Active Microelectronic Neurosensor Arrays for Implantable Brain Communication Interfaces

We have built a wireless implantable microelectronic device for transmitting cortical signals transcutaneously. The device is aimed at interfacing a microelectrode array cortical to an external computer for neural control applications. Our implantable microsystem enables presently 16-channel broadband neural recording in a nonhuman primate brain by converting these signals to a digital stream of infrared light pulses for transmission through the skin. The implantable unit employs a flexible polymer substrate onto which we have integrated ultra-low power amplification with analog multiplexing, an analog-to-digital converter, a low power digital controller chip, and infrared telemetry. The scalable 16-channel microsystem can employ any of several modalities of power supply, including via radio frequency by induction, or infrared light via a photovoltaic converter. As of today, the implant has been tested as a sub-chronic unit in non-human primates (~ 1 month), yielding robust spike and broadband neural data on all available channels.

Highly efficient ultra-low blaze angle multilayer grating

We have developed an advanced process for blaze angle reduction of x-ray gratings for the soft, tender, and EUV spectral ranges. The process is based on planarization of an anisotropically etched Si blazed grating followed by a chemically selective plasma etch. This provides a way to adjust the blaze angle to any lower value with high accuracy. Here we demonstrate the reduction of the blaze angle to an extremely low value of 0.04°±0.004°. For a 100 lines/mm grating with a Mo/Si multilayer coating, the grating exhibits diffraction efficiency of 58% in the 1^st diffraction order at a wavelength of 13.3 nm. This technique will be applicable to a wide range of uses of high efficiency gratings for synchrotron sources, as well as for Free Electron Lasers (FEL).

Accurate Determination of the Neutron Skin Thickness of ^{208}Pb through Parity-Violation in Electron Scattering

We report a precision measurement of the parity-violating asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A_{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(Q^{2}=0.00616  GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_{n}-R_{p}=0.283±0.071  fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ_{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo)  fm^{-3} leading to the interior baryon density ρ_{b}^{0}=0.1480±0.0036(exp)±0.0013(theo)  fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

Treatment outcomes in multidrug-resistant tuberculosis according to pyrazinamide susceptibility

BACKGROUND: Pyrazinamide (PZA) is an important anti-tuberculosis drug for multidrug-resistant tuberculosis (MDR-TB). However, PZA has recently been demoted within the hierarchy of TB drugs used for MDR-TB.METHODS: We conducted a retrospective cohort study to investigate treatment outcomes for simple MDR-TB (susceptible to both second-line injectable drugs and fluoroquinolones) according to PZA susceptibility.RESULTS: Among 216 pulmonary MDR-TB patients included in the study, 68 (31.5%) were PZA-resistant (PZA-R). The mean age was 41.8 years, and 63.4% were male. Baseline characteristics such as comorbidity, previous TB history, acid-fast bacilli (AFB) smear positivity and cavitation were similar in PZA-susceptible (PZA-S) and PZA-R patients. The number of potentially effective drugs was slightly higher among PZA-S patients than among the PZA-R (5.1 vs. 4.8, respectively; P = 0.003). PZA was more frequently used in PZA-S patients (73.0%) than in the PZA-R (14.7%), while para-aminosalicylic acid was more frequently used in PZA-R than in PZA-S patients (76.5% vs. 50.7%). The treatment success rate was similar in PZA-S (77.7%) and PZA-R (75.0%) patients. PZA resistance was not associated with treatment success in multivariate analysis.CONCLUSIONS: PZA-resistant simple MDR-TB patients had the same treatment success rate as the PZA-susceptible group even without using novel anti-TB drugs.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2  (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5  GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

Probing the Deuteron at Very Large Internal Momenta

We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5  (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0  GeV/c. We obtain data at fixed neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer q[over →]. The new data agree well with previous data, which reached p_{r}∼500  MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700  MeV/c.

Safety and efficacy of transarterial embolisation for treatment of dorsal pancreatic artery haemorrhage

AIM

To evaluate the safety and efficacy of transarterial embolisation (TAE) of dorsal pancreatic artery (DPA) haemorrhage.

MATERIALS AND METHODS

Nineteen consecutive patients (M:F = 16:3, mean age 59.6 years) who underwent TAE of DPA in three tertiary medical centres between January 2001 to January 2020 were reviewed retrospectively. Angiographic features and the technical and clinical outcomes of TAE were analysed.

RESULTS

The clinical presentations were a bloody drain from the Jackson-Pratt drainage tube (n=8), melaena (n=7), abdominal pain (n=4), and haematochezia (n=3). Angiographic findings included pseudoaneurysm (n=14), contrast media extravasation (n=4), or abrupt cut-off of the arterial branch (n=1). The NBCA (N-butyl-cyanoacrylate; n=4), microcoils (n=4), and a combination of these agents (n=7) were used as embolic agents. The most common origin of the DPA in the present study cohort was the splenic artery (n=7), followed by the coeliac trunk (n=4), common hepatic artery (n=4), and superior mesenteric artery (n=4). Technical and clinical success rates were 100% and 84.2% (16/19), respectively. Of the three clinically unsuccessful cases, two patients were revealed to have newly developed bleeding from another artery. The other patient expired 1 day after the TAE procedure due to a progression of hepatic failure. In one patient, an asymptomatic non-target embolisation occurred in the right posterior tibial artery as a procedure-related complication. No major complications were observed.

CONCLUSION

TAE is safe and effective for the management of bleeding from the DPA. It is important to be aware of the DPA as a potential bleeding source, including the relevant clinical characteristics.

High-Precision Determination of Oxygen K_{α} Transition Energy Excludes Incongruent Motion of Interstellar Oxygen

We demonstrate a widely applicable technique to absolutely calibrate the energy scale of x-ray spectra with experimentally well-known and accurately calculable transitions of highly charged ions, allowing us to measure the K-shell Rydberg spectrum of molecular O_{2} with 8 meV uncertainty. We reveal a systematic ∼450  meV shift from previous literature values, and settle an extraordinary discrepancy between astrophysical and laboratory measurements of neutral atomic oxygen, the latter being calibrated against the aforementioned O_{2} literature values. Because of the widespread use of such, now deprecated, references, our method impacts on many branches of x-ray absorption spectroscopy. Moreover, it potentially reduces absolute uncertainties there to below the meV level.

Low-dose CT angiography of the lower extremities: a comparison study of image quality and radiation dose

AIM

To investigate the image quality and radiation dose of ultralow-dose (ULD) and low-dose (LD) lower-extremity computed tomography (CT) angiography (LE-CTA) using the advanced modelled iterative reconstruction (ADMIRE) algorithm to detect peripheral arterial disease (PAD) in comparison with standard-dose (SD) CT.

MATERIALS AND METHODS

One hundred and seven consecutive patients were examined using LE-CTA at 70 kVp and a dual-source scanner to achieve three image sets using 30% (ULD), 70% (LD), and 100% (SD) tube loads. Qualitative analysis was conducted by examining the three image sets for overall quality. The image quality of arterial segments was analysed by two independent readers. In addition, the CT dose index (CTDI_vol) was measured in the three image sets.

RESULTS

The mean overall quality scores were 3.4±0.6 for ULD CT, 3.9±0.3 for LD CT, and 3.9±0.2 for SD CT. Both readers scored the arterial segments as 2-4 (adequate-excellent) in the three image sets. In addition, 89.4% (93/104) and 54.8% (57/104) segments of PAD with calcified plaques were scored 4 between SD and LD CT and between SD and ULD CT, respectively, and 45.2% (47/104) segments had a lower score by one point in ULD CT compared with SD CT. The mean CTDI_vol was 4.1±1.1 mGy for SD CT, 2.9±0.8 mGy for LD CT, and 1.2±0.3 mGy for ULD CT.

CONCLUSIONS

LD/ULD CT at 70 kVp using ADMIRE reconstruction enables a reduction in the radiation dose while enabling adequate evaluation or follow-up of PAD based on LE-CTA.

Development and Validation of a Deep Learning-Based Automatic Brain Segmentation and Classification Algorithm for Alzheimer Disease Using 3D T1-Weighted Volumetric Images

BACKGROUND AND PURPOSE

Limited evidence has suggested that a deep learning automatic brain segmentation and classification method, based on T1-weighted brain MR images, can predict Alzheimer disease. Our aim was to develop and validate a deep learning-based automatic brain segmentation and classification algorithm for the diagnosis of Alzheimer disease using 3D T1-weighted brain MR images.

MATERIALS AND METHODS

A deep learning-based algorithm was developed using a dataset of T1-weighted brain MR images in consecutive patients with Alzheimer disease and mild cognitive impairment. We developed a 2-step algorithm using a convolutional neural network to perform brain parcellation followed by 3 classifier techniques including XGBoost for disease prediction. All classification experiments were performed using 5-fold cross-validation. The diagnostic performance of the XGBoost method was compared with logistic regression and a linear Support Vector Machine by calculating their areas under the curve for differentiating Alzheimer disease from mild cognitive impairment and mild cognitive impairment from healthy controls.

RESULTS

In a total of 4 datasets, 1099, 212, 711, and 705 eligible patients were included. Compared with the linear Support Vector Machine and logistic regression, XGBoost significantly improved the prediction of Alzheimer disease (P < .001). In terms of differentiating Alzheimer disease from mild cognitive impairment, the 3 algorithms resulted in areas under the curve of 0.758-0.825. XGBoost had a sensitivity of 68% and a specificity of 70%. In terms of differentiating mild cognitive impairment from the healthy control group, the 3 algorithms resulted in areas under the curve of 0.668-0.870. XGBoost had a sensitivity of 79% and a specificity of 80%.

CONCLUSIONS

The deep learning-based automatic brain segmentation and classification algorithm allowed an accurate diagnosis of Alzheimer disease using T1-weighted brain MR images. The widespread availability of T1-weighted brain MR imaging suggests that this algorithm is a promising and widely applicable method for predicting Alzheimer disease.