scholarly journals Discovering the forbidden Raman modes at the edges of layered materials

2018 ◽  
Vol 4 (12) ◽  
pp. eaau6252 ◽  
Author(s):  
Yao Guo ◽  
Weixuan Zhang ◽  
Hanchun Wu ◽  
Junfeng Han ◽  
Yongliang Zhang ◽  
...  

The edges of layered materials have unique properties that substantially differ from the body regions. In this work, we perform a systematic Raman study of the edges of various layered materials (MoS2, WS2, WSe2, PtS2, and black phosphorus). The Raman spectra of the edges feature newly observed forbidden Raman modes, which are originally undetectable from the body region. By selecting the edge type and the polarization directions of the incident and scattered light, all forbidden Raman modes are distinctly detected. Optical simulations show that the edges of layered materials drastically distort the electromagnetic fields of both the incident and scattered light, so that the light interacts with the edges in a distinct way, which differs from its interactions with the body regions.

2012 ◽  
Vol 53 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Owen D Terreblanche ◽  
Savvas Andronikou ◽  
Linda T Hlabangana ◽  
Taryn Brown ◽  
Pieter E Boshoff

Background There is a heavy reliance on registrars for after-hours CT reporting with a resultant unavoidable error rate. Purpose To determine the after-hours CT reporting error rate by radiology registrars and influencing factors on this error rate. Material and Methods A 2-month prospective study was undertaken at two tertiary, level 1 trauma centers in Johannesburg, South Africa. Provisional CT reports issued by the registrar on call were reviewed by a qualified radiologist the following morning and information relating to the number, time and type of reporting errors made as well as the body region scanned, indication for the scan, year of training of the registrar, and workload during the call were recorded and analyzed. Results A total of 1477 CT scans were performed with an overall error rate of 17.1% and a major error rate of 7.7%. The error rate for 2nd, 3rd, and 4th year registrars was 19.4%, 15.1%, and 14.5%, respectively. A significant difference was found between the error rate in reporting trauma scans (15.8%) compared to non-trauma scans (19.2%) although the difference between emergency scans (16.9%) and elective scans (22.6%) was found to be not significant, a finding likely due to the low number of elective scans performed. Abdominopelvic scans elicited the highest number of errors (33.9%) compared to the other body regions such as head (16.5%) and cervical, thoracic, or lumbar spine (11.7%). Increasing workload resulted in a significant increase in error rate when analyzed with a generalized linear model. There was also a significant difference noted in the time of scan groups which we attributed to a workload effect. Missed findings were the most frequent errors seen (57.3%). Conclusion We found an increasing error rate associated with increasing workload and marked increase in errors with the reporting of abdominopelvic scans. There was a decrease in the error rate when looking an increasing year of training although this there was only found to be significant difference between the 2nd and 3rd year registrars.


Author(s):  
Susan Kotowski ◽  
Kermit Davis ◽  
Michael Jorgensen

As job rotation has become a widely used intervention strategy for the prevention of a wide variety of musculoskeletal disorders, there is a need for the development of assessment techniques that take into account the complexities of multiple body region stressors. The current study investigates the repeatability of a video-based analysis method that combines the exposure measure of four body regions: neck, shoulder, low back, and hand/wrist. Twelve analysts completed the assessment twice for 15 different job rotation schemes. The repeatability was found to be strong (ICC > 0.53) in many of the body regions when individual jobs were evaluated with minimal decrease in repeatability when the entire rotation scheme was considered. Overall, the video-based method provides a potential quick and easy method that will allow for the versatile evaluation needed for practitioners when quantifying exposure for job rotation schemes.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Nadezhda Rimskaya-Korsakova ◽  
Nadezda Karaseva ◽  
Timofei Pimenov ◽  
Hans Tore Rapp ◽  
Eve Southward ◽  
...  

Abstract Background Many annelids, including well-studied species such as Platynereis, show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within heteronomous species we describe the myogenesis and mesodermal delineation of segments in Siboglinum fiordicum during development. Results Employing confocal and transmission electron microscopy we show that the somatic longitudinal musculature consists of four separate strands, among which ventrolateral one is the most prominent and is proposed to drive the search movements of the head of the late metatrochophore. The somatic circular musculature lies inside the longitudinal musculature and is predominantly developed at the anterior end of the competent larva to support the burrowing behaviour. Our application of transmission electron microscopy allows us to describe the developmental order of the non-muscular septa. The first septum to form is supported by thick bundles of longitudinal muscles and separates the body into an anterior and a posterior region. The second group of septa to develop further divides the posterior body region (opisthosoma) and is supported by developing circular muscles. At the late larval stage, a septum reinforced by circular muscles divides the anterior body region into a forepart and a trunk segment. The remaining septa and their circular muscles form one by one at the very posterior end of the opisthosoma. Conclusions The heteronomous Siboglinum lacks the strict anterior to posterior sequence of segment formation as it is found in the most studied annelid species. Instead, the first septum divides the body into two body regions before segments are laid down in first the posterior opisthosoma and then in the anterior body, respectively. Similar patterns of segment formation are described for the heteronomous chaetopterid Chaetopterus variopedatus and serpulid Hydroides elegans and may represent an adaptation of these annelids to the settlement and transition to the sedentarian-tubiculous mode of life.


2021 ◽  
Author(s):  
Nadezhda Nikolaevna Rimskaya-Korsakova ◽  
Nadezda Karaseva ◽  
Timofei Pimenov ◽  
Hans Tore Rapp ◽  
Eve Southward ◽  
...  

Abstract BackgroundMany annelids, including well-studied species such as Platynereis, show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within heteronomous species we describe the myogenesis and mesodermal delineation of segments in Siboglinum fiordicum during development. ResultsEmploying confocal and transmission electron microscopy we show that the somatic circular musculature lies inside the longitudinal musculature and is predominantly developed at the anterior end of the larva. The longitudinal musculature consists of four separate strands at the ventral, dorsal, and ventrolateral body sides. Posteriorly, the longitudinal strands form a continuous layer. Our application of transmission electron microscopy allows us to describe the developmental order of the non-muscular septa. The first septum to form is supported by thick bundles of longitudinal muscles and separates the body into an anterior and a posterior region. The second group of septa to develop further divides the posterior body region (opisthosoma) and is supported by developing circular muscles. At the late larval stage, a septum reinforced by circular muscles divides the anterior body region into a forepart and a trunk segment. The remaining septa and their circular muscles form one by one at the very posterior end of the opisthosoma. Functionally, the prominent ventrolateral longitudinal muscles in the larva are proposed to drive the search movements of the head, while the anterior circular muscles and the posterior continuous layers of longitudinal muscles support the burrowing behaviour of the larva.ConclusionsThe heteronomous Siboglinum lacks the strict anterior to posterior sequence of segment formation as it is found in the most studied annelid species. Instead, the first septum divides the body into two body regions, before segments are layed down in first the posterior opisthosoma and then in the anterior body, respectively. Similar pattern of segment formation is described for the heteronomous chaetopterid Chaetopterus variopedatus and may represent an ancestral segmentation process in Annelida.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Federico Coccolini ◽  
Mario Improta ◽  
Edoardo Picetti ◽  
Luigi Branca Vergano ◽  
Fausto Catena ◽  
...  

AbstractCompartment syndrome can occur in many body regions and may range from homeostasis asymptomatic alterations to severe, life-threatening conditions. Surgical intervention to decompress affected organs or area of the body is often the only effective treatment, although evidences to assess the best timing of intervention are lacking. Present paper systematically reviewed the literature stratifying timings according to the compartmental syndromes which may beneficiate from immediate, early, delayed, or prophylactic surgical decompression. Timing of decompression have been stratified into four categories: (1) immediate decompression for those compartmental syndromes whose missed therapy would rapidly lead to patient death or extreme disability, (2) early decompression with the time burden of 3–12 h and in any case before clinical signs of irreversible deterioration, (3) delayed decompression identified with decompression performed after 12 h or after signs of clinical deterioration has occurred, and (4) prophylactic decompression in those situations where high incidence of compartment syndrome is expected after a specific causative event.


1988 ◽  
Vol 59 (2) ◽  
pp. 299-316 ◽  
Author(s):  
F. A. Lenz ◽  
J. O. Dostrovsky ◽  
R. R. Tasker ◽  
K. Yamashiro ◽  
H. C. Kwan ◽  
...  

1. We have studied the functional and somatotopic properties of 531 single mechanoreceptive thalamic neurons in humans undergoing stereotactic surgery for the control of movement disorders and pain. The majority of these somatosensory cells had small receptive fields (RFs) and were activated in a reproducible manner by mechanical stimuli applied to the skin or deep tissues. These neurons, which we termed "lemniscal," could be further classified into those responding to stimulation of cutaneous (76% of lemniscal sensory cells) or deep (24%) structures. 2. The incidence of neurons having cutaneous or mucosal RFs in the perioral region, thumb, and fingers (66%) was much higher than that of neurons having RFs elsewhere on the body. Most of the deep cells were activated by movements of and/or mechanical stimuli delivered to muscles or tendons controlling the elbow, wrist, and fingers. 3. Sequences of cells spanning several millimeters in the parasagittal plane often exhibited overlapping RFs. However, RFs changed markedly for cells separated by the same distances in the mediolateral direction. This suggests that the cutaneous somatotopic representation of each region of the body is organized into relatively thin sheets of cells oriented in the parasagittal plane. 4. By comparing neuronal RFs in different parasagittal planes in thalamus of individual patients we have identified a mediolateral representation of body surface following the sequence from: intraoral structures, face, thumb through fifth finger to palm, with forearm and leg laterally. 5. Along many trajectories in the parasagittal plane the sequence of cells with overlapping RFs was interrupted by another sequence of cells with RFs corresponding to a different body region. The RFs of the intervening sequence characteristically represented body regions known to be located more medially in thalamus (see 3 above). These findings could be explained if the lamellae postulated above were laterally convex. 6. Cells responding to deep stimulation (deep cells) could be further classified into those responding to joint movement (63%), deep pressure (15%), or both (22%). Deep cells were found usually at the anterior-dorsal border and sometimes at the posterior border of the region containing cells responding to cutaneous stimuli. Although there was some overlap in the RFs, deep cells representing wrist were found medial to those representing elbow, and both of these were found medial to cells representing leg.(ABSTRACT TRUNCATED AT 400 WORDS)


2015 ◽  
Vol 8 (2) ◽  
pp. 237-282 ◽  
Author(s):  
JOSITA C. MAOUENE ◽  
NITYA SETHURAMAN ◽  
MOUNIR M. MAOUENE ◽  
SANGO OTIENO

abstractPrior work on argument structure development has shown connections between abstract verb meaning and argument structure; neuroimaging and behavioral studies have shown connections between verb meaning and body effectors. Here we examine the contingencies between verbs, their most likely body region pairing, and argument structure. We ask whether the verbs used in six common syntactic frames are specifically linked to one of three main regions of the body:head, arm, leg.The speech of 20-month-olds (N= 67), 28-month-olds (N= 27), and their mothers (N= 54) (CHILDES: MacWhinney, 2000) was examined for the use of early-learned verbs (MCDI: Fenson, Dale, Reznick, Bates, Thal, & Pethick, 1994). In total, 89 verb types in 3321 utterances were coded for their associations with thehead, arm, andlegbody regions (associations taken from Maouene, Hidaka, & Smith, 2008). Significant non-random relations are found both overall and for each age group in analyses using multiple chi-square tests of independence and goodness-of-fit. These results are discussed in terms of their relevance for both argument structure development and embodied cognition, as evidence supporting a developmental path that has not been previously examined, in which the infant can use early and concrete perception-action information to learn later abstract syntactic achievements.


Author(s):  
Issahaku Shirazu ◽  
Y. B. Mensah ◽  
Cyril Schandorf ◽  
S. Y. Mensah

In x-ray computed tomography (CT), the most common parameters used to estimate and minimize patient dose is the CT dose index (CTDI) and DLP. The aim of the study is to serve as a reference values during QC for the purposes of QA in other to reduce doses to patients undergoing CT scan using the age and weight specific CT protocol set out by various manufacturers and other international organizations. This was done by recording CTDI and DLP values to patients within a specific age and weight bracket during scanning on the scanning console and on image data. The effective dose values represents an averaged dose to patients, hence the measurements are only an approximation of the dose to patient, these doses may be overestimated or underestimated by a factor of two or more with CTDI and DLP values in comparison with point dose values. CTDI and DLP were used to evaluate CT scanner output and estimating patient regional effective dose in this study. The estimated head CTDI scans base on the various protocol from all the hospitals increase from approximately 2.8mGy in newborns to approximately 8.7mGy in adults. Resulting with a variation of effective dose from 0.67mSv in new born to approximately 1.03mSv in oversize adults. Neonates head CT effective doses are higher than those for the normal adults except oversize adults as shown in Table 4.4. The chest, abdominal and pelvis CTDI values increases from 2.8, 2.5 and 2.7 mGy in neonates of approximately 3.4kg of weight to 19.84, 7.78 and 11.33mGy in adults of approximately 72.5kg of weight respectively. The estimated effective doses for neonates undergoing chest, abdomen and pelvis of the body CT were 0.83, 6.7, 4.87 and 5.52mSv, whereas those for normal-sized adults are 13.31, 4.61 and 5.34mSv respectively. Chest oversize patients’ examinations exceeded the recommended dose levels of 19.84mSv whiles the head, abdomen and pelvis were: 1.03, 7.16 and 5.98mSv respectively. It was concluded that patient body doses could be substantially minimized through careful selection of scanning parameters based on clinical indications of study, patient age, body size, and body region being examined. Additional dose reduction to superficial body regions would require the use of shielding materials.


2022 ◽  
Vol 355 ◽  
pp. 03022
Author(s):  
Linghao Du ◽  
Rui Wang ◽  
Lin Cui ◽  
Xiaolin Min ◽  
Qingyi Liu ◽  
...  

Automatic body region localization in medical three-dimensional (3D)-CT images is a critical step of computerized body-wide Automatic Anatomy Recognition (AAR) system, which can be applied for radiotherapy planning and interest slices retrieving. Currently, the complex internal structure of human body and time consuming computation are the main challenges for the localization. Therefore, this paper introduces and improves the YOLO-v3 model into the body region localization for these problems. First, seven categories of body regions in a CT volume image I are defined based on the modification version of our previous work. Second, an improved YOLO-v3 model is trained to classify each axial slice into one of the seven categories. Then, the effectiveness of the proposed method is evaluated on 3D-CT images that collected from 220 subjects. The experimental results demonstrate that the slice localizing error is less than 3 NoS (Number of slices), which is competitive to the state-of-the-art methods. Beyond this, our method is simple and computationally efficient owing to its less training time, and the average computational time for localizing a volume CT images is about 3 second, which shows potential for a further application.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
František Vejmělka ◽  
Jan Okrouhlík ◽  
Matěj Lövy ◽  
Gabriel Šaffa ◽  
Eviatar Nevo ◽  
...  

AbstractThe relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.


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