Effects of sintering temperature on morphology and mechanical characteristics of 3D printed porous titanium used as dental implant

Porous titanium samples were manufactured using the 3D printing and sintering method in order to determine the effects of final sintering temperature on morphology and mechanical properties. Cylindrical samples were printed and split into groups according to a final sintering temperature (FST). Irregular geometry samples were also printed and split into groups according to their FST. The cylindrical samples were used to determine part shrinkage, in compressive tests to provide stress-strain data, in microCT scans to provide internal morphology data and for optical microscopy to determine surface morphology. All of the samples were used in microhardness testing to establish the hardness. Below 1100 °C FST, shrinkage was in the region of 20% but increased to approximately 30% by a FST of 1300 °C. Porosity varied from a maximum of approximately 65% at the surface to the region of 30% internally. Between 97 and 99% of the internal porosity is interconnected. Average pore size varied between 24 μm at the surface and 19 μm internally. Sample hardness increased to in excess of 300 HV0.05 with increasing FST while samples with an FST of below 1250 °C produced an elastic–brittle stress/strain curve and samples above this displayed elastic–plastic behaviour. Yield strength increased significantly through the range of sintering temperatures while the Young's modulus remained fairly consistent.     

Enhancing the capacity of food consumption surveys of short duration to estimate long term consumer-only intakes by combination with a qualitative food frequency questionnaire

In principle, a proper risk assessment for a food chemical requires that the time-frame for food chemical intake estimates matches the time-frame for the toxicological assessments upon which the safety statements (ADI, PTW I, etc.) are based. For food additives, the toxicological assessments are based on exposure over a lifetime. While food consumption data cannot be collected over the lifetimes of individuals, the information should reflect habitual intakes as closely as possible. This study investigated the possibility of combining a 3-day food diary with a food frequency questionnaire to estimate mean consumer-only food intakes comparable to estimates based on a 14-day diary. The study population consisted of 948 teenagers and analysis was based on 32 clearly defined foods. For 47% of the foods, the difference was ≤ 1g/day. When expressed as portion sizes, 56% of the foods showed differences representing 14% of an average portion. When between-method differences (portions/day) were plotted against the mean of the methods, the mean between-method difference was 0.02 (± 0.06) portions/ day with limits of agreement of -0.10 to 0.14. This preliminary investigation suggests that the combined 3-day diary and FFQ method provides comparable estimates of mean consumer only intakes to a 14-day diary. Therefore, a qualitative FFQ may be a useful adjunct to a food consumption survey of short duration if estimates of longer term food intakes are required.     

Toward the interpretation of non-constructive reasoning as non-monotonic learning

We study an abstract representation of the learning process, which we call learning sequence, aiming at a constructive interpretation of classical logical proofs, that we see as learning strategies, coming from Coquand’s game theoretic interpretation of classical logic. Inspired by Gold’s notion of limiting recursion and by the Limit-Computable Mathematics by Hayashi, we investigate the idea of learning in the limit in the general case, where both guess retraction and resumption are allowed. The main contribution is the characterization of the limits of non-monotonic learning sequences in terms of the extension relation between guesses.     

Nutrient recovery and crop yield enhancement in irrigation with reclaimed wastewater: a case study

The paper reports results of treated wastewater reuse field experiments carried out in Apulia (Southern Italy). Fennel and lettuce were irrigated with four different water sources: three reclaimed wastewater streams, obtained by applying different treatment schemes to the same municipal wastewater, and a conventional source (well water). Differences between the three effluents were significant in terms of suspended solids and faecal indicators. Both lettuce and fennel yields were enhanced by the high content of nutrients in the effluent of one of the treatment plants, which had been operated for partial nitrogen removal. In particular, fennel productivity was enhanced by replacing chemical fertirrigation with the supply of nutrients contained in the irrigation water.     

Spontaneous conversion of gossypol to anhydrogossypol

An alkali-fast pigment is produced at room temperature when gossypol is dissolved in ethyl acetate. This pigment has been isolated from ethyl acetate as an orange crystalline material and identified as anhydrogossypol. The identity was established by identity of the infrared spectra with that of authentic anhydrogossypol; by elementary composition; by mixture-melting point behavior with authentic anhydrogossypol; and by the identity of the aniline derivatives produced from the orange crystalline product from ethyl acetate and authentic anhydrogossypol. One of the laboratories of the Southern Utilization Research and Development Division. Agricultural Research Service, U. S. Department of Agriculture.     

Use of cardiac troponin T rapid assay in the diagnosis of a myocardial injury secondary to electrical cardioversion

BACKGROUND AND HYPOTHESIS: This study was carried out to determine whether cardiac troponin T test in rapid assay gives positive results in patients previously submitted to cardioversion or electrical defibrillation. METHODS: Forty patients with supraventricular tachyarrhythmias lasting no more than 2 days were treated with electrical cardioversion. The total creatine phosphokinase (CPK)-MB isoenzyme and troponin T in rapid assay were measured at baseline and at 6, 12, and 24 h thereafter. RESULTS: Total CPK baseline levels were normal in all cases; within 4 h, the serum CPK levels increased by 98%, at 6 h by 111.5%, at 12 h by 168%, and at 24 h by 225% (p > 0.01). The CPK-MB isoenzyme showed no percentage increase of total CPK higher than 5%, measured at 6, 12, and 24 h after the shock, independent of the number of attempts of cardioversion. The troponin T test was also negative in all cases at baseline and at 6, 12, and 24 h after cardioversion. CONCLUSION: We conclude that the absence of elevations in CPK-MB levels and cardiac troponin T levels matched clinical and electrocardiographic results showing absence of myocardial damage after electrical cardioversion.     

Administration of 9-[2-(phosphonomethoxy)propyl]adenine (PMPA) for prevention of perinatal simian immunodeficiency virus infection in rhesus macaques

Simian immunodeficiency virus (SIV) infection of newborn macaques is a useful animal model to explore novel strategies to reduce perinatal human immunodeficiency virus (HIV) infection. The availability of two easily distinguishable virus isolates, SIVmac251 and the simian/human immunodeficiency virus chimera SHIV-SF33, allows tracing the source of infection following inoculation with both viruses by different routes. In the present study, we evaluated the efficacy of pre- and postinoculation treatment regimens with 9-[2-(phosphonomethoxy)propyl]adenine (PMPA) to protect newborn macaques against simultaneous oral SIVmac251 and intravenous SHIV-SF33 inoculation. Untreated newborns became persistently infected following virus inoculation. When three pregnant macaques were given a single subcutaneous dose of PMPA 2 hr before cesarean section, their newborns became SIV-infected following SIV and SHIV inoculation shortly after birth. In contrast, when four newborn macaques were inoculated simultaneously with SIV and SHIV, and started immediately on PMPA treatment for 2 weeks, only one animal became persistently SIV-infected; the remaining three PMPA-treated newborns, however, had some evidence of an initial transient virus infection but were seronegative and healthy at 8 months of age. Our data demonstrate that PMPA treatment can reduce perinatal SIV infection and suggest that similar strategies may also be effective against HIV.     

GC-EI-MS Analysis of Fatty Acid Composition in Brain and Serum of Twitcher Mouse

Globoid cell leukodystrophy or Krabbe disease is an inherited autosomal recessive disorder caused by mutations in the galactosylceramidase gene. The objective of the study was to present information about the fatty acid (FA) composition of the brain and serum of twitcher mice, a mouse model of Krabbe disease, compared to wild type, in order to identify biomarker of disease progression. We defined the FA profiles by identifying the main components present in serum and brain using GC‐EI‐MS analysis. The FA percentage composition was measured and data were analyzed considering the disease and the mouse age as experimental factors. Significant correlations were established, both in brain and in serum, in the fatty acid percentage composition of twitcher compared to wild type mice. The most abundant saturated fatty acid in brain was the palmitic acid (C16:0) with mean values significantly increased in twitcher mouse (p = 0.0142); moreover, three monounsaturated, three polyunsaturated (PUFA) and a plasmalogen were significantly correlated to disease. In the serum highly significant differences were observed between the two groups for three polyunsaturated fatty acids. In fact, the docosahexaenoic acid (C22:6n3c) content was significantly increased (p = 0.0116), while the C20 PUFA (C20:3n6c and C20:5n3c) were significantly decreased in twitcher serum samples. Our study shows a specific FA profile that may help to define a possible pattern that could distinguish between twitcher and wild type; these data are likely to provide insight in the identification of new biomarkers to monitor the disease progression and thereby permit the critical analysis of therapeutic approaches.     

Performing organic chemistry with inorganic compounds: electrophilic reactivity of selected nitrosyl complexes

The inorganic nitrosyl (NO(+)) complexes [Fe(CN) 5NO](2-), [Ru(bpy)2(NO)Cl](2+), and [IrCl 5(NO)](-) are useful reagents for the nitrosation of a variety of organic compounds, ranging from amines to the relatively inert alkenes. Regarding [IrCl 5(NO)](-), its high electrophilicity and inertness define it as a unique reagent and provide a powerful synthetic route for the isolation and stabilization of coordinated nitroso compounds that are unstable in free form, such as S-nitrosothiols and primary nitrosamines. Related to the high electrophilicity of [IrCl 5(NO)](-), an unusual behavior is described for its PPh 4(+) salt in the solid state, showing an electronic distribution represented by Ir(IV)-NO(*) instead of Ir (III)-NO(+) (as for the K(+) and Na(+) salts).