Coherent control of macroscopic quantum states in a single-Cooper-pair box

A small superconducting electrode (a single-Cooper-pair box) connected to a reservoir via a Josephson junction constitutes an artificial two-level system, in which two charge states that differ by 2e are coupled by tunneling of Cooper pairs. Despite its macroscopic nature involving a large number of electrons, the two-level system shows coherent superposition of the two charge states, and has been suggested as a candidate for a qubit, i.e. a basic component of a quantum computer. Here we report on time-domain observation of the coherent quantum-state evolution in the two-level system by applying a short voltage pulse that modifies the energies of the two levels nonadiabatically to control the coherent evolution. The resulting state was probed by a tunneling current through an additional probe junction. Our results demonstrate coherent operation and measurement of a quantum state of a single two-level system, i.e. a qubit, in a solid-state electronic device.Comment: 4 pages, 4 figures; to be published in Natur

Effect of standard and physiological cell culture temperatures on in vitro proliferation and differentiation of primary broiler chicken pectoralis major muscle satellite cells

Culture temperatures for broiler chicken cells are largely based on those optimized for mammalian species, although normal broiler body temperature is typically more than 3°C higher. The objective was to evaluate the effects of simulating broiler peripheral muscle temperature, 41°C, compared with standard temperature, 38°C, on the in vitro proliferation and differentiation of primary muscle-specific stem cells (satellite cells; SC) from the pectoralis major (PM) of broiler chickens. Primary SC cultures were isolated from the PM of 18-day-old Ross 708 × Yield Plus male broilers. SC were plated in triplicate, 1.8-cm2, gelatin-coated wells at 40,000 cells per well. Parallel plates were cultured at either 38°C or 41°C in separate incubators. At 48, 72, and 96 h post-plating, the culture wells were fixed and immunofluorescence-stained to determine the expression of the myogenic regulatory factors Pax7 and MyoD as well as evaluated for apoptosis using a TUNEL assay. After 168 h in culture, plates were immunofluorescence-stained to visualize myosin heavy chain and Pax7 expression and determine myotube characteristics and SC fusion. Population doubling times were not impacted by temperature (p ≥ 0.1148), but culturing broiler SC at 41°C for 96 h promoted a more rapid progression through myogenesis, while 38°C maintained primitive populations (p ≤ 0.0029). The proportion of apoptotic cells increased in primary SC cultured at 41°C (p ≤ 0.0273). Culturing at 41°C appeared to negatively impact fusion percentage (p < 0.0001) and tended to result in the formation of thinner myotubes (p = 0.061) without impacting the density of differentiated cells (p = 0.7551). These results indicate that culture temperature alters primary broiler PM SC myogenic kinetics and has important implications for future in vitro work as well as improving our understanding of how thermal manipulation can alter myogenesis patterns during broiler embryonic and post-hatch muscle growth

Quantum oscillations in two coupled charge qubits

Despite an apparent progress in implementing individual solid-state qubits, there have been no experimental reports so far on multi-bit gates required for building a real quantum computer. Here we report a new circuit comprising two coupled charge qubits. Using a pulse technique, we coherently mix quantum states and observe quantum oscillations whose spectrum reflects interaction between the qubits. Our results demonstrate the feasibility of coupling of multiple solid-state qubits and indicate the existence of entangled two-qubit states.Comment: 4 pages, 4 figures, submitted to Natur

Evaluation of Increasing Concentrations of Supplemental Choline Chloride on Modern Broiler Chicken Growth Performance and Carcass Characteristics

Choline has been demonstrated to partially substitute methionine in broiler chicken diets due to their interconnected biosynthesis pathways. Yet, research on the impacts of dietary choline supplementation on modern strains of high-yielding broilers is limited. The objective was to evaluate the effect of increasing additions of choline chloride on the performance and carcass characteristics of broilers fed reduced methionine diets and reared under summer environmental conditions. Ross 708 x Yield Plus male broilers were reared for 41 days on used litter in floor pens (n = 2232; 31 birds per pen). Birds were fed one of six corn and soybean meal-based, reduced methionine diets containing 0, 400, 800, 1200, 1600, or 2000 mg of added choline chloride per kg of feed. Diets were provided in three phases. On day 43, 10 birds per pen were processed. Increasing dietary choline resulted in similar body weight gain, reduced feed intake, and improved feed efficiency. Choline chloride supplementation linearly increased both breast and carcass yields while concomitantly increasing the incidence and severity of wooden-breast-affected fillets. These results indicate that supplementing reduced-methionine broiler diets with choline chloride during high environmental temperatures may improve feed efficiency and increase carcass and breast yields but may also increase wooden breast

Characterization of pectoralis major muscle satellite cell population heterogeneity, macrophage density, and collagen infiltration in broiler chickens affected by wooden breast

Muscle satellite cells (MSCs) are myogenic stem cells that play a critical role in post-hatch skeletal muscle growth and regeneration. Activation of regeneration pathways to repair muscle fiber damage requires both the proliferation and differentiation of different MSC populations as well as the function of resident phagocytic cells such as anti-inflammatory and pro-inflammatory macrophages. The Wooden Breast (WB) phenotype in broiler chickens is characterized by myofiber degeneration and extensive fibrosis. Previous work indicates that the resident MSC populations expressing the myogenic regulatory factors, Myf-5 and Pax7 are larger and more proliferative in broilers severely affected with WB vs. unaffected broilers. To further characterize the cellular and molecular changes occurring in WB-affected muscles, samples from pectoralis major (PM) muscles with varying severity of WB (WB score 0 = normal; 1 = mildly affected; 2 = severely affected) were collected at 25 and 43 days post-hatch (n = 8 per score per age) and processed for cryohistological and protein expression analyses. Collagen per field and densities of macrophages and MyoDC, Myf-5C, and Pax7C MSC populations were quantified on immunofluorescence-stained cryosections. Relative collagen protein expression was quantified by fluorescent Western Blotting. In both 25 and 43-daysold broilers, the proportion of collagen per field (P _ 0.021) and macrophage density (P _ 0.074) were greater in PM exhibiting severe WB compared with normal. At day 43, populations of MyoDC, Myf-5C:MyoDC MSC were larger and relative collagen protein expression was greater in WB-affected vs. unaffected broilers (P _ 0.05). Pax7C MSC relative to total cells was also increased as WB severity increased in 43-days-old broilers (P _ 0.05). Densities of Myf-5C (P = 0.092), MyoDC (P = 0.030), Myf5C:MyoDC (P = 0.046), and Myf-5C:MyoDC:Pax7C (P = 0.048) MSC were greater in WB score 1 birds compared with WB score 0 and 2 birds. Overall, alterations in the resident MSC and macrophage populations and collagen protein content were observed in WBaffected muscle. Further investigation will be required to determine how these changes in cell population kinetics and local autocrine and paracrine signaling are involved in the apparent dysregulation of muscle maintenance in WB-affected broilers

Combining Maternal and Post-Hatch Dietary 25-Hydroxycholecalciferol Supplementation on Broiler Chicken Growth Performance and Carcass Characteristics

Dietary inclusion of the vitamin D3 (D3) metabolite, 25-hydroxycholecalciferol (25OHD3), was demonstrated to improve broiler growth performance and breast meat yield. To assess the effect of combined maternal (MDIET) and post-hatch (PDIET) dietary 25OHD3 inclusion on broiler growth performance and carcass characteristics, a randomized complete block design experiment with a 2 × 2 factorial treatment structure was conducted. From 25 to 38 weeks of age, broiler breeder hens were provided with 1 of 2 MDIET formulated to contain: 5000 IU D3 (MCTL), or 2240 IU of D3 + 2760 IU of 25OHD3 per kg of feed (M25OHD3). Their chick offspring (n = 448; 224 per MDIET) hatched from eggs collected from 37 to 38 weeks of age were reared in 16 replicate pens with 7 birds per pen and fed 1 of 2 PDIET in 3 phases up to day 40 formulated to contain: 5000 IU of D3 per kg of feed (PCTL), or 2240 IU of D3 + 2760 IU of 25OHD3 per kg of feed (P25OHD3). No additive or synergistic effects of combining 25OHD3 inclusion in MDIET and PDIET were observed. Broilers from 25OHD3-fed hens (M25OHD3) were heavier on day 40 than those from hens fed only D3 (MCTL; 2.911 vs. 2.834 kg; p = 0.040). Tender weight (123 vs. 117 g) and yield (5.63 vs. 5.44%) were greater in the M25OHD3 broilers than the MCTL broilers (p = 0.006). Broilers fed 25OHD3 (P25OHD3) tended to have heavier breasts (637 vs. 615 g; p = 0.050), bone-in wings (215 vs. 210 g; p = 0.070), and boneless thighs (279 vs. 270 g; p = 0.078) compared with those fed only D3 (PCTL). Neither MDIET nor PDIET altered the severity of Wooden Breast and White Striping (p ≥ 0.106). Overall, including 25OHD3 in either the maternal or broiler diet increased broiler meat yield