Hydrodynamic and entropic effects on colloidal diffusion in corrugated channels

In the absence of advection, confined diffusion characterizes transport in many natural and artificial devices, such as ionic channels, zeolites, and nanopores. While extensive theoretical and numerical studies on this subject have produced many important predictions, experimental verifications of the predictions are rare. Here, we experimentally measure colloidal diffusion times in microchannels with periodically varying width and contrast results with predictions from the Fick-Jacobs theory and Brownian dynamics simulation. While the theory and simulation correctly predict the entropic effect of the varying channel width, they fail to account for hydrodynamic effects, which include both an overall decrease and a spatial variation of diffusivity in channels. Neglecting such hydrodynamic effects, the theory and simulation underestimate the mean and standard deviation of first passage times by 40\% in channels with a neck width twice the particle diameter. We further show that the validity of the Fick-Jakobs theory can be restored by reformulating it in terms of the experimentally measured diffusivity. Our work thus demonstrates that hydrodynamic effects play a key role in diffusive transport through narrow channels and should be included in theoretical and numerical models.Comment: 7 pages, 4 figure

Diffusion of Colloidal Rods in Corrugated Channels

In many natural and artificial devices diffusive transport takes place in confined geometries with corrugated boundaries. Such boundaries cause both entropic and hydrodynamic effects, which have been studied only for the case of spherical particles. Here we experimentally investigate diffusion of particles of elongated shape confined into a corrugated quasi-two-dimensional channel. Elongated shape causes complex excluded-volume interactions between particle and channel walls which reduce the accessible configuration space and lead to novel entropic free energy effects. The extra rotational degree of freedom also gives rise to a complex diffusivity matrix that depends on both the particle location and its orientation. We further show how to extend the standard Fick-Jacobs theory to incorporate combined hydrodynamic and entropic effects, so as, for instance, to accurately predict experimentally measured mean first passage times along the channel. Our approach can be used as a generic method to describe translational diffusion of anisotropic particles in corrugated channels.Comment: 12 pages and 4 figure

Shifting Control Algorithm for a Single-Axle Parallel Plug-In Hybrid Electric Bus Equipped with EMT

Combining the characteristics of motor with fast response speed, an electric-drive automated mechanical transmission (EMT) is proposed as a novel type of transmission in this paper. Replacing the friction synchronization shifting of automated manual transmission (AMT) in HEVs, the EMT can achieve active synchronization of speed shifting. The dynamic model of a single-axle parallel PHEV equipped with the EMT is built up, and the dynamic properties of the gearshift process are also described. In addition, the control algorithm is developed to improve the shifting quality of the PHEV equipped with the EMT in all its evaluation indexes. The key techniques of changing the driving force gradient in preshifting and shifting compensation phases as well as of predicting the meshing speed in the gear meshing phase are also proposed. Results of simulation, bench test, and real road test demonstrate that the proposed control algorithm can reduce the gearshift jerk and the power interruption time noticeably

Intermittent hypoxia index: a new indicator for assessing the degree of intermittent hypoxia in obstructive sleep apnea

ObjectiveIn order to objectively and accurately evaluate the degree of nocturnal intermittent hypoxia (IH) in patients with obstructive sleep apnea (OSA), we developed the Newton quadrature low oxygen load assessment system (NLAS) to seek a new, quantifiable, comprehensive evaluation index of intermittent hypoxia (intermittent hypoxia index, IHI).MethodsDemographic characteristics, anthropometric measurements, and polysomnography (PSG) parameters [oxygen desaturation index (ODI), lowest oxygen saturation (LSpO2), time below 90% saturation (T90)] of 732 patients with OSA who underwent multi-channel sleep monitoring at the Sleep Center of Affiliated Wuxi People’s Hospital, Nanjing Medical University, from 2019 to 2023 were retrospectively collected. The IHI was calculated using the NLAS (Certificate of Registration Number for Computer Software Copyright of the People’s Republic of China: 12208933), and its threshold was defined. Additionally, correlation analysis was performed between IHI and T90, LSpO2, and ODI.ResultsAmong the 732 patients with OSA, IHI showed significant correlations with T90 (r = 0.922) and LSpO2 (r = 0.866), and moderate correlation with ODI (r = 0.675). The threshold for diagnosing hypoxia in OSA patients using IHI was 7.178 (%s/min).ConclusionThis study demonstrates that IHI calculated using NLAS covers various dimensions of IH indices in OSA patients undergoing multi-channel sleep monitoring. It correlates with parameters such as T90, LSpO2, and ODI. Independent of existing IH assessment indices, IHI holds promise as a new comprehensive assessment index for evaluating the degree of nocturnal IH in OSA

An alternative novel tool for DNA editing without target sequence limitation: the structure-guided nuclease

Engineered endonucleases are a powerful tool for editing DNA. However, sequence preferences may limit their application. We engineer a structure-guided endonuclease (SGN) composed of flap endonuclease-1 (FEN-1), which recognizes the 3′ flap structure, and the cleavage domain of Fok I (Fn1), which cleaves DNA strands. The SGN recognizes the target DNA on the basis of the 3′ flap structure formed between the target and the guide DNA (gDNA) and cut the target through its Fn1 dimerization. Our results show that the SGN, guided by a pair of gDNAs, cleaves transgenic reporter gene and endogenous genes in zebrafish embryonic genome. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13059-016-1038-5) contains supplementary material, which is available to authorized users

Multiomics analysis of a resistant European turnip ECD04 during clubroot infection reveals key hub genes underlying resistance mechanism

The clubroot disease has become a worldwide threat for crucifer crop production, due to its soil-borne nature and difficulty to eradicate completely from contaminated field. In this study we used an elite resistant European fodder turnip ECD04 and investigated its resistance mechanism using transcriptome, sRNA-seq, degradome and gene editing. A total of 1751 DEGs were identified from three time points after infection, among which 7 hub genes including XTH23 for cell wall assembly and two CPK28 genes in PTI pathways. On microRNA, we identified 17 DEMs and predicted 15 miRNA-target pairs (DEM-DEG). We validated two pairs (miR395-APS4 and miR160-ARF) by degradome sequencing. We investigated the miR395-APS4 pair by CRISPR-Cas9 mediated gene editing, the result showed that knocking-out APS4 could lead to elevated clubroot resistance in B. napus. In summary, the data acquired on transcriptional response and microRNA as well as target genes provide future direction especially gene candidates for genetic improvement of clubroot resistance on Brassica species

High-flow nasal cannula oxygen therapy versus non-invasive ventilation in healthy respiratory physicians: a non-randomized study

BackgroundHigh-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) are commonly used for respiratory support. This study aims to first establish whether to use HFNC or NIV based on comfort levels, and subsequently evaluate diaphragmatic function under equivalent comfort levels to determine the optimal modality for clinical application.MethodsA self-controlled, non-randomized study was conducted with 10 healthy respiratory physicians as participants. Each subject was exposed to different HFNC settings, including flow rates of 20, 40, and 60 L/min at both 33 and 37°C. Additionally, participants were assessed under NIV mode. Comfort levels as the primary outcome were evaluated using the Visual Numerical Scale (VNS). Meanwhile, vital signs and diaphragmatic mobility were monitored through an electrocardiograph and ultrasound.ResultsHFNC at a flow rate of 20 L/min provided greater comfort than NIV. However, as the flow rate increased, this comfort benefit decreased. At 40 L/min, comfort levels were similar between HFNC and NIV, while at 60 L/min, HFNC was less comfortable than NIV. Notably, temperature variations between 33 and 37°C had no significant effect on comfort. In addition, under conditions of similar comfort, HFNC demonstrated slightly greater diaphragmatic mobility compared to NIV.ConclusionOur study indicated HFNC was the preferred choice for providing respiratory support at low to moderate flow rates in healthy volunteers not requiring respiratory support. By contrast, at higher flow rates, NIV discomfort was lower than HFNC discomfort

Maternal, neonatal, pregnancy outcome characteristics of pregnant women with high plasma cell-free DNA concentration in non-invasive prenatal screening: a retrospective analysis

ObjectiveCell-free DNA (cfDNA) is a useful biomarker in various clinical contexts. Herein, we aimed to identify maternal characteristics and pregnancy outcomes associated with a failed NIPS test due to high cfDNA concentrations.MethodsA retrospective study of cases with high plasma cfDNA concentration in pregnant women in which NIPS test was performed (from 174,318 cases). We reported the detection of 126 cases (118 with complete clinical information) in which the high amount of cfDNA did not allow the performance of NIPS and study the possible causes of this result.Results622 (0.35%) of 174,318 pregnant women had failed the NIPS test, including 126 (20.3%) cases with high plasma cfDNA concentrations. The failed NIPS due to high plasma cfDNA concentrations was associated with maternal diseases and treatment with low-molecular-weight heparin (LMWH). Further follow-up of the 118 pregnant women in the case group revealed that the pregnancy outcomes included 31 premature deliveries, 21 abortions. The cfDNA concentrations of pregnant women with preterm deliveries were 1.15 (0.89, 1.84), which differed significantly from those who had full-term deliveries.ConclusionsAmong pregnant women with high cfDNA concentrations, systemic autoimmune diseases, pregnancy complications and LMWH were associated with increased incidence of failed NIPS test. High maternal cfDNA concentrations may not be associated with chromosomal abnormalities in the fetus. However, they should be alerted to the possibility of preterm births and stillbirths. Further clinical studies on pregnant women with high cfDNA concentrations are required