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1.
Phys Rev Lett ; 131(5): 051601, 2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37595226

RESUMO

We find that the duality between color and kinematics can be used to inform the high energy behavior of effective field theories. Namely, we demonstrate that the massless gauge theory of Yang-Mills deformed by a higher-derivative F^{3} operator cannot be tree level color dual while consistently factorizing without a tower of additional four-point counterterms with rigidly fixed Wilson coefficients that reaches to the ultraviolet (UV). We find through explicit calculation a suggestive resummation, namely that their amplitudes are consistent with the α^{'} expansion of those generated by the (DF)^{2}+YM theory, a known color-dual theory where the F^{2} term has been given a mass squared proportional to 1/α^{'}. As a result, considering consistent double-copy construction as a physical principle implies that an F^{3}-based color-dual resolution of the UV divergence in N=4 supergravity comes at the cost of field-theoretic locality. Similarly, when double copying F^{3} with itself, double-copy consistency lifts R^{3} gravity to a family of gravity theories with an all-order tower of higher-derivative corrections, which includes the closed bosonic string as a standard adjoint-type double copy.

2.
J Parasitol Res ; 2022: 2606871, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36124129

RESUMO

Nowadays, despite the instauration of several control strategies, animal trypanosomiasis continues to be reported all over Uganda. Few canine African trypanosomiasis (CAT) studies have been carried out, yet dogs are known Trypanosoma reservoirs that share identical home ranges with livestock and serve as parasite link between livestock and humans. This study evaluates the prevalence of CAT in dogs in the Bwindi-Mgahinga and Queen Elizabeth conservation areas. This information will be useful to evaluate the possible role of dogs in the transmission cycle of Trypanosoma species in livestock and wild animals. Trypanosome tests using microhematocrit centrifugation/dark ground microscopy technique (MHCT) followed by conventional polymerase chain reaction (cPCR) were performed in blood samples collected from identified indigenous dogs (n = 124). Four (3.23%) out of 124 dogs were positive for CAT. One dog was positive with Trypanosoma congolense and three with T. vivax. There was no significant statistical difference in CAT prevalence rate in relation to dog's age, sex, and site (P > 0.05). This study reports what we believe is the first time detection of T. congolense and T. vivax in the indigenous dogs found in the Bwindi-Mgahinga and Queen Elizabeth conservation areas in western Uganda. The noticed T. congolense and T. vivax could be responsible for both canine and animal trypanosomiasis and represent a serious threat to the livestock industry. Therefore, there is a need for continuous trypanosomiasis surveillance and integrated management in contiguity to wildlife reserves.

4.
Phys Rev Lett ; 125(25): 251602, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33416367

RESUMO

Invoking increasingly higher dimension operators to encode novel UV physics in effective gauge and gravity theories traditionally means working with increasingly more finicky and difficult expressions. We find that the duality between color and kinematics provides a powerful tool towards drastic simplification. Local higher-derivative gauge and gravity operators at four points can be absorbed into simpler higher-derivative corrections to scalar theories, requiring only a small number of building blocks to generate gauge and gravity four-point amplitudes to all orders in mass dimension.

5.
South Asian J Cancer ; 6(3): 129-131, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28975123

RESUMO

BACKGROUND: T-cell lymphomas with anaplastic morphology typically comprise of anaplastic lymphoma kinase positive, anaplastic large cell lymphoma (ALK+ ALCL), ALK-negative ALCL (ALK- ALCL), and primary cutaneous ALCL (PC-ALCL). However, other entities such as diffuse large B-cell lymphoma, peripheral T-cell lymphoma, Hodgkin lymphoma, and undifferentiated carcinoma can also show similar anaplastic features. AIMS: To study the clinical features and histological spectrum of ALCL and emphasize the role of immunohistochemistry (IHC) in their diagnosis and categorization. SETTING AND DESIGN: Eight cases of ALCL diagnosed over a period of 4 years were selected for the study. MATERIALS AND METHODS: Histopathological review and IHC was performed on all cases. Two ALK+ ALCL cases were tested by fluorescent in situ hybridization (FISH) for t(2;5)(p23;q35). RESULTS: There were four cases of ALK+ ALCL and two each of ALK- ALCL and PC-ALCL. Histologically, all the subtypes showed pleomorphic and "hallmark" cells with strong CD30 expression and variable loss of T-cell antigens. One case of PC-ALCL was leukocyte common antigen (LCA) negative. Epithelial membrane antigen was positive in all the six systemic ALCL cases. Two cases tested for t(2;5)(p23;q35) by FISH were positive. CONCLUSIONS: Diagnosis of ALCL is based on recognizing the key morphological features, especially the presence of "hallmark" cells. IHC is essential for confirmation of diagnosis and excluding other malignancies with anaplastic morphology. The inclusion of CD30 in the initial IHC panel will help identify LCA negative cases and avoid misdiagnosis.

8.
Phys Rev Lett ; 105(6): 061602, 2010 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-20867971

RESUMO

In a previous paper we observed that (classical) tree-level gauge-theory amplitudes can be rearranged to display a duality between color and kinematics. Once this is imposed, gravity amplitudes are obtained using two copies of gauge-theory diagram numerators. Here we conjecture that this duality persists to all quantum loop orders and can thus be used to obtain multiloop gravity amplitudes easily from gauge-theory ones. As a nontrivial test, we show that the three-loop four-point amplitude of N=4 super-Yang-Mills theory can be arranged into a form satisfying the duality, and by taking double copies of the diagram numerators we obtain the corresponding amplitude of N=8 supergravity. We also remark on a nonsupersymmetric two-loop test based on pure Yang-Mills theory resulting in gravity coupled to an antisymmetric tensor and dilaton.

9.
Neurotox Res ; 15(3): 260-73, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19384599

RESUMO

Methylene blue (MB) is a diaminophenothiazine with potent antioxidant and unique redox properties that prevent morphologic degenerative changes in the mouse retina induced by rotenone, a specific mitochondrial complex I inhibitor. This study evaluated pigmented rats to determine whether MB's neuroprotective effects against rotenone-mediated retinal neurotoxicity have functional relevance and whether these effects are mediated by an improvement in neuronal energy metabolism in vivo. Visual function was behaviorally assessed by determining differences in the illuminance sensitivity threshold pre- and post-bilateral intravitreal injection of rotenone (200 microg/kg) or rotenone plus MB (70 microg/kg). Retinal degeneration was morphologically studied using unbiased stereological tools. Changes in histochemically determined cytochrome oxidase activity in the visual pathway were used to evaluate the impact of treatments on neuronal energy metabolism. Rotenone induced a 1.4 log unit increase in the illumination threshold compared to baseline, as well as a 32% decrease in ganglion cell layer cell (GCL) density, and a 56% decrease in GCL layer + nerve fiber layer thickness. Co-administration of MB prevented the changes in visual function and the retinal histopathology. Furthermore, rotenone induced a functional deafferentation of the visual system, as revealed by decreases in the metabolic activity of the retina, superior colliculus, and visual cortex. These metabolic changes were also prevented by MB. The results provided the first demonstration of MB's behavioral and metabolic neuroprotection against optic neuropathy, and implicate MB as a candidate neuroprotective agent with metabolic-enhancing properties that may be used in the treatment of neurodegenerative diseases associated with mitochondrial dysfunction.


Assuntos
Azul de Metileno/farmacologia , Fármacos Neuroprotetores/farmacologia , Doenças do Nervo Óptico/prevenção & controle , Adaptação Ocular/efeitos dos fármacos , Adaptação Ocular/fisiologia , Análise de Variância , Animais , Encéfalo/patologia , Encéfalo/ultraestrutura , Comportamento de Escolha/efeitos dos fármacos , Discriminação Psicológica/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Interações Medicamentosas , Complexo I de Transporte de Elétrons/metabolismo , Inseticidas/toxicidade , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , NADH Desidrogenase/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Doenças do Nervo Óptico/induzido quimicamente , Doenças do Nervo Óptico/patologia , Estimulação Luminosa/métodos , Ratos , Ratos Long-Evans , Tempo de Reação/efeitos dos fármacos , Retina/patologia , Rotenona/toxicidade , Vias Visuais/efeitos dos fármacos , Vias Visuais/patologia
10.
Pediatr Transplant ; 13(2): 171-6, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18482210

RESUMO

Impact of pretransplant splenectomy in patients with beta-thalassemia major undergoing an allogeneic SCT has never been addressed. Twenty-seven class III patients (29 transplants) had a pretransplant splenectomy. The outcome of these 29 transplants was compared with 76 transplants in class III who did not have a splenectomy. Patients in the splenectomy group were older (11.7 +/- 5.0 vs. 8.5 +/- 3.5 yr; p = 0.003) and had a larger liver size (5.7 +/- 1.8 vs. 4.4 +/- 1.6 cm; p = 0.000). Splenectomized patients had a significantly faster time to ANC >500/mm(3) (15.4 +/- 5.9 vs. 17.5 +/- 4 days; p = 0.002) and platelet >20 000/mm(3) (22.5 +/- 6.7 vs. 32.5 +/- 13.6 days; p = 0.000). The splenectomized group had a significantly reduced requirement of blood transfusion in the first 100 days post-transplant (5.5 +/- 5.1 vs. 7.2 +/- 5.4 units; p = 0.017). There were significantly more deaths related to peri-transplant infections in the post-splenectomy group (24% vs. 5.3%; p = 0.0001). The graft rejections were comparable between the two groups (20.7% vs. 14.5%; p = 0.55). The incidence of acute and chronic GVHD, late infections, and deaths from RRT was not significantly different between the two groups. The five-yr EFS (31.0 +/- 8.6 vs. 60.8 +/- 5.98; p = 0.003) and OS (39.7 +/- 9.3 vs. 71.8 +/- 5.5; p = 0.002) was significantly worse in the splenectomized group. In conclusion, pretransplant splenectomy among patients with beta-thalassemia major was associated with faster engraftment, reduced transfusion support, a higher incidence of peri-transplant infection related deaths, and a reduced EFS and OS.


Assuntos
Transplante de Células-Tronco/métodos , Talassemia beta/cirurgia , Talassemia beta/terapia , Adolescente , Transfusão de Sangue , Células da Medula Óssea/citologia , Criança , Estudos de Coortes , Intervalo Livre de Doença , Feminino , Doença Enxerto-Hospedeiro , Humanos , Masculino , Esplenectomia/métodos , Condicionamento Pré-Transplante/métodos , Transplante Homólogo , Resultado do Tratamento
11.
J Neurosci ; 28(50): 13511-21, 2008 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-19074024

RESUMO

Near-infrared light (NIL) promotes a wide range of biological effects including enhancement of energy production, gene expression and prevention of cell death. This is the first report of the in vivo neuroprotective effects of NIL against optic neuropathy induced by mitochondrial complex I inhibition. Subjects were pigmented rats that received single bilateral intravitreal doses of rotenone, a mitochondrial complex I inhibitor, or rotenone plus one of three different doses of NIL. Treatment effects were evaluated at behavioral, structural and neurochemical levels. Rotenone induced a decrease in visual function, as determined by changes in the dark-adapted illuminance sensitivity threshold, escape latency and rate of successful trials in a two-choice visual task, compared with vehicle-treated controls. Behavioral impairment correlated with a decrease in retinal and visual pathway metabolic activity, retinal nerve fiber layer thickness and ganglion cell layer cell density. These changes were prevented by NIL treatments in a dose-dependent manner. Whole-brain cytochrome oxidase and superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL. In whole-brain membrane isolates, NIL prevented the rotenone-induced decrease in cell respiration. The results show that NIL treatment can effectively prevent the neurotoxic effects of rotenone and that it might be used in the treatment of neurodegenerative disorders associated with mitochondrial dysfunction.


Assuntos
Encéfalo/efeitos da radiação , Raios Infravermelhos/uso terapêutico , Doenças do Nervo Óptico/fisiopatologia , Doenças do Nervo Óptico/radioterapia , Animais , Complexo I de Transporte de Elétrons/efeitos dos fármacos , Complexo IV da Cadeia de Transporte de Elétrons/efeitos da radiação , Imuno-Histoquímica , Masculino , Mitocôndrias/efeitos dos fármacos , Ratos , Ratos Long-Evans , Rotenona/toxicidade , Superóxido Dismutase/efeitos da radiação , Desacopladores/toxicidade
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