bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative DFT dual gas adsorption model of ZnO and Ag/ZnO with experimental applications as gas detection at ppb level
Authors: Kumar Utkarsh , Huang Shih-Ming , Deng Zu-Yin , Yang Cheng-Xin , Haung Wen-Min , Wu Chiu-Hsien
Published: November 2021

By experimental and density functional theory calculations, the toxic gases (O3 and NO2) sensing capability and mechanism of ZnO NRs and Ag/ZnO NRs have been comparatively studied in this work. Ag NPs arrays were employed for the growth of ZnO NRs. The experimental results show that when ZnO NRs are grown on Ag NPs, the response and adsorption rate towards the gases change significantly. The TDOS plot shows that the HOMO-LUMO gap changes after interaction with different oxidizing gases, and the peak intensity also decreases confirming the electron are transferred from ZnO to NO2 and O3. The response to gases decreases and the adsorption reaction rate increases in Ag/ZnO NRs, as calculated by the Eyring-Polanyi equation, which is very similar to our experimental data. We also find that the absorption coefficient is different for O3 and NO2. Finally, experimental response and theoretical results were compared and found to be in good agreement.
Understanding machine learning classifier decisions in automated radiotherapy quality assurance
Authors: Chen Yunsheng , Aleman Dionne M , Purdie Thomas G , McIntosh Chris
Published: November 2021

The complexity of generating radiotherapy treatments demands a rigorous quality assurance (QA) process to ensure patient safety and to avoid clinically significant errors. Machine learning classifiers have been explored to augment the scope and efficiency of the traditional radiotherapy treatment planning QA process. However, one important gap in relying on classifiers for QA of radiotherapy treatment plans is the lack of understanding behind a specific classifier prediction. We develop explanation methods to understand the decisions of two automated QA classifiers: (1) a region of interest (ROI) segmentation/labeling classifier, and (2) a treatment plan acceptance classifier. For each classifier, a local interpretable model-agnostic explanation (LIME) framework and a novel adaption of team-based Shapley values framework are constructed. We test these methods in datasets for two radiotherapy treatment sites (prostate and breast), and demonstrate the importance of evaluating QA classifiers using interpretable machine learning approaches. We additionally develop a notion of explanation consistency to assess classifier performance. Our explanation method allows for easy visualization and human expert assessment of classifier decisions in radiotherapy QA. Notably, we find that our team-based Shapley approach is more consistent than LIME. The ability to explain and validate automated decision-making is critical in medical treatments. This analysis allows us to conclude that both QA classifiers are moderately trustworthy and can be used to confirm expert decisions, though the current QA classifiers should not be viewed as a replacement for the human QA process.
A Geant4 Fano test for novel very high energy electron beams
Authors: McManus M , Romano F , Royle G , Palmans H , Subiel A
Published: November 2021

Objective. The boundary crossing algorithm available in Geant4 10.07-p01 general purpose Monte Carlo code has been investigated for a 12 and 200 MeV electron source by the application of a Fano cavity test. Approach. Fano conditions were enforced through all simulations whilst varying individual charged particle transport parameters which control particle step size, ionisation and single scattering. Main Results. At 12 MeV, Geant4 was found to return excellent dose consistency within 0.1% even with the default parameter configurations. The 200 MeV case, however, showed significant consistency issues when default physics parameters were employed with deviations from unity of more than 6%. The effect of the inclusion of nuclear interactions was also investigated for the 200 MeV beam and was found to return good consistency for a number of parameter configurations. Significance. The Fano test is a necessary investigation to ensure the consistency of charged particle transport available in Geant4 before detailed detector simulations can be conducted.
Radially-dependent ignition process of a pulsed capacitively coupled RF argon plasma over 300 mm-diameter electrodes: multi-fold experimental diagnostics
Authors: Su Zi-Xuan , Shi De-Hua , Liu Yong-Xin , Zhao Kai , Gao Fei , Wang You-Nian
Published: November 2021

A synergistic combination of multi-diagnostic methods are proposed to investigate temporal evolution of electrical and plasma parameters at various radial positions over 300 mm-diameter electrodes during the pre-ignition, ignition, and post-ignition phases of a pulsed capacitively coupled radio-frequency (RF) argon discharge. The electron density, n
e, and the optical emission intensity (OEI) of argon at 750.4 nm at different radial positions are measured time-resolved by using a hairpin probe and an optical probe, respectively. A B-dot probe is employed to determine the waveforms of the azimuthal magnetic field at different radii, from which the waveforms of the axial current density at corresponding radial positions are derived based on Ampere’s law. Then, the time evolution of the power density at various radii can be calculated, provided that the voltage drop between the electrodes is independent of radius. Meanwhile, the time-dependent total power deposited into the reactor is calculated with the voltage and the current waveforms measured by a voltage and a current probe at the power feeding point. It was found that during pre-ignition phase, the OEI and n
e cannot be measurable due to extremely low power deposition when the system exhibits pure capacitive impedance. During the ignition phase, the OEI, the power density, and the current density exhibit the most significant increase at the electrode center, while the time evolution of n
e measured by the hairpin probe seems to exhibit a relatively weak radial dependence during this phase. In particular, at r ⩽ 8 cm, the OEI at every radius was observed to change with time in the same manner as the power density during the ignition phase, because the RF power is absorbed primarily by electrons, which dissipate their energy via inelastic collisions. Shortly, the profile of n
e becomes edge-high during the post-ignition phase and remains thereafter until the end of the pulse-on period. Methodologically, the synergistic diagnostics lay the foundation for extensive studies on spatiotemporal evolution of plasma ignition process under broader conditions, e.g. electronegative gas, lower working gas pressure and very high driving frequency, widely used by practical etching process.
Quantitative fs-TALIF in high-pressure NRP discharges: calibration using VUV absorption spectroscopy
Authors: Dumitrache Ciprian , Gallant Arnaud , de Oliveira Nelson , Laux Christophe O , Stancu Gabi Daniel
Published: November 2021

This work presents a femtosecond two-photon absorption laser-induced fluorescence (fs-TALIF) diagnostic for measuring ground-state atomic nitrogen in nanosecond repetitively pulsed (NRP) discharges. Absolute atom density is obtained from the TALIF signal via a novel calibration technique based on one-photon direct absorption measurements performed in a low-pressure DC discharge. The Vacuum Ultraviolet (VUV) measurements were done at the Soleil synchrotron facility using the high-resolution Fourier-transform spectrometer (minimum linewidth Δ

ν

~

= 0.08 cm−1). The main goal of this work was to develop a quench-free diagnostic technique, which would allow measurements at elevated pressures with high spatial and temporal resolution. Here fs-TALIF measurements of N(4S) are demonstrated in the NRP post-discharge between 1–500 μs after the nanosecond high-voltage pulse. A maximum number density of N-atoms of 5 × 1016 cm−3 was measured at 1 μs after the pulse when the discharge was operated at 1 bar in pure nitrogen. This corresponds to a dissociation fraction of ∼0.1%. The fs-TALIF technique at high laser intensity regime (>1 TW cm−2) calibrated using VUV absorption was compared with the fs-TALIF at low laser intensity regime (<100 MW cm−2) calibrated via the well-established non-saturated TALIF technique using krypton as an etalon gas. It was found that the two measurements of N(4S) in the NRP post-discharge agree within a factor of 3. Importantly, the limit of detection of the fs-TALIF at high laser intensity regime was determined to be

n

N

(

S

4

)

∼
1

0

12

c

m

−
3

. This is approximately one order of magnitude better than previously reported by ns-TALIF in low-pressure discharges.
Phase separation near the charge neutrality point in FeSe1-x
Te
x
crystals with x < 0.15
Authors: Ovchenkov Y A , Chareev D A , Kozlyakova E S , Levin E E , Mikheev M G , Presnov D E , Trifonov A S , Volkova O S , Vasiliev A N
Published: November 2021

Our study of FeSe

1
−
x

Te
x
crystals with x < 0.15 shows that the phase separation in these compositions occurs into phases with a different stoichiometry of iron. This phase separation may indicate structural instability of the iron plane in the studied range of compositions. We tentatively propose an explanation of the structural instability of the iron plane in the studied layered compounds in terms of the possible change in the bond polarity and the peculiarity of the direct

d

−

d

exchange in the iron plane in the framework of the basic phenomenological description such as the Bethe–Slater curve. With this approach, when the distance between iron atoms is close to the value at which the sign of the magnetic exchange for some d orbitals changes, structural and electronic instability can occur. Anomalies in the crystal field near the point of charge neutrality can also be a significant component of this instability.
Gas molecules (CH4, CO, H2O and H2S) adsorption on VC (001)surface: a first principles study
Authors: Hao Zhenli , Chen Ruixin , Huang Jingtao , Lin Long , Liu Xiao , Wang Pengtao , Zhang Zhanying
Published: November 2021

The first principle plane wave pseudo-potential method based on density functional theory system is used to calculate and simulate the geometric structure, density of states and optical properties of intrinsic VC materials. And we further studied the adsorption performance of small gas molecules (CH4, CO, H2O, H2S) on the surface of VC(001). The most stable adsorption geometry of CH4, CO, H2O and H2S on the intrinsic VC(001) was determined, and the electronic structure and differential charge were calculated by the first principle method. The results show that the adsorption stability of the same molecule on the surface is related to the interaction position between the molecule and the surface after adsorption. According to the analysis of the differential charge density and the charge layout number, the charge layout number of the central atom C, O, S of the gas molecule increases after adsorption, and the adsorption strength of the gas molecule on the surface is CO > H2S > H2O > CH4. The H2S adsorbed on VC surface has the strongest adsorption energy (–1.442 eV) and more transfer charge (–0.12 e). The calculated dielectric function results shows that the existence of gases molecules inhibited the photon adsorbed on VC(001) surface. Our research provide a theoretical basis for further research on the gas sensing properties of material.
On the cosmological solutions in Weyl geometry
Authors: Berezin V.A. , Dokuchaev V.I. , Eroshenko Yu. N. , Smirnov A.L.
Published: November 2021

We investigated the possibility of construction the homogeneous and isotropic cosmological solutions in Weyl geometry. We derived the self-consistency condition which ensures the conformal invariance of the complete set of equations of motion. There is the special gauge in choosing the conformal factor when the Weyl vector equals zero. In this gauge we found new vacuum cosmological solutions absent in General Relativity. Also, we found new solution in Weyl geometry for the radiation dominated universe with the cosmological term, corresponding to the constant curvature scalar in our special gauge. Possible relation of our results to the understanding both dark matter and dark energy is discussed.
Suppression of toroidal Alfvén eigenmodes by the electron cyclotron current drive in KSTAR plasmas
Authors: Kim J. , Kang J. , Rhee T. , Jo J. , Han H. , Podestà M. , Lee J.H. , Lee S. , Bak J.G. , Choi M.J. , Nazikian R. , Jhang H. , Ko J. , Joung M. , Jeon Y.-M. , Na Y.-S. , Shinohara K. , Cheng C.Z.
Published: November 2021

Advanced operation scenarios such as high poloidal beta (β
P) or high q
min are promising concepts to achieve the steady-state high-performance fusion plasmas. However, those scenarios are prone to substantial Alfvénic activity, causing fast-ion transport and losses. Recent experiments with the advanced operation scenario on KSTAR tokamak have shown that the electron cyclotron current drive (ECCD) is able to mitigate and suppress the beam-ion driven toroidal Alfvén eigenmodes (TAEs) for over several tens of global energy confinement time. Co-current directional intermediate off-axis ECCD lowers the central safety factor slightly and tilts the central q-profile shape so that the continuum damping in the core region increases. Besides, the rise of central plasma pressure and increased thermal-ion Landau damping contribute to TAE stabilization. While the TAEs are suppressed, neutron emission rate and total stored energy increase by approximately 45% and 25%, respectively. Fast-ion transport estimated by TRANSP calculations approaches the classical level during the TAE suppression period. Substantial reduction in fast-ion loss and neutron deficit is also observed. Enhancement of fast-ion confinement by suppressing the TAEs leads to an increase of non-inductive current fraction and will benefit the sustainment of the long-pulse high-performance discharges.
A novel surface-integral-equation formulation for efficient and accurate electromagnetic analysis of near-zero-index structures
Authors: İbili Hande , Koyaz Yeşim , Özmü Utku , Karaosmanoğlu Barışcan , Ergül Özgür
Published: November 2021

We consider accurate and iteratively efficient solutions of electromagnetic problems involving homogenized near-zero-index (NZI) bodies using surface-integral-equation formulations in the frequency domain. NZI structures can be practically useful in a plethora of optical applications, as they possess near-zero permittivity and/or permeability values that cannot be found in nature. Hence, numerical simulations are of the utmost importance for rigorous design and analysis of NZI structures. Unfortunately, small values of electromagnetic parameters bring computational challenges in numerical solutions of homogeneous models. Conventional formulations available in the literature encounter stability issues that make them inaccurate and/or inefficient as permittivity and/or permeability approach zero. We propose a novel formulation that involves a well-balanced combination of operators and that can provide both accurate and efficient solutions for all NZI cases. Numerical results are presented to demonstrate the superior properties of the developed formulation in comparison to the conventional ones.
Integral models for spaces via the higher Frobenius
Authors: Yuan Allen
Published: November 2021

We give a fully faithful integral model for simply connected finite complexes in terms ofE∞\mathbb {E}_{\infty }-ring spectra and the Nikolaus–Scholze Frobenius. The key technical input is the development of a homotopy coherent Frobenius action on a certain subcategory ofpp-completeE∞\mathbb {E}_{\infty }-rings for each primepp. Using this, we show that the data of a simply connected finite complexXXis the data of its Spanier-Whitehead dual, as anE∞\mathbb {E}_{\infty }-ring, together with a trivialization of the Frobenius action after completion at each prime.

In producing the above Frobenius action, we explore two ideas which may be of independent interest. The first is a more general action of Frobenius in equivariant homotopy theory; we show that a version of Quillen’sQQ-construction acts on the∞\infty-category ofE∞\mathbb {E}_{\infty }-rings with “genuine equivariant multiplication,” which we call global algebras. The second is a “pre-group-completed” variant of algebraicKK-theory which we callpartialKK-theory. We develop the notion of partialKK-theory and give a computation of the partialKK-theory ofFp\mathbb {F}_pup topp-completion.
Slow Criticism: American Literary Studies as a World
Authors: Bentley Nancy
Published: November 2021

The authority of art in US society has declined even as cultural criticism has expanded and diversified, spreading to many sectors of society. While these conditions have affected American literary studies, scholars in the field produce criticism that can be distinguished from the criticism in other sectors by its commitment to historicist thought and by disciplinary standards for what it means to produce a “new reading.”
It’s in the timing: reduced temporal precision in neural activity of schizophrenia
Authors: Wolff Annemarie , Gomez-Pilar Javier , Zhang Jianfeng , Choueiry Joelle , de la Salle Sara , Knott Verner , Northoff Georg
Published: November 2021

Studies of perception and cognition in schizophrenia (SCZ) show neuronal background noise (ongoing activity) to intermittently overwhelm the processing of external stimuli. This increased noise, relative to the activity evoked by the stimulus, results in temporal imprecision and higher variability of behavioral responses. What, however, are the neural correlates of temporal imprecision in SCZ behavior? We first report a decrease in electroencephalography signal-to-noise ratio (SNR) in two SCZ datasets and tasks in the broadband (1–80 Hz), theta (4–8 Hz), and alpha (8–13 Hz) bands. SCZ participants also show lower inter-trial phase coherence (ITPC)—consistency over trials in the phase of the signal—in theta. From these ITPC results, we varied phase offsets in a computational simulation, which illustrated phase-based temporal desynchronization. This modeling also provided a necessary link to our results and showed decreased neural synchrony in SCZ in both datasets and tasks when compared with healthy controls. Finally, we showed that reduced SNR and ITPC are related and showed a relationship to temporal precision on the behavioral level, namely reaction times. In conclusion, we demonstrate how temporal imprecision in SCZ neural activity—reduced relative signal strength and phase coherence—mediates temporal imprecision on the behavioral level.
Occurrence of free N-glycans with a single GlcNAc at the reducing termini in animal sera
Authors: Huang Chengcheng , Seino Junichi , Fujihira Haruhiko , Sato Keiko , Fujinawa Reiko , Sumer-Bayraktar Zeynep , Ishii Nozomi , Matsuo Ichiro , Nakaya Shuichi , Suzuki Tadashi
Published: November 2021

Recent studies demonstrated the occurrence of sialyl free N-glycans (FNGs) in sera from a variety of animals. Unlike the intracellular FNGs that mainly carry a single N-acetylglucosamine at their reducing termini (Gn1-type), these extracellular FNGs have an N,N′-diacetylchitobiose at their reducing termini (Gn2-type). The detailed mechanism for how they are formed, however, remains unclarified. In this study, we report on an improved method for isolating FNGs from sera and found that, not only sialyl FNGs, but also neutral FNGs are present in animal sera. Most of the neutral oligomannose-type FNGs were found to be Gn1-type. We also found that a small portion of sialyl FNGs were Gn1-type. The ratio of Gn1-type sialyl FNGs varies between species, and appears to be partially correlated with the distribution of lysosomal chitobiase activity. We also identified small sialylated glycans similar to milk oligosaccharides, such as sialyl lactose or sialyl N-acetyllactosamine in sera. Our results indicate that there are varieties of free oligosaccharides in sera and the mechanism responsible for their formation is more complicated than currently envisaged.
Gene Expression Risk Scores for COVID-19 Illness Severity
Authors: Peterson Derick R , Baran Andrea M , Bhattacharya Soumyaroop , Branche Angela R , Croft Daniel P , Corbett Anthony M , Walsh Edward E , Falsey Ann R , Mariani Thomas J
Published: November 2021

Background

The correlates of coronavirus disease 2019 (COVID-19) illness severity following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are incompletely understood.

Methods

We assessed peripheral blood gene expression in 53 adults with confirmed SARS-CoV-2 infection clinically adjudicated as having mild, moderate, or severe disease. Supervised principal components analysis was used to build a weighted gene expression risk score (WGERS) to discriminate between severe and nonsevere COVID-19.

Results

Gene expression patterns in participants with mild and moderate illness were similar, but significantly different from severe illness. When comparing severe versus nonsevere illness, we identified >4000 genes differentially expressed (false discovery rate < 0.05). Biological pathways increased in severe COVID-19 were associated with platelet activation and coagulation, and those significantly decreased with T-cell signaling and differentiation. A WGERS based on 18 genes distinguished severe illness in our training cohort (cross-validated receiver operating characteristic-area under the curve [ROC-AUC] = 0.98), and need for intensive care in an independent cohort (ROC-AUC = 0.85). Dichotomizing the WGERS yielded 100% sensitivity and 85% specificity for classifying severe illness in our training cohort, and 84% sensitivity and 74% specificity for defining the need for intensive care in the validation cohort.

Conclusions

These data suggest that gene expression classifiers may provide clinical utility as predictors of COVID-19 illness severity.
Immune responses to bacterial lung infections and their implications for vaccination
Authors: Muruganandah Visai , Kupz Andreas
Published: November 2021

The pulmonary immune system plays a vital role in protecting the delicate structures of gaseous exchange against invasion from bacterial pathogens. With antimicrobial resistance becoming an increasing concern, finding novel strategies to develop vaccines against bacterial lung diseases remains a top priority. In order to do so, a continued expansion of our understanding of the pulmonary immune response is warranted. While some aspects are well characterized, emerging paradigms such as the importance of innate cells and inducible immune structures in mediating protection provide avenues of potential to rethink our approach to vaccine development. In this review, we aim to provide a broad overview of both the innate and adaptive immune mechanisms in place to protect the pulmonary tissue from invading bacterial organisms. We use specific examples from several infection models and human studies to depict the varying functions of the pulmonary immune system that may be manipulated in future vaccine development. Particular emphasis has been placed on emerging themes that are less reviewed and underappreciated in vaccine development studies.
Telemedicine Basics
Authors: Burke Guenevere , Lucas Jared
Published: November 2021

Telemedicine is a rapidly growing field in health care and emergency medicine. Telemedicine, telehealth, and virtual health refer to the use of telecommunications technology and electronic information to support health and provide care over distance. It has been used to improve access to health care in geographically remote areas for decades, but its use and recognized benefits have expanded considerably over the years, accelerated by the COVID-19 pandemic. This chapter provides a brief overview of the history of telemedicine, introduces key terms, and reviews basic definitions that are foundational to telemedicine practice. Finally, it summarizes a wide array of telehealth applications in emergency medicine, which are detailed further in later chapters.
Telehealth Training and Education
Authors: Joshi Aditi U. , Sikka Neal
Published: November 2021

Despite the rapid expansion of telehealth services, education and training regarding the telehealth modality have lagged and yet to be validated. While clinical skills are traditionally taught in undergraduate and graduate training programs, few programs currently teach telehealth-specific skills. This is particularly challenging given that both novice and experienced clinicians require training and components of that training are program-specific. Training should include clinicians, patients, their carepartners, and telepresenters as the future health care team is rapidly evolving and will require a collaborative approach. This chapter outlines the various types of telehealth education, the groups of learners for whom training should be targeted, and various models of training.
Quality Assessment in Emergency Telehealth
Authors: Goldwater Jason C. , Hollander Judd E.
Published: November 2021

Telemedicine is a modality for care delivery. The medicine is the same, but the manner in which it is delivered differs. As a result, quality should be assessed based on the care rendered for the given condition as well as in accordance with the National Quality Forum (NQF) Telemedicine framework, which has four domains—access, cost/financial, experience, and effectiveness. This framework for quality provides a foundation for developing objective measures to assess emergency telehealth. Among NQF Committee’s findings was that the use of various telehealth modalities improved access to health care services. The NQF also recommended measuring whether sufficient information was obtained during a telemedicine encounter to make clinical decisions regarding intervening or not intervening. It found that obtaining the appropriate actionable information was more important than measuring diagnostic accuracy.
Legal, Regulatory, and Reimbursement Considerations
Authors: Gilroy Alexis S. , Rockwell Kimberly L. , Rutenberg Adam , Marblestone Claire , Faget Kyle Y.
Published: November 2021

The expansion of health care services delivered through telehealth is impacted by numerous legal, regulatory, and reimbursement frameworks. Standard medical practices for consent, privacy, credentialing, and licensing apply to telehealth; however, the opportunity for cross-state practice complicates their application. Hospital-specific rules for credentialing and emergency stabilization must also be considered. Delivery of medical services is often driven by reimbursement, which for telehealth is governed by a complicated web of rules that vary by service, payer, and location. Temporary changes to these rules in association with the public health emergency (PHE) declared in response to the COVID-19 pandemic has rapidly reshaped the telemedicine regulatory landscape. Advocacy for smart legislation that improves and simplifies access to care is important to ensure equity of telehealth services.
Emergency Telepsychiatry
Authors: Horwath Ewald , Dell Thomas E. , Saliba Zeina
Published: November 2021

Emergency telepsychiatry is the evaluation and treatment of patients experiencing mental health crises using audio/video communications. Patients in hospital emergency departments (EDs) often experience long waits, delayed treatment, and uncomfortable conditions when in-person psychiatric care is not readily available; prolonged lengths of stay in the ED also increase hospital costs. Telepsychiatry can make psychiatric care more accessible and timely by linking mental health specialists in various locations to patients in EDs. Initial data indicate that the financial investment in emergency telepsychiatry is more than offset by savings in ED and hospital costs. Rapid availability of telepsychiatric consultation also improves the quality of care in EDs and leads to more appropriate and timely dispositions of patients.
Telehealth for Medication for Opioid Use Disorder Treatment
Authors: Chan Bill Wayne , Fatollahi Javad John , Kirilichin Natalie Lynn , Saliba Zeina
Published: November 2021

Medication for Opioid Use Disorder (mOUD), a type of Medications for Addiction Treatment (MAT), has proven to be the most efficacious and cost-effective treatment for individuals suffering from opioid use disorder (OUD). Early initiation of mOUD has been shown to increase retention in addiction treatment. Models of care integrating telehealth with mOUD offer the potential to implement mOUD in point-of-care settings, achieving effective tertiary prevention. Integrating telehealth and mOUD also addresses barriers to addiction treatment continuity, like transportation concerns and stigma. Funding for use of telehealth for addiction treatment is achieved primarily through government grants and insurance reimbursements. There are many legal constructs regarding the dissemination of mOUD, and while not usually permitted, guidelines during the COVID-19 pandemic have allowed for practitioners to be able to prescribe mOUD via telehealth without the requirement of an initial in-person examination.
Meninges and Ventricles
Authors: Laughlin Ruple S.
Published: November 2021

Knowledge of the normal structure and function of the meninges and ventricular system can aid in recognizing and understanding pathologic states. This chapter reviews the meninges, ventricular system, and cerebrospinal fluid (CSF) production. Three layers of meninges cover the brain and spinal cord: dura, arachnoid, and pia. They 1) protect the underlying brain and spinal cord, 2) serve as a support framework for important arteries and veins, and 3) enclose a fluid-filled cavity that is important for normal function of the brain and spinal cord.
Special Somatic Sensory Afferent Systems Overview
Authors: Eggers Scott D. , Benarroch Eduardo E.
Published: November 2021

The special somatic sensory afferent systems include the auditory, vestibular, and visual systems. Auditory and vestibular afferent information is received by cranial nerve VIII, which projects to central pathways. Cranial nerve II carries afferent visual information to central pathways. This chapter reviews the receptors and structural components of these special somatic sensory afferent systems. The ossicular chain (malleus, incus, and stapes) within the air-filled middle ear serves as a transformer that bridges the impedance mismatch between sound vibrations in air on the large tympanic membrane and the resulting vibrations onto the small stapedial footplate.
Anatomy of Peripheral Nerves, Neuromuscular Junctions, and Skeletal Muscles
Authors: Tracy Jennifer A.
Published: November 2021

After exiting the spinal cord, individual nerve roots coalesce into plexi and peripheral nerves that innervate muscle and skin. Clinical localization requires a working knowledge of this anatomy. By evaluating the distribution of muscle weakness, sensory loss, and reflexes, it is often possible to localize lesions and focus a differential diagnosis. The spinal nerve roots consist of dorsal and ventral roots that extend from the spinal cord. The dorsal root ganglion contains a bipolar neuron that is the sensory nerve cell body.
Brainstem and Cranial Nerves: Pons
Authors: Flemming Kelly D. , Brazis Paul W.
Published: November 2021

The pons extends from the pontomedullary junction to an imaginary line drawn from the exit of cranial nerve IV. Dorsal to the pons lies the cerebellum, which receives information and projects information back to the brainstem through the inferior, middle, and superior cerebellar peduncles. Important structures at this level include the corticospinal tracts, corticopontocerebellar fibers traveling through the middle cerebellar peduncle, the cerebellum, and cranial nerves V through VIII. Blood supply to the pons is from the basilar artery and its perforating vessels.
Supranuclear Ocular Motor Systems
Authors: Eggers Scott D.
Published: November 2021

Properly functioning eye movements facilitate a clear, stable view of the environment. Saccadic eye movements and nystagmus fast phases are 2 types of fast eye movements. Slow eye movements include smooth pursuit, vestibular, optokinetic, and vergence. Reflexive and voluntary conjugate eye movements incorporate cortical, subcortical (basal ganglia), and vestibulocerebellar input to the final common pathways of horizontal and vertical eye movements. The present chapter reviews the anatomy and dysfunction of the supranuclear input to conjugate gaze.
Thalamus
Authors: Flemming Kelly D. , Benarroch Eduardo E.
Published: November 2021

The diencephalon has 4 components: 1) the epithalamus, which includes the pineal body; 2) the dorsal thalamus, which is commonly considered to be the thalamus proper; 3) the ventral thalamus, consisting of the reticular nucleus and subthalamic nucleus; and 4) the hypothalamus. This chapter focuses on the dorsal thalamus and the ventral thalamus. The thalamus has 3 main functions: 1) relay input from subcortical structures to the cortex, 2) control (gate) which sensory information reaches the cortex, and 3) synchronize cortical activity that relates to consciousness.
Principles of Neuroendocrinology and Hypothalamic Function
Authors: Coon Elizabeth A. , Benarroch Eduardo E.
Published: November 2021

The hypothalamus is the neural center of the endocrine system, the regulator of the autonomic nervous system, and the circadian and seasonal clock for behavioral and sleep-wake functions. The hypothalamus maintains homeostasis by integrating cortical, limbic, and spinal inputs and by affecting hormone release, temperature regulation, intake of food and water, sexual behavior and reproduction, emotional responses, and diurnal rhythms. As the link from the nervous system to the endocrine system, the hypothalamus synthesizes and secretes neurohormones that stimulate or inhibit the secretion of pituitary hormones.
Limbic System
Authors: Ramanan Vijay K. , Benarroch Eduardo E.
Published: November 2021

Unlike the lobes of the cortex, which are regionally defined, the limbic “lobe” includes highly interconnected circuits that span cortical, subcortical, and brainstem components. The major functions of the limbic system include mediating emotional and behavioral responses, memory, and learning. From a functional standpoint, the limbic system can be conceptualized as including an anterior circuit, centered in the amygdala and primarily involved in emotion and behavioral drive, and a posterior circuit, centered in the hippocampus and crucial for encoding and retrieving declarative (explicit) memory.
Autonomic Nervous System
Authors: Cutsforth-Gregory Jeremy K.
Published: November 2021

The autonomic nervous system is involved in many important unconscious body functions. It is critical for maintaining the internal environment in response to changes in the external environment. The autonomic nervous system consists of peripheral components (sympathetic and parasympathetic nerves and ganglia) and central components (ventrolateral medulla, nucleus ambiguus, nucleus of the solitary tract, periaqueductal gray, anterior cingulate gyrus, insular cortex, amygdala, and hypothalamus). This chapter briefly reviews the anatomy and functional components of the autonomic nervous system and several anatomical clinical correlations.
Cortex: Topography and Organization
Authors: Caselli Richard J. , Jones David T.
Published: November 2021

The cerebral cortex is involved in various simple and complex activities. It consists of layers of neuronal cell bodies (ie, gray matter) that are organized into gyri (convolutions).The cortex can be divided into functional components in several ways. Various schemes are based on function, cytoarchitecture, topography, or Brodmann areas. The terminology can be confusing because the same area of cortex could be designated by several names. For instance, Brodmann area 17 is also called the primary visual cortex, the striate cortex, and the calcarine cortex. Brodmann designated 52 regions of the cerebral cortex according to cytoarchitecture.
Cellular Processes
Authors: Staff Nathan P. , Madigan Nicolas N.
Published: November 2021

Although cells in the nervous system contain all the cellular machinery that exists in other cells throughout the body, nervous system cells have many specialized functions that present unique challenges in the maintenance of cellular functionality and homeostasis. The unique morphology of neurons demands elaborate cytoarchitecture, energy production, and cellular processing machinery that are unparalleled in other parts of the body. This chapter presents a broad overview of cellular processes related to the cytoskeleton, axonal transport, protein processing, and energy metabolism within the nervous system. Breakdowns of these intricate processes are involved in many diseases of the nervous system, which are discussed in subsequent chapters.
Sleep Pathophysiology
Authors: Anders Gabriel , Lipford Melissa C.
Published: November 2021

Sleep is a natural, reversible, and periodic behavioral state characterized by perceptual inattention and decreased responsiveness to external stimuli. The processes governing sleep, sleep-wake transitions, and maintenance of wakefulness are mediated by complex physiologic mechanisms, the primary neurobiological substrates of which include the neocortex, basal forebrain, thalamus, hypothalamus, pontine tegmentum, and brainstem monoaminergic nuclei. Moreover, the integrity of brainstem autonomic respiratory control networks becomes critical in the maintenance of ventilation during sleep. Pathologic insults to these systems may result in a broad constellation of clinical deficits.
Patterns of Inheritance in Neurogenetic Disease
Authors: Gavrilova Ralitza H.
Published: November 2021

The human genome consists of approximately 22,000 genes that are encoded within the nuclear DNA and embedded in the chromosome. Mitochondria are the only cytoplasmic organelles that have their own DNA. Nuclear gene disorders and mitochondrial inheritance are discussed in this chapter. Nuclear gene disorders follow the patterns of inheritance originally described by Gregor Mendel. They often are referred to as single-gene disorders because 1 or more alleles of only 1 locus are the major determinants of phenotype.
Mood Disorders
Authors: Kung Simon
Published: November 2021

Mood disorders—depressive and bipolar disorders—are the second most common set of psychiatric disorders, behind anxiety disorders. The lifetime prevalence of any mood disorder in US adults is approximately 20%, and the 12-month prevalence is approximately 10%. Although depressive disorders and bipolar disorder have been split into 2 chapters in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition), the criteria have stayed the same as in its Fourth Edition, Text Revision while the terminology has changed slightly.
Psychotic Disorders
Authors: Rasmussen Keith G.
Published: November 2021

Common psychotic disorders and their treatment are reviewed in this chapter. The prevalence of schizophrenia is approximately 1%, a figure strikingly similar across countries and cultures. Mean age at onset for men is typically the early 20s, but for women, it is the late 20s. Schizophrenia only rarely remits entirely and is most often a chronic, disabling disorder characterized by exacerbations and partial remissions. It is associated with profound financial costs in terms of long-term needs for all aspects of functioning, including housing, medication, and medical care.
Impaired Consciousness and Coma
Authors: Hawkes Maximiliano A. , Wijdicks Eelco F. M.
Published: November 2021

The diagnosis of impaired consciousness or coma requires a rapid but thorough evaluation. Although impaired consciousness has many causes, clues can be gleaned from history and examination factors to deduce potential causes. Ancillary tests, including brain imaging and laboratory studies, may further aid in the diagnosis of impaired consciousness. Coma has various gradations. When all brain and brainstem functions cease and a known, irreversible brain injury is responsible, the condition is referred to as brain death.
Acute Spinal Cord Compression, Spinal Cord Trauma, and Peripheral Neural Injury
Authors: Marcellino Christopher R. , Wijdicks Eelco F. M.
Published: November 2021

Acute spinal cord compression with myelopathy is a neurologic emergency. Recognition of spinal cord compression, timely imaging, and treatment are important to restore and preserve neurologic function. This chapter reviews the causes and clinical approach to spinal cord compression. Traumatic and nontraumatic causes of spinal cord compression are addressed together because of their overlapping symptoms and management. The chapter concludes with a brief discussion of peripheral nerve injury.
Neuromuscular Disease in the Neuroscience Intensive Care Unit
Authors: Hawkes Maximiliano A. , Wijdicks Eelco F. M.
Published: November 2021

Neurologists may meet patients with neuromuscular disease and subsequent respiratory failure in the inpatient setting. Common clinical conditions include Guillain-Barré syndrome (GBS) and myasthenia gravis (MG). Recognition of impending respiratory failure for such patients is of great importance. This chapter describes general features of neuromuscular weakness and neuromuscular respiratory failure. In addition, it reviews the clinically important aspects of GBS, MG, and botulism. Finally, the chapter outlines the clinical symptoms, diagnosis, and treatment of critical illness polyneuropathy, a commonly encountered condition in the medical intensive care unit.
Diagnosis of Multiple Sclerosis
Authors: Tobin W. Oliver
Published: November 2021

Multiple sclerosis is the most common idiopathic inflammatory demyelinating disease of the central nervous system (CNS), with a prevalence of 1 in 500 to 1 in 2,000 people, depending on geography and various other factors. Idiopathic inflammatory demyelinating diseases are a group of related disorders that include acute disseminated encephalomyelitis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein–immunoglobulin G–associated CNS demyelinating disease.
Atypical Parkinsonian Syndromes
Authors: Chiu Shannon Y. , Cutsforth-Gregory Jeremy K.
Published: November 2021

The cardinal characteristics of parkinsonism are represented in the mnemonic TRAP: tremor at rest, rigidity, akinesia and bradykinesia, and postural instability. The parkinsonian phenotype encompasses a broad range of clinical and pathologic disorders; the most common (about 55% of cases) is idiopathic (sporadic) Parkinson disease. Rapid disease progression, poor initial response to dopaminergic therapy, or the early presence of certain other signs may suggest an atypical parkinsonian syndrome, sometimes called parkinsonism-plus syndrome.
Hyperkinetic Movement Disorders: Tremor and Myoclonus
Authors: Ali Farwa , Cutsforth-Gregory Jeremy K.
Published: November 2021

Hyperkinetic movement disorders are characterized by excess movement. Tremor and myoclonus are the most common hyperkinetic movement disorders and signify various possible underlying causes or diagnoses. Tremor is an involuntary, rhythmic, oscillatory movement of a body part. It can be distinguished from myoclonus by its regular frequency and from chorea by its stereotyped nature. The subtypes of tremor vary in frequency, conditions of activation and relief, and associated signs and symptoms. Tremor can be primary, being the only manifestation of a condition, or secondary, being symptomatic of a metabolic state or other underlying disease.
Hyperkinetic Movement Disorders: Chorea, Tic, and Dystonia
Authors: Coon Elizabeth A.
Published: November 2021

Hyperkinetic movement disorders are characterized by an excess of movement. This chapter outlines the classification, causes, and treatment of chorea, tic disorders, and dystonia. The term chorea refers to dancelike irregular, arrhythmic, rapid, involuntary movements that appear to flow between muscle groups. Athetosis, a slower and twisting dystonialike movement, may be superimposed with chorea, leading to choreoathetosis. Ballism is a form of high-amplitude and proximal chorea that has the appearance of flailing movement.
Childhood Movement Disorders
Authors: Youssef Paul E. , Mack Kenneth J.
Published: November 2021

The phenomenology and classification of movement disorders are similar for adults and children, but the causes and approach are distinct. In children, hyperkinetic disorders are more common than hypokinetic disorders. Furthermore, some disorders are present exclusively in infants and children; others may begin in childhood and persist into adulthood. This chapter focuses primarily on movement disorders that begin in childhood. Disorders that occur in children or adults without a specific predilection are covered in individual movement disorders sections.
Frontotemporal Dementias
Authors: Townley Ryan , Botha Hugo
Published: November 2021

Frontotemporal dementia (FTD) is a clinically and pathologically heterogeneous group of disorders caused by progressive degeneration of the frontal and temporal lobes. Frontal lobe functions include behavioral and personality control, executive function, and verbal expression. The temporal lobe is associated with behavior and language perception. Thus, the common clinical characterization of FTD is progressive changes in personality and behavior in addition to deficits in executive and language functions. Memory problems are typically not prominent during the early stage of illness.
Parkinsonism and Related Dementias
Authors: Savica Rodolfo , Turcano Pierpaolo , Boeve Bradley F.
Published: November 2021

The differential diagnosis for dementia is wide. A slowly progressive course for parkinsonism suggests a degenerative cause and helps to narrow the differential diagnosis considerably. In patients with dementia in combination with parkinsonism (often collectively termed the parkinsonism-related dementias), the 4 most common neurodegenerative entities are 1) Lewy body dementias (which include dementia with Lewy bodies and Parkinson disease with dementia); 2) corticobasal syndrome or corticobasal degeneration; 3) Richardson syndrome or progressive supranuclear palsy; and 4) frontotemporal dementia with parkinsonism.
Classification of Epilepsy
Authors: Khattak Jamal F. , Burkholder David B.
Published: November 2021

An understanding of the definitions, classification, and key characteristics of seizures and epilepsy is vital in the initial approach to a patient presenting with seizures. Classifying seizures appropriately helps narrow the differential diagnosis and guide further testing, treatment, and prognosis. This chapter reviews the basic definitions and classifications of seizures and epilepsy and summarizes select epilepsy syndromes. A seizure is a transient occurrence of signs or symptoms due to abnormal, excessive, or synchronous neuronal activity in the brain.
Evaluation of Seizures and Seizurelike Events
Authors: Parsons Angela M. , Drazkowski Joseph F.
Published: November 2021

Correctly diagnosing seizures and seizurelike events is important for numerous reasons, including safety issues, social consequences, and therapy. Patients with transient neurologic events of unknown cause are commonly admitted to hospitals, and an estimated 10% of the people in the United States have a seizure in their lifetime. These facts highlight the importance of diagnostic accuracy. History taking is imperfect, but it is still a cornerstone in making the proper diagnosis of transient neurologic events. Focused, supporting diagnostic tests may add accuracy in arriving at the proper diagnosis, but even with a good history, diagnostic testing, and physical examination findings, the diagnosis may be inaccurate. Self-reports of seizure frequency are notoriously inaccurate and often miss more than 50% of focal-onset seizures, especially if the seizures begin in the dominant hemisphere (largely because the effects of the event cause an altered level of consciousness).