Energy conversion efficiency in betavoltaic cells based on the diamond Schottky diode with a thin drift layer.

The HPHT diamond Schottky diode was assembled as a Metal/Intrinsic/p-doped structure betavoltaic cell (BC) with a very thin (1 µm) drift layer and tested under 5-30 keV electron beam irradiation using a scanning electron microscope (SEM). The effect of the ß-radiation energy and the backscattering of electrons on the energy conversion was studied. From the results obtained, it is shown that, the efficiency of the investigated BC increases from 1.01 to 3.75% with the decrease of ß-particle energy from 30 to 5 keV due to an increase of the electron beam absorption in a thin drift layer. Maximum efficiency is achieved when the electron beam energy is close to the average ß-decay energy of 3H. The BC maximum output power of the 1.6 µW was obtained at an electron beam energy of 15 keV, that matches the ß-decay energy of 63Ni. The total BC conversion efficiency at 15 keV electron-beam energy is about 3%. The calculations indicated that a preferable ß-source for the diamond based BCs with a thin (1 µm) drift layer is 63Ni.

Temperature-dependent impact of thermal aminolaevulinic acid photodynamic therapy on apoptosis and reactive oxygen species generation in human dermal fibroblasts.

BACKGROUND: Actinic keratoses (AKs) are generally accepted as common precursor lesions to invasive squamous cell carcinoma. Photodynamic therapy (PDT) is a common, in-office, field therapy modality used in the treatment of AKs. Clinical and laboratory observations have demonstrated that temperature modulation can affect PDT efficacy. OBJECTIVES: To demonstrate thermal PDT increases apoptotic cell death, and to investigate the mechanistic role of reactive oxygen species (ROS) free radicals in an in vitro human skin fibroblast model. METHODS: This study was completed using commercially available primary human skin fibroblasts treated with aminolaevulinic acid (ALA) at specific concentrations and controlled temperatures. Cell death, apoptosis and superoxide ROS levels were quantified. RESULTS: We found that thermal PDT with 0·5 mmol L(-1) ALA resulted in significant temperature-dependent increases in total apoptosis and superoxide ROS generation between 33 °C and 42 °C. CONCLUSIONS: Our results indicate that thermal PDT significantly increases apoptotic cell death through increased generation of superoxide ROS in a temperature-dependent manner.

An immunohistochemical panel to assess ultraviolet radiation-associated oxidative skin injury.

Ultraviolet (UV) radiation results in a significant loss in years of healthy life, approximately 1.5 million disability-adjusted life years (DALYs), and is associated with greater than 60,000 deaths annually worldwide that are attributed to melanoma and other skin cancers. Currently, there are no standardized biomarkers or assay panels to assess oxidative stress skin injury patterns in human skin exposed to ionizing radiation. Using biopsy specimens from chronic solar UV-exposed and UV-protected skin, we demonstrate that UV radiation-induced oxidative skin injury can be evaluated by an immunohistochemical panel that stains 8-hydroxydeoxyguanosine (8-OH-dG) to assess DNA adducts, 4-hydroxy-2-nonenal (HNE) to assess lipid peroxidation, and advanced glycation end products (AGEs) to assess protein damage. We believe this panel contains the necessary cellular biomarkers to evaluate topical agents, such as sunscreens and anti-oxidants that are designed to prevent oxidative skin damage and may reduce UV-associated skin aging, carcinogenesis, and inflammatory skin diseases. We envision that this panel will become an important tool for researchers developing topical agents to protect against UV radiation and other oxidants and ultimately lead to reductions in lost years of healthy life, DALYs, and annual deaths associated with UV radiation.

Laser and light-based treatment of Keloids--a review.

BACKGROUND: Keloids are an overgrowth of fibrotic tissue outside the original boundaries of an injury and occur secondary to defective wound healing. Keloids often have a functional, aesthetic, or psychosocial impact on patients as highlighted by quality-of-life studies. OBJECTIVES: Our goal is to provide clinicians and scientists an overview of the data available on laser and light-based therapies for treatment of keloids, and highlight emerging light-based therapeutic technologies and the evidence available to support their use. METHODS: We employed the following search strategy to identify the clinical evidence reported in the biomedical literature: in November 2012, we searched PubMed.gov, Ovid MEDLINE, Embase and Cochrane Reviews (1980-present) for published randomized clinical trials, clinical studies, case series and case reports related to the treatment of keloids. The search terms we utilized were 'keloid(s)' AND 'laser' OR 'light-emitting diode' (LED) OR 'photodynamic therapy' (PDT) OR 'intense pulsed light' OR 'low level light' OR 'phototherapy.' RESULTS: Our search yielded 347 unique articles. Of these, 33 articles met our inclusion and exclusion criteria. CONCLUSION: We qualitatively conclude that laser and light-based treatment modalities may achieve favourable patient outcomes. Clinical studies using CO2 laser are more prevalent in current literature and a combination regimen may be an adequate ablative approach. Adding light-based treatments, such as LED phototherapy or PDT, to laser treatment regimens may enhance patient outcomes. Lasers and other light-based technology have introduced new ways to manage keloids that may result in improved aesthetic and symptomatic outcomes and decreased keloid recurrence.

The effect of platelet-rich plasma (PRP) combined with a bone allograft on human periodontal ligament (PDL) cells.

The prominent purpose of the study was the evaluation of the in vitro mitogenic effect of three different homologous platelet-rich plasma (PRP) preparations (PRPa, PRPb, PRPc) on three different lines of periodontal ligament (PDL) cells (PDL(1,2,3)), cultured alone or in combination with a demineralized freeze-dried allograft (DFBA). PDL cell cultures were derived from the mid root of three maxillary caries-free premolars extracted for orthodontic reasons. Cells were grown and reached confluence. To evaluate the mitogenic effect of all exogenous factors (PRPa, PRPb, PRPc and DFBA) on PDL cells, specific number of cells (10.000/well) was cultured in the presence or absence of the above factors. Each PRP preparation (5% v/v) was added in all cell lines, in the absence or presence of 10 mg/ml of DFBA. The cells were also treated with 25 ng/ml bFGF (positive control). The mitogenic effect was evaluated 24 h after incubation, using the Trypan blue exclusion assay. The results revealed that all PRP preparations act as potent mitogens as they significantly induced cell proliferation on PDL(1,2,3) lines. All PRP preparations when added alone in the PDL cell cultures, exhibited a significant advantage over the positive control (bFGF). The addition of DFBA to PRP did not influence significantly cell proliferation in all cell lines, comparatively to PRP alone, at the time -period studied. The findings of this study demonstrate the beneficial role of PRP alone or combined with the bone graft on periodontal ligament cells in vitro, suggesting that it may be considered as a potential biological approach in periodontal regeneration.

Effect of rhTGF-ß1 combined with bone grafts on human periodontal cell differentiation.

Various techniques and materials have been proposed for the treatment of periodontal defects. In periodontal regeneration, periodontal ligament (PDL) cell differentiation as well as certain growth factors and their delivery system applied are critical. The purpose of this study was to evaluate the in vitro effect of recombinant human transforming growth factor-beta 1 (rhTGF-ß1) combined with two different bone grafts on human PDL (hPDL) cell differentiation. The hPDL cells were treated with TGF-ß1 alone or in combination with a calcified freeze-dried bone allograft (FDBA) and a porous biphasic calcium phosphate (BC) bone graft. Cell differentiation effect was estimated by measuring alkaline phosphatase (ALPase) activity and osteocalcin secretion. Results demonstrated that rhTGF-ß1 alone or in combination with FDBA and BC provoked a significant (p<0.05) increase in ALPase activity as compared with controls. The findings of this study confirmed the beneficial role of rhTGF-ß1 combined with FDBA and BC as carriers in periodontal regeneration.

Effect of rhBMP-7 combined with two bone grafts on human periodontal ligament cell differentiation.

The purpose of this study was to evaluate the in vitro effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) combined with demineralised freeze-dried bone allograft (DFDBA) and an inorganic bovine material with a synthetic peptide (PepGen P-15) on human periodontal ligament (hPDL) cell differentiation, in a time-dependent manner. hPDL cells were cultured and treated with: (1) 500 ng/ml of rhBMP-7, (2) 10 mg of DFDBA or PepGen P-15 and (3) their combination. Cell differentiation was estimated after 48 and 72 h by measuring alkaline phosphatase (ALPase) activity and osteocalcin (OC) secretion. The presence of rhBMP-7, DFDBA, PepGen P-15, rhBMP-7 + DFDBA and rhBMP-7+ PepGen P-15 promoted a significant increase of ALPase activity after 48 and 72 h. The combination of rhBMP-7 with DFDBA or PepGen P-15 did not lead to significant OC secretion. The results of this study imply that rhBMP-7 stimulates the early osteoblastic differentiation of hPDL cells and that DFDBA and PepGen P-15 could serve as carriers for rhBMP-7.

Eosinophilic granuloma masquerading as aggressive periodontitis.

BACKGROUND: Eosinophilic granuloma (EG) is the mildest and mainly localized form of the clinicopathologic spectrum of Langerhans' cell histiocytosis. It is a destructive osseous lesion characterized by a vast number of eosinophils and histiocytes. The etiology remains unknown. In this paper, a case of EG is presented that was initially diagnosed and treated as aggressive periodontitis (AP). METHODS: Despite treatment procedures, the EG continued to expand very quickly, destroying the lingual cortical bone and the neighboring soft tissues and exhibiting periosteal reaction. Diagnosis of EG was established on the basis of histopathologic and immunohistochemical evaluation. Moreover, certain manifestations in the skeletal and respiratory system were observed. RESULTS: Surgical curettage of the lesions was effective; however, corticosteroids and low-dose radiation were used as adjunctive therapy. CONCLUSION: The rapid progress of eosinophilic granuloma, the diagnostic problems, and the consequences of late diagnosis and treatment are discussed.