CMOS-compatible Hf0.5Zr0.5O2-based ferroelectric memory crosspoints fabricated with damascene process.

We report the fabrication of Hf0.5Zr0.5O2(HZO) based ferroelectric memory crosspoints using a complementary metal-oxide-semiconductor-compatible damascene process. In this work, we compared 12 and 56µm2crosspoint devices with the 0.02 mm2round devices commonly used as a benchmark. For all devices, a 9 nm thick ferroelectric thin film was deposited by plasma-enhanced atomic layer deposition on planarized bottom electrodes. The wake-up appeared to be longer for the crosspoint memories compared to 0.02 mm2benchmark, while all the devices reached a 2Prvalue of ∼50µC cm-2after 105cycles with 3 V/10µs squared pulses. The crosspoints stand out for their superior endurance, which was increased by an order of magnitude. Nucleation limited switching experiments were performed, revealing a switching time <170 ns for our 12 and 56µm2devices, while it remained in theµs range for the larger round devices. The downscaled devices demonstrate notable advantages with a rise in endurance and switching speed.

CMOS Compatible Hydrogen Sensor Using Platinum Gate and ALD-Aluminum Oxide.

In this study, a p-Si/ALD-Al2O3/Ti/Pt MOS (metal oxide semiconductor) device has been fabricated and used as a hydrogen sensor. The use of such a stack enables a reliable, industry-compatible CMOS fabrication process. ALD-Al2O3 has been chosen as it can be integrated into the back end of the line (BEOL) or in CMOS, post processing. The device response and recovery are demonstrated with good correlation between the capacitance variation and the hydrogen concentration. Detection down to 20 ppm at 140 °C was obtained and a response time of 56 s for 500 ppm was recorded.

Time Required for Gross Examination of Routine Second and Third Trimester Singleton Placentas by Pathologists' Assistants.

INTRODUCTION: In both Canada and the United States, workload measurement for anatomic pathology is mainly based on complexity and clinical significance of specimens, with gross examination being a considerable contributor. While Pathologists' Assistants (PAs) play an increasing role in gross examination, there is little known regarding the time required for PAs to complete grossing tasks. This information is essential for effective staffing and workload management in pathology laboratories. The objective of our study was to determine the time required for PAs to gross second and third trimester singleton placentas in a large tertiary hospital with a significant perinatal pathology service. MATERIALS AND METHODS: For our study, 7 certified PAs each grossed a minimum of 10 second and third trimester singleton placentas using a standard placental grossing protocol, an electronic laboratory information system, and voice recognition dictation software. Placental specimens requiring photography, sampling for ancillary studies, or immediate pathologist's consultation were excluded. We calculated average and standard deviation of grossing times for each PA, overall average grossing time, and 95% confidence interval using a mixed linear regression model. We analyzed the impact of PA job experience, degree obtained, and number of blocks prepared on overall average in a multivariate analysis. RESULTS: The mean grossing times for each PA ranged from 11.0 (standard deviation [sd] = 2.0) to 17.8 (sd = 4.5) minutes. The overall average grossing time was 14.5 minutes, with a 95% confidence interval of 11.7 to 17.3 minutes. In multivariate analysis, an increase in the number of blocks prepared was significantly associated with longer overall average grossing time. If 4 blocks were prepared consistently, the model predicted a slightly lower overall average of 13.3 minutes, with a 95% confidence interval of 10.9 to 15.7 minutes. DISCUSSION: To our knowledge, our study is the first to objectively report time required for PAs to perform gross examinations of routine second and third trimester singleton placentas. The methodology of our study is replicable and can be applied to other specimen types and laboratory settings. Previously, estimated grossing times for specimens were primarily based on retrospective surveys, which were susceptible to recall errors and subjectivity. However, our study demonstrates objective data collection is achievable. Furthermore, the data collected from this study offer valuable insights into the accuracy of previous and current pathology workload models for second and third trimester singleton placentas.

Colonic innate immune defenses and microbiota alterations in acute swine dysentery.

Brachyspira hyodysenteriae, an etiologic agent of swine dysentery (SD), is known for causing colitis. Although some aspects of colonic defenses during infection have been described previously, a more comprehensive picture of the host and microbiota interaction in clinically affected animals is required. This study aimed to characterize multiple aspects of colonic innate defenses and microbiome factors in B. hyodysenteriae-infected pigs that accompany clinical presentation of hemorrhagic diarrhea. We examined colonic mucus barrier modifications, leukocyte infiltration, cathelicidin expression, as well as microbiome composition. We showed that B. hyodysenteriae infection caused microscopic hemorrhagic colitis with abundant neutrophil infiltration in the colonic lamina propria and lumen, with minor macrophage infiltration. Mucus hypersecretion with abundant sialylated mucus in the colon, as well as mucosal colonization by [Acetivibrio] ethanolgignens, Lachnospiraceae, and Campylobacter were pathognomonic of B. hyodysenteriae infection. These findings demonstrate that B. hyodysenteriae produces clinical disease through multiple effects on host defenses, involving alterations of mucosal innate immunity and microbiota. Given that B. hyodysenteriae is increasingly resistant to antimicrobials, this understanding of SD pathogenesis may lead to future development of non-antibiotic and anti-inflammatory alternative therapeutics.

Oxygen vacancy engineering of TaOx-based resistive memories by Zr doping for improved variability and synaptic behavior.

Resistive switching (RS) devices are promising forms of non-volatile memory. However, one of the biggest challenges for RS memory applications is the device-to-device (D2D) variability, which is related to the intrinsic stochastic formation and configuration of oxygen vacancy (VO) conductive filaments (CFs). In order to reduce the D2D variability, control over the formation and configuration of oxygen vacancies is paramount. In this study, we report on the Zr doping of TaOx-based RS devices prepared by pulsed-laser deposition as an efficient means of reducing the VOformation energy and increasing the confinement of CFs, thus reducing D2D variability. Our findings were supported by XPS, spectroscopic ellipsometry and electronic transport analysis. Zr-doped films showed increased VOconcentration and more localized VOs, due to the interaction with Zr. DC and pulse mode electrical characterization showed that the D2D variability was decreased by a factor of seven, the resistance window was doubled, and a more gradual and monotonic long-term potentiation/depression in pulse switching was achieved in forming-free Zr:TaOxdevices, thus displaying promising performance for artificial synapse applications.

Conductive filament evolution dynamics revealed by cryogenic (1.5 K) multilevel switching of CMOS-compatible Al2O3/TiO2 resistive memories.

Non-volatile resistive switching devices are considered as prime candidates for next-generation memory applications operating at room temperature and above, such as resistive random-access memories or brain-inspired in-memory computing. However, their operability in cryogenic conditions remains to be mastered to adopt these devices as building blocks enabling large-scale quantum technologies via quantum-classical electronics co-integration. This study demonstrates multilevel switching at 1.5 K of Al2O3/TiO2-x resistive memory devices fabricated with complementary metal-oxide-semiconducto-compatible processes and materials. The I-V characteristics exhibit a negative differential resistance (NDR) effect due to a Joule-heating-induced metal-insulator transition of the Ti4O7 conductive filament. Carrier transport analysis of all multilevel switching I-V curves show that while the insulating regime follows the space charge limited current (SCLC) model for all resistance states, the conduction in the metallic regime is dominated by SCLC and trap-assisted tunneling for low- and high-resistance states respectively. A non-monotonic conductance evolution is observed in the insulating regime, as opposed to the continuous and gradual conductance increase and decrease obtained in the metallic regime during the multilevel SET and RESET operations. Cryogenic transport analysis coupled to an analytical model accounting for the metal-insulator-transition-induced NDR effects and the resistance states of the device provide new insights on the conductive filament evolution dynamics and resistive switching mechanisms. Our findings suggest that the non-monotonic conductance evolution in the insulating regime is due to the combined effects of longitudinal and radial variations of the Ti4O7 conductive filament during the switching. This behavior results from the interplay between temperature- and field-dependent geometrical and physical characteristics of the filament.

Human cathelicidin improves colonic epithelial defenses against Salmonella typhimurium by modulating bacterial invasion, TLR4 and pro-inflammatory cytokines.

The intestinal mucosa contributes to frontline gut defenses by forming a barrier (physical and biochemical) and preventing the entry of pathogenic microbes. One innate role of the human colonic epithelium is to secrete cathelicidin, a peptide with broad antimicrobial and immunomodulatory functions. In this study, the effect of cathelicidin in the maintenance of epithelial integrity, Toll-like receptor recognition, bacterial invasion and initiation of inflammatory response against Salmonella typhimurium is investigated in cultured human colonic epithelium. We found exogenous human cathelicidin restores the epithelial integrity in S. typhimurium-infected colonic epithelial (T84) cells by mostly post-translational effects associated with reorganization of zonula occludens (ZO)-1 tight junction proteins. Endogenous cathelicidin prevents S. typhimurium internalization as shown in colonic epithelial cells genetically deficient in the only human cathelicidin, LL-37 (shLL-37). Moreover, supplementation of shLL-37 cells with synthetic LL-37 reduces the grade of S. typhimurium internalization in a dose-dependent manner. Mechanistically, shLL-37 cells have lower gene expression of TLR4 and pro-inflammatory cytokine IL-1ß in response to S. typhimurium. Thus, human cathelicidin aids in the early colonic epithelial defenses against enteric S. typhimurium by preventing bacterial invasion and maintaining epithelial barrier integrity, likely to occur due to the production of sensing TLR4 and pro-inflammatory cytokines.

Source Separation Using Sensor's Frequency Response: Theory and Practice on Carbon Nanotubes Sensors.

Nowadays, there is an increased demand in integrated sensors for electronic devices. Multi-functional sensors provide the same amount of data using fewer sensors. Carbon nanotubes are non-selectively sensitive to temperature, gas and strain. Thus, carbon nanotubes are perfect candidates to design multi-functional sensors. In our study, we are interested in a dual humidity-temperature sensor. Here, we present a novel method to differentiate at least two sources using the sensor's frequency responses based on multiwall carbon nanotubes sensors. The experimental results demonstrate that there are temperature- or moisture-invariant frequencies of the impedance magnitude, and their values depend on the sensor's geometry. The proposed measurement model shows that source-invariant frequencies of the phase can be also determined. In addition, the source separation method is generalized to other materials or sources enabling multi-functional sensors for environment monitoring.

Tunable conductivity in mesoporous germanium.

Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10-3) Ω-1 cm-1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10-3 Ω-1 cm-1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.

Space-charge limited transport in large-area monolayer hexagonal boron nitride.

Hexagonal boron nitride (hBN) is a wide-gap material that has attracted significant attention as an ideal dielectric substrate for 2D crystal heterostructures. We report here the first observation of in-plane charge transport in large-area monolayer hBN, grown by chemical vapor deposition. The quadratic scaling of current with voltage at high bias corresponds to a space-charge limited conduction mechanism, with a room-temperature mobility reaching up to 0.01 cm(2)/(V s) at electric fields up to 100 kV/cm in the absence of dielectric breakdown. The observation of in-plane charge transport highlights the semiconducting nature of monolayer hBN, and identifies hBN as a wide-gap 2D crystal capable of supporting charge transport at high field. Future exploration of charge transport in hBN is motivated by the fundamental study of UV optoelectronics and the massive Dirac fermion spectrum of hBN.

A randomised study comparing the effect on ovarian activity of a progestogen-only pill (POP) containing desogestrel and a new POP containing drospirenone in a 24/4 regimen.

OBJECTIVES: Progestogen-only pills (POPs) are safer with respect to cardiovascular risks than contraceptives containing estrogens. Despite the increased contraceptive efficacy of a desogestrel-only pill compared with a traditional POP, POPs are still not widely used due to an unpredictable bleeding pattern. A new POP containing 4 mg drospirenone has been developed with a 24/4 intake regimen which may improve the bleeding pattern. The objectives of this study were to investigate ovulation inhibition with the new drospirenone-only pill in comparison with the desogestrel-only pill and, in addition, to assess the effects on cervical mucus permeability and bleeding. METHODS: Sixty-four healthy volunteers with proven ovulatory cycles were randomised and treated with either the drospirenone-only or the desogestrel-only pill during two 28-day cycles. Follicular diameter, endometrial thickness, and serum estradiol (E2) and progesterone concentrations were measured and Hoogland scores were determined. Additionally, cervical mucus scores, bleeding and return of ovulation were assessed. RESULTS: Both treatments effectively inhibited ovulation. Follicular diameter, E2 levels and Hoogland scores were equal, demonstrating efficient ovarian suppression. One subject in each group had a Hoogland score of 6, but the criteria for normal luteal activity were not fulfilled. In both groups, ovulation did not occur before day 9 of the post-treatment cycle. Cervical mucus permeability was suppressed in both groups. The median number of bleeding and spotting days was lower in the drospirenone group. CONCLUSIONS: The new drospirenone-only pill inhibited ovulation as effectively as the desogestrel-only pill despite the 4-day hormone-free interval.

Immunologic aspects of preeclampsia.

Preeclampsia is a syndrome with multiple etiologies. The diagnosis can be made without proteinuria in the presence of dysfunction of at least 1 organ associated with hypertension. The common pathophysiological pathway includes endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. There is evidence to support, among others, immunologic causes of preeclampsia. Unlike defense immunology, reproductive immunology is not based on immunologic recognition systems of self/non-self and missing-self but on immunotolerance and maternal-fetal cellular interactions. The main mechanisms of immune escape from fetal to maternal immunity at the maternal-fetal interface are a reduction in the expression of major histocompatibility complex molecules by trophoblast cells, the presence of complement regulators, increased production of indoleamine 2,3-dioxygenase, activation of regulatory T cells, and an increase in immune checkpoints. These immune protections are more similar to the immune responses observed in tumor biology than in allograft biology. The role of immune and nonimmune decidual cells is critical for the regulation of trophoblast invasion and vascular remodeling of the uterine spiral arteries. Regulatory T cells have been found to play an important role in suppressing the effectiveness of other T cells and contributing to local immunotolerance. Decidual natural killer cells have a cytokine profile that is favored by the presence of HLA-G and HLA-E and contributes to vascular remodeling. Studies on the evolution of mammals show that HLA-E, HLA-G, and HLA-C1/C2, which are expressed by trophoblasts and their cognate receptors on decidual natural killer cells, are necessary for the development of a hemochorial placenta with vascular remodeling. The activation or inhibition of decidual natural killer cells depends on the different possible combinations between killer cell immunoglobulin-like receptors, expressed by uterine natural killer cells, and the HLA-C1/C2 antigens, expressed by trophoblasts. Polarization of decidual macrophages in phenotype 2 and decidualization of stromal cells are also essential for high-quality vascular remodeling. Knowledge of the various immunologic mechanisms required for adequate vascular remodeling and their dysfunction in case of preeclampsia opens new avenues of research to identify novel biological markers or therapeutic targets to predict or prevent the onset of preeclampsia.

Abrasive-free chemical-mechanical planarization (CMP) of gold for thin film nano-patterning.

Despite high demand for gold film nanostructuring, patterning gold at the nanoscale still presents considerable challenges for current foundry-compatible processes. Here, we present a method based on abrasive-free chemical mechanical planarization (CMP) to planarize nanostructured gold surfaces with high selectivity against SiO2. The method is efficient in a damascene process and industry-compatible. Investigations into the material removal mechanism explore the effects of CMP parameters and show that the material removal rate is highly tunable with changes in slurry composition. Millimeter-scale arrays of gold nanostructures embedded in SiO2 were fabricated and the planarization dynamics were monitored over time, leading to the identification of distinct planarization phases and their correlation with the material removal mechanism. Finally, plasmonic cavities of gold nanostructure arrays over a gold mirror were fabricated. The cavities exhibited efficient plasmonic resonance in the visible range, aligning well with simulation results.

Structural plasticity for neuromorphic networks with electropolymerized dendritic PEDOT connections.

Neural networks are powerful tools for solving complex problems, but finding the right network topology for a given task remains an open question. Biology uses neurogenesis and structural plasticity to solve this problem. Advanced neural network algorithms are mostly relying on synaptic plasticity and learning. The main limitation in reconciling these two approaches is the lack of a viable hardware solution that could reproduce the bottom-up development of biological neural networks. Here, we show how the dendritic growth of PEDOT:PSS-based fibers through AC electropolymerization can implement structural plasticity during network development. We find that this strategy follows Hebbian principles and is able to define topologies that leverage better computing performances with sparse synaptic connectivity for solving non-trivial tasks. This approach is validated in software simulation, and offers up to 61% better network sparsity on classification and 50% in signal reconstruction tasks.

Effect of thermal annealing on the kinetics of rehydroxylation of Eu3+:La2O3 nanocrystals.

Europium-doped lanthanum oxide (5 mol % Eu(3+):La(2)O(3)) was prepared by calcining europium-doped lanthanum hydroxide (5 mol % Eu(3+):La(OH)(3)) previously synthesized by a simple hydrothermal method. Interestingly, we observed different emission Eu(3+) signatures depending on the phase of the host (lanthanum oxide or hydroxide) by cathodoluminescence. Taking into account that lanthanum oxide easily rehydroxylates in air, for the first time, we report the use of cathodoluminiscence as a novel characterization technique to follow the lanthanum oxide rehydroxylation reaction versus time according to different annealing procedures. Additionally, differential thermal-thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction techniques were used to identify the phases formed from the Eu(3+):La(OH)(3) depending on temperature and to study the evolution of La(2)O(3) to La(OH)(3) versus time. The results showed that the higher the temperature and the longer the annealing time, the higher the resistance to rehydroxylation of the Eu(3+):La(2)O(3) sample.

The probe profile and lateral resolution of scanning transmission electron microscopy of thick specimens.

Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as a function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as a function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 µm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens.

Three-dimensional electron energy deposition modeling of cathodoluminescence emission near threading dislocations in GaN and electron-beam lithography exposure parameters for a PMMA resist.

The Monte Carlo software CASINO has been expanded with new modules for the simulation of complex beam scanning patterns, for the simulation of cathodoluminescence (CL), and for the calculation of electron energy deposition in subregions of a three-dimensional (3D) volume. Two examples are presented of the application of these new capabilities of CASINO. First, the CL emission near threading dislocations in gallium nitride (GaN) was modeled. The CL emission simulation of threading dislocations in GaN demonstrated that a better signal-to-noise ratio was obtained with lower incident electron energy than with higher energy. Second, the capability to simulate the distribution of the deposited energy in 3D was used to determine exposure parameters for polymethylmethacrylate resist using electron-beam lithography (EBL). The energy deposition dose in the resist was compared for two different multibeam EBL schemes by changing the incident electron energy.

Chemical vapor deposition of porous GaN particles on silicon.

We present a technique for the direct deposition of nanoporous GaN particles on Si substrates without requiring any post-growth treatment. The internal morphology of the nanoporous GaN particles deposited on Si substrates by using a simple chemical vapor deposition approach was investigated, and straight nanopores with diameters ranging between 50 and 100 nm were observed. Cathodoluminescence characterization revealed a sharp and well-defined near band-edge emission at ∼365 nm. This approach simplifies other methods used for this purpose, such as etching and corrosion techniques that can damage the semiconductor structure and modify its properties.