Free boundary problem for the role of planktonic cells in biofilm formation and development

The dynamics of biofilm lifecycle are deeply influenced by the surrounding environment and the interactions between sessile and planktonic phenotypes. Bacterial biofilms typically develop in three distinct stages: attachment of cells to a surface, growth of cells into colonies, and detachment of cells from the colony into the surrounding medium. The attachment of planktonic cells plays a prominent role in the initial phase of biofilm lifecycle as it initiates the colony formation. During the maturation stage, biofilms harbor numerous microenvironments which lead to metabolic heterogeneity. Such microniches provide conditions suitable for the growth of new species, which are present in the bulk liquid as planktonic cells and can penetrate the porous biofilm matrix. We present a 1D continuum model on the interaction of sessile and planktonic phenotypes in biofilm lifestyle which considers both the initial attachment and colonization phenomena. The model is formulated as a hyperbolic-elliptic free boundary value problem with vanishing initial value. Hyperbolic equations reproduce the transport and growth of sessile species, while elliptic equations model the diffusion and conversion of planktonic cells and dissolved substrates. The attachment is modelled as a continuous, deterministic process which depends on the concentrations of the attaching species. The growth of new species is modelled through a reaction term in the hyperbolic equations which depends on the concentration of planktonic species within the biofilm. Existence and uniqueness of solutions are discussed and proved for the attachment regime. Finally, some numerical examples show that the proposed model correctly reproduces the growth of new species within the biofilm and overcomes the ecological restrictions characterizing the Wanner-Gujer type models.Comment: 17 pages, 9 figures, preprint versio

Different water and light regimes affect ionome composition in grapevine (Vitis vinifera L.)

Many inorganic cations play a major role in winemaking processes and wine quality. For this reason, chemistry at the elemental level ("ionomic") of the grape berry is of concern not only to the viticulturist, but also to the oenologist due to their direct impact on juice and must composition, which in turn affect wine quality. The aim of this research was to evaluate the effect of reduced irrigation and incident light (by means of micronized calcite) on the berry skin ionome of the Italian red grape 'Aglianico'. The study was carried out in a five-years-old vineyard (Vitis vinifera L. 'Aglianico') located in Southern Italy. Half of the plants (IRR) were drip irrigated, whereas the other half were not irrigated (NIR). Half of IRR and NIR plants were treated with Megagreen® micronized calcite. In all the treatments, plant water status and gas exchange were determined. The mean values of stem water potential (ψw) during the experiment were –1.02 and –1.10 MPa in IRR and NIR, respectively. The calcite treatments did not show changes in ψw values if compared to the untreated ones. The values of gas exchange were not statistically different among the four treatments. Grape berries were separated into three groups of mass, and the levels of macroelements, microelements and lanthanides were measured. Irrigation and calcite significantly affected macroelements distribution in all the three groups of mass, with Fe, Cu and Zn being significantly higher in the IRR and calcite-treated treatments. The effect of irrigation on the changes in microelement levels was significant for some elements. Calcite-treated vines showed higher mean values of Co, Cd, Hg and Pb. Regarding lanthanides, in calcite-untreated vines, irrigation determined significant decreases in average La, Ce, Nd, whereas in calcite-treated vines, increases in the mean concentrations of Ce, Nd, Sm, Gd, Dy, Er and Yb were found. Generally, lanthanide levels did not change between calcite-treated and untreated vines, and in all the treatments Lu resulted to be the most abundant one. Macroelements, microelements and lanthanide levels generally decreased with decreasing berry weight. The dynamics of the extractability of metals from grape berries to must during fermentation could be used to predict wine quality during the following processes and for wine traceability purposes.

Benthic enrichment in the Georgia Bight related to Gulf Stream intrusions and estuarine outwelling

The distribution patterns of benthic biomass (microbiota, meiofauna, and macrofauna) over the expansive continental shelf of the Georgia Bight suggest nutrient inputs from intrusions of deep Gulf Stream waters at the shelf break…

Subcutaneous emphysema during third molar surgery: a case report

Extraction of third molars is the most common surgical procedure performed in oral surgery on a daily basis and, despite surgical skills and expertise, complications may occur. Complications observed during or after third molar removal may include pain, swelling, bleeding, infection, sinus perforation and nerve damage. Fortunately, with a proper management and a good surgical technique, the incidence of such events is low. Subcutaneous emphysema associated with dental extraction occurs when the air from the high-speed dental handpiece is forced into the soft tissue through the reflected flap and invades the adjacent tissues, leading to swelling, crepitus on palpation and occasionally spreading through the tissue spaces of the fascial planes. Although rare, iatrogenic subcutaneous emphysema can have serious and potentially life-threatening consequences. Care should be taken when using air-driven handpieces. The access of air into the facial tissues is not limited to tooth extractions, but may also occur through other portals of entrance, such as endodontically treated teeth, periodontium and lacerations of intraoral soft tissues. When subcutaneous emphysema occurs, it must be quickly diagnosed and properly managed to reduce the risk of further complications. This report presents a case of subcutaneous emphysema occurred during extraction of a mandibular third molar extraction with the use of an air turbine handpiece. Case management is described and issues relative to the diagnosis and prevention of this surgical complication are discussed

CO2 laser ablation of oral leukoplakia: with or without extension of margins?

The purpose is to determine the sufficient extension of margins during laser ablation of oral leukoplakia and observe its short-term recurrence rate. Materials and Methods.The study was designed as a randomized controlled clinical trial was conducted on 33 oral leukoplakia lesions diagnosed in 30 patients (16 Females and 14 Males) with an age range between 39 and 79 years. The lesions were divided into three groups; Group A: 11 lesions in 11 patients, in which the laser ablation was done for the entire lesion without extension of margins; Group B: 11 lesions in 8 patients, in which the laser ablation was done for the lesion adding at least 3mm extension of margins; and finally the Group Control: consists of 11 untreated lesions in 11 patients, in which only “wait and see” approach was done. Results. Complete healing of 13 lesions occurred in both groups A and B. Complete regression of 3 lesions occurred in Group Control. After 6 months of follow-up, 6 of 9 lesions in both groups A and B that showed the recurrence, had shown an initial recurrence after 3 weeks of the laser ablation. Patients with no history of smoking habits showed complete healing of 87.5%, while in ex-smokers complete healing was 42.8%. The statistical analysis was performed, and the averages of all groups are significantly different (p <0.00001).Discussion.The primary treatment focuses on the elimination of associated risk factors (smoking, alcohol, and local irritating factors). In the literature, the recurrence rate varies between 13.6% and 40.7%, while in our study, it was 45.5% in Group A and 36.4% in Group B. Conclusion.The recommended extension of margins should be at least 3mm in width. Further research can be performed to evaluate the immediate re-ablation of the lesions which showed an initial recurrence after 3 weeks of laser ablation

Genotoxicity assessment of three nutraceuticals containing natural antioxidants extracted from agri-food waste biomasses

Grapes and apples are the most cultivated fruits in the Mediterranean basin and their agricultural processing is responsible for the production of a large amount of bio-waste. The reuse of this food biomass would increase the volume of recyclable/renewable biomaterial and lower the environmental impact due to the increasing demand for these biological products. To this purpose, agri-food waste from grape and apple processing have become an important source of phytochemicals, and many pharmaceutical industries are using it as starting material to produce dietary supplements, functional foods, and food additives for human consumption. In virtue of the chemical diversity and complexity of agri-food biowaste, developers and producers of nutraceuticals are advised to assess the safety of their final nutraceutical products, in compliance with European Food Safety Authority regulation. Here, we use the Ames test to assess the mutagenicity of three nutraceuticals obtained from agri-food waste biomasses: Taurisolo® from grape pomace of Vitis vinifera L. cv 'Aglianico', AnnurComplex® from Malus pumila M. cv 'Annurca' and Limoncella Apple Extract from Malus domestica B. cv 'Limoncella'. The results showed that all three nutraceuticals were non-mutagenic

A Phase III, randomized study to evaluate the immunogenicity and safety of an MF59®-adjuvanted A/H1N1 pandemic influenza vaccine in HIV-positive adults

AbstractBackground and aimsAntibody responses to vaccines are suboptimal in immunosuppressed HIV-positive individuals. This study aimed to evaluate the potential benefits of MF59® adjuvant or a second A/H1N1 influenza vaccine dose in HIV-positive adults.MethodHIV-positive adults (n=61) and HIV-negative controls (n=93) aged 18–60years received two doses of A/H1N1, either as MF59-adjuvanted A/H1N1 pandemic vaccine, or as part of a unadjuvanted seasonal influenza vaccine containing the pandemic strain. Immunogenicity was assessed against the vaccine strain, A/California/7/2009, by haemagglutination inhibition (HI) assay three weeks after the administration of each vaccine dose. Local and systemic reactions were recorded for three days after each vaccination. Unsolicited adverse events were recorded throughout the six-week study period.ResultsBoth adjuvanted and unadjuvanted vaccines met the European licensure criteria in HIV-positive and HIV-negative study groups after a single dose. Lower antibody titres were observed with both adjuvanted and unadjuvanted vaccine in HIV-positive compared to HIV-negative subjects. A second dose of either vaccine did not compensate for the lower response of HIV-infected subjects. In HIV-positive subjects, CD4+ T cell counts and levels of CD38 expression on CD8+ T cells remained stable throughout the study period. Both vaccine formulations were generally well tolerated, with no increased reactogenicity observed in response to the adjuvanted vaccine.ConclusionAntibody responses in HIV-positive subjects were acceptable but lower than those in healthy control subjects, whether subjects were immunized with one or two doses of adjuvanted or unadjuvanted vaccine. Vaccination did not affect rates of HIV replication, CD4+ T cells counts, or levels of CD38 expression among patients under successful antiretroviral treatment

May Polyphenols Have a Role Against Coronavirus Infection? An Overview of in vitro Evidence

The coronavirus infection is constantly diffusing worldwide and the incidence of death is dramatically increasing, representing one of the greatest disasters in human history. Nowadays, no effective therapeutic approaches have been licensed, despite the rising interest of the scientific research in this specific field, and the daily growing number of publications, while the need to find novel strategies is urgent. Evidence in the literature reported the antiviral activity of polyphenols, the largest class of bioactive compounds in nature. Interestingly, a limited number of studies investigated the efficacy of polyphenols from different raw materials, directly against coronaviruses. The present manuscript aimed to report this evidence and provide a viewpoint on the possibility to use it as a start point for the development of novel natural approaches against this viral infection, eventually designing further appropriate researches