21 research outputs found
PRECISION.array: An R Package for Benchmarking microRNA Array Data Normalization in the Context of Sample Classification
We present a new R package PRECISION.array for assessing the performance of data normalization methods in connection with methods for sample classification. It includes two microRNA microarray datasets for the same set of tumor samples: a re-sampling-based algorithm for simulating additional paired datasets under various designs of sample-to-array assignment and levels of signal-to-noise ratios and a collection of numerical and graphical tools for method performance assessment. The package allows users to specify their own methods for normalization and classification, in addition to implementing three methods for training data normalization, seven methods for test data normalization, seven methods for classifier training, and two methods for classifier validation. It enables an objective and systemic evaluation of the operating characteristics of normalization and classification methods in microRNA microarrays. To our knowledge, this is the first such tool available. The R package can be downloaded freely at https://github.com/LXQin/PRECISION.array
Repeated misdiagnosis of small intestine bronchogenic cyst: a case report
Bronchogenic cysts are uncommon congenital malformations of the respiratory system. These cysts can be categorized as intrapulmonary, mediastinal, or ectopic. Ectopic bronchogenic cysts, which lack distinctive clinical and imaging features, are particularly challenging to diagnose. This study presents a 48-year-old woman having a small intestinal bronchogenic cyst. She was repeatedly misdiagnosed as having an ovarian chocolate cyst or a cystic mass of bladder origin three years ago. However, no cyst was found during the operation. Half a year prior to presenting at our hospital, the patient developed frequent urination, prompting her to seek further treatment. We eventually discovered a cyst in the small intestine. The histological evaluation of the specimen showed a bronchogenic cyst. Small intestine bronchogenic cysts are extremely rare and easily misdiagnosed. It should be considered as one of the differential diagnoses of pelvic cysts. Particularly, when intraoperative exploration of the pelvic cavity fails to detect any cysts, consideration should be given to the possibility of small intestine bronchogenic cysts
Control of magnetic anisotropy by orbital hybridization in (La0.67Sr0.33MnO3)n/(SrTiO3)n superlattice
The asymmetry of chemical nature at the hetero-structural interface offers an
unique opportunity to design desirable electronic structure by controlling
charge transfer and orbital hybridization across the interface. However, the
control of hetero-interface remains a daunting task. Here, we report the
modulation of interfacial coupling of (La0.67Sr0.33MnO3)n/(SrTiO3)n
superlattices by manipulating the periodic thickness with n unit cells of
SrTiO3 and n unit cells La0.67Sr0.33MnO3. The easy axis of magnetic anisotropy
rotates from in-plane (n = 10) to out-of-plane (n = 2) orientation at 150 K.
Transmission electron microscopy reveals enlarged tetragonal ratio > 1 with
breaking of volume conservation around the (La0.67Sr0.33MnO3)n/(SrTiO3)n
interface, and electronic charge transfer from Mn to Ti 3d orbitals across the
interface. Orbital hybridization accompanying the charge transfer results in
preferred occupancy of 3d3z2-r2 orbital at the interface, which induces a
stronger electronic hopping integral along the out-of-plane direction and
corresponding out-of-plane magnetic easy axis for n = 2. We demonstrate that
interfacial orbital hybridization in superlattices of strongly correlated
oxides may be a promising approach to tailor electronic and magnetic properties
in device applications
Mimicking Neurotransmitter Release and Long‐Term Plasticity by Oxygen Vacancy Migration in a Tunnel Junction Memristor
Activated by action potentials and Ca2+ ion migration, neurotransmitters in biological synapses are released from vesicles at the presynaptic membrane to the cleft and bonded to receptors on the postsynaptic membrane. The bonded neurotransmitters modify the electrochemical properties of the postsynaptic membrane and, thereby, the synaptic plasticity, which forms the basis for learning, memory, emotion, cognition, and consciousness. Here, the oxygen vacancy transport in Au/SrTiO3 (STO)/La0.67Sr0.33MnO3 (LSMO) tunnel junctions is exploited to mimic neurotransmission processes in an artificial ionic electronic device. Using voltage pulses of varying number, amplitude, and polarity, it is demonstrated that reversible oxygen vacancy migration across the STO/LSMO interface provides stable multilevel resistance switching for octal memory devices and resembles the quantal, stochastic, and excitatory or inhibitory nature of neurotransmitter release dynamics. Moreover, fundamental synaptic behaviors including long‐termpotentiation/depression and various types of spike‐timing‐dependent plasticity characteristics are emulated, opening a promising biorealistic approach to the design of neuromorphic devices.Peer reviewe
Oil droplet self-transportation on oleophobic surfaces
Directional liquid transportation is important for a variety of biological processes and technical applications. Although surface engineering through asymmetric chemical modification or geometrical patterning facilitates effective liquid manipulation and enables water droplet self-transportation on synthetic surfaces, self-transportation of oil droplets poses a major challenge because of their low surface tension. We report oil droplet self-transportation on oleophobic surfaces that are microtextured with radial arrays of undercut stripes. More significantly, we observe three modes of oil motion on various sample surfaces, namely, inward transportation, pinned, and outward spreading, which can be switched by the structure parameters, including stripe intersection angle and width. Accompanying theoretical modeling provides an in-depth mechanistic understanding of the structure–droplet motion relationship. Finally, we reveal how to optimize the texture parameters to maximize oil droplet self-transportation capability and demonstrate spontaneous droplet movement for liquids down to a surface tension of 22.4 mN/m. The surfaces presented here open up new avenues for power-free liquid transportation and oil contamination self-removal applications in various analytical and fluidic devices.Peer reviewe
Optimization researches on the cooling-down process of the linde-hampson refrigeration system for a high-low temperature test chamber
This paper focus on the cooling-down performance of the LHRS for a high-low temperature test chamber, and proposed a new method to optimize the cooling-down process of the LHRS based on a quasi-steady-state simulation model to investigated the optimal MR concentration and the shifting strategy of suction pressure during the cooling-down process. Targeted on the maximum cooling capacity, the optimal suction pressure-evaporating temperature curve at a specified mixed refrigerant concentration can be obtained, which can be matched by the sectional suction pressure adjustment in the practical cooling-down process to reduce the overall cooling-down time. As an example, the fastest overall cooling-down time is achieved using the R50/R1150/R290/R600a mixed refrigerant (0.3/0.4/0.05/0.25 b y mole) and corresponding shifting parameters (including two shifting temperatures and three shifting pressures) for the sectional suction pressure adjustment, when the air temperature in the test chamber is dropped from 20 °C to −80 °C. The investigation results can provide good references for the industrial design of a high-low temperature test chamber. The optimization method used in this paper can also provide references for researches on cooling-down processes of other refrigeration systems using multi-component mixed refrigerants
Correction
The original version of this article contained an error in the legend to Figure 4. The yellow scale bar should have been defined as '∼600 nm', not '∼600 μm'. This has now been corrected in both the PDF and HTML versions of the article.Peer reviewe
Tunable Bandgap in Silicene and Germanene
By using ab initio calculations, we predict that a vertical electric field is able to open a band gap in semimetallic single-layer buckled silicene and germanene. The sizes of the band gap in both silicene and germanene increase linearly with the electric field strength. Ab initio quantum transport simulation of a dual-gated silicene field effect transistor confirms that the vertical electric field opens a transport gap, and a significant switching effect by an applied gate voltage is also observed. Therefore, biased single-layer silicene and germanene can work effectively at room temperature as field effect transistors