Detection of heat-stable antibacterial activity in cotyledonary and discoid placentas.

The placenta serves in immunological defense of the fetus, providing proteins essential for innate immunity. Maternal and fetal portions of two mammalian placenta types, discoid, and cotyledonary, were separated and analyzed for antibacterial activity using a culture-independent method. Antibacterial activity was detected in both maternal and fetal portions of all placenta types tested. Protease resistance and increased activity after boiling suggests that the factor is activated upon release from a larger molecule. Identification of this factor and the mechanism of activation will lead to a better understanding of the innate immune function provided by the placenta.

Extension of Tablo TrEatmeNt Duration (XTEND) study: successful 24 h prolonged therapy with Tablo in critical patients.

BACKGROUND: The Tablo® Hemodialysis System (Tablo) is an all in one, easy-to-learn device featuring integrated water purification, on demand dialysate production and two-way wireless data transmission and is approved for use in the acute, chronic, and home settings. Prior reports have demonstrated Tablo's ability to achieve clinical goals, seamlessly integrate into hospitals and reduce cost across a wide range of treatment times. Extension of the Tablo cartridge to 24 h allows prolonged therapy and even greater flexibility for prescribers in the acute setting. The objective is to report on the first ever experience with Tablo prolonged therapy between 12 and 24 h in critically ill patients treated at a single-center ICU. METHODS: Nursing staff were trained during a single training session on Tablo prolonged therapy. After a run-in period of five treatments, Tablo data were collected via real-time transmission to a cloud-based, HIPAA compliant platform and reviewed by site staff. Dialysis treatment delivery, clinically significant alarms, and clotting events were recorded. Sub-group analysis between COVID-19 positive and negative patients were reported. RESULTS: One hundred (100) consecutive Tablo prolonged treatments had a median prescribed treatment time of 24 h and a median achieved treatment time of 21.3 h. Median cartridge usage was 1.3 per treatment. The dialysis treatment time was delivered in 91% of treatments, with 6% ending early due to an alarm, and 3% ending due to clotting. Clinically significant alarms occurred at a median rate of 0.5 per treatment hour with a resolution time of 18 s. Median blood pump stoppage time related to these alarms was 2.3 min per treatment. Blood pump stoppage time was higher in the COVID-19 subgroup when compared to the non-COVID-19 subgroup. CONCLUSION: Tablo successfully achieves prescribed treatment time with minimal therapy interruptions from alarms or cartridge changes. This data demonstrates the effectiveness of Tablo in achieving personalization of treatments necessary for unstable patients and enabling successful delivery of extended therapy with minimal clotting. Tablo's prolonged therapy meets the needs of critically patients, including COVID-19 positive patients, requiring renal replacement therapy for greater than 12 h.

Unmasking the Resolution-Throughput Tradespace of Focused-Ion-Beam Machining.

Focused-ion-beam machining is a powerful process to fabricate complex nanostructures, often through a sacrificial mask that enables milling beyond the resolution limit of the ion beam. However, current understanding of this super-resolution effect is empirical in the spatial domain and nonexistent in the temporal domain. This article reports the primary study of this fundamental tradespace of resolution and throughput. Chromia functions well as a masking material due to its smooth, uniform, and amorphous structure. An efficient method of in-line metrology enables characterization of ion-beam focus by scanning electron microscopy. Fabrication and characterization of complex test structures through chromia and into silica probe the response of the bilayer to a focused beam of gallium cations, demonstrating super-resolution factors of up to 6 ± 2 and improvements to volume throughput of at least factors of 42 ± 2, with uncertainties denoting 95% coverage intervals. Tractable theory models the essential aspects of the super-resolution effect for various nanostructures. Application of the new tradespace increases the volume throughput of machining Fresnel lenses by a factor of 75, enabling the introduction of projection standards for optical microscopy. These results enable paradigm shifts of sacrificial masking from empirical to engineering design and from prototyping to manufacturing.

Electron and X-ray Focused Beam-Induced Cross-Linking in Liquids: Toward Rapid Continuous 3D Nanoprinting and Interfacing using Soft Materials.

Multiphoton polymer cross-linking evolves as the core process behind high-resolution additive microfabrication with soft materials for implantable/wearable electronics, tissue engineering, microrobotics, biosensing, drug delivery, etc. Electrons and soft X-rays, in principle, can offer even higher resolution and printing rates. However, these powerful lithographic tools are difficult to apply to vacuum incompatible liquid precursor solutions used in continuous additive fabrication. In this work, using biocompatible hydrogel as a model soft material, we demonstrate high-resolution in-liquid polymer cross-linking using scanning electron and X-ray microscopes. The approach augments the existing solid-state electron/X-ray lithography and beam-induced deposition techniques with a wider class of possible chemical reactions, precursors, and functionalities. We discuss the focused beam cross-linking mechanism, the factors affecting the ultimate feature size, and layer-by-layer printing possibilities. The potential of this technology is demonstrated on a few practically important applications such as in-liquid encapsulation of nanoparticles for plasmonic sensing and interfacing of viable cells with hydrogel electrodes.

Low-Resistance, High-Yield Electrical Contacts to Atom Scale Si:P Devices Using Palladium Silicide.

Scanning tunneling microscopy (STM) enables the fabrication of two-dimensional δ-doped structures in Si with atomistic precision, with applications from tunnel field-effect transistors to qubits. The combination of a very small contact area and the restrictive thermal budget necessary to maintain the integrity of the δ layer make developing a robust electrical contact method a significant challenge to realizing the potential of atomically precise devices. We demonstrate a method for electrical contact using Pd2Si formed at the temperature of silicon overgrowth (250 °C), minimizing the diffusive impact on the δ layer. We use the transfer length method to show our Pd2Si contacts have very high yield (99.7% +0.2% -1.5%) and low resistivity (272±41Ωµm) in contacting mesa-etched Si:P δ layers. We also present three terminal measurements of low contact resistance (<1 kΩ) to devices written by STM hydrogen depassivation lithography with similarly high yield (100% +0% -3.2%).

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles.

The vertical dimensions of complex nanostructures determine the functions of diverse nanotechnologies. In this paper, we investigate the unknown limits of such structure-function relationships at subnanometer scales. We begin with a quantitative evaluation of measurement uncertainty from atomic force microscopy, which propagates through our investigation from ion beam fabrication to fluorescent particle characterization. We use a focused beam of gallium ions to subtractively pattern silicon surfaces, and silicon nitride and silicon dioxide films. Our study of material responses quantifies the atomic limits of forming complex topographies with subnanometer resolution of vertical features over a wide range of vertical and lateral dimensions. Our results demonstrate the underutilized capability of this standard system for rapid prototyping of subnanometer structures in hard materials. We directly apply this unprecedented dimensional control to fabricate nanofluidic devices for the analytical separation of colloidal nanoparticles by size exclusion. Optical microscopy of single nanoparticles within such reference materials establishes a subnanometer limit of the fluidic manipulation of particulate matter and enables critical-dimension particle tracking with subnanometer accuracy. After calibrating for optical interference within our multifunctional devices, which also enables device metrology and integrated spectroscopy, we reveal an unexpected relationship between nanoparticle size and emission intensity for common fluorescent probes. Emission intensity increases supervolumetrically with nanoparticle diameter and then decreases as nanoparticles with different diameters photobleach to similar values of terminal intensity. We propose a simple model to empirically interpret these surprising results. Our investigation enables new control and study of structure-function relationships at subnanometer scales.

Strain Engineering a 4a×√3a Charge Density Wave Phase in Transition Metal Dichalcogenide 1T-VSe2.

We report a rectangular charge density wave (CDW) phase in strained 1T-VSe2 thin films synthesized by molecular beam epitaxy on c-sapphire substrates. The observed CDW structure exhibits an unconventional rectangular 4a×√3a periodicity, as opposed to the previously reported hexagonal 4a×4a structure in bulk crystals and exfoliated thin layered samples. Tunneling spectroscopy shows a strong modulation of the local density of states of the same 4a×√3a CDW periodicity and an energy gap of 2ΔCDW = (9.1 ± 0.1) meV. The CDW energy gap evolves into a full gap at temperatures below 500 mK, indicating a transition to an insulating phase at ultra-low temperatures. First-principles calculations confirm the stability of both 4a×4a and 4a×√3a structures arising from soft modes in the phonon dispersion. The unconventional structure becomes preferred in the presence of strain, in agreement with experimental findings.

Nanoscale imaging and spectroscopy of band gap and defects in polycrystalline photovoltaic devices.

Improving the power conversion efficiency of photovoltaic (PV) devices is challenging because the generation, separation and collection of electron-hole pairs are strongly dependent on details of the nanoscale chemical composition and defects which are often poorly known. In this work, two novel scanning probe nano-spectroscopy techniques, direct-transmission near-field scanning optical microscopy (dt-NSOM) and photothermal induced resonance (PTIR), are implemented to probe the distribution of defects and the bandgap variation in thin lamellae extracted from polycrystalline CdTe PV devices. dt-NSOM provides high-contrast spatially-resolved maps of light transmitted through the sample at selected wavelengths. PTIR provides absorption maps and spectra over a broad spectral range, from visible to mid-infrared. Results show variation of the bandgap through the CdTe thickness and from grain to grain that is spatially uncorrelated with the distributions of shallow and deep defects.

A preliminary evaluation of the TOPAS system for the treatment of fecal incontinence in women.

OBJECTIVES: The TOPAS AMS pelvic floor repair system is a self-fixating polypropylene mesh intended for use to reinforce soft tissues where weakness exists in the gynecological and gastroenterological anatomy. It is not available commercially in any country. This was a preliminary study conducted to obtain initial clinical experience with the TOPAS system for the treatment of fecal incontinence (FI) in women. METHODS: This was a prospective study conducted at 5 centers in the United States. Women with FI who failed 1 or more conservative therapies were candidates for the study. Fecal incontinence was assessed with a bowel diary, Cleveland Clinic incontinence scores (CCISs), and Fecal Incontinence Quality of Life (FIQOL) questionnaires, and patients were followed prospectively up to 24 months. Treatment success was defined as a reduction in number of FI episodes of 50% or more compared with baseline. RESULTS: A total of 29 women (mean age, 60.6 years) were implanted with the TOPAS system. Mean number of FI episodes per 14 days decreased from 6.9 at baseline to 3.5 at 24 months of follow-up, and the reduction was significant for the entire follow-up period compared with baseline (P < 0.001). A total of 55.6% of the subjects reported treatment success. The CCIS and FIQOL scores for all domains were significantly improved during the overall follow-up period compared with baseline (P < 0.001). The most common procedure and/or device-related adverse events were de novo urinary incontinence, including bladder spasms (n = 6), worsening FI (n = 2), and constipation (n = 2). No device-related erosions or extrusions were reported. CONCLUSIONS: Initial experience of the TOPAS system demonstrated a significant improvement in FI episodes, CCIS and FIQOL scores, and a benign safety profile. These results indicate that the TOPAS system has potential as a new therapeutic option for FI, but it needs to be confirmed in a larger study.

A metallacarborane redox mediator for an enzyme-immobilized chitosan-modified bioanode.

We describe here the first report of a metallacarborane complex as a redox mediator in a functioning biofuel cell. Specifically, we have prepared a water-soluble salt of the complex anion [commo-3,3'-Fe-(closo-2,1-C(2)B(9)H(11))(2)](-) and employed it as a redox mediator for glucose oxidation using chitosan/multiwalled carbon nanotube-modified electrodes comprising immobilized glucose oxidase. Experiments have indicated an increased amperometric response to glucose feeding, providing the complex mediator was initially supplied in the phosphate buffer electrolyte solution. Cathodic peak currents increased to a maximum of 1.24mA/cm(2) up to the saturating threshold concentration of glucose, indicating a significant degree of metallacarborane-enzyme communication and supporting the notion of a proposed metallacarborane redox mediator in biofuel cells. Upon incorporation of the mediator by anion exchange in the chitosan with the enzyme prior to measurement, however, an attenuated response to glucose feeding was detected, despite efforts to use different tactics to cast such films on the electrode such as a bilayer scheme. It is believed that the uptake of significant quantities of the metallacarborane into the chitosan is sponsoring a gross change in the microstructure of the biopolymer. This is supported by SEM imaging of the metallacarborane-modified chitosan, which revealed a remarkable transformation of the biopolymer scaffold.