137 research outputs found
New Method for Well Kick Tolerance Calculation
Well kick is an important basic parameter in the well drilling operation, and it directly determines the Casing layers as well as casing depth. At the same time it also directly determines whether the well drilling will be performed continuously or whether the well-killing operation should be carried out in the well drilling process. Based on the current questions about the well kick tolerance values, the influence caused by several factors such as invasion amount of formation fluid, the distribution of formation fluid in the wellbore and the shut-in casing pressure should be taken into consideration. According to the annular multiphase flow theory, the well kick tolerance calculation model is brought out, besides the relationship between well kick tolerance and formation fluid permeability as well as formation pressure forecasting error is simulated and analyzed. Based on the above analysis it can be seen from the result that when the permeability increases, the well kick tolerance goes up by following the exponential function module. And when the formation pressure forecasting error increases, well kick tolerance goes up significantly. Therefore the simulation result could used to effectively direct the well structure design for complex deep wells.Key words: Well kick tolerance; Casing depth; Permeability; Formation pressure; Well structur
Dietary intake, antioxidants, minerals and vitamins in relation to childhood asthma: a Mendelian randomization study
BackgroundCurrently, there is limited and inconsistent evidence regarding the risk association between daily dietary intake, antioxidants, minerals, and vitamins with Childhood Asthma (CA). Therefore, this study employs Mendelian Randomization (MR) methodology to systematically investigate the causal relationships between daily dietary intake, serum antioxidants, serum minerals, and the circulating levels of serum vitamins with CA.MethodsThis study selected factors related to daily dietary intake, including carbohydrates, proteins, fats, and sugars, as well as serum antioxidant levels (lycopene, uric acid, and β-carotene), minerals (calcium, copper, selenium, zinc, iron, phosphorus, and magnesium), and vitamins (vitamin A, vitamin B6, folate, vitamin B12, vitamin C, vitamin D, and vitamin E), using them as Instrumental Variables (IVs). Genetic data related to CA were obtained from the FinnGen and GWAS Catalog databases, with the primary analytical methods being Inverse Variance Weighting (IVW) and sensitivity analysis.ResultsFollowing MR analysis, it is observed that sugar intake (OR: 0.71, 95% CI: 0.55–0.91, P: 0.01) is inversely correlated with the risk of CA, while the intake of serum circulating magnesium levels (OR: 1.63, 95% CI: 1.06–2.53, P: 0.03), fats (OR: 1.44, 95% CI: 1.06–1.95, P: 0.02), and serum vitamin D levels (OR: 1.14, 95% CI: 1.04–1.25, P: 0.02) are positively associated with an increased risk of CA.ConclusionThis study identified a causal relationship between the daily dietary intake of sugars and fats, as well as the magnesium and vitamin D levels in serum, and the occurrence of CA. However, further in-depth research is warranted to elucidate the specific mechanisms underlying these associations
Advances in CRISPR/Cas gene therapy for inborn errors of immunity
Inborn errors of immunity (IEIs) are a group of inherited disorders caused by mutations in the protein-coding genes involved in innate and/or adaptive immunity. Hematopoietic stem cell transplantation (HSCT) is a mainstay definitive therapy for many severe IEIs. However, the lack of HLA-matched donors increases the risk of developing severe immunological complications. Gene therapy provides long-term clinical benefits and could be an attractive therapeutic strategy for IEIs. In this review, we describe the development and evolution of clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated proteins (Cas) gene-editing systems, including double-strand break (DSB)-based gene editing and DSB-free base editing or prime editing systems. Here, we discuss the advances in and issues associated with CRISPR/Cas gene editing tools and their potential as therapeutic alternatives for IEIs. We also highlight the progress of preclinical studies for the treatment of human genetic diseases, including IEIs, using CRISR/Cas and ongoing clinical trials based on this versatile technology
Graphene-Complex-oxide Nanoscale Device Concepts
The integration of graphene with complex-oxide heterostructures such as
LaAlO/SrTiO offers the opportunity to combine the multifunctional
properties of an oxide interface with the electronic properties of graphene.
The ability to control interface conduction through graphene and understanding
how it affects the intrinsic properties of an oxide interface are critical to
the technological development of novel multifunctional devices. Here we
demonstrate several device archetypes in which electron transport at an oxide
interface is modulated using a patterned graphene top gate. Nanoscale devices
are fabricated at the oxide interface by conductive atomic force microscope
(c-AFM) lithography, and transport measurements are performed as a function of
the graphene gate voltage. Experiments are performed with devices written
adjacent to or directly underneath the graphene gate. Unique capabilities of
this approach include the ability to create highly flexible device
configurations, the ability to modulate carrier density at the oxide interface,
and the ability to control electron transport up to the
single-electron-tunneling regime, while maintaining intrinsic transport
properties of the oxide interface. Our results facilitate the design of a
variety of nanoscale devices that combine unique transport properties of these
two intimately coupled two-dimensional electron systems.Comment: 27 pages, 10 figure
Rapid and Unconditional Parametric Reset Protocol for Tunable Superconducting Qubits
Qubit initialization is a critical task in quantum computation and
communication. Extensive efforts have been made to achieve this with high
speed, efficiency and scalability. However, previous approaches have either
been measurement-based and required fast feedback, suffered from crosstalk or
required sophisticated calibration. Here, we report a fast and high-fidelity
reset scheme, avoiding the issues above without any additional chip
architecture. By modulating the flux through a transmon qubit, we realize a
swap between the qubit and its readout resonator that suppresses the excited
state population to 0.08% 0.08% within 34 ns (284 ns if photon depletion
of the resonator is required). Furthermore, our approach (i) can achieve
effective second excited state depletion, (ii) has negligible effects on
neighbouring qubits, and (iii) offers a way to entangle the qubit with an
itinerant single photon, useful in quantum communication applications.Comment: 38 pages, 15 figure
The gut microbiome in atherosclerotic cardiovascular disease
The gut microbiota may play a role in cardiovascular diseases. Here, the authors perform a metagenome-wide association study on stools from individuals with atherosclerotic cardiovascular disease and healthy controls, identifying microbial strains and functions associated with the disease
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