1,100 research outputs found
Effects of the oxylipin-producing diatom Skeletonema marinoi on gene expression levels of the calanoid copepod Calanus sinicus
Abstract Diatoms are eukaryotic unicellular plants that constitute one of the major components of marine phytoplankton, comprising up to 40% of annual productivity at sea and representing 25% of global carbon-fixation. Diatoms have traditionally been considered a preferential food for zooplankton grazers such as copepods, but, in the last two decades, this beneficial role has been challenged after the discovery that many species of diatoms produce toxic metabolites, collectively termed oxylipins, that induce reproductive failure in zooplankton grazers. Diatoms are the dominant natural diet of Calanus sinicus, a cold-temperate calanoid copepod that supports secondary production of important fisheries in the shelf ecosystems of the Northwest Pacific Ocean, Yellow Sea, Sea of Japan and South China Sea. In this study, the effect of the oxylipin-producing diatom Skeletonema marinoi on C. sinicus has been evaluated by analyzing expression level changes of genes involved in defense and detoxification systems. Results show that C. sinicus is more resistant to a diet of this diatom species in terms of gene expression patterns, compared to the congeneric species Calanus helgolandicus which is an important constituent of the temperate waters of the Atlantic Ocean and northern Mediterranean Sea. These findings contribute to the better understanding of genetic and/or phenotypic flexibility of copepod species and their capabilities to cope with stress by identifying molecular markers (such as stress and detoxification genes) as biosensors for environmental perturbations (e.g. toxins and contaminants) affecting marine copepods
Decayed, missing and filled teeth index and dental anomalies in long-term survivors leukaemic children: a prospective controlled study
Objective: The aim of this prospective controlled study is the comparison between long-term children survived
leukaemia and a control group in terms of the decayed, missing or filled permanent teeth (DMFT) and dental
anomalies.
Study design: Fifty-two long term children survived leukaemia, aged from 8 to 15 years (27 females, 25 males;
mean age 11.5 years) were evaluated for the possible effects of the anti-leukaemic therapy on dental development
and compared to a control group of 52 healthy children (27 females, 25 males, mean age 11 years). All long-term
children who survived were at least 24 months in continuous complete remission. The study of the dental status
with a routine oral examination and panoramic radiographs was performed. The DMFT (recorded according to
the WHO criteria) and dental anomalies were registered and evaluated.
Results: The results of this study evidence that long-term children survived leukaemia, in comparison with the
control group, have an higher risk to develop dental caries and show a greater severity of dental anomalies including V-shaped roots, dental agenesis, microdontia, enamel dysplasias.
Conclusions: Paediatric patients with haemathological diseases require a special attentions in dental care in addition to the antineoplastic treatment. Therefore, oral hygiene and oral health can be maintained thanks to a close
cooperation between the paediatric oncohaematologists, pediatrics dental surgeons and dental hygienists
Interplay of plasma-induced and fast thermal nonlinearities in a GaAs-based photonic crystal nanocavity
We investigate the nonlinear response of GaAs-based photonic crystal cavities
at time scales which are much faster than the typical thermal relaxation rate
in photonic devices. We demonstrate a strong interplay between thermal and
carrier induced nonlinear effects. We have introduced a dynamical model
entailing two thermal relaxation constants which is in very good agreement with
experiments. These results will be very important for Photonic Crystal-based
nonlinear devices intended to deal with practical high repetition rate optical
signals.Comment: 10 pages, 8 figures, Phys Rev A (accepted
An Alternative Approach for the Treatment of Major Aphthosis: Case Report
An effective treatment for aphthous stomatitis is not still available and its treatment consists only of therapeutic measures to suppress its symptoms. We report a case of a 60-year caucasian woman presented a 16-year history of episodes of multiple major recurrent ulcers in the oral mucosa. Topical application of Oralmedic® caused an improvement of pain, discomfort and healing of the aphthous ulcer. No adverse events or side effects were recorded. Oralmedic® is an effective topical device for the major aphthous ulcers treatmen
Test Structures for the Characterization of the Gate Resistance in 16 nm FinFET RF Transistors
The gate resistance is a parasitic element in transistors for RF and millimeter-wave circuits that can negatively impact power gain and noise figure. To develop accurate device models, a reliable measurement methodology is crucial. This article reviews the standard measurement methodology used in the literature and proposes also an additional method, which is evaluated using suitable test structures in a 16 nm FinFET process. The advantages and disadvantages of the two approaches are discussed along with their respective application scenarios
Promising activities of marine natural products against hematopoietic malignancies
According to the WHO classification of tumors, more than 150 typologies of hematopoietic and lymphoid tumors exist, and most of them remain incurable diseases that require innovative approaches to improve therapeutic outcome and avoid side effects. Marine organisms represent a reservoir of novel bioactive metabolites, but they are still less studied compared to their terrestrial counterparts. This review is focused on marine natural products with anticancer activity against hematological tumors, highlighting recent advances and possible perspectives. Until now, there are five commercially available marine-derived compounds for the treatment of various hematopoietic cancers (e.g., leukemia and lymphoma), two molecules in clinical trials, and series of compounds and/or extracts from marine micro-and macroorganisms which have shown promising properties. In addition, the mechanisms of action of several active compounds and extracts are still unknown and require further study. The continuous upgrading of omics technologies has also allowed identifying enzymes with possible bioactivity (e.g., L-asparaginase is currently used for the treatment of leukemia) or the enzymes involved in the synthesis of bioactive secondary metabolites which can be the target of heterologous expression and genetic engineering
Response of key stress-related genes of the seagrass Posidonia oceanica in the vicinity of submarine volcanic vents
Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO2) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO2, which is the main gaseous component of the emissions, may directly or indirectly confound the biota responses to high CO2. Here we used for the first time the expression of antioxidant and stress-related genes of the seagrass Posidonia oceanica to assess the stress levels of the species. Our hypothesis is that unknown factors are causing metabolic stress that may confound the putative effects attributed to CO2 enrichment only. We analyzed the expression of 35 antioxidant and stress-related genes of P. oceanica in the vicinity of submerged volcanic vents located in the islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize gene expression patterns. Fifty-one percent of genes analyzed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls at both Ischia and Panarea, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The up-regulation of genes involved in the free radical detoxification response (e.g., CAPX, SODCP and GR) indicates that, in contrast with Ischia, P. oceanica at the Panarea site faces stressors that result in the production of reactive oxygen species, triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. These proteins are activated to adjust stress-accumulated misfolded proteins and prevent their aggregation as a response to some stressors, not necessarily high temperature. This is the first study analyzing the expression of target genes in marine plants living near natural CO2 vents. Our results call for contention to the general claim of seagrasses as "winners" in a high-CO2 world, based on observations near volcanic vents. Careful consideration of factors that are at play in natural vents sites other than CO2 and acidification is required. This study also constitutes a first step for using stress-related genes as indicators of environmental pressures in a changing ocean.project HighGrass "High-CO2 effects on seagrass photosynthetic ecophysiology" [PTDC/MAREST/3687/2012]; MIUR Italian flagship project RITMARE; ESF COST Action "Seagrass Productivity: from genes to ecosystem management
Aging and oral care: An observational study of characteristics and prevalence of oral diseases in an Italian cohort
Background: Poor oral health is a common condition in patients suffering from dementia. Several aspects of this systemic pathology contribute to causing oral problems: cognitive impairment, behavior disorders, communication and, motor skills deterioration, low levels of cooperation and medical-nursing staff incompetency in the dental field. Objectives: The objectives of this study were to evaluate the prevalence and the characteristics of oral pathology in a demented elderly population, as well as to check the association between the different degree of dementia and the oral health condition of each patient. Materials and Methods: In this observational study (with cross-sectional design) two groups of elderly patients suffering from dementia, living in two different residential care institutions were recruited. The diagnosis of dementia of each included patient was performed using the Clinical Dementia Rating Scale. In order to evaluate the oral health condition of the included subjects, each patient underwent a physical examination of the oral cavity, during which different clinical parameters were analyzed (number of remaining teeth, oral mucosa, periodontal tissues, bone crests). To each parameter, a score was assigned. Spearman’s Rho test was used. Results: Regarding the prevalence of oral pathology in elderly suffering from dementia, it emerged that 20.58% of the included patients had mucosal lesions and/or new mucosal formations (in most cases undiagnosed and therefore untreated). The prevalence of periodontal disease was equal to 82.35% and a marked clinically detectable reabsorption of bone crests was found in almost all patients (88.23%). 24.13% of patients, who underwent the oral examination, had totally edentulous maxillae and/or with retained roots, without prosthetic rehabilitations. The correlation index r showed the presence of a linear correlation (inverse relationship) between the degree of dementia and the state of health of the oral cavity of each patient. Conclusions: Several factors contribute to poor oral health in the elderly suffering from dementia: cognitive functions deterioration, behavioral disorders and inadequate medical-staff nursing training on oral hygiene. This study also demonstrated that the lower the dementia degree is, the lower tends to be the oral health status. In order to guarantee a complete assistance to these patients, residential care institutions should include in their healthcare program specific dental protocols
Fem and Von Mises analysis of OSSTEM ® dental implant structural components: evaluation of different direction dynamic loads
Abstract
PURPOSE:
The objective of this investigation is to study prosthodontics and internal components resistance to the masticatory stress and considering different force directions by using Finite Element Method analysis (FEM). The structural materials of the components are usually Titanium alloy grade 4 or 5 and thus, guarantee the integration of the fixture in the bone due to the osteointegration phenomena. Even if the long-term dental implant survival rate is easy to be obtained and confirmed by numerous researches, the related clinical success, due to the alteration of the mechanical and prosthodontics components is still controversial.
METHODS:
By applying engineering systems of investigations like FEM and Von Mises analyses, it has been investigated how dental implant material was held against the masticatory strength during the dynamic masticatory cycles. A three-dimensional system involved fixture, abutment and the connection screws, which were created and analyzed. The elastic features of the materials used in the study were taken from recent literature data.
RESULTS:
Data revealed a different response for both types of devices, although implant neck and dental abutment showed better results for all conditions of loading while the abutment screw represented aweak point of the system.
CONCLUSION:
The data of this virtual model showed all the features of different prosthetic retention systems under the masticatory load. Clinicians should find better prosthetic balance in order to better distribute the stress over the component and to guarantee patients' clinical long-term results
FEM and Von Mises analysis on prosthetic crowns structural elements: evaluation of different applied materials
The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions
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