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1.
Nature ; 540(7631): 94-96, 2016 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-27851735

RESUMEN

The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto's tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin's present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.

2.
Nature ; 539(7627): 65-68, 2016 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-27626378

RESUMEN

A unique feature of Pluto's large satellite Charon is its dark red northern polar cap. Similar colours on Pluto's surface have been attributed to tholin-like organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location on Charon implicates the temperature extremes that result from Charon's high obliquity and long seasons in the production of this material. The escape of Pluto's atmosphere provides a potential feedstock for a complex chemistry. Gas from Pluto that is transiently cold-trapped and processed at Charon's winter pole was proposed as an explanation for the dark coloration on the basis of an image of Charon's northern hemisphere, but not modelled quantitatively. Here we report images of the southern hemisphere illuminated by Pluto-shine and also images taken during the approach phase that show the northern polar cap over a range of longitudes. We model the surface thermal environment on Charon and the supply and temporary cold-trapping of material escaping from Pluto, as well as the photolytic processing of this material into more complex and less volatile molecules while cold-trapped. The model results are consistent with the proposed mechanism for producing the observed colour pattern on Charon.

3.
J Intern Med ; 276(5): 470-85, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24494798

RESUMEN

OBJECTIVES: The complement system is involved in many immune complex-mediated kidney diseases, yet its role in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD) has not been examined in detail. METHODS AND RESULTS: Screening of the glycoproteome of urine samples from ADPKD patients revealed that levels of complement factor B (CFB), serpin peptidase inhibitor, complement component 1 inhibitor (SERPING1) and complement component 9 (C9) increased, whereas complement component 1, r subcomponent-like (C1RL), CD55 and CD59 levels decreased with disease progression. Immunostaining and Western blot analysis confirmed the enhanced expression of CFB and C9 in cystic kidneys from ADPKD patients. Immunostaining also showed that the expressions of CFB and C9 in renal biopsy tissues from patients with other types of chronic kidney disease were lower than in tissues from ADPKD patients. The effect of the complement inhibitor rosmarinic acid (RMA) was evaluated in Pkd1(-/-) mice and Han:SPRD Cy/+ rats. Compared with vehicle-treated Pkd1(-/-) animals, RMA-treated mice had significantly lower serum creatinine (-50%) and blood urea nitrogen (-78%) levels, two kidneys/body weight ratio (-60%) and renal cystic index (-60%). Similar results were found in Cy/+ rats. Lower numbers of Ki67-positive nuclei and inflammatory cells and reduced fibrosis were observed in both animal models upon treatment with RMA. CONCLUSIONS: These results suggest that excessive activation of the alternative complement pathway is associated with ADPKD progression, probably mediated by cyst-lining epithelial cell proliferation, tubulointerstitial inflammatory cell infiltration and fibrosis. Targeting the complement system might represent a new therapeutic strategy for ADPKD.


Asunto(s)
Vía Alternativa del Complemento , Riñón Poliquístico Autosómico Dominante/inmunología , Adulto , Animales , Proliferación Celular , Complemento C3/metabolismo , Complemento C4/metabolismo , Complemento C9/metabolismo , Factor B del Complemento/metabolismo , Vía Alternativa del Complemento/efectos de los fármacos , Proteínas del Sistema Complemento/orina , Progresión de la Enfermedad , Células Epiteliales/metabolismo , Fibrosis , Humanos , Riñón/metabolismo , Riñón/patología , Ratones Noqueados , Persona de Mediana Edad , Riñón Poliquístico Autosómico Dominante/patología , Riñón Poliquístico Autosómico Dominante/orina , Ratas
4.
Phys Rev Lett ; 112(11): 117801, 2014 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-24702420

RESUMEN

We measure the ultrafast recombination of photoexcited quasiparticles (holon-doublon pairs) in the one dimensional Mott insulator ET-F(2)TCNQ as a function of external pressure, which is used to tune the electronic structure. At each pressure value, we first fit the static optical properties and extract the electronic bandwidth t and the intersite correlation energy V. We then measure the recombination times as a function of pressure, and we correlate them with the corresponding microscopic parameters. We find that the recombination times scale differently than for metals and semiconductors. A fit to our data based on the time-dependent extended Hubbard Hamiltonian suggests that the competition between local recombination and delocalization of the Mott-Hubbard exciton dictates the efficiency of the recombination.


Asunto(s)
Compuestos Heterocíclicos/química , Modelos Químicos , Nitrilos/química , Fleroxacino/análogos & derivados , Fleroxacino/química , Óptica y Fotónica , Presión
5.
Phys Rev Lett ; 112(7): 072501, 2014 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-24579591

RESUMEN

The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A=124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

6.
Poult Sci ; 92(6): 1498-504, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23687145

RESUMEN

Clostridium perfringens is an anaerobic, spore-forming bacterium that may lead to necrotic enteritis, resulting in poor feed efficiency and increased mortality in chickens. It is estimated that C. perfringens infects almost 1 million people in the United States every year. The objective of this research was to compare the Fung double tube (FDT) and conventional Petri plates using 3 different media to detect and enumerate Clostridium spp. in chicken intestines. Nine Cobb 500 broilers were randomly selected and euthanized at 21 and 42 d of age for a total of 18 samples. The jejunum and ileum from each broiler were harvested and studied in 2 methods and 3 media combinations, utilizing a 2 × 3 factorial totaling 6 treatments. The 2 methods were FDT and conventional Petri plates, and the 3 media were Shahidi-Ferguson Perfringens (SFP) with egg yolk supplement, polymyxin B, and kanamycin (E); SFP with polymyxin B and kanamycin (P); and SFP with d-cycloserine (C). Enumerations were performed after 24 h of incubation at 37°C. At 21 d, counts using medium C with FDT (4.51 log10 cfu/g) and plates (2.38 log10 cfu/g) were higher (P < 0.05) than using media E or P. On d 42, there were no differences among plate treatments and medium E had the highest counts (0.98 log10 cfu/g). Of all the FDT, medium C (5.35 log10 cfu/g) had the highest counts (P < 0.05), followed by medium P (3.54 log10 cfu/g). This study illustrates that the FDT method is able to enumerate Clostridium spp. at higher levels (P < 0.001) than the conventional Petri plate method; therefore, the FDT should be implemented and further explored.


Asunto(s)
Técnicas Bacteriológicas/veterinaria , Pollos/microbiología , Clostridium/clasificación , Clostridium/aislamiento & purificación , Intestinos/microbiología , Animales , Técnicas Bacteriológicas/métodos , Infecciones por Clostridium/diagnóstico , Infecciones por Clostridium/microbiología , Infecciones por Clostridium/veterinaria , Medios de Cultivo , Masculino , Enfermedades de las Aves de Corral/diagnóstico , Enfermedades de las Aves de Corral/microbiología
7.
Physiol Genomics ; 44(23): 1154-63, 2012 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-23073384

RESUMEN

The discovery of causal mechanisms associated with nonsyndromic craniosynostosis has proven to be a difficult task due to the complex nature of the disease. In this study, differential transcriptome correlation analysis was used to identify two molecularly distinct subtypes of nonsyndromic craniosynostosis, termed subtype A and subtype B. In addition to unique correlation structure, subtype A was also associated with high IGF pathway expression, whereas subtype B was associated with high integrin expression. To identify a pathologic link between altered gene correlation/expression and the disease state, phosphorylation assays were performed on primary osteoblast cell lines derived from cases within subtype A or subtype B, as well as on primary osteoblast cell lines with novel IGF1R variants previously reported by our lab (Cunningham ML, Horst JA, Rieder MJ, Hing AV, Stanaway IB, Park SS, Samudrala R, Speltz ML. Am J Med Genet A 155A: 91-97, 2011). Elevated IRS1 (pan-tyr) and GSK3ß (ser-9) phosphorylation were observed in two novel IGF1R variants with receptor L domain mutations. In subtype A, a hypomineralization phenotype coupled with decreased phosphorylation of IRS1 (ser-312), p38 (thr-180/tyr-182), and p70S6K (thr-412) was observed. In subtype B, decreased phosphorylation of IRS1 (ser-312) as well as increased phosphorylation of Akt (ser-473), GSK3ß (ser-9), IGF1R (tyr-1135/tyr-1136), JNK (thr-183/tyr-187), p70S6K (thr-412), and pRPS6 (ser-235/ser-236) was observed, thus implicating the activation of IRS1-mediated Akt signaling in potentiating craniosynostosis in this subtype. Taken together, these results suggest that despite the stimulation of different pathways, activating phosphorylation patterns for IRS1 were consistent in cell lines from both subtypes and the IGF1R variants, thus implicating a key role for IRS1 in the pathogenesis of nonsyndromic craniosynostosis.


Asunto(s)
Craneosinostosis/genética , Proteínas Sustrato del Receptor de Insulina/genética , Activación Transcripcional , Transcriptoma/genética , Línea Celular , Células Cultivadas , Niño , Preescolar , Análisis por Conglomerados , Craneosinostosis/clasificación , Craneosinostosis/patología , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Humanos , Lactante , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Osteoblastos/citología , Osteoblastos/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Proteína S6 Ribosómica/genética , Proteína S6 Ribosómica/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/genética , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Transducción de Señal/genética , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
8.
Phys Rev Lett ; 109(2): 027003, 2012 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-23030197

RESUMEN

We report magnetic-field and angular-dependent high-resolution specific-heat measurements of the organic superconductor ß''-(BEDT-TTF)2SF5CH2CF2SO3. When the magnetic field is aligned precisely within the conducting BEDT-TTF layer, at low temperatures a clear upturn of the upper critical field beyond the Pauli limit of 9.73 T is observed, hinting at the emergence of a Fulde-Ferrell-Larkin-Ovchinnikov state. This upturn disappears when the field is oriented out of plane by more than ∼0.5 deg. For smaller out-of-plane angles, the specific-heat anomaly at T(c) sharpens and a second peaky phase transition appears within the superconducting state.

9.
Phys Rev Lett ; 108(11): 117202, 2012 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-22540505

RESUMEN

We present a combined neutron diffraction and bulk thermodynamic study of the natural mineral linarite PbCuSO4(OH)2, this way establishing the nature of the ground-state magnetic order. An incommensurate magnetic ordering with a propagation vector k=(0,0.186,1/2) was found below T(N)=2.8 K in a zero magnetic field. The analysis of the neutron diffraction data yields an elliptical helical structure, where one component (0.638µ(B)) is in the monoclinic ac plane forming an angle with the a axis of 27(2)°, while the other component (0.833µ(B)) points along the b axis. From a detailed thermodynamic study of bulk linarite in magnetic fields up to 12 T, applied along the chain direction, a very rich magnetic phase diagram is established, with multiple field-induced phases, and possibly short-range-order effects occurring in high fields. Our data establish linarite as a model compound of the frustrated one-dimensional spin chain, with ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor interactions. Long-range magnetic order is brought about by interchain coupling 1 order of magnitude smaller than the intrachain coupling.

10.
Haemophilia ; 16(6): 858-65, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20491962

RESUMEN

Muscle haematoma represents 10-25% of bleeds in patients with severe haemophilia. There is limited consensus on diagnostic or treatment strategies and little knowledge about the natural history of muscle haematoma and optimal treatment goals. The aim of this review was to perform a systematic description of the natural history of muscle haematoma in healthy athletes, focusing on diagnosis, classification and treatment options. Publications and educational textbooks on management of sports injuries were used as data source. Muscle haematomas occur following contusion, strain, or laceration and can be categorized as mild, moderate, or severe. Muscle haematoma may be inter- or intramuscular. In healthy athletes, the healing process takes 20-40 days. Optimal diagnosis includes history, physical examination (inspection, palpation, active and passive range of motion (ROM) test, muscle length test, isometric strength test, biomechanical examination, full spinal examination, peripheral nerve test and slump test), ultrasound, MRI or CT. Treatment is conducted based on: (i) super-acute stage, control of the bleeding and minimizing the size of the haematoma; (ii) acute stage, restoration of pain-free ROM; (iii) subacute stage, functional rehabilitation; and (iv) gradual return to normal activity. Treatment and preventive strategies include RICE (rest, ice, compression and elevation), protected mobilization, stretching and strengthening exercises, manual therapy (articular, neural and soft tissue mobilization and massage), correction of movement dysfunction, functional rehabilitation and electro-therapeutic interventions. The study reviews the natural history of muscle haematoma and state-of-the-art diagnosis and treatment in healthy athletes. Results may be useful to optimize diagnosis and treatment of muscle haematoma in patients with haemophilia.


Asunto(s)
Traumatismos en Atletas/complicaciones , Traumatismos en Atletas/rehabilitación , Hematoma/complicaciones , Hematoma/terapia , Hemofilia A/complicaciones , Músculo Esquelético/lesiones , Traumatismos en Atletas/diagnóstico , Traumatismos en Atletas/fisiopatología , Hematoma/diagnóstico , Hematoma/fisiopatología , Humanos , Músculo Esquelético/fisiopatología
11.
Haemophilia ; 16(6): 926-31, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20491963

RESUMEN

Muscle haematomas (MH) represent 10-25% of all bleeds in patients with severe haemophilia. We performed a cross-sectional survey on current practice in the management of MH with participation from 22 consultants. The respondents reported 492 MH/year, corresponding an average of 25/centre, mostly associated with trauma. Iliopsoas (55%), calf (18%) and thigh (18%) bleeds were scored as most serious. Half of the respondents distinguished between contusion and strains, whereas the majority (68.2%) did not categorize bleedings as intra- or intermuscular, although 77.3% routinely used ultrasound. Half of the respondents used a standard protocol for the management of MH. Twenty of 22 (90.9%) respondents offered physiotherapy in the hospital following MH, with no clear consensus on timing and type of treatment. In a theoretical case, for a 70-kg patient with a soleus triceps haematoma, the average initial dose of factor VIII was 2730 U (range: 1750-4000) twice daily for 3-5 days. In a similar case of a patient with inhibitors, 31.8% reported first-line and only use of either recombinant factor VIIa (rFVIIa) or activated prothrombin complex concentrate (APCC), while 36.4% switched between bypassing agents. Using rFVIIa, the median dose was 100 µg/kg (range: 85-270) and with APCC, the median dose was 70 U kg(-1) (range: 50-100). The majority (68.2%) did not use antifibrinolytics. Resolution of pain (81.8% & 77.3%) was regarded as the key clinical marker of arrest of bleeding as compared with diminished swelling and improved range of motion. The survey outlines limited consensus in the management of MH in patients with haemophilia and highlights potential topics for future studies.


Asunto(s)
Hematoma/terapia , Hemofilia A/complicaciones , Hemofilia A/terapia , Enfermedades Musculares/terapia , Factores de Coagulación Sanguínea/uso terapéutico , Estudios Transversales , Humanos , Especialidad de Fisioterapia , Encuestas y Cuestionarios
12.
Science ; 367(6481)2020 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-32054694

RESUMEN

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.

13.
Science ; 167(3918): 497-9, 1970 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-17781468

RESUMEN

Ten Apollo 11 specimnens were divided into 24 samtples. Sodillim contents of 8 diverse specimens clluster tightly abolit 0.3 percent. Plagioclase separated from sample 10044 contains aboltt 1.09 percent Na; barium is not enriched in the plagioclase separate. Contents of the rare earths are strikingly high, and relative abtmndances resemble those of calcium-rich achondrites or abyssal basalts but are depleted in Eu by factors of 2 to 3 and in La by about 20 percent. The plagioclase separate is enriched in Eu and pyroxenes (and opaqtte minerals are Eu-depleted. Fine fractions of 10044 are abotit 20 to 40 percent richer in most rare earths (50 percent for Eu) than coarse fractions, probably becaitse of the presence of small grains in which rare earths are mnarkedly concentrated. "Microgabbro" 10045 is imnpoverished, relative to the soil, in rare eartlhs and Hf. Ratios by mass of Zr to Hf are comlparatively low. Abttndances of Mn, Co, Fe, Sc and Cr stiggest systematic differences between igneous rocks on one hanid and breccias and "soil" on the other. Fromn the Co abuindances, no more than about 3 percent of the present "soil" can consist of chondritic mleteorite conitamination.

14.
Poult Sci ; 98(11): 5820-5830, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31392330

RESUMEN

The addition of fiber in chick feeds is known to dilute nutrients; as a result, this may reduce nutrient digestibility and performance. However, recent studies suggest that moderate inclusion of insoluble fibers (2 to 3%) may stimulate gizzard development, which could result in better nutrient utilization and chick growth. The previous fiber sources evaluated were subject to wide fluctuation in their nutritional and chemical composition due to variation in processing. Miscanthus giganteus is a C4 grass purposefully grown for its fiber content which has a consistent fiber composition compared to food process residues. The objectives of this study were to determine the effect of dietary fiber source and particle size on day-old chick performance and nutrient digestibility. Day-old chicks (8 chicks per cage, 5 cages per treatment) were fed diets containing 3% of either sepiolite (SEP), cellulose (CEL), coarse beet pulp (BP), fine BP, coarse Miscanthus grass (MG), and fine MG. At the end of days 7, 14, and 21, chicks and experimental diets were weighed to compute average daily gain and feed intake. In addition, excreta from the previous 48 h of each data capture point was collected to determine nutrient digestibility. In general, chicks fed diets containing fiber consumed more feed, gained more weight, and had better feed conversion rate than birds fed the SEP diet. Particle size of the fiber had no effect on chick performance; however, nutrient utilization was higher (P < 0.05) for chicks fed coarse fiber particles compared to these fed fine fiber particles. Birds fed diets containing MG performed similar to chicks fed CEL (P > 0.05), but digestibility coefficients of birds fed BP diets were generally higher than chicks fed MG diets. In conclusion, chicks performed better with fiber in their diet and MG was comparable to CEL.


Asunto(s)
Pollos/fisiología , Fibras de la Dieta/metabolismo , Digestión/efectos de los fármacos , Nutrientes/fisiología , Tamaño de la Partícula , Poaceae/química , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales/efectos de los fármacos , Animales , Beta vulgaris/química , Celulosa/administración & dosificación , Celulosa/metabolismo , Dieta/veterinaria , Fibras de la Dieta/administración & dosificación , Fibras de la Dieta/clasificación , Silicatos de Magnesio/administración & dosificación , Silicatos de Magnesio/metabolismo , Masculino , Distribución Aleatoria
15.
Poult Sci ; 98(3): 1371-1378, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30351365

RESUMEN

New protein ingredients are used to support pet food market growth and the development of new products while maintaining animal dietary needs. However, novel protein sources (e.g., spray-dried chicken, and (or) rice, pea, and potato protein concentrates) have limited data available regarding their protein quality. The objective of this study was to evaluate protein ingredients used in the pet food industry by laboratory analysis and a chick growth assay as a model. Following analysis for proximate and amino acid composition, chicks (six birds per pen with four pens per treatment) were fed experimental diets for 10 d. Diets contained 10% crude protein from each of the experimental protein sources (spray-dried egg-SDEG; spray-dried egg white-SDEW, spray-dried inedible whole egg-SDIE, chicken by-product meal-CBPM, chicken meal-CKML, low-temperature fluid bed air-dried chicken-LTCK, low-temperature and pressure fluid bed dried chicken-LTPC, spray-dried chicken-SDCK, whey protein concentrate-WPCT, corn gluten meal-CGML, corn protein concentrate-CPCT, potato protein isolate-PPIS, rice protein concentrate-RPCT, pea protein isolate-PEPI, soy protein isolate-SPIS, and soybean meal-SBML) along with an N-free diet (negative control). Chicks fed SDEG, SDIE, and LTPC had the highest protein efficiency ratio (PER; P < 0.0001; 5.18, 5.37, and 5.33, respectively), LTCK and SDCK were intermediate (4.54 and 4.79), and the CBPM and CKML were the lowest among the poultry proteins for EAA:NEAA, PER, and Lys availability. Among the vegetable proteins, PPIS and SBML had the highest PER values (3.60 and 3.48, P < 0.0001). In general, the chick PER method ranked the quality of animal protein sources higher than vegetable proteins, and these results were consistent with the EAA:NEAA ratio and Lys availability.


Asunto(s)
Aminoácidos/análisis , Alimentación Animal/análisis , Proteínas en la Dieta/metabolismo , Proteínas en la Dieta/normas , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Pollos/metabolismo , Dieta/veterinaria , Proteínas en la Dieta/administración & dosificación , Proteínas del Huevo/análisis , Valor Nutritivo , Proteínas de Plantas/análisis , Productos Avícolas/análisis , Proteína de Suero de Leche/análisis
16.
Astrobiology ; 19(7): 831-848, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30907634

RESUMEN

We present the case for the presence of complex organic molecules, such as amino acids and nucleobases, formed by abiotic processes on the surface and in near-subsurface regions of Pluto. Pluto's surface is tinted with a range of non-ice substances with colors ranging from light yellow to red to dark brown; the colors match those of laboratory organic residues called tholins. Tholins are broadly characterized as complex, macromolecular organic solids consisting of a network of aromatic structures connected by aliphatic bridging units (e.g., Imanaka et al., 2004; Materese et al., 2014, 2015). The synthesis of tholins in planetary atmospheres and in surface ices has been explored in numerous laboratory experiments, and both gas- and solid-phase varieties are found on Pluto. A third variety of tholins, exposed at a site of tectonic surface fracturing called Virgil Fossae, appears to have come from a reservoir in the subsurface. Eruptions of tholin-laden liquid H2O from a subsurface aqueous repository appear to have covered portions of Virgil Fossae and its surroundings with a uniquely colored deposit (D.P. Cruikshank, personal communication) that is geographically correlated with an exposure of H2O ice that includes spectroscopically detected NH3 (C.M. Dalle Ore, personal communication). The subsurface organic material could have been derived from presolar or solar nebula processes, or might have formed in situ. Photolysis and radiolysis of a mixture of ices relevant to Pluto's surface composition (N2, CH4, CO) have produced strongly colored, complex organics with a significant aromatic content having a high degree of nitrogen substitution similar to the aromatic heterocycles pyrimidine and purine (Materese et al., 2014, 2015; Cruikshank et al., 2016). Experiments with pyrimidines and purines frozen in H2O-NH3 ice resulted in the formation of numerous nucleobases, including the biologically relevant guanine, cytosine, adenine, uracil, and thymine (Materese et al., 2017). The red material associated with the H2O ice may contain nucleobases resulting from energetic processing on Pluto's surface or in the interior. Some other Kuiper Belt objects also exhibit red colors similar to those found on Pluto and may therefore carry similar inventories of complex organic materials. The widespread and ubiquitous nature of similarly complex organic materials observed in a variety of astronomical settings drives the need for additional laboratory and modeling efforts to explain the origin and evolution of organic molecules. Pluto observations reveal complex organics on a small body that remains close to its place of origin in the outermost regions of the Solar System.


Asunto(s)
Atmósfera/análisis , Medio Ambiente Extraterrestre/química , Plutón , Purinas/análisis , Pirimidinas/análisis , Atmósfera/química , Hielo , Metano/análisis , Espectrofotometría Infrarroja , Compuestos Orgánicos Volátiles/análisis , Agua/química
17.
Science ; 363(6430): 955-959, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30819958

RESUMEN

The flyby of Pluto and Charon by the New Horizons spacecraft provided high-resolution images of cratered surfaces embedded in the Kuiper belt, an extensive region of bodies orbiting beyond Neptune. Impact craters on Pluto and Charon were formed by collisions with other Kuiper belt objects (KBOs) with diameters from ~40 kilometers to ~300 meters, smaller than most KBOs observed directly by telescopes. We find a relative paucity of small craters ≲13 kilometers in diameter, which cannot be explained solely by geological resurfacing. This implies a deficit of small KBOs (≲1 to 2 kilometers in diameter). Some surfaces on Pluto and Charon are likely ≳4 billion years old, thus their crater records provide information on the size-frequency distribution of KBOs in the early Solar System.

18.
Science ; 364(6441)2019 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-31097641

RESUMEN

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

19.
Curr Dev Nutr ; 2(12): nzy073, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30569030

RESUMEN

BACKGROUND: Corn- and soybean-based fortified blended foods (FBFs) have been the primary food aid product provided by the United States. Sorghum and cowpea have been suggested as alternative FBF commodities because they are drought-tolerant, grown in food aid-receiving areas, and not genetically modified. Extrusion processing has also been suggested to improve the quality of these FBFs. OBJECTIVES: The aim of this study was to determine the protein quality and iron and vitamin A bioavailability of novel FBFs in broiler chickens. METHODS: Whey protein concentrate (WPC)-containing FBFs corn-soy blend 14, sorghum-soy, and sorghum-cowpea (SC); a soy protein isolate (SPI)-containing SC FBF (SC+SPI); 2 reformulated, overprocessed SC FBFs (O-SC+WPC, O-SC+SPI); and a nonextruded WPC-containing SC FBF were developed. Nonextruded corn-soy blend plus (CSB+), a currently used FBF, and a gamebird starter/grower diet were used as comparison diets. In the prepared FBF study, 9 groups of 8-d-old broiler chicks (n = 10) consumed prepared FBFs for 21 d. In the dry study, 8 groups of 4-d-old broiler chicks (n = 24; control: n = 23) consumed dry FBFs for 14 d. Results were analyzed by 1-factor ANOVA with least-significant-difference test. RESULTS: In the prepared study, novel formulated FBFs significantly increased caloric and protein efficiency and nonsignificantly increased body weight gain, despite similar food intake compared with CSB+. In the dry study, novel formulated FBFs, except for O-SC+SPI, significantly increased food intake, caloric efficiency, and protein efficiency and nonsignificantly increased body-weight gain compared with CSB+. Novel formulated FBFs nonsignificantly and significantly increased hepatic iron concentrations compared with all FBFs in the prepared and dry studies, respectively. CONCLUSION: Novel formulated FBFs, apart from O-SC+SPI, resulted in improved protein efficiencies and hepatic iron concentrations compared with CSB+, suggesting that they are of higher nutritional quality.

20.
J Dairy Sci ; 90(10): 4740-53, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17881697

RESUMEN

Evaluations of 4 soybean meal (SBM) products were conducted in 3 experiments. The 4 products were 1) solvent SBM (SSBM), 2) SSBM treated with 0.05% baker's yeast and toasted at 100 degrees C (YSBM), 3) expeller SBM (ESBM), and 4) lignosulfonate-treated SBM (LSBM). Multiparous Holstein cows (n = 32; 152 +/- 63 d in milk; body weight = 708 +/- 77 kg; producing 41 +/- 7 kg/d of milk at the beginning of the study) were used in a 4 x 4 Latin square design with 28-d periods to investigate cow responsiveness to supplemental ruminally undegradable protein (RUP) from the SBM products. Dietary treatments were formulated by substituting all of the SSBM and part of the ground corn with YSBM, ESBM, or LSBM to yield isonitrogenous diets. Diets were formulated to provide adequate ruminally degradable protein, but deficient RUP and metabolizable protein supplies. No differences among dietary treatments were observed for dry matter intake, body weight gain, milk and component yields, or efficiency of milk production. The lack of response to changes in SBM source was likely due to an adequate RUP and metabolizable protein supply by all the diets. In situ ruminal degradations of YSBM and LSBM were slower than those of SSBM or ESBM; thus, RUP contents of YSBM and LSBM were greater than those of SSBM or ESBM. The RUP of all SBM products had similar small intestinal digestibility. Available Lys contents, estimated chemically or by using a chick growth assay, were less for YSBM and LSBM than for SSBM or ESBM, suggesting deleterious effects of processing on Lys availability in YSBM and LSBM.


Asunto(s)
Bovinos/fisiología , Dieta/veterinaria , Glycine max/metabolismo , Lisina/metabolismo , Lisina/farmacocinética , Alimentación Animal/análisis , Animales , Disponibilidad Biológica , Peso Corporal , Pollos/crecimiento & desarrollo , Pollos/metabolismo , Proteínas en la Dieta/metabolismo , Ingestión de Alimentos , Femenino , Mucosa Intestinal/metabolismo , Lactancia/fisiología , Leche/química , Leche/metabolismo , Nitrógeno/metabolismo , Rumen/metabolismo
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