susceptibility model. We investigated a dinucleotide repeat 969 bp upstream from the transcription start site of the IGF1 gene for possible associations with plasma IGF1 levels and breast cancer risk in a multiethnic group of postmenopausal women. Furthermore, we investigated the relation between race/ethnicity, mean plasma IGF1 levels and breast cancer rates in the Hawaii/Los Angeles Multiethnic Cohort. The mean age-adjusted IGF1 level among Latino-American women, 116 ng ml(-1), was statistically significantly lower than the mean age-adjusted IGF1 levels for each of the three other racial/ethnic groups, African-American, Japanese-American and Non-Latino White women (146, 144 and 145 ng ml(-1), respectively) (P<0.0001). Latino-American women have the lowest breast cancer rates of any racial/ethnic group in the cohort. These results support the investigation of an expansion of the hypothesis for an important role of IGF1 in breast cancer tumorigenesis to different racial/ethnic groups and to postmenopausal women. It is unlikely that any involvement of IGF1 in breast cancer aetiology is mediated by the IGF1 dinucleotide repeat polymorphism, which was not significantly associated with circulating IGF1 levels nor breast cancer risk in this study. Research into relevant determinants of IGF1 levels in the blood must continue

Antiemetics: American Society of Clinical Oncology focused guideline update

Purpose: To update a key recommendation of the American Society of Clinical Oncology antiemetic guideline. This update addresses the use of the oral combination of netupitant (a neurokinin 1 [NK1] receptor antagonist) and palonosetron (a 5-hydroxytryptamine-3 [5-HT3] receptor antagonist) for the prevention of acute and delayed nausea and vomiting in patients receiving chemotherapy. Methods: An update committee conducted a targeted systematic literature review and identified two phase III clinical trials and a randomized phase II dose-ranging study. Results: In one phase III trial, the oral combination of netupitant and palonosetron was associated with higher complete response rates (no emesis and no rescue medications) compared with palonosetron alone in patients treated with anthracycline plus cyclophosphamide chemotherapy (74% v 67% overall; P = .001). In another phase III trial, the oral combination of netupitant and palonosetron was safe and effective across multiple cycles of moderately or highly emetogenic chemotherapies. In the phase II dose-ranging study, each dose of netupitant (coadministered with palonosetron 0.50 mg) produced higher complete response rates than palonosetron alone among patients receiving cisplatin-based chemotherapy. The highest dose of netupitant (ie, 300 mg) was most effective. Recommendations: All patients who receive highly emetogenic chemotherapy regimens (including anthracycline plus cyclophosphamide) should be offered a three-drug combination of an NK1 receptor antagonist, a 5-HT3 receptor antagonist, and dexamethasone. The oral combination of netupitant and palonosetron plus dexamethasone is an additional treatment option in this setting. The remaining recommendations from the 2011 ASCO guideline are unchanged pending a full update. Additional information is available at www.asco.org/guidelines/antiemetics and www.asco.org/guidelineswiki

Coping with the Lionfish Invasion: can targeted removals yield beneficial effects?

Invasive species generate significant environmental and economic costs, with maintenance management constituting a major expenditure. Such costs are generated by invasive Indo-Pacific lionfish (Pterois spp.) that further threaten already stressed coral reefs in the western Atlantic Ocean and Caribbean Sea. This brief review documents rapid range expansion and potential impacts of lionfish. In addition, preliminary experimental data from targeted removals contribute to debates about maintenance management. Removals at sites off Little Cayman Island shifted the size frequency distribution of remaining lionfish toward smaller individuals whose stomachs contained less prey and fewer fish. Fewer lionfish and decreased predation on threatened grouper, herbivores and other economically and ecologically important fishes represent key steps toward protecting reefs. However, complete evaluation of success requires long-term data detailing immigration and recruitment by lionfish, compensatory growth and reproduction of lionfish, reduced direct effects on prey assemblages, and reduced indirect effects mediated by competition for food. Preventing introductions is the best way to avoid impacts from invasive species and early detection linked to rapid response ranks second. Nevertheless, results from this case study suggest that targeted removals represent a viable option for shifting direct impacts of invasive lionfish away from highly vulnerable components of ecosystems