The aim of the study was to investigate the prevalence of mutations of basal core promoter (BCP) and precore (PreC) region of hepatitis B virus (HBV) and their association with hepatocellular ...carcinoma. A total of 341 untreated older HBV patients were divided into three groups: chronic hepatitis B (CHB, 185), cirrhotic hepatocellular carcinoma (LC‐HCC, 113) and non‐cirrhotic hepatocellular carcinoma (non‐LC‐HCC, 43). HBV BCP and PreC mutations and genotypes were determined by direct sequencing. Using univariate analysis, age (≥45 years), single mutations including A1896 and A1899 and multiple mutations T1762/A1764 + A1896, T1762/A1764 + A1899 and T1762/A1764 + A1896 + A1899 were more frequently detected in LC‐HCC and non‐LC‐HCC patients than in CHB patients. BCP T1762/A1764 mutations were highly detected in LC‐HCC patients than in CHB patients. Multivariate logistic regression analysis (adjusted for age and gender) revealed that among HBeAg‐positive patients, BCP T1762/A1764 mutations (OR, 5.975; P = 0.05), PreC A1899 mutation (OR, 4.180; P = 0.013) and multiple mutations T1762/A1764 + A1899 (OR, 6.408; P = 0.006) were independently associated with the development of LC‐HCC; PreC A1899 mutation (OR, 7.347; P = 0.034) was also independently associated with the development of non‐LC‐HCC. On the other hand, among HBeAg‐negative patients, PreC A1896 mutation (OR, 5.176; P = 0.002) and multiple mutations T1762/A1764 + A1896 (OR, 4.149; P = 0.007) were independently associated with the development of non‐LC‐HCC. These results indicated that older age (≥45 years) was associated with LC‐HCC and non‐LC‐HCC development. BCP T1762/A1764 mutations and PreC A1899 mutation were associated with the LC‐HCC development in HBeAg‐positive patients. PreC A1896 mutation was associated with the non‐LC‐HCC development in HBeAg‐negative patients.
Abstract
The charge-trapping memory devices with a structure Pt/Al
2
O
3
/(Ta
2
O
5
)
x
(TiO
2
)
1
−
x
/Al
2
O
3
/p-Si (x = 0.9, 0.75, 0.5, 0.25) were fabricated by using rf-sputtering and atomic ...layer deposition techniques. A special band alignment between (Ta
2
O
5
)
x
(TiO
2
)
1
−
x
and Si substrate was designed to enhance the memory performance by controlling the composition and dielectric constant of the charge-trapping layer and reducing the difference of the potentials at the bottom of the conduction band between (Ta
2
O
5
)
x
(TiO
2
)
1
−
x
and Si substrate. The memory device with a composite charge storage layer (Ta
2
O
5
)
0.5
(TiO
2
)
0.5
shows a density of trapped charges 3.84 × 10
13
/cm
2
at ± 12 V, a programming/erasing speed of 1 µs at ± 10 V, a 8% degradation of the memory window at ± 10 V after 10
4
programming/erasing cycles and a 32% losing of trapped charges after ten years. The difference among the activation energies of the trapped electrons in (Ta
2
O
5
)
x
(TiO
2
)
1
−
x
CTM devices indicates that the retention characteristics are dominated by the difference of energy level for the trap sites in each TTO CTM device.
To evaluate the radiation dose and diagnostic image quality of low-dose computed tomography (CT) of the paranasal sinus in children, with acquisition at an ultra-low tube voltage (70 kVp) combined ...with the Flash technique.
Eighty paediatric patients underwent CT of the paranasal sinus and were divided into two groups according to different protocols (group A: 80 kVp protocol with conventional spiral mode n=40 and group B: 70 kVp protocol with Flash scan mode n=40). For each examination, the CT dose index (CTDIvol), dose–length product (DLP), and effective dose (ED) were estimated. The image noise, signal-to-noise ratio (SNR), and overall subjective diagnostic image quality were also evaluated.
For radiation dose, the CTDIvol (mGy), DLP (mGy·cm), and ED (mSv) values of the 70 kVp protocol were significantly lower than those of the 80 kVp protocol (CTDIvol: 1.57±0.009 versus 0.39±0.004 mGy, p<0.001; DLP: 19.88±2.01 versus 6.31±0.52 mGy·cm, p<0.001; ED: 0.079±0.016 versus 0.024±0.005 mSv, p<0.001). Compared with those of the 80-kVp protocol, the image noise increased by 40.7% (p=0.113), the SNRsoft-tissue decreased by 48.9%, and the SNRbone increased by 10.1% with the 70-kVp protocol (p=0.176 and 0.227, respectively). There was no significant difference in the overall subjective image quality grades between these two groups (p=0.15).
When imaging the paranasal sinus in children, an ultra-low tube voltage (70 kVp) combined with the Flash CT technique can reduce the radiation dose significantly while maintaining diagnostic image quality with clinically acceptable image noise.
•Evaluation of ultra-low tube voltage (70 kVp) combined with Flash scan technique.•A new scan protocol could significantly reduce the CT scan dose of children's paranasal sinus.•The new scan protocol could produce virtually no artifacts caused by pediatric patient motion.•The new scan protocol could maintain image quality for accurate diagnosis at an ultra-low dose level.
The gut microbiota is central to human health, but its establishment in early life has not been quantitatively and functionally examined. Applying metagenomic analysis on fecal samples from a large ...cohort of Swedish infants and their mothers, we characterized the gut microbiome during the first year of life and assessed the impact of mode of delivery and feeding on its establishment. In contrast to vaginally delivered infants, the gut microbiota of infants delivered by C-section showed significantly less resemblance to their mothers. Nutrition had a major impact on early microbiota composition and function, with cessation of breast-feeding, rather than introduction of solid food, being required for maturation into an adult-like microbiota. Microbiota composition and ecological network had distinctive features at each sampled stage, in accordance with functional maturation of the microbiome. Our findings establish a framework for understanding the interplay between the gut microbiome and the human body in early life.
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•Gut microbiomes of 98 mothers and their infants during the first year of life was assessed•Cessation of breast-feeding drives the maturation of the infant gut microbiome•Shifts in signature species demonstrate nonrandom transitions in the infants’ gut•Changes in nutrient and xenobiotic metabolism mark maturation of the gut microbiome
Bäckhed et al. assessed the gut microbiomes of 98 Swedish mothers and their infants during the first year of life. Cessation of breast-feeding was identified as a major factor in determining gut microbiota maturation, with distinct shifts in signature species being hallmarks of its functional maturation.
Laser spectroscopy stands out as a powerful tool to investigate atomic and nuclear properties and also test fundamental theories by precisely measuring the energy levels in highly charged ions. In ...this work, the fine-structure splitting 1s22s2S1/2−1s22p2P1/2 transition in lithium-like 16O5+ has been investigated in a laser spectroscopy experiment at the heavy-ion storage ring CSRe. The excitation resonance of the tunable narrowband UV laser and the ions was observed using a Schottky resonator with very high sensitivity. The experimental uncertainties including the ion beam velocity determination, the space charge effects, laser wavelength calibration, and angular misalignment between the laser and ion beam were analyzed, and the 2S1/2−2P1/2 transition wavelength was determined to be λ0= 103.45(38) nm. The primary source of experimental uncertainty arises from the inaccurate measurement of the high voltage applied on the electron cooler and therewith the ion beam velocity at the CSRe. In order to solve this problem, a high-precision divider to precisely measure the high-voltage of the electron cooler is under construction, which is expected to improve the present experimental accuracy by three orders of magnitude. In addition, an XUV optical detector equipped with an off-axis parabolic mirror has been developed and installed at the CSRe for the investigation of slow dipole-forbidden transitions in highly charged ions, such as hyperfine splitting and M1 transitions. The experimental studies presented here pave the way for future laser spectroscopy experiments at the CSRe as well as at the future larger-scale scientific facility HIAF in China.
Paired box (Pax) proteins 3 and 7 are associated with activation of muscle satellite cells and play a major role in hyperplastic and hypertrophic growth in postnatal skeletal muscle fibers. The ...objective of this study was to evaluate the effect of housing system on abundance of Pax3 and Pax7 in postnatal chicken skeletal muscles. At 42 d, 1,200 chickens with similar BW were randomly assigned to cage, pen, and free-range group. The mRNA abundance was measured in pectoralis major and thigh muscle at d 56, 70, and 84, and the protein expression was quantified at d 84. Increases in mRNA abundance of PAX3 and PAX7 with age were less pronounced in caged system chickens than in pen and free-range chickens from d 56 to 84, and free-range chickens showed a more pronounced increase in gene expression with age compared with penned chickens. At d 84, quantities of PAX3 and PAX7 mRNA and protein were highest in both pectoralis major and thigh muscle of chickens raised in the free-range group, lowest in penned chickens, and intermediate in caged chickens (P < 0.05). These data indicate that housing system may influence muscle fiber muscle accretion by coordinating the expression of Pax3 and Pax7 in adult chicken skeletal muscles.
A significant deceleration effect on a stored coasting ion beam by a continuous-wave laser light was observed in the Schottky-noise spectrum during the laser experiments with lithium-like oxygen ion ...beams stored at a relativistic energy of 275.7 MeV/u at the heavy-ion storage ring CSRe in Lanzhou, China. The observed deceleration range of the laser (Δp/p≈5.7×10−6) is much broader than the expected capture range (Δp/p≈3.6×10−8), as calculated from the natural linewidth of the O5+ ion’s electronic transition (2S1/2−2P1/2). In order to explain this huge deviation, a phase space tracking code has been developed to investigate the interaction between the stored coasting ion beam and the laser light. Simulations reveal that the deceleration range of the typically narrow CW laser force is highly enlarged by taking into account the transverse betatron oscillation of the ions with larger emittance and the angular misalignment of the laser light direction. The experimental observation is well described by the systematic simulations. The present work is crucial for forthcoming laser cooling and precision laser spectroscopy experiments and simulations on heavy highly charged ions at the CSRe and the future facility HIAF.
The low permeability reservoir perfect an important role of energy replacement in petroleum industry. Aiming at the problem of low prediction accuracy of the deep profile control in low permeability ...reservoirs and the lack of theoretical basis for the tracking and adjustment of projects, the variation characteristics of relaxation time are determined based on the viscoelastic experiments of movable gels with different concentrations, shear rates and angular velocities. The viscoelastic mobile gel apparent viscosity model considering the relaxation time kinetics is established based on the Maxwell theory and the pressure prediction model for the expanded granular/mobile gel deep profile control in low permeability reservoirs is established. Finally, the real production data of profile control wells in Yushulin oilfield in China is taken as an example, the application effects of the new pressure prediction model considering the viscoelasticity, the pressure model without viscoelasticity and the numerical simulation model are compared and verified. The results show that the gel exhibits viscoelasticity at high shear rate, and when the gel concentration is increased from 500 mg/L to 1500 mg/L, the relaxation time decreases from 1.04 s to 0.08 s and from 6.3 s to 0.8 s before and after gelation, respectively. The application effects of the models show that the new model takes into account the viscoelasticity of the gel, which is 12.3 percentage points higher than that of the traditional pressure model based on the reservoir engineering method and 10.6 percentage points higher than that of the numerical simulation model.
This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall ...anywhere in the range of 1 to 100 nm. We devote the most attention to 1D nanostructures that have been synthesized in relatively copious quantities using chemical methods. We begin this article with an overview of synthetic strategies that have been exploited to achieve 1D growth. We then elaborate on these approaches in the following four sections: i) anisotropic growth dictated by the crystallographic structure of a solid material; ii) anisotropic growth confined and directed by various templates; iii) anisotropic growth kinetically controlled by supersaturation or through the use of an appropriate capping reagent; and iv) new concepts not yet fully demonstrated, but with long‐term potential in generating 1D nanostructures. Following is a discussion of techniques for generating various types of important heterostructured nanowires. By the end of this article, we highlight a range of unique properties (e.g., thermal, mechanical, electronic, optoelectronic, optical, nonlinear optical, and field emission) associated with different types of 1D nanostructures. We also briefly discuss a number of methods potentially useful for assembling 1D nanostructures into functional devices based on crossbar junctions, and complex architectures such as 2D and 3D periodic lattices. We conclude this review with personal perspectives on the directions towards which future research on this new class of nanostructured materials might be directed.
Current research activities concentrating on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—are comprehensively reviewed. Chemical methods of synthesis are introduced and a range of growth mechanisms discussed in terms of shape control. The generation of heterostructured nanowires is detailed, as is the range of unique properties of 1D nanostructures. The assembly of 1D nanostructures into functional devices is also mentioned. The article concludes with perspectives on future research and related issues.
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