Technetium-99 immobilization in low-temperature nuclear waste forms often relies on additives that reduce environmentally mobile pertechnetate (TcO4 –) to insoluble Tc(IV) species. However, this is ...a short-lived solution unless reducing conditions are maintained over the hazardous life cycle of radioactive wastes (some ∼10,000 years). Considering recent experimental observations, this work explores how rapid formation of ettringite Ca6Al2(SO4)3(OH)12·26(H2O), a common mineral formed in cementitious waste forms, may be used to directly immobilize TcO4 –. Results from ab initio molecular dynamics (AIMD) simulations and solid-phase characterization techniques, including synchrotron X-ray absorption, fluorescence, and diffraction methods, support successful incorporation of TcO4 – into the ettringite crystal structure via sulfate substitution when synthesized by aqueous precipitation methods. One sulfate and one water are replaced with one TcO4 – and one OH– during substitution, where Ca2+-coordinated water near the substitution site is deprotonated to form OH– for charge compensation upon TcO4 – substitution. Furthermore, AIMD calculations support favorable TcO4 – substitution at the SO4 2– site in ettringite rather than gypsum (CaSO4·2H2O, formed as a secondary mineral phase) by at least 0.76 eV at 298 K. These results are the first of their kind to suggest that ettringite may contribute to TcO4 – immobilization and the overall lifetime performance of cementitious waste forms.
Ettringite is a naturally occurring mineral found in cementitious matrices that is known for its ability to incorporate environmentally mobile oxyanion contaminants. To better assess this ...immobilization mechanism for contaminants within cementitious waste forms intended for nuclear waste storage, this work explores how mixed oxyanion contaminants compete for ettringite incorporation and influence the evolving mineralogy. Ettringite was precipitated in the presence of TcO
, IO
, and/or CrO
, known contaminants of concern to nuclear waste treatment, over pre-determined precipitation periods. Solution analyses quantified contaminant removal, and the collected solid was characterized using bulk and microprobe X-ray diffraction coupled with pair distribution function and microprobe X-ray fluorescence analyses. Results suggest that ≥96% IO
is removed from solution, regardless of ettringite precipitation time or the presence of TcO
or CrO
. However, TcO
removal remained <20%, was not significantly improved with longer ettringite precipitation times, and decreased to zero in the presence of IO
. When IO
is co-mingled with CrO
, calcite and gypsum are formed as secondary mineral phases, which allows for oxyanion partitioning, e.g., IO
incorporation into ettringite, and CrO
incorporation into calcite. Results from this work exemplify the importance of competitive immobilization when assessing waste form performance and environmental risk of contaminant release.
Ettringite is a naturally occurring mineral found in cementitious matrices that is known for its ability to incorporate environmentally mobile oxyanion contaminants. To better assess this ...immobilization mechanism for contaminants within cementitious waste forms intended for nuclear waste storage, this work explores how mixed oxyanion contaminants compete for ettringite incorporation and influence the evolving mineralogy. Ettringite was precipitated in the presence of TcO4–, IO3–, and CrO42- known contaminants of concern to nuclear waste treatment, over pre-determined precipitation periods. Solution analyses quantified contaminant removal, and the collected solid was characterized using bulk and microprobe X-ray diffraction coupled with pair distribution function and microprobe X-ray fluorescence analyses. Results suggest that ≥96% IO3– is removed from solution, regardless of ettringite precipitation time or the presence of TcO4– or CrO42-. However, TcO4– removal remained <20%, was not significantly improved with longer ettringite precipitation times, and decreased to zero in the presence of IO3–. When IO3– is co-mingled with CrO42-, calcite and gypsum are formed as secondary mineral phases, which allows for oxyanion partitioning, e.g., IO3– incorporation into ettringite, and CrO42- incorporation into calcite. Results from this work exemplify the importance of competitive immobilization when assessing waste form performance and environmental risk of contaminant release.
Liver disease is increasingly prevalent in the world and in our country, the need for liver transplantation is increasing; In our country, there are more and more centers that perform liver ...transplantation. This study aimed to report the results of the liver transplant program at the Hospital General of México “Dr. Eduardo Liceaga” (HGM) during the last four years.
Retrospective, observational study. The records of all patients who received transplants in the last four years at the HGM were reviewed, documenting age, etiology, transplant indication, survival, and mortality. Descriptive statistics were performed.
For four years, 36 patients were transplanted, 22 men (61.1%) and 14 women (38.9%) aged 51 ± 10.2 years, the most frequent etiology is alcohol consumption (33%), followed by autoimmune hepatitis (17%), and liver disease associated with metabolic dysfunction (14%). Three deaths have been reported. Figures 1 and 2.
The experience in liver transplantation in the HGM has increased, although, in the pandemic, there was a global decrease; since they were restarted, the number of transplant patients is increasingly important, already competing with the rest of the centers in the country. The main cause for transplantation is alcohol consumption, which is a very frequent pathology in our country.
The HGM liver transplant program has grown, the main cause of transplantation is alcohol consumption, and mortality is very low.
The resources used in this study were from the hospital without any additional financing
The authors declare no potential conflicts of interest.
Objectives
Aging is accompanied by a decline in several aspects of the cognitive function, having negative personal and socioeconomic impacts. Dietary supplements could be beneficial for preventing ...age-related cognitive decline. In this context, we examined whether the nutritional supplement Mente Activa® has beneficial effects on aging-related cognitive deficits without inducing side effects.
Methods
Mente Activa® was administered to old rats (n= 30 treated rats and n= 30 control rats) during 5 months, and the Morris water maze was used to test the learning capacities of the animals. The first assessment was conducted before the nutritional intervention (age of 18-19 months), to determine the baseline of the performance of animals on this test, and the second assessment was performed at the end of the treatment (23-24 moths). In order to examine possible secondary effects of this nutritional supplement, plasma, heart anatomy and liver parameters were evaluated.
Results
Our data indicate that supplemented rats showed less escape latency, distance swum, higher use of spatial search strategies, and crossed the former platform location with higher frequency than control rats. These effects were specific of the treatment, indicating that this nutritional supplement has a beneficial effect on spatial memory. On the other hand, the regular intake of Mente Activa® did not induce any negative effects in plasma parameters and heart size.
Conclusions
Aged rats under a sustained dietary intake of the nutritional supplement Mente Activa® displayed improved learning and memory abilities compared to the non-treated rats. These results suggest the therapeutic potential and safety of use of Mente Activa® for age-related cognitive deficits, particularly, in the onset of the first cognitive dysfunction symptoms.
Ettringite is a naturally occurring mineral found in cementitious matrices that is known for its ability to incorporate environmentally mobile oxyanion contaminants. To better assess this ...immobilization mechanism for contaminants within cementitious waste forms intended for nuclear waste storage, this work explores how mixed oxyanion contaminants compete for ettringite incorporation and influence the evolving mineralogy. Ettringite was precipitated in the presence of TcO4 –, IO3 –, and/or CrO4 2–, known contaminants of concern to nuclear waste treatment, over pre-determined precipitation periods. Solution analyses quantified contaminant removal, and the collected solid was characterized using bulk and microprobe X-ray diffraction coupled with pair distribution function and microprobe X-ray fluorescence analyses. Results suggest that ≥96% IO3 – is removed from solution, regardless of ettringite precipitation time or the presence of TcO4 – or CrO4 2–. However, TcO4 – removal remained <20%, was not significantly improved with longer ettringite precipitation times, and decreased to zero in the presence of IO3 –. When IO3 – is co-mingled with CrO4 2–, calcite and gypsum are formed as secondary mineral phases, which allows for oxyanion partitioning, e.g., IO3 – incorporation into ettringite, and CrO4 2– incorporation into calcite. Results from this work exemplify the importance of competitive immobilization when assessing waste form performance and environmental risk of contaminant release.
Jasmonates are specific signal molecules in plants that are involved in a diverse set of physiological and developmental processes. However, methyl jasmonate (MeJA) has been shown to have a negative ...effect on root growth and, so far, the biochemical mechanism for this is unknown. Using Catharanthus roseus hairy roots, we were able to observe the effect of MeJA on growth inhibition, cell disorganization and cell death of the root cap. Hairy roots treated with MeJA induced the perturbation of mitochondrial membrane integrity and a diminution in ATP biosynthesis. Furthermore, several proteins were identified that were involved in energy and secondary metabolism; the changes in accumulation of these proteins were observed with 100 μM MeJA. In conclusion, our results suggest that a switch of the metabolic fate of hairy roots in response to MeJA could cause an increase in the accumulation of secondary metabolites. This is likely to have important consequences in the production of specific alkaloids important for the pharmaceutical industry.
ABSTRACT The avocado drymifolia is sensitive to the attack of mistletoe, while, “Hass” and “Mendez” exhibit tolerance. This difference could be related to the secondary metabolites produced by the ...plant. The biochemical profile of drymifolia, Hass and Mendez avocados was determined, as well as the relationship with mistletoe sensitivity/tolerance. Twenty-seven drymifolia individuals, one Hass and one Mendez, from three localities of Michoacan, Mexico, were evaluated. The extraction and analysis of the volatile compounds were carried out by gas chromatography coupled to mass spectrometry and the results were compared with the spectra of the NIST library. The most abundant secondary metabolites were estragole, caryophyllene, (+)-4-carene and γ-terpinene, with 95.0, 88.0 and 90.1 %, of the total of 116 compounds identified, in drymifolia, Hass and Mendez, respectively. In avocado Hass 1,3,4,5,6,7-hexahydro-2,5,5-trimethyl-2H-2,4aethanonaphthalene (0.84 %), α-Cubebene (0.33 %), 2,4,6-octatrienoic acid (0.24 %) and α-phellandrene (0.21 %) were identified and in Mendez, thymol (0.06 %) but these compounds were not identified in any avocado drymifolia. In addition, 2,5-bisbenzaldehyde showed 21.7X and 19.7X times more concentration in Hass and Mendez, respectively, than in drymifolia. The avocado drymifolia presented more secondary metabolites, but the most abundant compounds were shared in the three varieties. The secondary metabolites not found in avocado drymifolia could be related to mistletoe tolerance.
Young-onset Parkinson's disease (YOPD), defined by onset at <50 years, accounts for approximately 10% of all Parkinson's disease cases and, while some cases are associated with known genetic ...mutations, most are not. Here induced pluripotent stem cells were generated from control individuals and from patients with YOPD with no known mutations. Following differentiation into cultures containing dopamine neurons, induced pluripotent stem cells from patients with YOPD showed increased accumulation of soluble α-synuclein protein and phosphorylated protein kinase Cα, as well as reduced abundance of lysosomal membrane proteins such as LAMP1. Testing activators of lysosomal function showed that specific phorbol esters, such as PEP005, reduced α-synuclein and phosphorylated protein kinase Cα levels while increasing LAMP1 abundance. Interestingly, the reduction in α-synuclein occurred through proteasomal degradation. PEP005 delivery to mouse striatum also decreased α-synuclein production in vivo. Induced pluripotent stem cell-derived dopaminergic cultures reveal a signature in patients with YOPD who have no known Parkinson's disease-related mutations, suggesting that there might be other genetic contributions to this disorder. This signature was normalized by specific phorbol esters, making them promising therapeutic candidates.
Metabolic stress induced by high-fat (HF) diet leads to cognitive dysfunction and aging, but the physiological mechanisms are not fully understood. Senescence-accelerated prone mouse (SAMP8) models ...were conducted under metabolic stress conditions by feeding HF for 15 weeks, and the preventive effect of resveratrol was studied. This dietary strategy demonstrates cognitive impairment in SAMP8-HF and significant preventive effect by resveratrol-treated animals. Hippocampal changes in the proteins involved in mitochondrial dynamics optic atrophy-1 protein (OPA1) and mitofusin 2 (MFN2) comprised a differential feature found in SAMP8-HF that was prevented by resveratrol. Electronic microscopy showed a larger mitochondria in SAMP8-HF + resveratrol (SAMP8-HF + RV) than in SAMP8-HF, indicating increases in fusion processes in resveratrol-treated mice. According to the mitochondrial morphology, significant increases in the I-NDUFB8, II-SDNB, III-UQCRC2, and V-ATPase complexes, in addition to that of voltage-dependent anion channel 1 (VDAC1)/porin, were found in resveratrol-treated animals with regard to SAMP8-HF, reaching control-animal levels. Moreover, tumor necrosis factor alpha (TNF-α) and interleukin (IL-6) were increased after HF, and resveratrol prevents its increase. Moreover, we found that the HF diet affected the Wnt pathway, as demonstrated by β-catenin inactivation and modification in the expression of several components of this pathway. Resveratrol induced strong activation of β-catenin. The metabolic stress rendered in the cognitive and cellular pathways altered in SAMP8 focus on different targets in order to act on preventing cognitive impairment in neurodegeneration, and resveratrol can offer therapeutic possibilities for preventive strategies in aging or neurodegenerative conditions.
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