Working memory enhancement using real-time phase-tuned transcranial alternating current stimulation.

Background: Prior work has shown that transcranial alternating current stimulation (tACS) of parietooccipital alpha oscillations (8-14 Hz) can modulate working memory (WM) performance as a function of the phase lag to endogenous oscillations. However, leveraging this effect using real-time phase-tuned tACS has not been feasible so far due to stimulation artifacts preventing continuous phase tracking.

Objectives And Hypothesis: We aimed to develop a system that tracks and adapts the phase lag between tACS and ongoing parietooccipital alpha oscillations in real-time.

The Prevalence and Association of Biofilms With Otitis Media With Effusion: A Systematic Review and Meta-Analysis.

Purpose: We aimed to identify the role of bacterial biofilms in the chronicity of otitis media with effusion and its resistance to antibiotics. We illustrated this role by reviewing, analyzing, and correlating the findings with the results of the included studies to reach clear evidence.

Methods: A comprehensive search of electronic databases (Scopus, PubMed, Web of Science, Cochrane, and GHL databases) was performed for all studies using the following strategy till April 2021 with the search terms: Biofilm and Middle ear effusion.

In vivo phase-dependent enhancement and suppression of human brain oscillations by transcranial alternating current stimulation (tACS).

Transcranial alternating current stimulation (tACS) can influence perception and behavior, with recent evidence also highlighting its potential impact in clinical settings, but its underlying mechanisms are poorly understood. Behavioral and indirect physiological evidence indicates that phase-dependent constructive and destructive interference between the applied electric field and brain oscillations at the stimulation frequency may play an important role, but in vivo validation during stimulation was unfeasible because stimulation artifacts impede single-trial assessment of brain oscillations during tACS. Here, we attenuated stimulation artifacts to provide evidence for phase-dependent enhancement and suppression of visually evoked steady state responses (SSR) during amplitude-modulated tACS (AM-tACS).

Invasive fungal rhinosinusitis associated with COVID-19: Course changes and prognosis predictors.

Background: This study aimed to analyze the behavior of acute invasive fungal rhinosinusitis (AIFRS) associated with COVID-19 infection as there has been an increase in the rate of AIFRS cases in the last two years, and many reports connected this rising with the COVID-19 infection. We studied most factors that may impact the prognosis as a trial to find the most affecting factors to improve the outcomes.

Methods: It was a retrospective observational study that included cases from four tertiary referral institutions between November 2020 to February 2022.

Breaking the boundaries of interacting with the human brain using adaptive closed-loop stimulation.

The human brain is arguably one of the most complex systems in nature. To understand how it operates, it is essential to understand the link between neural activity and behavior. Experimental investigation of that link requires tools to interact with neural activity during behavior.

Non-invasive Imaging of Antisense Oligonucleotides in the Brain via In Vivo Click Chemistry.

Purpose: The treatment of complex neurological diseases often requires the administration of large therapeutic drugs, such as antisense oligonucleotide (ASO), by lumbar puncture into the intrathecal space in order to bypass the blood-brain barrier. Despite the growing number of ASOs in clinical development, there are still uncertainties regarding their dosing, primarily around their distribution and kinetics in the brain following intrathecal injection. The challenge of taking measurements within the delicate structures of the central nervous system (CNS) necessitates the use of non-invasive nuclear imaging, such as positron emission tomography (PET).

Spontaneous representation of numerosity zero in a deep neural network for visual object recognition.

Conceiving "nothing" as a numerical value zero is considered a sophisticated numerical capability that humans share with cognitively advanced animals. We demonstrate that representation of zero spontaneously emerges in a deep learning neural network without any number training. As a signature of numerical quantity representation, and similar to real neurons from animals, numerosity zero network units show maximum activity to empty sets and a gradual decrease in activity with increasing countable numerosities.

Advancing sensory neuroprosthetics using artificial brain networks.

Implementation of effective brain or neural stimulation protocols for restoration of complex sensory perception, e.g., in the visual domain, is an unresolved challenge.

A set of electroencephalographic (EEG) data recorded during amplitude-modulated transcranial alternating current stimulation (AM-tACS) targeting 10-Hz steady-state visually evoked potentials (SSVEP).

Transcranial alternating current stimulation (tACS) can affect perception, learning and cognition, but the underlying mechanisms are not well understood. A promising strategy to elucidate these mechanisms aims at applying tACS while electric or magnetic brain oscillations targeted by stimulation are recorded. However, reconstructing brain oscillations targeted by tACS remains a challenging problem due to stimulation artifacts.

Investigating new CT contrast agents: a phantom study exploring quantification and differentiation methods for high-Z elements using dual-energy CT.

Objectives: To develop a dual-energy CT method for differentiating and quantifying high-Z contrast elements and to evaluate the limitations based on element concentration and atomic number by using an anthropomorphic phantom study.

Methods: Mass spectrometry standards for iodine, barium, gadolinium, ytterbium, tantalum, gold, and bismuth were diluted from 10.0 to 0.

Stimulation artifact source separation (SASS) for assessing electric brain oscillations during transcranial alternating current stimulation (tACS).

Brain oscillations, e.g. measured by electro- or magnetoencephalography (EEG/MEG), are causally linked to brain functions that are fundamental for perception, cognition and learning.

Number detectors spontaneously emerge in a deep neural network designed for visual object recognition.

Humans and animals have a "number sense," an innate capability to intuitively assess the number of visual items in a set, its numerosity. This capability implies that mechanisms to extract numerosity indwell the brain's visual system, which is primarily concerned with visual object recognition. Here, we show that network units tuned to abstract numerosity, and therefore reminiscent of real number neurons, spontaneously emerge in a biologically inspired deep neural network that was merely trained on visual object recognition.

Breast Tumor Microcalcification Induced by Bone Morphogenetic Protein-2: A New Murine Model for Human Breast Tumor Diagnosis.

Widespread use of screening mammography has recently increased the detection of breast microcalcifications. These nonpalpable microcalcifications with specific features in breast tissues are clinically considered an early indicator of breast carcinoma. Our goal in this study was to develop a murine breast microcalcification model for optimizing imaging.

Separating High-Z Oral Contrast From Intravascular Iodine Contrast in an Animal Model Using Dual-Layer Spectral CT.

Rationale And Objectives: To show that water and iodine two-material decomposition images from dual-layer dual-energy spectral X-ray computed tomography (DECT) can be used to separate intravascular iodine contrast from simultaneously administered oral tantalum, tungsten, or rhenium contrast in an animal model.

Materials And Methods: In this Institutional Animal Care and Use Committee approved study, four female Fischer rats were given simultaneous intravenous and oral X-ray computed tomography contrast. Intravenous iodine contrast was administered via tail vein injection.

Pseudoenhancement effects on iodine quantification from dual-energy spectral CT systems: A multi-vendor phantom study regarding renal lesion characterization.

Purpose: To measure the effect of pseudoenhancement on spectral CT iodine quantification as a function of lesion size, lesion iodine level, background iodine level, helical versus axial scanning, and spectral CT scanner type in a phantom model.

Materials And Methods: A custom-built water-filled cylindrical phantom contained either six small vials (8 mm diameter) or six large vials (27 mm diameter) of aqueous iopamidol solutions (0, 0.5, 1.

Interspike interval analysis and spikelets in presubicular head-direction cells.

Head-direction (HD) neurons are thought to provide the mammalian brain with an internal sense of direction. These cells, which selectively increase their firing when the animal's head points in a specific direction, use the spike rate to encode HD with a high signal-to-noise ratio. In the present work, we analyzed spike train features of presubicular HD cells recorded juxtacellularly in passively rotated rats.

Manipulating Hippocampal Place Cell Activity by Single-Cell Stimulation in Freely Moving Mice.

Learning critically depends on the ability to rapidly form and store non-overlapping representations of the external world. In line with their postulated role in episodic memory, hippocampal place cells can undergo a rapid reorganization of their firing fields upon contextual manipulations. To explore the mechanisms underlying such global remapping, we juxtacellularly stimulated 42 hippocampal neurons in freely moving mice during spatial exploration.

Testing the Efficacy of Single-Cell Stimulation in Biasing Presubicular Head Direction Activity.

To support navigation, the firing of head direction (HD) neurons must be tightly anchored to the external space. Indeed, inputs from external landmarks can rapidly reset the preferred direction of HD cells. Landmark stimuli have often been simulated as excitatory inputs from "visual cells" (encoding landmark information) to the HD attractor network; when excitatory visual inputs are sufficiently strong, preferred directions switch abruptly to the landmark location.

Amplifying the sensitivity of zinc(II) responsive MRI contrast agents by altering water exchange rates.

Given the known water exchange rate limitations of a previously reported Zn(II)-sensitive MRI contrast agent, GdDOTA-diBPEN, new structural targets were rationally designed to increase the rate of water exchange to improve MRI detection sensitivity. These new sensors exhibit fine-tuned water exchange properties and, depending on the individual structure, demonstrate significantly improved longitudinal relaxivities (r1). Two sensors in particular demonstrate optimized parameters and, therefore, show exceptionally high longitudinal relaxivities of about 50 mM(-1) s(-1) upon binding to Zn(II) and human serum albumin (HSA).

Nuclear spin hyperpolarization of the solvent using signal amplification by reversible exchange (SABRE).

Here we report the polarization of the solvent OH protons by SABRE using standard iridium-based catalysts under slightly acidic conditions. Solvent polarization was observed in the presence of a variety of structurally similar N-donor substrates while no solvent enhancement was observed in the absence of substrate or para-hydrogen (p-H2). Solvent polarization was sensitive to the polarizing field and catalyst:substrate ratio in a manner similar to that of substrate protons.

Charge and hydrophobicity effects of NIR fluorophores on bone-specific imaging.

Recent advances in near-infrared (NIR) fluorescence imaging enabled real-time intraoperative detection of bone metastases, bone growth, and tissue microcalcification. Pamidronate (PAM) has been widely used for this purpose because of its high binding affinity toward bone and remarkable therapeutic effects. Herein we describe the development of a series of PAM-conjugated NIR fluorophores that varied in net charges and hydrophobicity, and compared their bone targeting efficiency, biodistribution, and blood clearance.

Structure-activity relationship of nerve-highlighting fluorophores.

Nerve damage is a major morbidity associated with numerous surgical interventions. Yet, nerve visualization continues to challenge even the most experienced surgeons. A nerve-specific fluorescent contrast agent, especially one with near-infrared (NIR) absorption and emission, would be of immediate benefit to patients and surgeons.

Rapid and Facile Microwave-Assisted Surface Chemistry for Functionalized Microarray Slides.

We describe a rapid and facile method for surface functionalization and ligand patterning of glass slides based on microwave-assisted synthesis and a microarraying robot. Our optimized reaction enables surface modification 42-times faster than conventional techniques and includes a carboxylated self-assembled monolayer, polyethylene glycol linkers of varying length, and stable amide bonds to small molecule, peptide, or protein ligands to be screened for binding to living cells. We also describe customized slide racks that permit functionalization of 100 slides at a time to produce a cost-efficient, highly reproducible batch process.

High-throughput screening of small molecule ligands targeted to live bacteria surface.

The discovery of small molecule ligands targeted to the surface of live pathogenic bacteria would enable an entirely new class of antibiotics. We report the development and validation of a microarray-based high-throughput screening platform for bacteria that exploits 300 μm diameter chemical spots in a 1 in. × 3 in.

cGMP-Compatible preparative scale synthesis of near-infrared fluorophores.

Image-guided surgery using optical imaging requires the availability of large quantities of clinical-grade fluorophores. We describe the cGMP-compatible synthesis of the zwitterionic heptamethine indocyanine near-infrared fluorophore ZW800-1 at the 10 g scale (~1000 patient doses) using facile and efficient solvent purification, and without the need for column chromatography. ZW800-1 has >90% yield at the final step and >99% purity as measured by fluorescence and evaporative light scatter detection.