A COUNTEREXAMPLE FOR IMPROVED SOBOLEV INEQUALITIES OVER THE 2-ADIC GROUP

Chamorro, Diego Korean Mathematical Society 2013 대한수학회논문집 Vol.28 No.2

On the framework of the 2-adic group $\mathcal{Z}_2$, we study a Sobolev-like inequality where we estimate the $L^2$ norm by a geometric mean of the BV norm and the $\dot{B}_{\infty}^{-1,{\infty}}$ norm. We first show, using the special topological properties of the $p$-adic groups, that the set of functions of bounded variations BV can be identified to the Besov space ˙$\dot{B}_1^{1,{\infty}}$. This identification lead us to the construction of a counterexample to the improved Sobolev inequality.

Neuroprotectants in the Era of Reperfusion Therapy

Ángel Chamorro 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.2

For decades, numerous pharmacological and non-pharmacological strategies have been evaluated without success to limit the consequences of the ischemic cascade, but more rarely the therapies were explored as add on remedies on individuals also receiving reperfusion therapies. It is plausible that these putative neuroprotectants never reached the ischemic brain in adequate concentrations. Currently, the concept of neuroprotection incorporates cerebral perfusion as an obligatory substrate upon which ischemic brain survival depends, and it is plausible that some of the compounds tested in previous neuroprotection trials might have resulted in more favorable results if reperfusion therapies had been co-administered. Nonetheless, pharmacological or mechanical thrombectomy are frequently powerless to fully reperfuse the ischemic brain despite achieving a high rate of recanalization. This review covers in some detail the importance of the microcirculation, and the barriers that may hamper flow reperfusion at the microcirculatory level. It describes the main mechanisms leading to microcirculatory thrombosis including oxidative/nitrosative stress and refers to recent efforts to ameliorate brain perfusion in combination with the co-administration of neuroprotectants mainly aimed at harnessing oxidative/nitrosative brain damage.

The Protective Effect of Dietary Arthrospira (Spirulina) maxima Against Mutagenicity Induced by Benzo[alpha]pyrene in Mice

Germán Chamorro-Cevallos,Leticia Garduño-Siciliano,Elizdath Martínez-Galero,Angélica Mojica-Villegas,Nicole Pages,Gabriela Gutiérrez-Salmeán 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.5

Benzo[alpha]pyrene (B[a]P) was used to test the possible antimutagenic effects of Arthrospira (Spirulina) maxima (SP) on male and female mice. SP was orally administered at 0, 200, 400, or 800 mg/kg of body weight to animals of both sexes for 2 weeks before starting the B[a]P (intraperitoneal injection) at 125 mg/kg of body weight for 5 consecutive days. For the male dominant lethal test, each male was caged with two untreated females per week for 3 weeks. For the female dominant lethal test, each female was caged for 1 week with one untreated male. All the females were evaluated 13–15 days after mating for incidence of pregnancy, total corpora lutea, total implants and pre- and postimplant losses. SP protected from B[a]P-induced pre- and postimplant losses in the male dominant lethal test, and from B[a]P-induced postimplantation losses in treated females. Moreover, SP treatment significantly reduced the detrimental effect of B[a]P on the quality of mouse semen. Our results illustrate the protective effects of SP in relation to B[a]P-induced genetic damage to germ cells. We conclude that SP, owing mainly to the presence of phycocyanin, could be of potential clinical interest in cancer treatment or prevention of relapse.

A Subthreshold PMOS Analog Cortex Decoder for the (8, 4, 4) Hamming Code

Jorge Pérez-Chamorro,Cyril Lahuec,Fabrice Seguin,Gerald Le Mestre,Michel Jézéquel 한국전자통신연구원 2009 ETRI Journal Vol.31 No.5

This paper presents a method for decoding high minimal distance (dmin) short codes, termed Cortex codes. These codes are systematic block codes of rate 1/2 and can have higher dmin than turbo codes. Despite this characteristic, these codes have been impossible to decode with good performance because, to reach high dmin, several encoding stages are connected through interleavers. This generates a large number of hidden variables and increases the complexity of the scheduling and initialization. However, the structure of the encoder is well suited for analog decoding. A proof-of-concept Cortex decoder for the (8, 4, 4) Hamming code is implemented in subthreshold 0.25-µm CMOS. It outperforms an equivalent LDPC-like decoder by 1 dB at BER=10-5 and is 44 percent smaller and consumes 28 percent less energy per decoded bit.

Cerebrovascular Events in Older Patients With Patent Foramen Ovale: Current Status and Future Perspectives

Farjat-Pasos Julio I.,Chamorro Angel,Lanthier Sylvain,Robichaud Mathieu,Mengi Siddhartha,Houde Christine,Rodés-Cabau Josep 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.3

Patent foramen ovale (PFO) closure, along with medical therapy, has emerged as the therapeutic gold standard in younger (<60-year-old) patients with a PFO-related stroke for preventing recurrent events. However, PFO management guidelines lack definite recommendations for older (>60 years) patients with a PFO-related cerebrovascular event, a complex group of patients who were mostly excluded from PFO closure clinical trials. Nevertheless, several studies have shown a higher prevalence of PFO among older patients with cryptogenic stroke, and its presence has been associated with an increased risk of recurrent events. Furthermore, older patients exhibit a higher prevalence of high-risk PFO anatomical features, present inherent age-related risk factors that might increase the risk of paradoxical embolism through a PFO, and have a higher incidence of ischemic events after a PFO-related event. Additionally, observational studies have shown the safety and preliminary efficacy of PFO closure in older PFO-related stroke patients. Yet, higher rates of recurrent cerebrovascular events and new-onset atrial fibrillation were observed in some studies among older patients compared to their younger counterparts. After careful case-by-case evaluation, including the assessment of hidden potential cardioembolic sources of a cryptogenic stroke other than PFO, transcatheter PFO closure might be a safe and effective therapeutic option for preventing recurrent thromboembolic events in patients >60 years with a high-risk PFO-associated stroke. Ongoing trials will provide important insights into the role of PFO closure in the elderly population.

Impact of Shift Work on the Eating Pattern, Physical Activity and Daytime Sleepiness Among Chilean Healthcare Workers

Farias, Rut,Sepulveda, Alejandro,Chamorro, Rodrigo Occupational Safety and Health Research Institute 2020 Safety and health at work Vol.11 No.3

We evaluated the eating pattern, physical activity, and daytime sleepiness level in Chilean shift workers. Fifty, middle-aged adult health workers from a public hospital in Santiago, Chile, were included: a group undergoing shift work (shift workers, including at least one "night shift" and one "long day", n = 33), and day workers under traditional schedule (from 8:00 to 17:00h, n = 17). Body composition, physical activity, and daytime sleepiness levels, and diet characteristics (diet composition, meals' timing, and diet quality) were assessed. Despite similar total energy intake, shift worker showed lower carbohydrate (% of energy) and higher protein intake (both P < 0.01), decreased diet quality, an irregular eating pattern, and delayed meal timing (all P < 0.05). Physical activity and daytime sleepiness levels did not differ between groups. Findings from this first Chilean study in healthcare shift workers support the fact that meal timing and diet quality appear as critical factors for upcoming intervention studies in this group.

Effect of Spirulina maxima and Its Protein Extract on Micronuclei Induction by Hydroxyurea in Pregnant Mice and Their Fetuses

Isela A ´ lvarez-Gonza´lez,Jorge Va´zquez-Sa´nchez,Germa´n Chamorro-Cevallos,Eduardo Madrigal-Bujaidar 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.11

The purpose of the present report was to determine the inhibitory effect of Spirulina maxima (Sm) and its protein extract (PE), mainly consisting of C-phycocyanin, on the increase in micronuclei and bone marrow cytotoxicity induced by hydroxyurea (HU) in pregnant mice and their fetuses. The two tested antimutagenic agents were administered daily from day 10 to day 18 of pregnancy, and HU (300 mg/kg) was administered once on day 16 of the assay. The experimental design also included mice that were administered only Sm or PE (1000 and 400 mg/kg, respectively), two control groups that were administered with vehicles (water and 0.5% Tween 80), and one additional group that was treated solely with HU. Blood samples from the pregnant mice and their fetuses were examined at day 19 of pregnancy. Significant increases in the number of micronucleated polychromatic erythrocytes and in the total number of micronucleated erythrocytes were observed in all HU-treated animals. In contrast, similarly low numbers of micronuclei were observed in the two control groups and in the groups treated with Sm and PE alone. The administration of Sm (100, 500, and 1000 mg/kg) and PE (100, 200, and 400 mg/kg) to HU-treated animals conferred moderate genotoxic protection (*30%) and some protection against the cytotoxicity induced by HU in mice. The obtained results provide new information regarding the capacity of the tested agents to confer protection to adult mice and transplacentally, as well as on a specific subclass of micronuclei.

Protective Effect of Grapefruit Juice on the Teratogenic and Genotoxic Damage Induced by Cadmium in Mice

Nancy Argu¨elles,Isela A ´ lvarez-Gonza´lez,Germa´n Chamorro,Eduardo Madrigal-Bujaidar 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.10

In the present study, we injected pregnant mice at Day 7 of gestation with cadmium chloride (CC) (1.5 mg/kg) intraperitoneally and determined its effect on the frequency of fetal malformations at Day 17 of pregnancy. On the same day, we also determined the level of micronucleated polychromatic erythrocytes (MNPEs) and of micronucleated normochromatic erythrocytes (MNNEs) in blood cells of both the mothers and their fetuses. A significant increase in the number of malformations was found, mainly exencephaly, micrognathia, ablephary, microphthalmia, and clubfoot, as well as a significant increase in the amount of MNPEs and MNNEs. In addition, pregnant mice were administered grapefruit juice (GJ) orally from Days 0 to 17 of the experiment (from 200 to 800 μL/g) to evaluate the potential of the juice in preventing the damage induced by CC. We found a dose-dependent decrease in the number of visceral and skeletal malformations, as well as in the number of MNPEs and MNNEs, in both the mothers and their fetuses. Furthermore, we determined the level of DNA oxidation by measuring levels of the adduct 8-hydroxy-2′-deoxyguanosine, and we found a significant increase in such level induced by CC; in contrast, there was a significant decrease when we added GJ. Therefore, the observed teratogenic and genotoxic protection can probably be related with the antioxidant potential of GJ.

Sustainable Management Framework for Transportation Assets: Application to Urban Pavement Networks

Cristina Torres-Machi,Cristina Torres-Machi,Pablo Godoy,Alondra Chamorro,Claudio Mourgues,Carlos Videla 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Transportation assets play a crucial role in the development of society, being the backbone of socio-economic development but also a key contributor to climate change. Transportation asset management systems include a set of tools to support agencies in the decision on which infrastructure of a network should be preserved, maintained and/or rehabilitated. However, the evaluation of these networks has traditionally focused on economic and technical aspects of interurban networks. Considering the direct impacts on the evolution of social and natural environments, management of these assets needs to be sustainable. This article proposes a methodology for the sustainable management of transportation assets, by integrating technical, economic, environmental, social and political aspects in the Life Cycle-Assessment of a network. The methodology proposes a framework that integrates these aspects in the various components and processes considered in a management system. It incorporates a Geographic Information System as the main platform to pursue the socio-political analysis based on geographical referencing of formalized variables. The proposed framework is applied to a case study for the management of an urban pavement network. Outcomes demonstrate that it is possible to integrate sustainable aspects, despite their diverse nature, in a management system supported by a Geographic Information System.

Antioxidant Effect of Spirulina (Arthrospira) maxima on Chronic Inflammation Induced by Freund’s Complete Adjuvant in Rats

Gabriel Alfonso Gutie´rrez-Rebolledo,Marcela Galar-Martı´nez,Rosa Virginia Garcı´a-Rodrı´guez,Germa´n A. Chamorro-Cevallos,Ana Gabriela Herna´ndez-Reyes,Elizdath Martı´nez-Galero 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.8

One of the major mechanisms in the pathogenesis of chronic inflammation is the excessive production of reactive oxygen and reactive nitrogen species, and therefore, oxidative stress. Spirulina (Arthrospira) maxima has marked antioxidant activity in vivo and in vitro, as well as anti-inflammatory activity in certain experimental models, the latter activity being mediated probably by the antioxidant activity of this cyanobacterium. In the present study, chronic inflammation was induced through injection of Freund’s complete adjuvant (CFA) in rats treated daily with Spirulina (Arthrospira) maxima for 2 weeks beginning on day 14. Joint diameter, body temperature, and motor capacity were assessed each week. On days 0 and 28, total and differential leukocyte counts and serum oxidative damage were determined, the latter by assessing lipid peroxidation and protein carbonyl content. At the end of the study, oxidative damage to joints was likewise evaluated. Results show that S. maxima favors increased mobility, as well as body temperature regulation, and a number of circulating leukocytes, lymphocytes, and monocytes in specimens with CFA-induced chronic inflammation and also protects against oxidative damage in joint tissue as well as serum. In conclusion, the protection afforded by S. maxima against development of chronic inflammation is due to its antioxidant activity.