On finite-size effects in computer simulations using the Ewald potential

We discuss the origin and relevance for computer simulations of a strong finite-size effect that appears when using the Ewald summation formula. It can be understood as arising from a volume-dependent shift of the potential in a finite, periodic box relative to the infinite volume limit. This shift is due to the fact that the ``zero of energy'' for a periodic system cannot be defined by letting the interacting particles be separated by an infinite distance; the correct definition corresponds to setting its \bbox k=\bbox 0 Fourier mode to zero. The implications of this effect for computer simulations are discussed.Comment: Submitted to Journal of Chemical Physic

Copper accumulation in vineyard soils: Rhizosphere processes and agronomic practices to limit its toxicity.

Viticulture represents an important agricultural practice in many countries worldwide. Yet, the continuous use of fungicides has caused copper (Cu) accumulation in soils, which represent a major environmental and toxicological concern. Despite being an important micronutrient, Cu can be a potential toxicant at high concentrations since it may cause morphological, anatomical and physiological changes in plants, decreasing both food productivity and quality. Rhizosphere processes can, however, actively control the uptake and translocation of Cu in plants. In particular, root exudates affecting the chemical, physical and biological characteristics of the rhizosphere, might reduce the availability of Cu in the soil and hence its absorption. In addition, this review will aim at discussing the advantages and disadvantages of agronomic practices, such as liming, the use of pesticides, the application of organic matter, biochar and coal fly ashes, the inoculation with bacteria and/or mycorrhizal fungi and the intercropping, in alleviating Cu toxicity symptoms

Random forests highlight the combined effect of environmental heavy metals exposure and genetic damages for cardiovascular diseases

Heavy metals are a dangerous source of pollution due to their toxicity, permanence in the environment and chemical nature. It is well known that long-term exposure to heavy metals is related to several chronic degenerative diseases (cardiovascular diseases, neoplasms, neurodegenerative syndromes, etc.). In this work, we propose a machine learning framework to evaluate the severity of cardiovascular diseases (CVD) from Human scalp hair analysis (HSHA) tests and genetic analysis and identify a small group of these clinical features mostly associated with the CVD risk. Using a private dataset provided by the DD Clinic foundation in Caserta, Italy, we cross-validated the classification performance of a Random Forests model with 90 subjects affected by CVD. The proposed model reached an AUC of 0.78 ± 0.01 on a three class classification problem. The robustness of the predictions was assessed by comparison with different cross-validation schemes and two state-ofthe-art classifiers, such as Artificial Neural Network and General Linear Model. Thus, is the first work that studies, through a machine learning approach, the tight link between CVD severity, heavy metal concentrations and SNPs. Then, the selected features appear highly correlated with the CVD phenotype, and they could represent targets for future CVD therapies

Global sexual fertility in the opportunistic pathogen aspergillus fumigatus and identification of new supermater strains

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. A sexual cycle in Aspergillus fumigatus was first described in 2009 with isolates from Dublin, Ireland. However, the extent to which worldwide isolates can undergo sexual reproduction has remained unclear. In this study a global collection of 131 isolates was established with a near 1:1 ratio of mating types. All isolates were crossed to MAT1-1 or MAT1-2 Irish strains, and a subset of isolates from different continents were crossed together. Ninety seven percent of isolates were found to produce cleistothecia with at least one mating partner, showing that sexual fertility is not limited to the Irish population but is a characteristic of global A. fumigatus. However, large variation was seen in numbers of cleistothecia produced per cross, suggesting differences in the possibility for genetic exchange between strains in nature. The majority of crosses produced ascospores with >50% germination rates, but with wide variation evident. A high temperature heat shock was required to induce ascospore germination. Finally, a new set of highly fertile MAT1-1 and MAT1-2 supermater strains were identified and pyrimidine auxotrophs generated for community use. Results provide insights into the potential for the A. fumigatus sexual cycle to generate genetic variation and allow gene flow of medically important traits

Evaluation of microbial contamination of air in two haematology departments equipped with ventilation systems with different filtration devices

Background. Nosocomial infections (NI) are above all due to health-care workers practices, but also the contamination of the environment could lead to their rise in health-care facilities. Introduction. In the last years, the incidence of NI has increased due to a substantial rise in the number of immuno-compromised patients. These patients are often gathered in hospital areas declared at ?high risk? of infection such as Hematology and Bone Marrow Transplant ward. In this study, we evaluated microbial contamination of the air in two divisions with high risk patients, focusing on the validity of the air system with correla- tion to the presence or not of the HEPA absolute filters. Methods. An environmental surveillance study has been carried out in two Divisions of Haematology, in two different Hospitals. Investigations have been performed by sampling air and by analyzing bacterial and fungal growth on microbiology plates after an incubation period. Results. Unit A, without HEPA filters in the ventilation systems, showed a gradual increase in the bacterial load 20 and 60 days after cleaning of the ventilation system. Mycetes and Aspergilli were not present in basal conditions, at 20 or 60 days after decontamination. Unit B, equipped with HEPA filters placed at the inlet vents, showed extremely low values of the bacterial load either in basal conditions or upon inspection 60 days after cleaning. No mycetes were present. Discussion. From the results obtained, it was evident that fol- lowing the cleaning operation, the quality of the air is excellent in both types of equipment, since no mycetes were present and the bacterial load was inf. 20 CFU/mc in all the sites tested. However, although in subsequent controls mycetes were absent in both types of equipment, a great difference in the suspended bacterial load was found: Unit B was close to sterility whereas in Unit A a progressive increase was observed

Extended adjuvant endocrine treatment for premenopausal women: A Delphi approach to guide clinical practice

The use of an aromatase inhibitor (AI) in combination with ovarian function suppression (OFS) has become the mainstay of adjuvant endocrine therapy in high-risk premenopausal patients with hormone receptor-positive breast cancer. Although five years of such therapy effectively reduces recurrence rates, a substantial risk of late recurrence remains in this setting. Multiple trials have shown that extending AI treatment beyond five years could offer further protection. However, as these studies comprised only postmenopausal patients, no direct evidence currently exists to inform about the potential benefits and/or side effects of extended AI + OFS therapies in premenopausal women. Given these grey areas, we conducted a Delphi survey to report on the opinion of experts in breast cancer treatment and summarize a consensus on the discussed topics. A total of 44 items were identified, all centred around two main themes: 1) defining reliable prognostic factors to pinpoint premenopausal patients eligible for endocrine therapy extension; 2) designing how such therapy should optimally be administered in terms of treatment combinations and duration based on patients’ menopausal status. Each item was separately discussed and anonymously voted by 12 experts representing oncological institutes spread across Italy. The consensus threshold was reached in 36 out of 44 items (82%). Herein, we discuss the levels of agreement/disagreement achieved by each item in relation to the current body of literature. In the absence of randomized trials to guide the tailoring of extended AI treatment in premenopausal women, conclusions from our study provide a framework to assist routine clinical practice

326peffectiveness of trastuzumab emtansine tdm1 in patients with her2 positive advanced breast cancer abc progressing after taxane plus pertuzumab plus trastuzumab

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Controversial topics in metastatic HR+/HER2- breast cancer: Guiding treatment by a modified Delphi approach

The treatment of HR+/HER2- metastatic breast cancer with cyclin-dependent kinases 4 and 6 inhibitors combined with endocrine therapy has recently emerged as the most relevant therapeutic strategy. However, in routine clinical practice, the best therapeutic approach in patients with comorbidities at early relapsing or ab initio metastatic disease, PI3KCA mutation, is still debated among oncologists. Given these areas of uncertainty, we conducted a Delphi survey to describe and confront the level of agreement or disagreement between clinicians working in referral vs local spoke oncological hospitals and summarize a consensus on these debated topics. In total, 56 items were drafted using the Nominal Group Technique and used for the Delphi Survey. A total of 46 clinicians participated in the survey. Overall, the consensus threshold among all participants was reached in 46/56 items (82%), and Delphi Survey results showed a high level of consensus. For the 10 items (18%) that did not reach the consensus threshold, possible explanations considering differences in clinical practice and recent findings from literature are provided in the Discussion. Outcomes from the present survey may help guide treatment in multiple comorbidities, early recurring and ab initio metastatic disease, and PI3KCA mutation, where evidence from randomized trials and level 1 evidence is currently missing