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β-Alanine and its derivatives are important starting materials for the preparation of peptides or compounds with biological activity. In this work, the authors are presenting a new approach for the synthesis of N-alkyl-β-amino acids and N-alkyl-β-amino esters using dendrimeric intermediates in a one-pot reaction, with friendly reaction conditions. Dendrimeric compounds, with a pentaerythritol core, were easy prepared and used to obtain the β-amino acid derivatives and β-amino esters with good yields. This paper presents the first reaction where dendrimers are used for synthesizing organic compounds. Spectroscopic characterization by 1H- and 13C-NMR of dendrimers and final products is also presented.
Childhood obesity is considered one of the most serious public health problems of the 21st century. Obesity-associated inflammation could be one of the mechanisms that triggers insulin resistance that could drive systemic alterations such as metabolic disorder. Recently, circulating levels of S100A4 has been associated with insulin resistance and subcutaneuous white adipose tissue inflammation independently of body mass index (BMI) in a cohort of obese adults. Nonetheless, the link between S100A4 and insulin resistance in children is still not known yet. Thus, the aim of the study was to determine if S100A4 plasma levels were associated with insulin resistance status in a cohort of prepuberal children.
Material and methods:
In this case-control multicentre study, 250 prepuberal children took part and were stratified in six groups according to sex, obesity stage and insulin resistance status. Blood samples were withdrawn in resting conditions after an overnight fasting. Anthropometric measurements and a routine biochemical analyses were performed. Homeostasis model assessment for insulin resistance index (HOMA-IR) was calculated using fasting plasma glucose and insulin values. S100A4 plasma levels were determined by ELISA CSBEL02032HU (Cusabio Biotech, Wuhan, China).
A lineal multiple regresión (α = 0.05) identified a significative association between S100A4 plasma levels and HOMA-IR in the cohort; each HOMA-IR increasing unit correlated with an increase of 0.008mg/dL in S100A4 plasma levels. (SE = 0.003 and p = 0.02). Moreover, we also observed a positive significative association between S100A4 plasma levels and glucose blood levels (p = 0.005) and BMI (p = 0.008). Inter-group comparations analyses revealed significative differences between normal-weight and insulino-resistant obese boys (p = 0.024). The same result was obtained between normal-weight and insulino-resistant obese girls (p = 0.04), finding a higher S100A4 concentration in insulino- resistant children. As expected, plasma S100A4 levels were also higher in obese children versus normal-weight children (p = 0.02).
These data could be clinical relevant due to the possible potential of S100A4 protein as a new circulating biomarker of resistance insulin in a cohort of prepuberal children. These results are supported by other studies in obese adults and adolescents. In conclusion, these results suggest that S100A4 is associated with obesity and insulin resistance in prepuberal children. However, more studies are needed to study the implication and mechanism of this protein in the development of insulin resistance.
Lifestyles are involved in the pathogenesis of depression and many of these factors can be modified for the potential prevention of depression. Our aim was to assess the association between a healthy-lifestyle score, that includes some less-studied lifestyle indicators, and the risk of depression.
We followed 14,908 participants initially free of any history of depression in the “Seguimiento Universidad de Navarra” (SUN) cohort. Information was collected biennially from 1999 to December 2016. We calculated a healthy-lifestyle score (0–10 points), previously associated with cardioprotection, by giving one point to each of the following components: never smoking, physical activity (> 20 METs-h/week), Mediterranean diet adherence (≥ 4 points), healthy body mass index (≤ 22 kg/m2), moderate alcohol consumption (women 0.1–5 g/d; men 0.1–10 g/d of ethanol), avoidance of binge drinking (never more than 5 alcoholic drinks in a row), low television exposure (≤ 2 h/d), short afternoon nap (≤ 30 min/day), time spent with friends (>1 h/d) and working at least 40 h/week.
During a median follow-up of 10.4 years, we observed 774 new cases of major depression among participants initially free of depression. The highest category (8–10 factors) showed a significant inverse association with a 32% relative risk reduction for depression compared to the lowest category (0–3 factors) (multivariable-adjusted hazard ratio: 0.68; 95% CI:0.49-0.95) (p for trend = 0.010).
Adopting a healthy-lifestyle was associated with a lower risk of incident depression in the SUN cohort. This index, including ten simple healthy lifestyle habits, may be useful for a more integrative approach to depression prevention.
Insulin resistance (IR) is the major driver for the development of obesity-associated metabolic and cardiovascular complications. It is well known that IR increase physiologically during puberty; hence, pubertal maturation might favour this metabolic risk in obese children. Recently, a study carried out in adult women with obesity has identified a new adipokine, known as S100A4, strongly associated with IR and inflammation in adipose tissue. On the contrary, little is known about the implication of S100A4 in the development of such metabolic disturbances during the onset and course of pubertal development.
Materials and methods:
A longitudinal study was conducted on 53 Spanish girls distributed in six experimental conditions according to their obesity and IR status (before (T0) and after (T1) the onset of puberty). Anthropometric and biochemical parameters were evaluated in all samples and time points. Classification of pubertal stage was made according to the Tanner scale. S100A4 protein levels were quantified by ELISA CSB-EL02032HU in plasma samples (Cusabio Biotech, Wuhan, China). The statistical analysis of the results was carried out with the “nlme” package in R v3.4.4, using a mixed-effects linear model with random intercept and slope.
At a significance level of alpha = 0.05, a linear mixed-effects model reported a significant association (P = 0.03) between the interaction term “time*experimental group” and S100A4 levels. Post-hoc pairwise comparisons between experimental groups revealed a strong association between a worsening/improvement of the IR status and the increase/decrease of S100A4 levels (yielding significant results for 5 of the 15 comparisons (P = 0.008, P = 0.04, P = 0.02, P = 0.04 and P = 0.02)). Furthermore, a multiple linear regression model reported a positive correlation between the increase in S100A4 levels and the increase in HOMA values during the course of puberty (B = 6.03, SE = 2.66 and P = 0.028).
The S100A4 protein is strongly associated with the development of IR in girls with childhood obesity and this association is accentuated during pubertal development. Increase in S100A4 levels could be one of the molecular mechanisms by which pubertal maturation favour an increased metabolic risk in children with obesity.
Based on wettability and reaction interfaces previously reported, as well as on thermodynamic considerations, a likely mechanism has been proposed for the chemical interaction taking place at the metal/ceramic interface during wettability experiments carried out by the so-called “sessile drop” method. The experiments involved three Ag-Cu-based brazing alloys [Cusil (Ag-28wt.%Cu), Cusil-ABA (Ag-34.6wt.%Cu-1.58wt.%Ti) and Incusil-ABA (Ag-26.6wt.%Cu-12.4wt.%In-0.89wt.%Ti)] and as polished and pre-oxidized pressure-less sintered silicon carbide (PLS-SiC), with a total holding time of 90 minutes at 850 °C, under a Zr sponge-gettered vacuum of 10-4/10-5 Torr.
An alternative method for the standardless quantitative x-ray diffraction analysis of mixtures of inorganic crystalline phases proposed in the literature several years ago is presented. Our method requires only previously calculated μ*i values from tabulated data for all phases present in the mixtures. It does not require either the determination of calibration constants or the use of external standards, but it does require that the number of analyzed mixtures is larger than or equal to the number of phases present in them, and that the chemical composition of the mixtures are significantly different from each other. The integrated intensities of the chemically pure phases are estimated by a least-squares procedure from XRD data obtained from the mixtures. The method was tested against data published in the literature, with good results. Finally, a general expression for the “Normalized Height Law” proposed on an empirical basis by other researchers, has been theoretically derived.
In the present study, aiming to control the setting reaction and to increase the strength of hydroxyapatite-based biocements, gelatin, citric acid and malonic acid, and combinations of them, were used as binders. The mechanical strength of the developed biocements was evaluated after 1 to 15 days of exposure (aging) to air with 100% relative humidity at 37-40 °C. Especially for the case of gelatin, the mechanical properties of the biocements increased as a function of aging time in the humid environment. In this case, the standard compressive strength increased from ∼19 to ∼40 MPa, while the diametral compressive strength increased from ∼2 to ∼12 MPa, between day 1 and day 15 of aging. These values are similar to those reported in the past for HAp-containing biocements added with a variety of organic or inorganic binders. However, the resulting setting times were too long. Thus, it was proposed that crosslinking of gelatin by a suitable chemical agent during the application of the prepared HAp-based biocements could be a potential way to control their handling and setting characteristics, while preserving their good mechanical properties, good biocompatibility, and good solubilization characteristics in the presence of biological fluids.
Glasses and glass-ceramics of the system Diopside [D, CaMgSi2O6] - Fluorapatite [FAp, Ca5(PO4)3F] were synthesized and characterized. The studied theoretical phase compositions were (wt%): 1) 70% D-30% FAp, 2) 60% D-40% FAp and 3) 80% D-20% FAp. The glass-ceramics were synthesized by isothermal treatment of the corresponding parent glasses at either 800, 900 or 1000 °C, with holding times of either 30 min, 2 h or 5 h at high temperature. The in vitro bioactivities of all materials were tested in Kokubo’s Simulated Body Fluid (SBF), for 21 days at pH = 7.4 and 37 °C. All materials were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM/EDS). In all cases, the in vitro bioactivity increased with decreasing crystallization degree in the materials, which was likely due to an inhibitory effect of the structural changes occurring during thermal treatment of the glasses. This was more accentuated for long thermal treatments. After 21 days of soaking in the SBF, an apatite-like surface layer, with a Ca/P molar ratio close to 1.67, was formed in the case of the parent glass of composition 2. This was attributed to an enhancing effect of so-called “phase separation” phenomenon that took place during the synthesis of that particular glass. Lastly, the MgO content of the glasses made no clear difference on their in vitro bioactivity.
Hydroxyapatite [HAp, Ca5(PO4)3(OH)] was synthesized by chemical precipitation, using H3PO4 and Ca(OH)2 as chemical precursors. The precursors were slowly mixed in suitable proportions aiming to obtain Ca/P molar ratios of 1.5, 1.67 or 2.0 in the reacting suspension. This was followed by 21.5 h of aging. Both reaction and aging stages were carried out under an atmosphere of still ambient air and under continuous stirring, either at room temperature, 60 or 90 °C. The precipitates were characterized by ICP-AES and XRD. The results suggested that the most suitable Ca/P molar ratio for the production of pure phase HAp is Ca/P = 1.67, as long as the initial Ca(OH)2 particle size and/or the suspension pH are carefully controlled, especially when the synthesis is carried out above room temperature.
Cordierite (Mg2Al4Si5O18), Mullite (Al4+2xSi2-2xO10-x) and Cordierite-Mullite ceramic materials were obtained from a stoichiometric mixture of coal fly ash (CFA) as a source of SiO2 and Al2O3, plus high-purity MgO and Al2O3. The starting stoichiometric mixtures were homogenized, and then uniaxially pressed, cold isostatically pressed, and sintered at 1200-1600 °C for 2-5 h. The sintered materials were characterized by X-ray diffraction, scanning electron microscopy, Vickers microhardness, density and four-point flexural strength. In general, the desired phases tended to form in the composites at temperatures of 1350 or 1400 °C, with a considerable amount of glassy phase developing from 3 h onwards at one of those two temperatures, depending on the composite composition. The microstructure of the composites consisted of a matrix of Cordierite and interwoven needles of Mullite. The bulk density decreased, while the flexural strength and the Vickers microhardness increased with increasing nominal content of Mullite in the composites. A synergistic effect taking place between Cordierite and Mullite enhances the mechanical properties of the composites.
Glass-ceramics of eutectic composition in the wollastonite [W, CaO⋅SiO2]- tricalcium phosphate [TCP, β-Ca3(PO4)2] binary system were synthesized by using the glass-crystallization method. The parent glass was crystalized at 800-1300 °C for 0.5-5 h. The in vitro bioactivity of the synthesized glass-ceramics was tested in Kokubo’s Simulated Body Fluid (SBF) for 7-21 days, at pH = 7.4 and 37 °C. All materials were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM/EDS). The results showed that metastable Apatite phase [Ap, Ca10(PO4)6O], plus W and TCP phases expected according to the binary phase diagram, were formed. Ap was the first phase formed at 900 °C/0.5 h, which was followed by formation of W phase at 900 °C/2 h and of TCP phase at 1200 °C/0.5 h. The relative proportion of the formed crystalline phases was a function of heat treatment temperature and time. A eutectic microstructure was obtained for the materials heat-treated at 1300 °C for 2 or 5 h. All glass-ceramics showed the formation of a hydroxyapatite (HAp)-like layer during the in vitro bioactivity tests. After 21 days of soaking in SBF, the samples treated at 1300 °C/5 h showed a behavior similar to that typically shown by Bioeutectic® material, while the materials heat-treated at lower temperatures tended to form denser HAp-like layers, with similar thicknesses but with higher Ca/P molar ratios.
The effects of thermal treatments on the thermoluminescent (TL) signal of NaCl (ACS reagent) induced by gamma radiation were investigated. Samples of NaCl were thermally treated at 500, 800 and 1000 °C and characterized by X-Ray diffraction and scanning electron microscopy. After their exposure 0.1 to 150 Gy of gamma radiation from a gamma-ray source of 60Co, a TL curve for each temperature of treatment was obtained. We observed a different TL behavior on the irradiated samples as a function of the temperature applied during the thermal treatments. For the sample treated at 500 °C, three peaks centered at 102, 133 and 228 °C were observed. Samples treated at 800 and 1000 °C showed two main peaks at 128 and 220 °C and 136 and 219 °C, respectively; however, the highest TL intensity signal was observed for the sample at 800 °C. All samples showed a linear dependency of the integrated TL intensity from the signal emitted as function of the irradiation time. This is an important advantage because NaCl could be applied as a very low cost thermoluminescent dosimetric material. A comparison between the TL signal induced by gamma radiation in pure and Eu doped NaCl is also reported.
The Asian citrus psyllid Diaphorina citri Kuwayama is a destructive insect pest in citriculture, because it is an efficient vector of the proteobacteria ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. africanus’ (Laf) and ‘Ca. L. americanus’ (Lam). These bacteria cause the ‘huanglongbing’ disease or ‘greening’ or ‘yellow dragon’ disease. The disease kills the plant and reduces fruit production. This insect pest is susceptible to entomopathogenic fungi, and we report the use of different strains of Metarhizium anisopliae, Cordyceps bassiana and Isaria fumosorosea against the nymphs and adults of D. citri under field conditions. The fungi were applied four times using a concentration of 2 × 1013 conidia/ha with a time interval of 15 days between applications. The percentage of control of Cb 108, Ma 65, Ma 14 and Ifr 4 was 60, 50, 40 and 35% in nymphs, and 50, 50, 42 and 22% in adults, respectively. Metarhizium anisopliae, C. bassiana and I. fumosorosea applied on Persian lime groves are more effective in reducing higher density of nymphs than adults of D. citri.
In this work the effect on the adsorption of Cr (VI) by thermally treated Hydrotalcite-like Material (HTM) synthesized by the sol-gel method with a Mg/Al = 2 was studied. The characterization of the HTM before and after Cr (VI) removal, as well as the kinetic studies were carried out. When the HTM are thermally treated at 350ºC the hydrotalcite crystalline structure remains and the textural properties improve. The Cr (VI) adsorption capacity of HTM was 125 mg of Cr (VI) / g of HTM. This capacity augments at 132 mg of Cr (VI) / g of HTM after heating HTM at 300°C. The crystallinity as well the porosity of the HTM diminished after adsorption of Cr (VI), due to the obstruction of both the pores and the interlayer space. The adsorption of Cr (VI) occurred before 4 minutes contact time. It can be concluded that HTM exhibits a high Cr (VI) adsorption capacity in a short time.
Glass-ceramics based on hypo-eutectic (GC1) and hyper-eutectic (GC2) compositions of the Wollastonite (W, CaSiO3) - Tricalcium Phosphate [TCP, Ca3(PO4)2] binary system, which are saturated with SiO2 during the glass melting stage, are synthesized by the petrurgic method, using cooling rates of 0.5, 1 or 2°C/h. All synthesized materials are subjected to in vitro bioactivity tests using Kokubo's Simulated Body Fluid (SBF). Primary a-Cristobalite is formed in all cases. Metastable Apatite [Ap, Ca10(PO4)6O] and W phases are additionally formed, in general, in the GC1 glass-ceramics, as well as in the GC2 material obtained at a cooling rate of 0.5°C/h. However, at faster cooling rates, TCP is formed instead of Ap phase in the latter composition. During the bioactivity tests, a hydroxyapatite [HAp, Ca10(PO4)6(OH)2]-like surface layer is formed in all materials. It is proposed that GC2 glass-ceramics cooled at a rate of 1°C/h have the potential to show good in vivo osseointegration properties.
Diet has an important role in the prevention and treatment of hypertension. In early epidemiological studies, conducted mainly in the USA, monounsaturated fatty acids showed a deleterious association with blood pressure or no relationship at all. However, more recent studies, conducted in Mediterranean countries, have shed new light on this issue. In the present review we summarise the main results of epidemiological studies and feeding trials, and explain the possible mechanisms through which monounsaturated fatty acids, and specifically olive oil as the major dietary source of this type of fat in Mediterranean countries, could exert a favourable effect on blood pressure.
Echinococcus granulosus antigen B (AgB) is encoded by a gene family and is involved in the evasion of the host immune response. E. granulosus exists as a number of strains (G1–G10) that differ in biological characteristics. We used PCR-SSCP followed by DNA sequencing to evaluate sequence variation and transcription profile of AgB in 5 E. granulosus strainsNucleotide sequence data reported in this paper are available in the GenBankTM database under the Accession numbers AY569341-AY569371, AY159484, AY159485, AY608606, AY608607, AY614001.. Twenty-four genomic sequences were isolated and clustered in 3 groups related to 2 of the 5 reported AgB genes. AgB4 genes were present in almost all strains, whereas AgB2 were present as functional genes exclusively in G1/G2 cluster, and as non-functional genes in G5 and the G6/G7 cluster, suggesting inter-strain variation. The AgB transcription patterns, analysed by RT-PCR, showed that AgB2 and AgB4 genes were transcribed in G1, while only the AgB4 gene was transcribed in G7 strain. Cysts from the same strain or cluster shared more genomic and cDNA variants than cysts from different strain or cluster. The level of nucleotide and deduced amino acid sequence variation observed is higher than that reported so far for coding genes of other helminths. Neutrality was rejected for AgB2 genes. These data show the genetic polymorphism of antigen-coding genes among genetically characterized strains of E. granulosus.