Nearly Barrierless Polarization Switching Mechanisms in ZrO Having Perpendicular In-Plane Domain Walls.

The polarization switching mechanism in ferroelectric ZrO involves the nucleation and subsequent migration of nonpolar domain boundaries; however, the fundamental mechanism driving this process remains inadequately understood. The present study introduces a mechanism for nearly barrierless polarization switching in 180° domain walls, facilitated by a the half-unit-cell nonpolar phase between oppositely polarized domains. Based on density functional theory (DFT) calculations, two types of 180° domain walls are explored, featuring head-to-head and tail-to-tail polarization boundaries, with nonpolar orthorhombic and tetragonal 4/ phases as the respective domain walls.

Thermal Transport at the AlN-SiC Interface and Grain Boundary of AlN.

AlN is deposited on silicon carbide (SiC) for high-power electronics; in these devices, AlN acts as both a buffer layer for the growth of the active device and a thermal conductor. However, the mechanism of thermal transport through the AlN-SiC interfaces and through grain boundaries of AlN has not been clearly analyzed, even though AlN forms grain boundaries during the deposition process. The thermal properties of the AlN-SiC interface and the inversion domain boundaries (IDBs) of AlN were examined by a phonon transport model based on a nonequilibrium Green function formalism and first-principles calculations.

CAR expression in invasive breast carcinoma and its effect on adenovirus transduction efficiency.

Background: Breast cancer is the second leading cause of death in women, with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) as the two most common forms of invasive breast cancer. While estrogen receptor positive (ER+) IDC and ILC are treated similarly, the multifocality of ILC presents challenges in detection and treatment, worsening long-term clinical outcomes in patients. With increasing documentation of chemoresistance in ILC, additional treatment options are needed.

Enhanced Corrosion Resistance in Aluminum-Based Electrolyzer Components via Stoichiometry Tuned Atomic Layer-Deposited TiO Films.

Titanium (Ti) is widely used as anode current collectors in proton exchange membrane (PEM)-based water electrolyzers due to its self-passivated oxide layer, which protects it from corrosion in acidic solutions. However, the cost of the material and machining process for Ti is high. A wider utilization of water electrolyzers to produce hydrogen could be favored by the use of less expensive coated aluminum (Al) substrates, which could potentially replace high-cost Ti-based components.

High Thermal Conductivity of Submicrometer Aluminum Nitride Thin Films Sputter-Deposited at Low Temperature.

Aluminum nitride (AlN) is one of the few electrically insulating materials with excellent thermal conductivity, but high-quality films typically require exceedingly hot deposition temperatures (>1000 °C). For thermal management applications in dense or high-power integrated circuits, it is important to deposit heat spreaders at low temperatures (<500 °C), without affecting the underlying electronics. Here, we demonstrate 100 nm to 1.

A Local and Abscopal Effect Observed with Liposomal Encapsulation of Intratumorally Injected Oncolytic Adenoviral Therapy.

This study evaluated the in vivo therapeutic efficacy of oncolytic serotype 5 adenovirus TAV255 in CAR-deficient tumors. In vitro experiments were performed with cell lines that expressed different levels of CAR (HEK293, A549, CT26, 4T1, and MCF-7). Low CAR cells, such as CT26, were poorly transduced by Ad in vitro unless the adenovirus was encapsulated in liposomes.

Full Remission of CAR-Deficient Tumors by DOTAP-Folate Liposome Encapsulation of Adenovirus.

Adenovirus (Ad)-based vectors have shown considerable promise for gene therapy. However, Ad requires the coxsackievirus and adenovirus receptor (CAR) to enter cells efficiently and low CAR expression is found in many human cancers, which hinder adenoviral gene therapies. Here, cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-folate liposomes (Df) encapsulating replication-deficient Ad were synthesized, which showed improved transfection efficiency in various CAR-deficient cell lines, including epithelial and hematopoietic cell types.

Development of Adenovirus Containing Liposomes Produced by Extrusion vs. Homogenization: A Comparison for Scale-Up Purposes.

Adenovirus (Ad) is a widely studied viral vector for cancer therapy as it can be engineered to cause selective lysis of cancer cells. However, Ad delivery is limited in treating cancers that do not have coxsackievirus and adenovirus receptors (CAR). To overcome this challenge, Ad-encapsulated liposomes were developed that enhance the delivery of Ads and increase therapeutic efficacy.

Correction: Hafnium-zirconium oxide interface models with a semiconductor and metal for ferroelectric devices.

[This corrects the article DOI: 10.1039/D1NA00230A.].

Remote Oxygen Scavenging of the Interfacial Oxide Layer in Ferroelectric Hafnium-Zirconium Oxide-Based Metal-Oxide-Semiconductor Structures.

Discovery of ferroelectricity in HfO has sparked a lot of interest in its use in memory and logic due to its CMOS compatibility and scalability. Devices that use ferroelectric HfO are being investigated; for example, the ferroelectric field-effect transistor (FEFET) is one of the leading candidates for next generation memory technology, due to its area, energy efficiency and fast operation. In an FEFET, a ferroelectric layer is deposited on Si, with an SiO layer of ∼1 nm thickness inevitably forming at the interface.

Tetravalent Doping in Fluorite-Based Ferroelectric Oxides for Reduced Voltage Operations.

First-principles calculations show a reduced energy barrier for polarization switching via a bulk phase transition by doping of hafnium-zirconium oxide (HZO). The tetragonal 4/ phase serves as a transition state for polarization switching of the polar orthorhombic Pca2 phase. Due to the high symmetry of the tetragonal phase, dopants can form more energetically favorable local oxygen bonding configurations in the tetragonal phase versus the orthorhombic phase.

Selective Pulsed Chemical Vapor Deposition of Water-Free TiO/AlO and HfO/AlO Nanolaminates on Si and SiO in Preference to SiCOH.

Highly selective and smooth TiO/AlO and HfO/AlO nanolaminates were deposited by water-free pulsed chemical vapor deposition (CVD) at 300 °C using titanium isopropoxide (Ti(OPr)) and hafnium tertbutoxide (Hf(OBu)) with trimethylaluminum (TMA). TMA was found to be the key factor for enhancing nucleation selectivity on SiO or Si versus SiCOH (hydrophobic, nonporous low dielectric). With precise dosing of TMA, selective nucleation of TiO/AlO and HfO/AlO nanolaminates was achieved and smoother films were formed with higher selectivity compared to single precursor TiO and HfO CVD.

Sub-Nanometer Interfacial Oxides on Highly Oriented Pyrolytic Graphite and Carbon Nanotubes Enabled by Lateral Oxide Growth.

A new generation of compact and high-speed electronic devices, based on carbon, would be enabled through the development of robust gate oxides with sub-nanometer effective oxide thickness (EOT) on carbon nanotubes or graphene nanoribbons. However, to date, the lack of dangling bonds on sp oriented graphene sheets has limited the high precursor nucleation density enabling atomic layer deposition of sub-1 nm EOT gate oxides. It is shown here that by deploying a low-temperature AlO (LT AlO) process, involving atomic layer deposition (ALD) of AlO at 50 °C with a chemical vapor deposition (CVD) component, a high nucleation density layer can be formed, which templates the growth of a high- dielectric, such as HfO.

Hafnium-zirconium oxide interface models with a semiconductor and metal for ferroelectric devices.

Density functional theory (DFT) is employed to investigate ferroelectric (FE) hafnium-zirconium oxide stack models for both metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) structures. The role of dielectric (DE) interlayers at the ferroelectric interfaces with metals and semiconductors and the effects of thickness scaling of FE and DE layers were investigated using atomic stack models. A high internal field is induced in the FE and DE layers by the FE polarization field which can promote defect generation leading to limited endurance.

Immunostimulatory TLR7 agonist-nanoparticles together with checkpoint blockade for effective cancer immunotherapy.

Mono- or dual-checkpoint inhibitors for immunotherapy have changed the paradigm of cancer care; however, only a minority of patients responds to such treatment. Combining small molecule immuno-stimulators can improve treatment efficacy, but they are restricted by poor pharmacokinetics. In this study, TLR7 agonists conjugated onto silica nanoparticles showed extended drug localization after intratumoral injection.

Understanding the Mechanism of Electronic Defect Suppression Enabled by Nonidealities in Atomic Layer Deposition.

Silicon germanium (SiGe) is a multifunctional material considered for quantum computing, neuromorphic devices, and CMOS transistors. However, implementation of SiGe in nanoscale electronic devices necessitates suppression of surface states dominating the electronic properties. The absence of a stable and passive surface oxide for SiGe results in the formation of charge traps at the SiGe-oxide interface induced by GeO.

Thickness and Sphericity Control of Hollow Hard Silica Shells through Iron (III) Doping: Low Threshold Ultrasound Contrast Agents.

Silica particles are convenient ultrasound imaging contrast agents because of their long imaging time and ease of modification; however, they require a relatively high insonation power for imaging and have low biodegradability. In this study, 2 μm ultrathin asymmetric hollow silica particles doped with iron (III) (Fe(III)-SiO) are synthesized to produce biodegradable hard shelled particles with a low acoustic power threshold comparable with commercial soft microbubble contrast agents (Definity) yet with much longer in vivo ultrasound imaging time. Furthermore, high intensity focused ultrasound ablation enhancement with these particles shows a 2.

Conjugation of a Small-Molecule TLR7 Agonist to Silica Nanoshells Enhances Adjuvant Activity.

Stimulation of Toll-like receptors (TLRs) and/or NOD-like receptors on immune cells initiates and directs immune responses that are essential for vaccine adjuvants. The small-molecule TLR7 agonist, imiquimod, has been approved by the FDA as an immune response modifier but is limited to topical application due to its poor pharmacokinetics that causes undesired adverse effects. Nanoparticles are increasingly used with innate immune stimulators to mitigate side effects and enhance adjuvant efficacy.

Band Structure Engineering of Layered WSe One-Step Chemical Functionalization.

Chemical functionalization is demonstrated to enhance the p-type electrical performance of two-dimensional (2D) layered tungsten diselenide (WSe) field-effect transistors (FETs) using a one-step dipping process in an aqueous solution of ammonium sulfide [(NH)S(aq)]. Molecularly resolved scanning tunneling microscopy and spectroscopy reveal that molecular adsorption on a monolayer WSe surface induces a reduction of the electronic band gap from 2.1 to 1.

Engineering High- k/SiGe Interface with ALD Oxide for Selective GeO Reduction.

Suppression of electronic defects induced by GeO at the high- k gate oxide/SiGe interface is critical for implementation of high-mobility SiGe channels in complementary metal-oxide-semiconductor (CMOS) technology. Theoretical and experimental studies have shown that a low defect density interface can be formed with an SiO -rich interlayer on SiGe. Experimental studies in the literature indicate a better interface formation with AlO in contrast to HfO on SiGe; however, the mechanism behind this is not well understood.

MRI-guided transurethral insonation of silica-shell phase-shift emulsions in the prostate with an advanced navigation platform.

Purpose: In this study, the efficacy of transurethral prostate ablation in the presence of silica-shell ultrasound-triggered phase-shift emulsions (sUPEs) doped with MR contrast was evaluated. The influence of sUPEs on MR imaging assessment of the ablation zone was also investigated.

Methods: sUPEs were doped with a magnetic resonance (MR) contrast agent, Gd O , to assess ultrasound transition.

Ultralow Defect Density at Sub-0.5 nm HfO/SiGe Interfaces via Selective Oxygen Scavenging.

The superior carrier mobility of SiGe alloys make them a highly desirable channel material in complementary metal-oxide-semiconductor (CMOS) transistors. Passivation of the SiGe surface and the associated minimization of interface defects between SiGe channels and high- k dielectrics continues to be a challenge for fabrication of high-performance SiGe CMOS. A primary source of interface defects is interfacial GeO .

Identifying lost surgical needles with visible and near infrared fluorescent light emitting microscale coating.

Background: Retained foreign bodies (RFOs) have substantial clinical and financial consequences. In laparoscopic surgery, RFOs can be a cause of needing to convert a minimally invasive surgery (MIS) procedure to an open operation. A coating for surgical models was developed to augment localization of needles using fluorescence appropriate for open and minimally invasive surgeries procedures.

Focal Liver Lesions: Computer-aided Diagnosis by Using Contrast-enhanced US Cine Recordings.

Purpose To assess the performance of computer-aided diagnosis (CAD) systems and to determine the dominant ultrasonographic (US) features when classifying benign versus malignant focal liver lesions (FLLs) by using contrast material-enhanced US cine clips. Materials and Methods One hundred six US data sets in all subjects enrolled by three centers from a multicenter trial that included 54 malignant, 51 benign, and one indeterminate FLL were retrospectively analyzed. The 105 benign or malignant lesions were confirmed at histologic examination, contrast-enhanced computed tomography (CT), dynamic contrast-enhanced magnetic resonance (MR) imaging, and/or 6 or more months of clinical follow-up.