Reliable Retention Research Articles

BiFeO3/SrTiO3 superlattice-like based ferroelectric memristors with pronounced artificial synaptic plasticity

Memristors are attracting widespread attention for their multilevel storage capacity and synaptic learning ability. Ferroelectric memristors, with resistance switching based on polarization reversal, offer uniform threshold voltage and analog resistance modulation. By preparing superlattice-like ferroelectric films, the ferroelectric properties can be significantly enhanced, thereby improving the memristive characteristics. In this study, the constructed BiFeO3/SrTiO3 (BFO/STO) superlattice-like structure increases the remanent polarization by approximately 200 % compared to a single-layer BFO structure, as well as the dramatically enhanced resistance switching performance. Notably, the Pt/(BFO/STO)2/NSTO device shows superior storage performance, with extended endurance (1000 cycles), reliable retention (10000 seconds) and fundamental synaptic behaviors being demonstrated. Finally, simulations for handwritten digit recognition classification, involving modulation of conductance to vary synaptic weights, achieve an impressive accuracy of 87.46 %, showing great promising for applications in information storage and neuromorphic computing.

Polar metabolomics using trichloroacetic acid extraction and porous graphitic carbon stationary phase

IntroductionAccurately identifying and quantifying polar metabolites using untargeted metabolomics has proven challenging in comparison to mid to non-polar metabolites. Hydrophilic interaction chromatography and gas chromatography–mass spectrometry are predominantly used to target polar metabolites.ObjectivesThis study aims to demonstrate a simple one-step extraction combined with liquid chromatography–mass spectrometry (LC–MS) that reliably retains polar metabolites.MethodsThe method involves a MilliQ + 10% trichloroacetic acid extraction from 6 healthy individuals serum, combined with porous graphitic carbon liquid chromatography–mass spectrometry (LC–MS). The coefficient of variation (CV) assessed retention reliability of polar metabolites with logP as low as − 9. QreSS (Quantification, Retention, and System Suitability) internal standards determined the method's consistency and recovery efficiency.ResultsThe method demonstrated reliable retention (CV < 0.30) of polar metabolites within a logP range of − 9.1 to 5.6. QreSS internal standards confirmed consistent performance (CV < 0.16) and effective recovery (70–130%) of polar to mid-polar metabolites. Quality control dilution series demonstrated that ~ 80% of annotated metabolites could be accurately quantified (Pearson’s correlation coefficient > 0.80) within their concentration range. Repeatability was demonstrated through clustering of repeated extractions from a single sample.ConclusionThis LC–MS method is better suited to covering the polar segment of the metabolome than current methods, offering a reliable and efficient approach for accurate quantification of polar metabolites in untargeted metabolomics.

Development and a validation study of comprehensive prescription writing rubrics for medical students

Background: Prescribing is a complex task for physicians, with many global reports of errors. This study evaluates a comprehensive rubric for medical student prescribing skills regarding validity and reliability. Methods: Twenty-one third-year medical students participated in three separate prescribing exams. Two pharmacology professors rated the students' prescriptions using a rubric covering ten criteria. Messick validity framework was utilised to enhance the study’s validity. Generalisability theory (G-theory) helped determine the source of variance and the optimal number of raters and test occasions. Results: Content validity was ensured by three experts and alignment with the Thai Medical Council criterion. The Inter-rater and test-retest reliability were acceptable. The rubric had a Cronbach's alpha 0.70 with item-test correlation, all above 0.40. G-theory indicated that 54.93% of the total variance was due to performance and 27.57% to the interaction between performance and occasions, with a minimal residual variance of 4.28%. To reach an acceptable Phi-coefficient (≥0.70), three occasions with one rater (Phi-coefficient=0.76) or two occasions with two raters (Phi-coefficient=0.72) are needed. Conversely, the Phi-coefficient was low on a single occasion. Conclusion: The study introduces a comprehensive rubric and description of a prescription writing programme to minimise potential prescribing errors in pre-clinical years. Furthermore, more assessment opportunities enhance knowledge retention and assessment reliability.

Orientation-dependent tunneling electroresistance in Pt/Pb(Zr,Ti)O3/Nb:SrTiO3 ferroelectric tunnel junctions

Orientation anisotropy is a well-known essential character for polarization characteristics of ferroelectric materials, which has been widely investigated in conventional ferroelectric random access memories. In this work, we study the effects of orientation on the tunneling electroresistance (TER) of ferroelectric tunnel junctions (FTJs). Rhombohedral Pb(Zr[Formula: see text],Ti[Formula: see text])O3 (PZT) that has the polar axis along the [Formula: see text] orientation is adopted as potential barriers and two kinds of FTJs that are composed of (001)- and (111)-oriented PZT barriers and Nb:SrTiO3 (Nb:STO) electrodes, respectively, are fabricated. The (111)-oriented Pt/PZT/Nb:STO FTJ exhibits a giant ON/OFF ratio of [Formula: see text], about 30 times that of the (001)-oriented device, due to the lowered PZT barrier in the ON state and the widen Schottky barrier in the OFF state based on current and capacitance analyses. In addition, compared to the (001)-oriented device, the (111)-oriented FTJ shows a sharper and faster switching between the ON and OFF states according to the nucleation-limited-switching dynamics model, giving rise to good linearity in memristive behaviors for synaptic plasticity and reliable retention and endurance properties for the resistance switching. The improved TER properties are ascribed to larger effective polarizations and 180∘ switching in the (111)-oriented PZT barrier. These results facilitate the design and fabrication of high-performance FTJ devices with the optimization of crystallographic orientation and polarization switching characteristics.

Stabilizing Interfacial Behaviors of Ni‐rich Cathodes by Upcycling of Oyster Shells Waste

AbstractLayered lithium oxides (LNCM), with over 60% Ni, are promising cathode materials for electric vehicles due to their high capacity. however, reliable cycling retention cannot easily achieved owing to the instability of the interface. Here, recycled oyster shell (OS) is employed as an efficient precursor for the surface modification of LNCM cathodes; subsequently, Ca‐based artificial cathode–electrolyte interphases (CEI) are obtained at the LNCM interfaces through a simple calcination process. When the pulverized OS is calcined with LNCM cathode materials at elevated temperatures, CaCO3 is converted to CaO via thermal decomposition at the LNCM interface, which effectively protects the unstable interface. Microscopic analyses indicate the nanodomain island‐type CEI layers embedded after OS calcination. The OS‐coated LNCM cathode materials increase the cycling retention after 100 cycles (93.8% vs. 62.7%) and decrease the internal cell pressure by preventing electrolyte decomposition. Incorporating Ca into the LNCM cathode materials also inhibits microcrack formation because of the improvement in particle hardness and the remarkable decrease in the irreversible dissolution of transition metals from LNCM cathodes, considering that Ca plays a crucial role in scavenging fluoride species. Consequently, recycling OS as a functional LNCM precursor is an innovative approach for enhanced cycling retention.

A novel solution to improve static and dynamic retention characteristics by enhancing hydrogen passivation with in situ LD-TEOS/TEOS dual layer

We proposed a novel solution to improve both static and dynamic retention characteristics by additional etching of the thickness of Silicon Boron Nitride (SIBN), stopper when oxide etch, with in situ dual low deposition-tetraethyl orthosilicate (LD-TEOS)/TEOS Dual layer. As Dynamic Random Access Memory Cells shrink, it is difficult to obtain reliable retention properties, so it becomes more significant to reduce the number of interface trap (Nit) by hydrogen passivation. In this work, Nit decreased by reducing the thickness of SIBN, which has low hydrogen diffusion coefficients, improve the static and dynamic retention characteristics simultaneously through enhancing hydrogen passivation with in situ LD-TEOS Dual layer compensating for Metal contact to Other Bit line pad distance margin risk.

Large-scale NiFe2O4-based cermets prepared by composite extrusion modelling: From high-qualified composite feedstock to dense sintered microstructure

Combining with the advantages from mature technologies of fused deposition modelling and powder injection molding, 3D NiFe2O4-based cermet with weight over 1.3 kg and relative density of 95.8 % were fabricated by composite extrusion modelling using polyoxymethylene-based feedstock. Microstructure and rheological properties of the feedstock, roles of printing parameters on the morphology green samples and related catalytic debinding, sintering properties of cermets were investigated in detail. Uniformly dispersed cermet powders in feedstock were confirmed, due to the good wettability between the powders and binders. The feedstock with high solid loading of 58 vol% exhibited shear-thinning behavior and contained high storage modulus for reliable shape retention. With optimized printing parameters, a high compression ratio (layer height/nozzle diameter) over 2.5 tended to shrink the size of stacking pores, resulting in dense green samples. Catalytic debinding was proved to be defect-free and efficient debinding route, which was successfully used to deal with dense cubic samples with thickness of 30 mm. Sintered samples showed uniform microstructure with interconnected FeCuNi and Ni(Fe)Fe2O4 phases. Except for partial stacking pores in the fracture section, polished cermets exhibited mirror-like surfaces, indicating the good controlling of the final microstructure and performance of 3D cermets.

A floating-gate field-effect transistor memory device based on organic crystals with a built-in tunneling dielectric by a one-step growth strategy.

A floating-gate organic field-effect transistor (FG-OFET) memory device is becoming a promising candidate for emerging non-volatile memory applications due to the advantages of its sophisticated data-storage mechanism and reliable long-term data retention capacity. However, a conventional FG-OFET memory device suffers from complex fabrication technologies and poor mechanical flexibility, which limits its practical applications. Here, we propose a facile one-step liquid-surface drag coating strategy to fabricate a layered stack of 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (Dif-TES-ADT) crystals and high-quality insulating polymer polystyrene (PS). The liquid surface enhances the spreading area of an organic solution and facilitates the unidirectional growth of organic crystals. In the bilayer-structured blend, the bottom PS polymer and the top Dif-TES-ADT semiconductor serve as a tunneling dielectric and an active memory layer of an FG-OFET memory device, respectively. Consequently, a flexible FG-OFET memory device with a large memory window of 41.4 V, a long retention time of 5000 s, and a high current ON/OFF ratio of 105 could be achieved, showing the best performance ever reported for organic thin film-based FG-OFET memory devices. In addition, multi-level data storage (3 bits per cell) can be achieved by tuning the gate voltage magnitude. Our work not only provides a general strategy for the growth of high-quality organic crystals, but also paves the way towards high-performance flexible memory devices.

Force calculation and new design of the grip unit pliers metallurgical crane

In the rolling shops of metallurgical enterprises connected with the processing of steel ingots in the preparation (slabbing, blooming) well taps with pincer grabbers are used. Such cranes work in the sections of heating wells, where they are used, first of all, for planting ingots in the well and issuing them for rolling after heating. In addition, cranes can be used to perform auxiliary operations for well maintenance and equipment repair. During the design processing of tong grippers of such cranes, there is a need to determine the ingot clamping forces, which in this gripping device are related to the weight of the ingot itself and the weight of the tongs of the crane. In addition, the design features of the clamping zone itself are of great importance, that is, the design of the parts that transfer the clamping forces to the ingot. These parts are called cores. It is clear that the clamping force and the design of the cores must guarantee reliable retention and safe movement of the ingot. During the operation of the crane, the cores are subjected to a wide range of loads: shock, compressive, crushing loads from impact. At the same time, being in contact with the heated ingot, they themselves heat up to the same temperature. And because they are periodically cooled in tanks with water, they work even in conditions of cyclic heat changes. The design and physical condition of the cores are of great importance for the reliability of the tick gripper. Untimely replacement of cores can lead to negative consequences during ingot retention, cause it to break off with the destruction of the circle, damage to floor equipment and danger to service personnel. Several options for new, more effective designs are proposed in the work based on the force calculation of the pincer gripper and the analysis of the advantages and disadvantages of modern core designs. The authors created a mathematical model of the interaction between the core and the ingot to check the depth of penetration of the core into the body of the ingot and compared it with the indicators of known cores. It was found that at the ingot release temperatures, the depth of penetration into the body of the ingot for cores of the new design is 4 times less than for conventional conical cores. The use of these designs will ensure the reliability of the gripping device while simultaneously improving the quality of the workpiece by reducing the number of cracks and dips associated with damage to the faces of the ingot from deep indentation of the cores

A novel highly stretchable, freeze-resistant, and recyclable organohydrogel by waterborne polyurethane and DMSO-H2O binary solvent enhanced for multifunctional sensors

Conductive hydrogels have gained significant attention for wearable devices in recent years. However, hydrogel suffers from limitations such as poor stretchability, freezing under cold climates, and drying out in harsh environments, which restrict its practical applications. To address these issues. We synthesize waterborne polyurethane (WPU) and add it to the polyvinyl alcohol (PVA) hydrogel to enhance its mechanical properties. Additionally, DMSO is introduced to the system, aiming to enhance the environmental stability of the hydrogel through its interaction with water. Hence, we prepare a novel organohydrogel by incorporating WPU into PVA in a dimethyl sulfoxide (DMSO)-water (H2O) binary solvent system by one-pot method. The addition of DMSO and WPU enhances the mechanical properties of the organohydrogel, resulting in high mechanical strength (1.27 MPa), excellent stretchability (874%), and superior toughness (3.62 MJ/m3). In addition, the organohydrogel presents reliable freeze resistance and water retention properties due to DMSO interaction with water. More significantly, the organohydrogel can be recycled and reshaped into various shapes through a simple process. The reconstructed organohydrogel still has the original's mechanical properties and sensing capabilities and can continue to be used in flexible electronic devices. Moreover, the organohydrogel is developed for flexible multifunctional sensors, exhibiting high sensitivity (G = 1.89), a rapid response time (141 ms), and exceptional fatigue resistance (100 cycles). Notably, the sensor signals remain stable even after storage in extreme conditions. This study expands the working field of flexible hydrogel sensors and provides a new idea for the sustainable development of next-generation flexible hydrogel sensors.

Enhancing polarization retention in BiFeO3 domain wall nanodevices through controlled space charge redistribution

Ferroelectric thin films with binary switchable polarization offer promising applications in domain wall (DW) memory. However, achieving reliable polarization retention in size-reduced devices remains challenging. In this study, we present a planar ferroelectric BiFeO3 DW nanodevice demonstrating stable polarization retention through electrical cycling. By precisely controlling the device size, including the width and gap of planar Pt electrodes, we observed a back-switching process in switched polarization within 20 min, as characterized by ex-situ piezoresponse force microscopy (PFM). To overcome this issue, long-time alternating voltage pulse cycling effectively suppressed the back-switching behavior, leading to symmetrized polarization coercive voltages of the device. PFM characterization further confirmed the persistence of the artificially created DW between the electrode pair. This improved polarization retention was attributed to the migration of mobile charged defects, such as oxygen vacancies, at the domain boundary. The presence of these defects generated a local built-in field, which screened the net polarization induced by the charged DW. Upon erasing the DW, the local built-in field gradually dissipated during opposite voltage poling, resulting in restored poor polarization retention and asymmetric coercive voltage in the nanodevices. This work presents a promising approach to utilize defect redistribution for stabilizing the switched polarization in the development of high-density ferroelectric DW memory.

Characterization of a high throughput approach for large scale retention measurement in liquid chromatography

Many contemporary challenges in liquid chromatography—such as the need for “smarter” method development tools, and deeper understanding of chromatographic phenomena—could be addressed more efficiently and effectively with larger volumes of experimental retention data than are available. The paucity of publicly accessible, high-quality measurements needed for the development of retention models and simulation tools has largely been due to the high cost in time and resources associated with traditional retention measurement approaches. Recently we described an approach to improve the throughput of such measurements by using very short columns (typically 5 mm), while maintaining measurement accuracy. In this paper we present a perspective on the characteristics of a dataset containing about 13,000 retention measurements obtained using this approach, and describe a different sample introduction method that is better suited to this application than the approach we used in prior work. The dataset comprises results for 35 different small molecules, nine different stationary phases, and several mobile phase compositions for each analyte/phase combination. During the acquisition of these data, we have interspersed repeated measurements of a small number of compounds for quality control purposes. The data from these measurements not only enable detection of outliers but also assessment of the repeatability and reproducibility of retention measurements over time. For retention factors greater than 1, the mean relative standard deviation (RSD) of replicate (typically n=5) measurements is 0.4%, and the standard deviation of RSDs is 0.4%. Most differences between selectivity values measured six months apart for 15 non-ionogenic compounds were in the range of +/- 1%, indicating good reproducibility. A critically important observation from these analyses is that selectivity defined as retention of a given analyte relative to the retention of a reference compound (kx/kref) is a much more consistent measure of retention over a time span of months compared to the retention factor alone. While this work and dataset also highlight the importance of stationary phase stability over time for achieving reliable retention measurements, we are nevertheless optimistic that this approach will enable the compilation of large databases (>> 10,000 measurements) of retention values over long time periods (years), which can in turn be leveraged to address some of the most important contemporary challenges in liquid chromatography. All the data discussed in the manuscript are provided as Supplemental Information.

The Electrode‐Ferroelectric Interface as the Primary Constraint on Endurance and Retention in HZO‐Based Ferroelectric Capacitors

AbstractFerroelectric hafnium‐zirconium oxide is one of the most relevant CMOS‐compatible materials for next‐generation, non‐volatile memory devices. Nevertheless, performance reliability remains an issue. With TiN electrodes (the most reported electrode material), Hf‐Zr‐based ferroelectric capacitors struggle to provide reliable retention due to electrode‐ferroelectric interface interactions. Although Hf‐Zr‐based ferroelectric capacitors are fabricated with other electrodes, the focus is predominantly directed toward obtaining a large ferroelectric response. The impact of the electrodes on data retention for these ferroelectrics remains underreported and greater insight is needed to improve device reliability. Here, a comprehensive set of electrodes are evaluated with emphasis on the core ferroelectric memory reliability metrics of endurance, retention, and imprint. Metal‐ferroelectric‐metal capacitors comprised of a Hf0.5Zr0.5O2 layer deposited between different combinations of nitride (TiN, TiAlN, and NbN), pure metal (W), and oxide (MoO2, RuO2, and IrO2) top and bottom electrodes are fabricated for the investigation. From the electrical, physical, and structural analysis, the low reactivity of the electrode with the ferroelectric is found to be key for improved reliability of the ferroelectric capacitor. This understanding of interface properties provides necessary insight for the broad implementation of Hf‐Zr‐based ferroelectrics in memory technology and, overall, boosts the development of next‐generation memories.

Stem Cell Therapy Enriched Fat Grafting for the Reconstruction of Craniofacial Deficits.

Twelve subjects with at least two regions of craniofacial volume deficit were enrolled, and they underwent fat grafting with SVF-enriched or standard fat grafting to each area. All patients had bilateral malar regions injected with SVF-enriched graft on one side and control standard fat grafting to the contralateral side. Outcome assessments included demographic information, volume retention determined by CT scans, SVF cell populations assessed by flow cytometry, SVF cell viability, complications, and appearance ratings. Follow-up was 9 months. All patients had improvement in appearance. There were no serious adverse events. There was no significant difference in volume retention between the SVF-enriched and control regions overall (50.3% versus 57.3%, P = 0.269) or comparing malar regions (51.4% versus 56.7%, P = 0.494). Patient age, smoking status, obesity, and diagnosis of diabetes did not impact volume retention. Cell viability was 77.4% ± 7.3%. Cellular subpopulations were 60.1% ± 11.2% adipose derived stem cells, 12.2 ± 7.0% endothelial cells, and 9.2% ± 4.4% pericytes. A strong positive correlation was found between CD146+ CD31-pericytes and volume retention (R = 0.863, P = 0.027). Autologous fat transfer for reconstruction of craniofacial defects is effective and safe, leading to reliable volume retention. However, SVF enrichment does not significantly impact volume retention.

Estimation of retention parameters from temperature programmed gas chromatography

A fast and reliable method is presented to evaluate retention parameters of the distribution-centric 3-parameter model from temperature programed gas chromatographic measurements. Based on a fully differentiable model of the migration of solutes in a gas chromatographic (GC) system, Newton's method with a trust region is used to determine the three parameters, respectively the three parameters and the column diameter, of several solutes as the minima of the difference between measured and calculated retention times. The determined retention parameters can then be used in method development, using the simulation of GC separation. The results of the retention parameters are compared to the parameters determined using isothermal GC measurements and show good agreement, with deviations of less than 0.5% (1.8 K) for the most important parameter of characteristic temperature Tchar. Using the estimated retention parameters, additional GC separations are simulated and compared with measurements. Retention times in additional temperature programmed measurements could be predicted with less than 0.7% deviation. Four to five different temperature programs are enough to determine reliable retention parameters. Unless the column diameter and the column length are exactly known, it is preferable to also estimate the diameter (more precisely the L/d-ratio) together with the retention parameters.

Size-dependent polarization retention in ferroelectric BiFeO3 domain wall memories

Reliable polarization retention in a single crystal-like ferroelectric thin film is crucial for the effective implementation of ferroelectric domain wall (DW) memories. This ensures that the saved information can be non-destructively read out by identifying the resistive state of the memory with a voltage signal below the coercive voltage (Vc) of the ferroelectric film. However, stabilizing a small volume of switched polarization for ultra-high-density information storage applications is still challenging due to its back-switching behavior at zero electric field. In this study, we investigated the polarization retention of ferroelectric BiFeO3 (BFO) thin film devices with size-variable Pt electrodes. With the scaling down of the device size, the switched polarizations became more susceptible to depolarization field and ferroelastic stress arising at the artificially created domain boundary. We found that BFO devices featuring a switched polarization area larger than 7 × 106 nm2 demonstrated both long-term polarization retention and a current rectification ratio of 4.5:1 induced by DW manipulation. As the device size decreases, the retention time of the switched polarization reduces gradually, which results in the disappearance of the device current due to the DW being eliminated by the back-switching of the polarization. A plot was created to illustrate the relationship between the current retention time and the switched polarization area on the surface of the BFO thin films. Furthermore, the unsustainable polarization retention facilitates a higher current rectification ratio of 48:1, which is suitable for non-destructive information readout with a voltage pulse larger than Vc in high-density ferroelectric DW memories.

Surface Modification of a Titanium Carbide MXene Memristor to Enhance Memory Window and Low‐Power Operation

AbstractWith the demand for low‐power‐operating artificial intelligence systems, bio‐inspired memristor devices exhibit potential in terms of high‐density memory functions and the emulation of the synaptic dynamics of the human brain. The 2D material MXene attracts considerable interest for use in resistive‐switching memory and artificial synapse devices owing to its excellent physicochemical properties in memristor devices. However, few memristive and synaptic MXene devices that display increased switching performances are reported, with no significant results. Herein, the conductivity of MXene (Ti3C2Tx) is engineered via etching and oxidation to enhance the switching performance of the device. The exceptional properties of partially oxidized MXene memristors include large memory windows and low threshold biases, and the complex spike‐timing‐dependent plasticity synaptic rules are also emulated. The low threshold potential distribution, reliable retention time (104 s), and distinct resistance states with a high ON–OFF ratio (&gt;104) are the main memory‐related features of this device. The experimentally determined switching potentials of the optimized device are also uniformly distributed, according to a statistical probability‐based approach. This investigation may promote the essential material properties for use in high‐density non‐volatile memory storage and artificial synapse systems in the field of innovative nanoelectronic devices.

Using an Attachment System with PEEK Matrices for Single-Implant Overdentures: In Vitro Retention Force.

Single-implant overdentures (SIOs) represent a major biomechanical challenge in terms of prosthetic retention. The Novaloc attachment system has the potential to overcome those challenges when used for SIOs, due to the use of PEEK matrices. This study compared the retentive force of the Novaloc attachment to the traditional Locator system, before and after cyclic insertion-removal cycles. Three Novaloc matrices (white, yellow, and green, corresponding to low, medium, and high retention, respectively) and Locator (medium retention) were tested, totalling four groups. Retentive force was measured using an Imada force gauge before and after 1095 insertion-removal cycles, corresponding to a year of SIO wearing. Retention was tested with the implants angulated at 0, 10, and 20°. Data for the different groups, angles, and cycling periods were tested via linear regression analysis and two-way ANOVA (α = 0.05). Although the Locator system yielded higher retention forces in general, it lost a much higher percentage of retention with cycling. This trend was similar with the three angles, with forces being inversely proportional to the implant angulation. The authors conclude that Novaloc may provide more reliable retention for SIOs due to their higher resistance to insertion-removal cycling.

Experimental and First‐Principles Study of Visible Light Responsive Memristor Based on CuAlAgCr/TiO2/W Structure for Artificial Synapses with Visual Perception

AbstractThe development of vision bionic systems is indispensable for the perception, memory, and processing of optical signals, which promotes the exploration of efficient visual perception systems. In this work, a simple and novel two‐terminal optoelectronic memristor based on the CuAlAgCr/TiO2/W (CTW) structure is prepared, where the CuAlAgCr high‐entropy alloys are employed as the top electrode for the first time. Before annealing, the CTW optoelectronic memristor exhibited fascinating performance, including uniformly distributed operating voltage, reliable data retention, and a higher switching ratio. Moreover, the optoelectronic memristor can be reversibly switched between volatile and nonvolatile memories by adjusting compliance currents. The CTW optoelectronic memristor annealed in air exhibits various artificial synaptic functions, such as short‐term memory, optical learning, and forgetting behavior under the illumination of the laser. The photo‐response current is increased from nano‐ampere to micro‐ampere level. Furthermore, a logic function unit based on CTW optoelectronic memristor is proposed, which realizes “AND” operation. Furthermore, first‐principles calculations of the CTW structure are performed to describe the influence of photocarriers on the barrier height at the CuAlAgCr‐TiO2 interface, revealing the working mechanism of the CTW optoelectronic memristor. This work has greatly facilitated the development of optically operated artificial synaptic devices and vision bionic systems.

Reliable cell retention of mammalian suspension cells in microfluidic cultivation chambers

Microfluidic cultivation, with its high level of environmental control and spatio-temporal resolution of cellular behavior, is a well-established tool in today’s microfluidics. Yet, reliable retention of (randomly) motile cells inside designated cultivation compartments still represents a limitation, which prohibits systematic single-cell growth studies. To overcome this obstacle, current approaches rely on complex multilayer chips or on-chip valves, which makes their application for a broad community of users infeasible. Here, we present an easy-to-implement cell retention concept to withhold cells inside microfluidic cultivation chambers. By introducing a blocking structure into a cultivation chamber’s entrance and nearly closing it, cells can be manually pushed into the chamber during loading procedures but are unable to leave it autonomously in subsequent long-term cultivation. CFD simulations as well as trace substance experiments confirm sufficient nutrient supply within the chamber. Through preventing recurring cell loss, growth data obtained from Chinese hamster ovary cultivation on colony level perfectly match data determined from single-cell data, which eventually allows reliable high throughput studies of single-cell growth. Due to its transferability to other chamber-based approaches, we strongly believe that our concept is also applicable for a broad range of cellular taxis studies or analyses of directed migration in basic or biomedical research.