Effect of kolsterising treatment on surface properties of a duplex stainless steel

In recent years, attempts of engineering the surface of duplex stainless steels were made in order to enhance their hardness and tribological properties, without affecting their corrosion resistance. A possibility of improving these properties is provided by a family of processes developed by Prof. B.H. Kolster in the Netherlands in the late 1980’s. These processes (usually referred to as Kolsterising® treatments) consist in a low temperature surface carburizing, which involves the diffusion of large quantities of carbon atoms (up to 6-7 wt.%) into the steel at a diffusion temperature below 450 °C. In the present paper a characterization of the surface layer of Kolsterised duplex SAF 2205 stainless steel was carried out to study the effects of this treatment on surface properties. The characterization includes optical metallographic examination, microhardness tests and SEM-EDS investigation on the Kolsterised steel in the as treated condition and after annealing treatments at 200, 250, 300 350 and 400°C for 10 hours, to evaluate the stability of Kolsterised layer’s properties with a moderate increase in temperature. Moreover, complying with ASTM G48-03 Method E Standard, in order to evaluate the effect of the Kolsterising® treatment on steel pitting resistance, the critical pitting temperature was obtained for Kolsterised duplex SAF 2205 stainless steel compared with the base metal

Ocular manifestations in Gorlin-Goltz syndrome

Background: Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients. Results: Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients. Conclusions: The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients

Análisis de los datos de radiación solar disponibles en Ushuaia, Argentina

Se presentan los promedios mensuales de la irradiación global diaria registrados en Ushuaia por la Red Solarimétrica y por la estación VAG. Se analiza el comportamiento de los promedios mensuales de irradiación difusa diaria y se establece una relación lineal entre la fracción difusa/global y el índice de claridad, lo que permite validar la relación propuesta por Suehrcke como una apropiada herramienta de estimación.We present monthly mean values of daily global irradiation measured in Ushuaia, given by the Solarimetric Network and GAW stations. We analyzed the behavior of monthly mean values of diffuse irradiation and established a linear relationship between diffuse/global ratio and clearness index; so it is possible to confirm the validity of Suehrcke’equation as an appropriate instrument for estimating mean global irradiation.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Antiparasitic effect of stilbene and terphenyl compounds against trypanosoma cruzi parasites

Background: Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. No progress in the treatment of this pathology has been made since Nifurtimox was introduced more than fifty years ago, and this drug is considered very aggressive and may cause several adverse effects. This drug currently has severe limitations, including a high frequency of undesirable side effects and limited efficacy and availability, so research to discover new drugs for the treatment of Chagas disease is imperative. Many drugs available on the market are natural products as found in nature or compounds designed based on the structure and activity of these natural products. Methods: This study evaluated the in vitro antiparasitic activity of a series of previously synthesized stilbene and terphenyl compounds in T. cruzi epimastigotes and intracellular amastigotes. The action of the most selective compounds was investigated by flow cytometric analysis to evaluate the mechanism of cell death. The ability to induce apoptosis or caspase-1 inflammasomes was assayed in macrophages infected with T. cruzi after treatment, comparing it with that of Nifurtimox. Results: The stilbene ST18 was the most potent compound of the series. It was slightly less active than Nifurtimox in epimastigotes but most active in intracellular amastigotes. Compared to Nifurtimox, it was markedly less cytotoxic when tested in vitro on normal cells. ST18 was able to induce a marked increase in parasites positive for Annexin V and monodansylcadaverine. Moreover, ST18 induced the activation, in infected macrophages, of caspase-1, a conserved enzyme that plays a major role in controlling parasitemia, host survival and the onset of the adaptive immune response in Trypanosoma infection. Conclusions: The antiparasitic activity of ST18 together with its ability to activate caspase-1 in infected macrophages and its low toxicity toward normal cells makes this compound interesting for further clinical investigation

Análisis de los datos de radiación solar disponibles en Ushuaia, Argentina

Se presentan los promedios mensuales de la irradiación global diaria registrados en Ushuaia por la Red Solarimétrica y por la estación VAG. Se analiza el comportamiento de los promedios mensuales de irradiación difusa diaria y se establece una relación lineal entre la fracción difusa/global y el índice de claridad, lo que permite validar la relación propuesta por Suehrcke como una apropiada herramienta de estimación.We present monthly mean values of daily global irradiation measured in Ushuaia, given by the Solarimetric Network and GAW stations. We analyzed the behavior of monthly mean values of diffuse irradiation and established a linear relationship between diffuse/global ratio and clearness index; so it is possible to confirm the validity of Suehrcke’equation as an appropriate instrument for estimating mean global irradiation.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Análisis de los datos de radiación solar disponibles en Ushuaia, Argentina

Se presentan los promedios mensuales de la irradiación global diaria registrados en Ushuaia por la Red Solarimétrica y por la estación VAG. Se analiza el comportamiento de los promedios mensuales de irradiación difusa diaria y se establece una relación lineal entre la fracción difusa/global y el índice de claridad, lo que permite validar la relación propuesta por Suehrcke como una apropiada herramienta de estimación.We present monthly mean values of daily global irradiation measured in Ushuaia, given by the Solarimetric Network and GAW stations. We analyzed the behavior of monthly mean values of diffuse irradiation and established a linear relationship between diffuse/global ratio and clearness index; so it is possible to confirm the validity of Suehrcke’equation as an appropriate instrument for estimating mean global irradiation.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Evaluating Ecklonia maxima water-soluble polysaccharides as a growth promoter of tomato seedlings and resistance inducer to Fusarium wilt

Alternatives to chemicals for plant management are increasingly used to reduce environmental pollution. Seed treatment with natural products may act as a priming effect by stimulating seedling growth and plant defence responses against fungal pathogens. In this framework, algae produce a wide variety of bioactive metabolites, which can be used in agriculture as biofertilizers or biostimulants. The purpose of this study was to investigate the possible role of water-soluble polysaccharides (WSPs) from the brown alga Ecklonia maxima applied on tomato seed in enhancing plant growth and inducing resistance to Fusarium oxysporum via modulation of multiple physiological parameters and metabolic pathways. Here, we first characterized the E. maxima WSPs by FT-IR spectroscopy, and then we tested the WSPs as growth promoters on tomato seedlings, and the physiological and defence responses of plants during pathogen infection. We found that WSP seed treatment without pathogen challenge stimulated seedling height and root growth by 24.5 and 62.9%, respectively. Under pathogen infection, plants exhibited long-lasting resistance against F. oxysporum until 46 days after seed treatment. The metabolic changes associated with resistance to Fusarium wilt in plant roots were related to an increase in phenols, flavonoids and protein contents as well as a higher chitinase and beta-1,3-D-glucanase enzyme activity. Moreover, PR1a, PR3 and other defence gene expressions were significantly increased. Resistance to F. oxysporum as a result of WSP seed treatment was also supported by FT-IR analysis of tomato roots. Infected roots showed a decrease in the relative intensity of the bands due to the syringyl ring and amide I and amide II in proteins. In contrast, WSP treatment alone and in the presence of the pathogen exhibited a spectral profile similar to that of the control. This research emphasizes the potential role of algal polysaccharides applied by seed treatment in promoting seedling growth and priming plant resistance against soil-borne pathogens

Hyperpigmented spots at fundus examination: a new ocular sign in neurofibromatosis type I

Background: Neurofibromatosis Type I (NF1), also termed von Recklinghausen disease, is a rare genetic disorder that is transmitted by autosomal dominant inheritance, with complete penetrance and variable expressivity. It is caused by mutation in the NF1 gene on chromosome 17 encoding for neurofibromin, a protein with oncosuppressive activity, and it is 50% sporadic or inherited. The disease is characterized by a broad spectrum of clinical manifestations, mainly involving the nervous system, the eye and skin, and a predisposition to develop multiple benign and malignant neoplasms. Ocular diagnostic hallmarks of NF1 include optic gliomas, iris Lisch nodules, orbital and eyelid neurofibromas, eyelid café-au-lait spots. Choroidal nodules and microvascular abnormalities have recently been identified as additional NF1-related ocular manifestations. The present study was designed to describe the features and clinical significance of a new sign related to the visual apparatus in NF-1, represented by hyperpigmented spots (HSs) of the fundus oculi. Results: HSs were detected in 60 (24.1%) out of 249 patients with NF1, with a positive predictive value of 100% and a negative predictive value of 44.2%. None of the healthy subjects (150 subjects) showed the presence of HSs. HSs were visible under indirect ophthalmoscopy, ultra-wide field (UWF) pseudocolor imaging and red-only laser image, near-infrared reflectance (NIR)-OCT, but they were not appreciable on UWF green reflectance. The location and features of pigmentary lesions matched with the already studied NF1-related choroidal nodules. No significant difference was found between the group of patients (n = 60) with ocular HSs and the group of patients (n = 189) without ocular pigmented spots in terms of age, gender or severity grading of the disease. A statistically significant association was demonstrated between the presence of HSs and neurofibromas (p = 0.047), and between the presence of HSs and NF1-related retinal microvascular abnormalities (p = 0.017). Conclusions: We described a new ocular sign represented by HSs of the fundus in NF1. The presence of HSs was not a negative prognostic factor of the disease. Following multimodal imaging, we demonstrated that HSs and choroidal nodules were consistent with the same type of lesion, and simple indirect ophthalmoscopy allowed for screening of HSs in NF1

Effect of Kolsterising treatment on surface properties of a duplex stainless steel

In recent years, attempts of engineering the surface of duplex stainless steels were made in order to enhancetheir hardness and tribological properties, without affecting their corrosion resistance. A possibility ofimproving these properties is provided by a family of processes developed by Prof. B.H. Kolster in theNetherlands in the late 1980’s. These processes (usually referred to as Kolsterising® treatments) consist in a lowtemperature surface carburizing, which involves the diffusion of large quantities of carbon atoms (up to 6-7wt.%) into the steel at a diffusion temperature below 450 °C. In the present paper a characterization of thesurface layer of Kolsterised duplex SAF 2205 stainless steel was carried out to study the effects of this treatmenton surface properties. The characterization includes optical metallographic examination, microhardness testsand SEM-EDS investigation on the Kolsterised steel in the as treated condition and after annealing treatments at200, 250, 300, 350 and 400°C for 10 hours, to evaluate the stability of Kolsterised layer’s properties with amoderate increase in temperature. Moreover, complying with ASTM G48-03 Method E Standard, in order toevaluate the effect of the Kolsterising® treatment on steel pitting resistance, the critical pitting temperature wasobtained for Kolsterised duplex SAF 2205 stainless steel compared with the base metal