Bidirectional Encoder Representations from Transformers (BERT) and BERT-based approaches are the current state-of-the-art in many natural language processing (NLP) tasks; however, their application ...to document classification on long clinical texts is limited. In this work, we introduce four methods to scale BERT, which by default can only handle input sequences up to approximately 400 words long, to perform document classification on clinical texts several thousand words long. We compare these methods against two much simpler architectures -- a word-level convolutional neural network and a hierarchical self-attention network -- and show that BERT often cannot beat these simpler baselines when classifying MIMIC-III discharge summaries and SEER cancer pathology reports. In our analysis, we show that two key components of BERT -- pretraining and WordPiece tokenization -- may actually be inhibiting BERT's performance on clinical text classification tasks where the input document is several thousand words long and where correctly identifying labels may depend more on identifying a few key words or phrases rather than understanding the contextual meaning of sequences of text.
Purpose
Severe traumatic brain injury (TBI) leads to acute coma and may result in prolonged disorder of consciousness (pDOC). We aimed to determine whether right median nerve electrical stimulation ...is a safe and effective treatment for accelerating emergence from coma after TBI.
Methods
This randomised controlled trial was performed in 22 centres in China. Participants with acute coma at 7–14 days after TBI were randomly assigned (1:1) to either routine therapy and right median nerve electrical stimulation (RMNS group) or routine treatment (control group). The RMNS group received 20 mA, 300 μs, 40 Hz stimulation pulses, lasting 20 s per minutes, 8 h per day, for 2 weeks. The primary outcome was the proportion of patients who regained consciousness 6 months post-injury. The secondary endpoints were Glasgow Coma Scale (GCS), Full Outline of Unresponsiveness scale (FOUR), Coma Recovery Scale-Revised (CRS-R), Disability Rating Scale (DRS) and Glasgow Outcome Scale Extended (GOSE) scores reported as medians on day 28, 3 months and 6 months after injury, and GCS and FOUR scores on day 1 and day 7 during stimulation. Primary analyses were based on the intention-to-treat set.
Results
Between March 26, 2016, and October 18, 2020, 329 participants were recruited, of whom 167 were randomised to the RMNS group and 162 to the control group. At 6 months post-injury, a higher proportion of patients in the RMNS group regained consciousness compared with the control group (72.5%,
n
= 121, 95% confidence interval (CI) 65.2–78.7% vs. 56.8%,
n
= 92, 95% CI 49.1–64.2%,
p
= 0.004). GOSE at 3 months and 6 months (5 interquartile range (IQR) 3–7 vs. 4 IQR 2–6,
p
= 0.002; 6 IQR 3–7 vs. 4 IQR 2–7,
p
= 0.0005) and FOUR at 28 days (15 IQR 13–16 vs. 13 interquartile range (IQR) 11–16,
p
= 0.002) were significantly increased in the RMNS group compared with the control group. Trajectory analysis showed that significantly more patients in the RMNS group had faster GCS, CRS-R and DRS improvement (
p
= 0.01, 0.004 and 0.04, respectively). Adverse events were similar in both groups. No serious adverse events were associated with the stimulation device.
Conclusion
Right median nerve electrical stimulation is a possible effective treatment for patients with acute traumatic coma, that will require validation in a confirmatory trial.
The collective modes of the superconducting (SC) order parameter fluctuation can provide key insights into the nature of the superconductor, such as the pairing symmetry and orbital nature of the ...cooper pairs. Their detection has been challenging. Recently, a family of charge density wave (CDW) superconductors has emerged in non-magnetic kagome materials AV3Sb5 (A=K, Rb, Cs), exhibiting evidence for unprecedented time-reversal symmetry breaking CDW, roton-pair density wave (PDW), and higher-charge flux quantization. However, the collective behaviors of the cooper pairs have not been studied. Here, we report a distinct collective mode in the kagome superconductors CsV3-xTaxSb5. Using scanning tunneling microscope/spectroscopy (STM/S), we observe a "peak-dip-hump" feature in the tunneling conductance-a defining signature of collective excitations. The spectral lineshape is well-described by two SC gap functions, one isotropic and one anisotropic, and a bosonic mode due to electron-mode coupling. With increasing x, the two SC gaps, with different pair-breaking strengths and thus different orbital/band characters, move closer in energy, merge into two isotropic gaps of equal amplitude, and then increase synchronously. The collective mode energy, on the other hand, decreases monotonically to well below the quasi-particle excitation gap 2{\Delta} and survives even after the CDW order is suppressed at large x. We identify the collective mode as the Leggett mode of the relative phases between different SC components in the multi-band superconductor or the exotic Bardasis-Schrieffer mode due to a subleading SC component. Our findings provide valuable insights on the nature of the SC ground state and collective excitations, their evolution with Ta-substitutions, and offer a new pathway to study the origin of superconductivity and its interplay with CDW order in kagome superconductors.
Controlling charge-density-wave (CDW) orders in two-dimensional (2D) crystals has attracted a great deal of interest because of their fundamental physics and their demand inse in miniaturized ...devices. In this work, we systematically studied the size-dependent CDW orders in single-layer hetero/homo-NbSe
stacking junctions. We found that the CDW orders in the top 1T-NbSe
layer of the junctions are highly dependent on its lateral size. For the 1T/2H-NbSe
heterojunction, the critical lateral size of 1T-NbSe
islands for the formation of well-defined CDW orders is ∼26 nm, whereas below 15 nm, the CDW orders melt. However, for the 1T/1T-NbSe
homojunction, the CDW orders in the islands can persist even with a lateral size of <11 nm. Our findings illuminate the fresh phenomenon of size-dependent CDW orders existing in 2D van der Waals hetero/homojunctions and provide useful information for the control of CDW orders.
Abstract
Water electrolysis is a promising technique for carbon neutral hydrogen production. A great challenge remains at developing robust and low‐cost anode catalysts. Many pre‐catalysts are found ...to undergo surface reconstruction to give high intrinsic activity in the oxygen evolution reaction (OER). The reconstructed oxyhydroxides on the surface are active species and most of them outperform directly synthesized oxyhydroxides. The reason for the high intrinsic activity remains to be explored. Here, a study is reported to showcase the unique reconstruction behaviors of a pre‐catalyst, thiospinel CoFe
2
S
4
, and its reconstruction chemistry for a high OER activity. The reconstruction of CoFe
2
S
4
gives a mixture with both Fe–S component and active oxyhydroxide (Co(Fe)O
x
H
y
) because Co is more inclined to reconstruct as oxyhydroxide, while the Fe is more stable in Fe–S component in a major form of Fe
3
S
4
. The interface spin channel is demonstrated in the reconstructed CoFe
2
S
4
, which optimizes the energetics of OER steps on Co(Fe)O
x
H
y
species and facilitates the spin sensitive electron transfer to reduce the kinetic barrier of O–O coupling. The advantage is also demonstrated in a membrane electrode assembly (MEA) electrolyzer. This work introduces the feasibility of engineering the reconstruction chemistry of the precatalyst for high performance and durable MEA electrolyzers.
Layered semiconductors show promise as channel materials for field-effect transistors (FETs). Usually, such devices incorporate solid back or top gate dielectrics. Here, we explore deionized (DI) ...water as a solution top-gate for field-effect switching of layered semiconductors including SnS2, MoS2, and black phosphorus. The DI water gate is easily fabricated, can sustain rapid bias changes, and its efficient coupling to layered materials provides high on–off current ratios, near-ideal subthreshold swing, and enhanced short-channel behavior even for FETs with thick, bulk-like channels, where such control is difficult to realize with conventional back gating. Screening by the high-k solution gate eliminates hysteresis due to surface and interface trap states and substantially enhances the field-effect mobility. The onset of water electrolysis sets the ultimate limit to DI water gating at large negative gate bias. Measurements in this regime show promise for aqueous sensing, demonstrated here by the amperometric detection of glucose in aqueous solution. In conclusion, DI water gating of layered semiconductors can be harnessed in research on novel materials and devices, and it may with further development find broad applications in microelectronics and sensing.
To understand whether p53 gene mutation is an early or late event in esophageal carcinogenesis, biopsy samples of esophageal epithelium from symptom-free subjects in a high incidence area, Huixian ...county of Henan Province, China, were analyzed. Mutations in exons 5, 6, 7, and 8 of p53 were analyzed by single-strand conformation polymorphism analysis and DNA sequencing. Among the 37 biopsy samples showing accumulation of p53 protein in immunohistochemical staining, missense mutations of p53 gene were detected in 1 of 3 samples with normal epithelia, 3 of 23 samples with basal cell hyperplasia, and 4 of 11 samples with dysplasia. All mutations occurred at exon 5 with 3 at codon 175, 2 at codon 176, and 1 each at codons 159, 135, and codon 132. Of the 8 mutations, there were 3 G to A transitions and 3 G to T transversions. To understand the mutation spectrum and possible causative factors of esophageal cancer in this area, surgically resected human primary esophageal carcinomas from Linxian county were analyzed for p53 gene mutations in exons 5, 6, 7, and 8. Mutations were detected in 16 of 29 samples (55%). Twelve samples contained different missense point mutations, with 75% transitions (7 G to A and 2 A to G) and 25% transversions (2 G to T and 1 G to C). Most of the mutations were located at either exon 5 or exon 7. A deletion and an insertion of nucleotides leading to frame-shift mutations were detected in each of two other samples. The results demonstrate that p53 protein accumulation and gene mutation may occur at very early stages of esophageal carcinogenesis. In carcinomas, there was a higher frequency of p53 gene mutations, which accounts for most of the cases with p53 protein accumulation.
