Biologically plausible computing systems require fine‐grain tuning of analog synaptic characteristics. In this study, lithium‐doped silicate resistive random access memory with a titanium nitride ...(TiN) electrode mimicking biological synapses is demonstrated. Biological plausibility of this RRAM device is thought to occur due to the low ionization energy of lithium ions, which enables controllable forming and filamentary retraction spontaneously or under an applied voltage. The TiN electrode can effectively store lithium ions, a principle widely adopted from battery construction, and allows state‐dependent decay to be reliably achieved. As a result, this device offers multi‐bit functionality and synaptic plasticity for simulating various strengths in neuronal connections. Both short‐term memory and long‐term memory are emulated across dynamical timescales. Spike‐timing‐dependent plasticity and paired‐pulse facilitation are also demonstrated. These mechanisms are capable of self‐pruning to generate efficient neural networks. Time‐dependent resistance decay is observed for different conductance values, which mimics both biological and artificial memory pruning and conforms to the trend of the biological brain that prunes weak synaptic connections. By faithfully emulating learning rules that exist in human's higher cortical areas from STDP to synaptic pruning, the device has the capacity to drive forward the development of highly efficient neuromorphic computing systems.
In this study, lithium‐doped silicate resistive random access memory with a titanium nitride (TiN) electrode is shown to mimic biological synapses. The TiN electrode effectively stores lithium ions, a principle widely adopted from battery construction, and enables reliable state‐dependent decay. This device offers multi‐bit functionality and synaptic plasticity, short‐term memory and long‐term memory, spike‐timing‐dependent plasticity and paired‐pulse facilitation.
The recent progress of efficiency improvement, emission color tuning, and lifetime elongation of blue organic light-emitting diodes (OLEDs) is reviewed. The latter is one of the most important ...bottlenecks for OLED development. The current status of blue light-emitting material design with emission mechanisms such as fluorescence (F), phosphorescence (Ph), thermally activated delayed fluorescence (TADF), and hybridized local and charge transfer (HLCT) is introduced in the first part of this review. Compared to red and green devices, the long exciton lifetime of the high energy triplet exciton in a blue OLED is the one of the main issues. To avoid the accumulation of high energy triplet excitons in the emitter for blue OLEDs, assisted triplet-triplet fluorescence (TTF) and Hyperfluorescence™ are employed to harvest the triplet excitons. In the second part of this review, we focus on issues from an application viewpoint: what are the requirements of blue OLEDs for display and lighting technologies in terms of efficiency, color, and lifetime? Key performance metrics of blue OLEDs with different technologies over time are summarized. Independent of technology, the trend is similar: the external quantum efficiency improves for the first stage of research, followed by color tuning, and then finally lifetime elongation. The state-of-the-art device performance of blue OLEDs with various emission mechanisms is illustrated. Although Ph- and TADF-emission based devices show satisfactory efficiency and electroluminescence (EL) spectra, despite having a lower efficiency TTF-emission based devices are the mainstream for real applications due to their relatively long operation lifetime. Blue Ph-OLEDs have the potential for lighting applications with suitable material selection and device design. We collected the published results and tried our best to make a fair comparison of the operation lifetime among different technologies. Finally, we discuss the possible future outlook from different viewpoints including new materials, device designs, and applications of blue OLEDs.
Emission mechanisms for OLEDs and their characteristics.
Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity ...and to understand details of the anion-graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g
with Coulombic efficiency ∼98%, at a current density of 99 mA g
(0.9 C) with clear discharge voltage plateaus (2.25-2.0 V and 1.9-1.5 V). The cell has a capacity of 60 mAh g
at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C-Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.
Standard inactivated influenza vaccines are poorly immunogenic in immunologically naive healthy young children, who are particularly vulnerable to complications from influenza. For them, there is an ...unmet need for better influenza vaccines. Oil-in-water emulsion-adjuvanted influenza vaccines are promising candidates, but clinical trials yielded inconsistent results. Here, we meta-analyze randomized controlled trials with efficacy data (3 trials, n = 15,310) and immunogenicity data (17 trials, n = 9062). Compared with non-adjuvanted counterparts, adjuvanted influenza vaccines provide a significantly better protection (weighted estimate for risk ratio of RT-PCR-confirmed influenza: 0.26) and are significantly more immunogenic (weighted estimates for seroprotection rate ratio: 4.6 to 7.9) in healthy immunologically naive young children. Nevertheless, in immunologically non-naive children, adjuvanted and non-adjuvanted vaccines provide similar protection and are similarly immunogenic. These results indicate that oil-in-water emulsion adjuvant improves the efficacy of inactivated influenza vaccines in healthy young children at the first-time seasonal influenza vaccination.
Solid‐state triplet–triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light‐emitting diode (OLED)) is demonstrated. A conventional green ...fluorophore, tris‐(8‐hydroxyquinoline)aluminum (Alq3), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet–triplet annihilation emitter, 9,10‐bis(2′‐naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq3 green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq3 sensitizer with lower bandgap, 1‐(2,5‐dimethyl‐4‐(1‐pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq3 and ADN as a triplet‐diffusion‐and‐singlet‐blocking layer. DMPPP exhibits triplet energy close to Alq3 and higher than ADN, as well as higher singlet energy than both Alq3 and ADN. It allows triplet diffusion from Alq3 to ADN, but blocks the SQ of the blue TTAUC signal by Alq3. 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq3/DMPPP/ADN) OLED.
Efficient triplet–triplet annihilation upconversion (TTAUC) in an electroluminescence device with a fluorescent sensitizer is demonstrated. Under electrical pumping, 75% of the triplets are generated in the fluorophore, which can be used as the sensitizer for the TTAUC process by heterojunction trilayer structure. Operation lifetime increases and the overall conversion intrinsic efficiency of TTAUC reaches 86.1%.
Intercellular heterogeneity occurs widely under both normal physiological environments and abnormal disease-causing conditions. Several attempts to couple spatiotemporal information to cell states in ...a microenvironment were performed to decipher the cause and effect of heterogeneity. Furthermore, spatiotemporal manipulation can be achieved with the use of photocaged/photoactivatable molecules. Here, we provide a platform to spatiotemporally analyze differential protein expression in neighboring cells by multiple photocaged probes coupled with homemade photomasks. We successfully established intercellular heterogeneity (photoactivable ROS trigger) and mapped the targets (directly ROS-affected cells) and bystanders (surrounding cells), which were further characterized by total proteomic and cysteinomic analysis. Different protein profiles were shown between bystanders and target cells in both total proteome and cysteinome. Our strategy should expand the toolkit of spatiotemporal mapping for elucidating intercellular heterogeneity.
Quantitative phase imaging (QPI) has been investigated to retrieve optical phase information of an object and applied to biological microscopy and related medical studies. In recent examples, ...differential phase contrast (DPC) microscopy can recover phase image of thin sample under multi‐axis intensity measurements in wide‐field scheme. Unlike conventional DPC, based on theoretical approach under partially coherent condition, we propose a new method to achieve isotropic differential phase contrast (iDPC) with high accuracy and stability for phase recovery in simple and high‐speed fashion. The iDPC is simply implemented with a partially coherent microscopy and a programmable thin‐film transistor (TFT) shield to digitally modulate structured illumination patterns for QPI. In this article, simulation results show consistency of our theoretical approach for iDPC under partial coherence. In addition, we further demonstrate experiments of quantitative phase images of a standard micro‐lens array, as well as label‐free live human cell samples.
The left‐hand side panel shows individual phase contrast images in isotropic differential phase contrast (iDPC) dataset with corresponding gradient amplitude mask on top‐right side. White arrows denote phase gradient direction of each phase contrast image. The figure in right‐hand side is quantitative phase image of alive human adipose‐derived stem cells reconstructed using iDPC dataset.
Extracellular vesicles (EVs) are an important regulatory factor for natural killer cell activity (NKA) in the tumor microenvironment. The relationship between circulating EVs in the peripheral blood ...and natural killer (NK) cells in prostate cancer (PCa) is unclear. This study aimed at investigating the key regulators in the interaction between circulating EVs and NK cells in PCa patients before and after tumor removal. NK‐cell characteristics were prospectively assessed in 79 patients treated with robot‐assisted laparoscopic radical prostatectomy preoperatively and postoperatively. Compared with healthy donors, the existence of prostate tumors increased the number of circulating EVs and altered ligand expression of EVs. Circulating EVs extracted from cancer patients significantly decreased NKA of NK cells compared with those extracted from healthy donors. Upon treatment with an inhibiting antibody or small interfering RNA, natural killer cell protein group 2A (NKG2A) was identified as the main NKA regulator in cancer patients for accepting the signal from circulating EVs. After surgery, NKA was increased and NKG2A expression on NK cells was significantly reduced. The expression of ligands for natural killer cell protein group 2D (NKG2D) on EVs and the level of circulation EVs both significantly increased. With the decrease in NKG2A levels on NK cells and the increase in total NKG2D ligands on circulating EVs, which was increased postoperatively, both NKG2A on NK cells and NKG2D ligands on circulating exosomes are main regulators of NKA restoration after prostatectomy.
More circulating extracellular vesicles (EVs) and downregulated natural killer cell activity (NKA) were found in prostate tumor patients. The inhibiting receptor, natural killer cell protein group 2A (NKG2A), was shown to be the main receptor regulating NKA through EV binding. After prostatectomy, the number of circulating EVs increased, which subsequently increased NKA by decreasing NKG2A on NK cells and increasing total NKG2D (activating receptor for NKA) ligands on EVs.
In this study, we demonstrated a blue phosphorescent organic light-emitting diode (BPOLED) based on a host with two carbazole and one trizole (2CbzTAZ) moiety, ...9,9'-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)-1,3-phenylene)bis(9H-carbazole), that exhibits bipolar transport characteristics. Compared with the devices with a carbazole host (N,N'-dicarbazolyl-3,5-benzene, (mCP)), triazole host (3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, (TAZ)), or a physical mixture of mCP:TAZ, which exhibit hole, electron, and bipolar transport characteristics, respectively, the BPOLED with the bipolar 2CbzTAZ host exhibited the lowest driving voltage (6.55 V at 10 mA/cm
), the highest efficiencies (maximum current efficiency of 52.25 cd/A and external quantum efficiency of 23.89%), and the lowest efficiency roll-off, when doped with bis2-(4,6-difluorophenyl)pyridinato-C2,N(picolinato)iridium(III) (FIrpic) as blue phosphor. From analyses of light leakage of the emission spectra of electroluminescence, transient electroluminescence, and partially doped OLEDs, it was found that the recombination zone was well confined inside the emitting layer and the recombination rate was most efficient in a 2CbzTAZ-based OLED. For the other cases using mCP, TAZ, and mCP:TAZ as hosts, electrons and holes transported with different routes that resulted in carrier accumulation on different organic molecules and lowered the recombination rate.
In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO₂ aeration on the biomass production and lipid accumulation of Nannochloropsis oculata ...in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO₂, the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142gL⁻¹ d⁻¹ with 2% CO₂ aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO₂, the biomass and lipid productivity could reach to 0.372 and 0.084gL⁻¹ d⁻¹, respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151gL⁻¹ d⁻¹ in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121gL⁻¹ d⁻¹ in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO₂ and operated by one-day replacement.
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