Neurosurgical vignettes in question and answer format provide robust prep for the ABNS oral exam! Neurosurgery Case Review: Questions and Answers, 2nd Edition by Remi Nader, Abdulrahman Sabbagh, ...Samer Elbabaa, Hosam Al-Jehani, Jaime Gasco, and Cristian Gragnaniello provides a robust study guide for the American Board Neurological Surgery and the Royal College of Physicians and Surgeons of Canada oral board examinations. The second edition expands on the highly successful first edition, presenting 148 cases commonly encountered by neurosurgeons in clinical practice. The cases are broadly divided into seven sections--tumor, vascular intracranial pathology, trauma, pediatric, functional, spine, and peripheral nerves. The chapters are arranged in a manner that mirrors the oral board exam. Each case includes a brief clinical scenario followed by questions on presentation, diagnosis, imaging, management, surgical detail, complications, and outcome. The presented information is backed by the latest available evidence-based references and data. Key Features: * Contributions from internationally renowned neurosurgical educators * Detailed answers enhance readers' knowledge and provide guidance on how to respond to questions asked in the oral board exams * More than 750 high-quality images, many in full color, ensure visual understanding of key concepts * Suggested readings at the end of cases offer additional study resources This is an indispensable, one-stop resource for neurosurgical residents and fellows prepping for the ABNS and Royal College oral board examinations. Neurosurgeons studying for recertification will also find this book an invaluable reference for rapid review.
The power conversion efficiency of solar cells based on copper (I) oxide (Cu2O) is enhanced by atomic layer deposition of a thin gallium oxide (Ga2O3) layer. By improving band‐alignment and ...passivating interface defects, the device exhibits an open‐circuit voltage of 1.20 V and an efficiency of 3.97%, showing potential of over 7% efficiency.
Abstract
We present high-resolution high-sensitivity observations of the Class 0 protostar RCrA IRS5N as part of the Atacama Large Milimeter/submilimeter Array large program Early Planet Formation in ...Embedded Disks. The 1.3 mm continuum emission reveals a flattened continuum structure around IRS5N, consistent with a protostellar disk in the early phases of evolution. The continuum emission appears smooth and shows no substructures. However, a brightness asymmetry is observed along the minor axis of the disk, suggesting that the disk is optically and geometrically thick. We estimate the disk mass to be between 0.007 and 0.02
M
⊙
. Furthermore, molecular emission has been detected from various species, including C
18
O (2–1),
12
CO (2–1),
13
CO (2–1), and H
2
CO (3
0,3
− 2
0,2
, 3
2,1
− 2
2,0
, and 3
2,2
− 2
2,1
). By conducting a position–velocity analysis of the C
18
O (2–1) emission, we find that the disk of IRS5N exhibits characteristics consistent with Keplerian rotation around a central protostar with a mass of approximately 0.3
M
⊙
. Additionally, we observe dust continuum emission from the nearby binary source IRS5a/b. The emission in
12
CO toward IRS5a/b seems to emanate from IRS5b and flow into IRS5a, suggesting material transport between their mutual orbits. The lack of a detected outflow and large-scale negatives in
12
CO observed toward IRS5N suggests that much of the flux from IRS5N is being resolved out. Using a 1D radiative transfer model, we infer the mass of the envelope surrounding IRS5N to be ∼1.2
M
⊙
. Due to this substantial surrounding envelope, the central IRS5N protostar is expected to be significantly more massive in the future.
Abstract
We present the four-year survey results of monthly submillimeter monitoring of eight nearby (<500 pc) star-forming regions by the JCMT Transient Survey. We apply the Lomb–Scargle Periodogram ...technique to search for and characterize variability on 295 submillimeter peaks brighter than 0.14 Jy beam
−1
, including 22 disk sources (Class II), 83 protostars (Class 0/I), and 190 starless sources. We uncover 18 secular variables, all of them protostars. No single-epoch burst or drop events and no inherently stochastic sources are observed. We classify the secular variables by their timescales into three groups: Periodic, Curved, and Linear. For the Curved and Periodic cases, the detectable fractional amplitude, with respect to mean peak brightness, is ∼4% for sources brighter than ∼0.5 Jy beam
−1
. Limiting our sample to only these bright sources, the observed variable fraction is 37% (16 out of 43). Considering source evolution, we find a similar fraction of bright variables for both Class 0 and Class I. Using an empirically motivated conversion from submillimeter variability to variation in mass accretion rate, six sources (7% of our full sample) are predicted to have years-long accretion events during which the excess mass accreted reaches more than 40% above the total quiescently accreted mass: two previously known eruptive Class I sources, V1647 Ori and EC 53 (V371 Ser), and four Class 0 sources, HOPS 356, HOPS 373, HOPS 383, and West 40. Considering the full protostellar ensemble, the importance of episodic accretion on few years timescale is negligible—only a few percent of the assembled mass. However, given that this accretion is dominated by events on the order of the observing time window, it remains uncertain as to whether the importance of episodic events will continue to rise with decades-long monitoring.
Abstract We performed radiative transfer calculations and observing simulations to reproduce the 1.3 mm dust-continuum and C 18 O (2–1) images in the Class I protostar R CrA IRS7B-a, observed with ...the ALMA Large Program “Early Planet Formation in Embedded Disks (eDisk).” We found that a dust disk model passively heated by the central protostar cannot reproduce the observed peak brightness temperature of the 1.3 mm continuum emission (∼195 K), regardless of the assumptions about the dust opacity. Our calculation suggests that viscous accretion heating in the disk is required to reproduce the observed high brightness temperature. The observed intensity profile of the 1.3 mm dust-continuum emission along the disk minor axis is skewed toward the far side of the disk. Our modeling reveals that this asymmetric intensity distribution requires flaring of the dust along the disk vertical direction with the scale height following h / r ∼ r 0.3 as a function of radius. These results are in sharp contrast to those of Class II disks, which show geometrically flat dust distributions and lower dust temperatures. From our modeling of the C 18 O (2–1) emission, the outermost radius of the gas disk is estimated to be ∼80 au, which is larger than that of the dust disk (∼62 au), to reproduce the observed distribution of the C 18 O (2–1) emission in IRS 7B-a. Our modeling unveils a hot and thick dust disk plus a larger gas disk around one of the eDisk targets, which could be applicable to other protostellar sources in contrast to more evolved sources.
Abstract
We present high-resolution Karl G. Jansky Very Large Array (VLA) observations of the protostar L1527 IRS at 7 mm, 1.3 cm, and 2 cm wavelengths. We detect the edge-on dust disk at all three ...wavelengths and find that it is asymmetric, with the southern side of the disk brighter than the northern side. We confirm this asymmetry through analytic modeling and also find that the disk is flared at 7 mm. We test the data against models including gap features in the intensity profile, and though we cannot rule such models out, they do not provide a statistically significant improvement in the quality of fit to the data. From these fits, we can, however, place constraints on allowed properties of any gaps that could be present in the true, underlying intensity profile. The physical nature of the asymmetry is difficult to associate with physical features owing to the edge-on nature of the disk, but it could be related to spiral arms or asymmetries seen in other imaging of more face-on disks.
Abstract
We present the first results from the Early Planet Formation in Embedded Disks Atacama Large Millimeter/submillimeter Array Large Program toward Oph IRS43, a binary system of solar mass ...protostars. The 1.3 mm dust continuum observations resolve a compact disk, ∼6 au radius, around the northern component and show that the disk around the southern component is even smaller, ≲3 au. CO,
13
CO, and C
18
O maps reveal a large cavity in a low-mass envelope that shows kinematic signatures of rotation and infall extending out to ∼2000 au. An expanding CO bubble centered on the extrapolated location of the source ∼130 yr ago suggests a recent outburst. Despite the small size of the disks, the overall picture is of a remarkably large and dynamically active region.
MicroRNAs are important negative regulators of protein-coding gene expression and have been studied intensively over the past years. Several measurement platforms have been developed to determine ...relative miRNA abundance in biological samples using different technologies such as small RNA sequencing, reverse transcription-quantitative PCR (RT-qPCR) and (microarray) hybridization. In this study, we systematically compared 12 commercially available platforms for analysis of microRNA expression. We measured an identical set of 20 standardized positive and negative control samples, including human universal reference RNA, human brain RNA and titrations thereof, human serum samples and synthetic spikes from microRNA family members with varying homology. We developed robust quality metrics to objectively assess platform performance in terms of reproducibility, sensitivity, accuracy, specificity and concordance of differential expression. The results indicate that each method has its strengths and weaknesses, which help to guide informed selection of a quantitative microRNA gene expression platform for particular study goals.
Solar cells are produced by atomic layer deposition (ALD) of n‐type amorphous zinc‐tin‐oxide buffer layers on electrochemically deposited p‐type cuprous oxide, Cu2O, absorber layers. The diethylzinc ...precursor in the ALD process reduces Cu2+‐related defects at the heterojunction interface, improving the solar‐cell open‐circuit voltage. An NREL‐certified power conversion efficiency of 2.85% is reported.
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