High-resolution Studies Research Articles

NIMG-02. DEVELOPING A RADIOMIC HIERARCHICAL GAUSSIAN PROCESS BOOSTING MODEL TO PREDICT PRIMARY TUMOR ORIGIN FROM MULTICENTRIC LONGITUDINAL MRI DATA OF BRAIN METASTASES

Abstract Focal neurologic deficits due to brain metastases might be the initial presentation in patients with cancer. Common approaches to investigate the occult primary malignancy include a whole-body PET-CT, whole-body MRI, studying tumor markers, or histopathological examination. Most of these modalities are expensive, time-consuming, invasive, and delay treatment. The field of radiomics leverages quantitative features extracted from images to improve the decision-making process in clinical practices. Although not easily understandable, these features are proxies for the tumor’s shape, contour, texture, and intensity patterns. They can help understand tumor heterogeneity, predict tumor behavior, and assess treatment response. We propose a robust radiomic workflow using longitudinal MRI data from 914 high-resolution imaging studies from 12 different centers (Ocaña-Tienda et al. (2023), Ramakrishnan et al. (2023), Wang et al. (2023)) to predict the origin of brain metastases from brain MRI scans. After using ensemble feature selection methods, we trained three fixed-effects and one mixed-effects multiclass classification model to account for longitudinal data. Fixed-effects logistic regression and support vector kernel models performed the worst (AUC 0.74 and 0.75, respectively), while the random forest performed better (AUC 0.97). The mixed-effects hierarchical Gaussian process boosting (GPBoost) model performed the best with an accuracy of 85.8%, precision of 85.4%, sensitivity of 85.8%, specificity of 95.7%, and an AUC of 0.98. In one-versus-rest classification, the GPBoost model identified the primary tumor as melanoma with the highest accuracy (96.1%) and non-small cell lung cancer with the lowest accuracy (89.0%). Developing such models holds great promise in reducing patient and institutional costs, improving time to effective treatment, and enhancing overall survival rates through personalized therapy approaches. In the future, we hope that incorporating newer patient data and refining the model to improve external validity would enable more accurate and generalizable predictions, leading to better clinical outcomes across diverse populations.

INNV-02. BRAINMETS: A CLINICIAN-FRIENDLY SOFTWARE TO MANUALLY SEGMENT BRAIN METASTASES AND DETECT PRIMARY TUMOR ORIGIN USING DEEP LEARNING

Abstract Estimates suggest that around 20%-40% of cancer patients are affected by brain metastases. A subset of these patients first present with central nervous system manifestations with an unknown primary. The issue then arises regarding which region of the body should be imaged, if not the entire body, exposing the patient to more radiation. To address this issue, streamline workflows, and save precious time, we developed a software clinicians can use to identify primary tumor locus. “BrainMets” is a user-friendly software that handles a DICOM input, allows the user to segment the region(s) of interest manually, and uses a deep learning model to predict the most likely tumor origin. The model is a mixed-effects neural network pre-trained on radiomic features from open-source data by Ocaña-Tienda et al. (2023) using 637 high-resolution imaging studies from 10 different medical centers with an accuracy of 90.5%, precision of 92.7%, recall of 87.8%, and F1 score of 90.2%. The software leverages the open-source software 3D-Slicer to help segment regions of interest, extract radiomic features, and make predictions. It is built using Flask, a Python package for backend development. The frontend user interface is created using HTML/CSS and Bootstrap. The “BrainMets” software thus strives to enhance diagnostic workflow significantly, reduce appointment times for scans, and improve patient experience. Future enhancements include integrating more AI models, improving healthcare IT system compatibility, and updating datasets to boost predictive accuracy and generalizability. This tool sets a new standard in personalized medicine, optimizing treatment strategies for cancer patients with brain metastases. As adoption increases, it could substantially improve patient outcomes and reduce healthcare costs associated with misdiagnosis and overtreatment. Further research and development will focus on expanding its applicability across various types of cancers.

Impact of chlorine substitution on valence orbitals and ionization dynamics in 3-chloropyridine: Insights from high-resolution vacuum ultraviolet mass-analyzed threshold ionization study.

In this study, the effects of chlorine substitution on the valence orbitals and electronic states of 3-chloropyridine (3-CP) were investigated utilizing high-resolution vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy and computational methods. High-quality vibrational spectra were obtained from the VUV-MATI spectra of 3-CP isotopomers (35Cl and 37Cl), revealing high-quality vibrational spectra for the lowest cationic states. The adiabatic ionization energies (AIEs) of these isotopomers were accurately determined, providing detailed information about the electronic structure and ionization dynamics. Intense spectra peaks were linked with the D1 excited state of the 3-CP cation, with vibronic transitions in this state closely matching those predicted by Franck-Condon simulations. This provided insights into the cationic structure and the roles of the highest occupied molecular orbital (HOMO) and the HOMO-1. The HOMO was primarily a π orbital of the pyridine ring, while the HOMO-1 consisted of nonbonding orbitals. The AIEs suggested that meta-chlorine substitution stabilizes nonbonding orbitals less effectively than ortho substitution, indicating closely spaced electronic states in the 3-CP cation. Minor discrepancies in vibrational frequencies and intensities, particularly above 800cm-1, suggested the presence of vibronic coupling, warranting further investigation. Overall, this study provided a comprehensive understanding of the vibronic and ionization properties of 3-CP, emphasizing the influence of the position of the chlorine substitution on molecular orbitals and the value of advanced theoretical and experimental approaches for analyzing the vibrational spectra of complex molecules.

Deep north atlantic circulation strength: Glacial-interglacial variability over the last 400,000 years

Most of the high-resolution studies investigating the past variability of the deep North Atlantic circulation are focused on recent timescales, but little is known for periods older than the last glacial period. Based on magnetic, elemental and physical grain-size proxies of three pairs of sediment cores located South of Iceland, we reconstructed the past changes in grain-size and basaltic-derived grain concentration over the last 400 ka (1 ka = 1000 years). The source and grain-size proxies exhibit highly similar variations between the three sites, suggesting they are affected by the same regional process. Persistently lower concentrations and finer grain-sizes recorded in the southernmost and deeper site compared to the northern sites indicate a North to South gradient that is consistent with the southward transport of sediments from a northern basaltic source by a deep current. Therefore, we interpret changes recorded by the ensemble of proxies at the three sites as past variations in the ISOW intensity. These new results show persistent influence, over the entire 400 ka, of a southward deep-water flow in the subpolar North Atlantic, from 1800 to 2800 m water depth. The “off mode” of deep Atlantic circulation during Heinrich events suggested by many studies is therefore questioned. This study extends the previous observations made for the 20–65 ka period over the last 400 ka. Our results also show that the three studied sites are bathed by a deep-water mass formed in the Nordic Seas, during both glacial and interglacial periods, suggesting that the present-day convection areas were still active during glacial periods. Our ISOW intensity records are highly similar to those of deep-water ventilation. We propose that the strength of overflows in the North Atlantic regulates the volume of North Atlantic Deep Water (NADW) and its southward transport in the Atlantic basin. Therefore, the Southern source waters may only act as an opportunistic component of the deep Atlantic circulation, invading or retreating depending on the NADW strength.

Fully human monoclonal antibody targeting the cysteine-rich substrate-interacting region of ADAM17 on cancer cells

ADAM17 sheds EGFR/erbB ligands and triggers oncogenic pathways that lead to the progression of solid tumors. We targeted the ADAM17 disintegrin and cysteine rich domain region (D+C) to generate a panel of single-chain antibody fragments (scFvs) that selectively bind to the D or C domains of ADAM17, but not of ADAM10 or ADAM19. From the panel, we selected one scFv, referred to as C12, based on its high binding affinity towards the target, and re-formatted it to a full IgG for further studies. High-resolution cryo-electron microscopy studies documented that the mAb binds to the ADAM17 C-domain that in ADAM proteases, notably ADAM10 and ADAM17, is known to impart substrate-specificity. The C12 mAb significantly inhibited EGFR phosphorylation in cancer cell lines by hindering the cleavage of EGFR ligands tethered to the cell surface. This inhibition provides a mechanism for potential anti-tumor effects, and indeed C12 diminished the viability of a variety of EGFR-expressing cancer cell lines. Cell-based ELISA studies revealed that C12 preferentially bound to activated ADAM17 present on tumor cells, as compared to the autoinhibited ADAM17 that is the predominant form on HEK293 and other non-tumor cells. C12 also exhibited tumor growth inhibition in an ovarian cancer xenograft mouse model. Consistent with its selective tumor cell binding in vitro, radioimmuno PET (positron emission tomography) imaging with 89Zr-DFO-C12 in mouse xenograft models confirmed tumoral accumulation of the C12 mAb.

Benthic habitat mapping of the glass sponge (Vazella pourtalesii), and associated community composition on Sambro Bank, Scotian Shelf, Canada

Sponges have been identified as ecosystem engineers, providing habitat structure for many other benthic organisms, but are vulnerable to the impacts of bottom contact fishing. The Sambro Bank Sponge Conservation Area (SBSCA) protects a globally unique aggregation of the glass sponge (Vazella pourtalesii) off the east coast of Canada. Here, we present the first comprehensive, high-resolution mapping study of this site. Multispectral multibeam echosounder (MBES) mapping at three operating frequencies and benthic drop camera surveys were conducted at the SBSCA in 2022. Video data were analysed to quantify the abundance and location of V. pourtalesii and all associated benthic fauna and sediment characteristics. Using the MBES data as predictor variables, the study created a generalized linear mixed model of V. pourtalesii presence in the SBSCA, with 90.1% accuracy. Four seafloor benthoscape classes were identified from the video imagery, with statistically distinct benthic macrofaunal communities associated with each class. The study creates a baseline assessment of the current community composition and habitat characteristics of the site, which can be used for future ecological monitoring and management.

Gold Meets Selenium: Dual Activation of Selenium-Containing Propargyl Alcohols Towards the Synthesis of 2H-Chromenes and Mechanistic Insights.

Herein, we report the synthesis of seleno-substituted chromenes from selenoalkynes and phenols. In this cascade reaction, the applied gold catalyst not only functions as a π-acid, but also as a Lewis acid, enabling the propargylic substitution in the first step to connect the oxygen carbon bond. Under the optimal reaction condition a total of 26 chromenes were accessible by this modular access. During scale up experiments, the hydrolysis of the vinylselenium substructure to the corresponding chromenones was observed. By revisiting the electron-rich starting materials, four chromenones were produced following a one-pot reaction using a single gold catalyst. To better understand the interaction of gold and selenium, a series of nuclear magnetic resonance studies and high-resolution mass spectrometry studies were performed, which led to the proposal of a mechanism for this transformation.

Scanning Transmission Soft X-Ray Microscopy Probes Topical Drug Delivery of Rapamycin Facilitated by Microneedles.

Scanning Transmission X-ray microscopy (STXM) is a sensitive and selective probe for the penetration of rapamycin which is topically applied to human skin ex vivo and is facilitated by skin treatment with microneedles puncturing the skin. Inner-shell excitation serves as a selective probe for detecting rapamycin by changes in optical density as well as linear combination modeling using reference spectra of the most abundant species. The results indicate that mechanical damage induced by microneedles allows this drug to accumulate in the stratum corneum without reaching the viable skin layers. This is unlike intact skin which shows no drug penetration at all and underscores the mechanical impact of microneedle skin treatment. These results are compared to drug penetration profiles of other drugs highlighting the importance of skin barriers. High spatial resolution studies also indicate that the lipophilic drug rapamycin is observed in corneocytes. Attempts in data evaluation are reported to probe rapamycin also in the lipid layers between the corneocytes, which was not accomplished before. These results are compared to recent results on rapamycin uptake in skin where barrier impairment was induced by pre-treatment with the enzyme trypsin and drug formulations leading to occlusion.

Chronic ankle instability: a cadaveric anatomical and 3D high-resolution MRI study for surgical reconstruction procedures

ObjectivesTo quantitatively investigate the anatomy of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) for surgical reconstruction procedures in chronic ankle instability (CAI).Methods3D MRI was performed on five fresh-frozen cadaveric ankles using six different spatial resolutions (0.3 × 0.3 × 0.3 mm3, 0.45 × 0.45 × 0.45 mm3, 0.6 × 0.6 × 0.6 mm3, 0.75 × 0.75 × 0.75 mm3, 0.9 × 0.9 × 0.9 mm3, 1.05 × 1.05 × 1.05 mm3). After comparing the MRI results with cadaver dissection, a resolution of 0.45 × 0.45 × 0.45 mm³ was selected for bilateral ankles MRI on 24 volunteers. Classification of the ATFL and four distances of surgically relevant bony landmarkers were analyzed (distance 1 and 3, the fibular origin of the ATFL and CFL to the tip of fibula, respectively; distance 2, the talar insertion of the ATFL to the bare zone of talus; distance 4, the calcaneal insertion of the CFL to the peroneal tubercle).ResultsIn subjective evaluation, the interobserver ICC was 0.95 (95% confidence interval (CI): 0.94–0.97) between two readers. The spatial resolution of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 received highest subjective score on average and demonstrated highest consistency with autopsy measurements in objective evaluation. Measurements on the 48 volunteer ankles, distance 1 in type I and II were 12.65 ± 2.08 mm, 13.43 ± 2.06 mm (superior-banded in Type II) and 7.69 ± 2.56 mm (inferior-banded in Type II) (means ± SD), respectively. Distance 2 in type I and II were 10.90 ± 2.24 mm, 11.07 ± 2.66 mm (superior-banded in Type II), and 18.44 ± 3.28 mm (inferior-banded in Type II), respectively. Distance 3 and 4 were 4.71 ± 1.04 mm and 14.35 ± 2.22 mm, respectively.ConclusionWe demonstrated the feasibility of quantifying the distances between bony landmarkers for surgical reconstruction surgery in CAI using high-resolution 3D MRI.Critical relevance statementHigh-resolution 3D MRI examination may have a guiding effect on the preoperative evaluation of chronic ankle instability patients.Key PointsSpatial resolutions of 0.3 × 0.3 × 0.3 mm3 and 0.45 × 0.45 × 0.45 mm3 demonstrated highest consistency with autopsy measurements.The spatial resolution of 0.45 × 0.45 × 0.45 mm3 was conformed more to clinical needs.3D MRI can assist surgeons in developing preoperative plans for chronic ankle instability.Graphical

Achieving the 1D Atomic Chain Limit in Van der Waals Crystals.

Experiments with graphene have demonstrated that 2D van der Waals materials can be stable, robust, and efficiently manipulated at the level of individual atomic planes. However, the stability and manipulation of 1D van der Waals materials and individual atomic chains remains elusive. Here, the ability to exfoliate and process two representative van der Waals materials containing 1D motifs, namely MoI3 and Ta2Se8I, at the scale of individual atomic chains is demonstrated. High-resolution transmission electron microscopy and atomic force microscopy studies confirm the presence of stable individual atomic chains of MoI3 at room temperature. It is further shown that 1D van der Waals materials with low exfoliation energy, such as Ta2Se8I, can be processed with electron beams to achieve suspended individual atomic chains. Ab initio calculations corroborate the findings regarding the cleavage energies and the thermodynamic stability of individual atomic chains in these 1D van der Waals materials. These results demonstrate that the top-down approach in material processing can be extended to the scale of individual chains.

Engineering Boron Vacancy Defects in Boron Nitride Nanotubes.

Spin defects in hexagonal boron nitride (hBN) are emerging as promising platforms for quantum sensing applications. In particular, the negatively charged boron vacancy (VB-) centers have been engineered in bulk hBN and few-layer hBN flakes, and employed for sensing. Here, we investigate the engineering of VB- spin defects in boron nitride nanotubes (BNNTs). The generated spin defects are distributed along and around the BNNTs. Moreover, in contrast to hBN flakes, the spins in BNNTs exhibit a directional response relative to the direction of a surrounding magnetic field, which is consistent with the tubular geometry. The unique geometry of BNNTs allows for a more controlled and predictable placement of spin defects compared to bulk hBN, paving the way for innovative sensing applications with high spatial resolution and optomechanical studies of spin defects in hBN.

OML: an online multi-particle locating method for high-resolution single-event effects studies

OML: an online multi-particle locating method for high-resolution single-event effects studies

12441 Factors Affecting The Evaluation Of Adrenal Incidentalomas

Abstract Disclosure: A. Poloju: None. S.K. Pabich: None. S. Syed: None. A. Krueger: None. A. Chiu: None. Introduction: Adrenal incidentalomas are increasingly being detected, owing to the increasing number of high-resolution radiologic studies performed. While most of the nodules are non-functional, 10-15% are hormonally active and hence merit workup. We assessed the rates of, and factors associated with appropriate workup of these nodules. Methods: A retrospective analysis of CT chest and abdominal scans between Jan 1, 2021, and June 1, 2022, in adults ≥18 years at a single tertiary care center was performed. Reports were screened with key phrases to identify adrenal nodules. A chart review was conducted to confirm the reported nodule, obtain demographic data, obtain data on co-morbid conditions, and evaluate for biochemical and radiologic workup. Exclusion criteria included: patients deceased at the time of our review, previously diagnosed nodules, sub-centimeter lesions, and adrenal hemorrhage. Patients were categorized as being from high or low disadvantaged neighborhoods based on their Area Deprivation Index (ADI) score. ADI above the 50th percentile was categorized as more disadvantaged. Charleston Comorbidity Index (CCI), a 10-year survival predictor based on the presence of common diseases was abstracted. Patients with any biochemical workup were compared to patients with no workup. Bivariate analysis was performed using chi-squared and Student’s t-test analysis. A multivariate logistic regression was performed to evaluate factors associated with biochemical workup. Results: A total of 533 records were reviewed. After applying the above exclusion criteria, a total of 245 patients were included in our analysis. Baseline characteristics included: 58.7% female and 41.2% male. 67.3% had hypertension diagnosis, 22% had sleep apnea diagnosis, and 30.6% had diabetes diagnosis. 86% were White, 5.7% Black, 3.2% Hispanic, 3.2% Asian, and 1.6% Other. 71% of the patients had no biochemical workup, 18% had partial workup, and 11% had full workup. Factors associated with having either partial or full workup compared to no workup included female sex (OR 2.33, CI 1.23-4.41), internal medicine/family medicine provider ordering the scan compared to Emergency Department providers (OR 3.84, CI 1.61-9.14), and ADI scores below the 50th percentile (OR 1.98, CI 1.04-3.78). There was no statistically significant difference based on age, race, ethnicity, and CCI. There was no significant difference in the workup for hypercortisolism based on the presence of co-morbid conditions like diabetes, sleep apnea, and overweight/obesity. Conclusions: In our study population, the rates of guideline-based biochemical workup of adrenal incidentalomas were very low at 11%. Factors associated with having at least partial biochemical workup included less socioeconomic disadvantage, female sex, and studies ordered by primary care providers. Presentation: 6/3/2024

High-resolution observations of shallow-water acoustic propagation with distributed acoustic sensing.

Distributed acoustic sensing (DAS), converting fiber-optic cables into dense acoustic sensors, is a promising technology that offers a cost-effective and scalable solution for long-term, high-resolution studies in ocean acoustics. In this paper, the telecommunication cable of Martha's Vineyard Coastal Observatory (MVCO) is used to explore the feasibility of cable localization and shallow-water sound propagation with a mobile acoustic source. The MVCO DAS array records coherent, high-quality acoustic signals in the frequency band of 105-160 Hz, and a two-step inversion method is used to improve the location accuracy of DAS channels, reducing the location uncertainty to ∼2 m. The DAS array with refined channel positions enables the high-resolution observation of acoustic modal interference. Numerical simulations that reproduce the observed interference pattern suggest a compressional speed of 1750 m/s in the sediment, which is consistent with previous in situ geoacoustic measurements. These findings demonstrate the long-term potential of DAS for high-resolution ocean acoustic studies.

Exploring the binding mode of phenyl and vinyl boronic acids to human carbonic anhydrases

Boronic acids are an interesting but still poorly studied class of carbonic anhydrase inhibitors. Previous investigations proved that derivatives incorporating aromatic, arylalkyl, and arylalkenyl moieties are low micromolar to millimolar inhibitors for several α- and β-CAs involved in pathologic states.Here we report a high-resolution X-ray study on two classes of boronic acids (phenyl and vinyl) in complex with hCA II. Our results unambiguously clarify the binding mode of these molecules to the human carbonic anhydrase active site, which occurs through their tetrahedral anionic form, regardless of the nature of the organic scaffold. Data here presented contribute to the understanding of the inhibition mechanism of boronic acids that can be fruitfully used for the rational design of novel and effective isozyme-specific carbonic anhydrase inhibitors.

Geomorphic processes within the La Gomera-Tenerife Channel (Canary Islands): Decoding the interaction of bottom currents with seabed topography

The La Gomera-Tenerife Channel is a narrow passage between La Gomera and Tenerife Islands, i.e., two volcanic edifices of the Canary Archipelago (Atlantic Ocean). A geophysical study was conducted to identify the main geomorphic processes affecting the seabed and their interplay. In particular, submetric resolution bathymetric and side scan sonar backscatter data were collected in the southern sector of the Channel, down to 1200 m water depth. Their integrated analysis revealed a complex seabed morphology and a variety of morpho-sedimentary features, resulting from three main geomorphic processes: submarine volcanic activity, mass wasting (e.g., turbidity currents, small landslides and exotic blocks emplaced by a massive landslide event), and bottom currents activity. Bottom currents strongly reshaped the seabed into bedforms, confined drifts and moats. Although the flanks of volcanic islands are typically dominated by mass wasting and volcanic features, our results indicate that bottom current activity can be predominant in confined settings and around topographic features due to modification of flow patterns and enhancement of current flows.This study is the first to document volcanic, mass wasting and bottom current features within the La Gomera-Tenerife Channel. Furthermore, it provides insights on: i) morpho-sedimentary reconstructions of narrow passages between volcanic islands; ii) interplay among different geomorphic processes; iii) oceanographic reconstructions. The variety of geomorphic processes shaping the La Gomera-Tenerife Channel makes this area significant for high-resolution studies. Moreover, it provides new insights on poorly known processes, such as: the interaction of bottom currents with complex topography and bottom current morpho-dynamic in curved moats.

Effect of hiatal hernia and esophagogastric junction morphology on esophageal motility: Evidence from high-resolution manometry studies.

High-resolution Manometry (HRM) is the most sensitive and specific test available for clinical assessment of hiatal hernia (HH), a common condition defined as the separation between the Lower Esophageal Sphincter (LES) and crural diaphragm (CD). While the link between HH and Gastroesophageal Reflux Disease (GERD) is established, the potential association of HH with esophageal dysmotility, independently from GERD, is uncertain. This study aimed to analyze if HH, with or without GERD, can associate with esophageal motility disorders. Consecutive patients without previous esophageal surgery who underwent HRM between 2018 and 2022 were enrolled. All patients with symptoms suggestive of GERD underwent impedance-pH testing off-therapy. HH was defined as a separation >1 cm between LES and CD, and esophagogastric junction (EGJ) morphology was classified as: Type I, when there was no separation between LES and CD; Type II, in case of minimal separation (>1 and <3 cm); Type III, when ≥3 cm of separation was present. Demographic and clinical characteristics were collected at baseline, including Age, Gender, Alcohol-, Coffee- and Smoke-habits, GERD diagnosis and symptoms' duration. Two cohorts of patients, with and without HH, were retrospectively individuated, and their association with Ineffective Peristalsis, Hypercontractile Esophagus and Outflow Obstruction was analyzed with univariate and multivariate Logistic regressions using the statistical software R. 848 consecutive patients were enrolled, and 295 cases of HH (34.8%), subdivided into 199 (23.5%) Type II- and 96 (11.3%) Type III-EGJ patients, were identified. Ineffective peristalsis was diagnosed in 162 (19.1%) subjects, Hypercontractile esophagus in 32 (3.8%), and Outflow Obstruction in 91 (10.7%), while GERD was present in 375 (44.2%) patients. HH was significantly associated with Ineffective Peristalsis (p < 0.001) and GERD (p < 0.001). Furthermore, HH resulted to be a risk factor for Ineffective peristalsis (OR 2.0, 95% CI 1.4-2.8, p < 0.001) both when the analysis was conducted in all the 848 subjects, independently from GERD, and when it was carried out in patients without GERD (OR 2.3, 95% CI 1.02-5.3, p = 0.04). The risk for Ineffective Peristalsis increased 1.3 times for every centimeter of HH. No statistically significant association was found between HH and Outflow obstruction or Hypercontractile Esophagus. An increasing separation between the LES and CD may lead to a gradual and significant elevation in the risk of Ineffective Peristalsis. Interestingly, this association with HH is true in patients with and in those without GERD, suggesting that the anatomical alteration seems to play a major role in motility change.

Quantum State-Dependent Fragmentation Dynamics of D2S Molecules Following Excitation at Wavelengths ∼ 129.1 and ∼ 139.1 nm.

The first high-resolution translational spectroscopy studies of D atom photoproducts following excitation to the Rydberg states of D2S are reported. Excitation at wavelengths λ ∼ 139.1 nm reveals an unusual 'inverse' isotope effect; the 1B1(3da1←2b1) Rydberg state of D2S predissociates much faster than its counterpart in H2S. This is attributed to accidental near resonance with a vibrationally excited level of a lower-lying, more heavily predissociated Rydberg state of D2S that boosts the probability of nonadiabatic coupling to the dissociation continuum with 1A″ symmetry. Excitation at λ ∼ 129.1 nm populates the 1B1(4da1←2b1) Rydberg state, which predissociates more slowly and allows the study of ways in which the branching into different quantum states of the SD products varies with the choice of parent excited (JKaKc) level. All excited parent levels yield both ground (X) and electronically excited (A) state SD fragments. The former are distributed over a wide range of rovibrational (v″, N″) levels, while the population of levels with low v' and high N' is favored in the latter. These trends reflect the topographies of the dissociative 1A″ (1A') potential energy surfaces that correlate with the respective dissociation limits. Rotational motion about the b-inertial axis in the excited state molecule increases the relative yield of SD(A) products, consistent with dissociation by rotationally (Coriolis-) induced coupling from the photoexcited Rydberg level to the 1A' continuum. Molecules excited to the rotationless (JKaKc = 000) level also yield some SD(A) products, however, confirming the operation of a rival fragmentation pathway wherein photoexcited molecules decay by initial vibronic coupling to the 1A″ continuum, with subsequent nonadiabatic coupling between the 1A″ and 1A' continua enabling access to the D + SD(A) limit.

Natural and anthropogenic forcing of ecological and environmental changes at Lake Qilu, SW China, since the last deglaciation

The ecological evolution of lakes and their watersheds and the driving mechanisms are a key topic in paleoenvironmental research. However, the relative impacts of human activities and climate change on lake ecosystems since the last deglaciation remain unclear. We conducted a high-resolution study of the chain length distribution and concentration of n-alkanes in a sediment core from Lake Qilu in SW China, to reveal the ecological changes and their controlling factors since 14.6 cal kyr BP. Based on studies of modern samples, short-chain, medium-chain, and long-chain n-alkanes are associated with bacteria/algae, aquatic plants, and terrestrial plants, respectively. Combining the ACL17–33, Paq, and Σn-alkane indices, we found that both aquatic and terrestrial plants proliferated at Lake Qilu from 14.6 to 6 cal kyr BP, which was associated with a relatively warm and wet climate and dynamic strong winds. During the interval from 6 to 2 cal kyr BP, aquatic plants flourished, accompanied by a rapid surge in the regional productivity, primarily due to human activities. After 2 cal kyr BP, anthropogenic eutrophication was the primary cause of the increase in bacteria and algae populations. These results suggest that, before 6 cal kyr BP, climatic factors dominated the n-alkanes distribution; whereas after 6 cal kyr BP, human activities became the primary factor controlling the n-alkanes and ecological changes in Lake Qilu.

Effects of Idiopathic Restless Leg Syndrome on Intima-Media Thickness of Carotid Artery: A Case Control Study

Purpose: Restless legs syndrome is claimed to be associated with a higher risk of cardiovascular diseases. Intima-media thickness has been reported to be the most valuable surrogate marker and predictor of atherosclerosis progression and upcoming cardiovascular diseases. In this study, we aimed to evaluate the relationship between restless legs syndrome and intima-media thickness of the carotid artery. Materials and Methods: In this case-control study, a total of 23 patients with restless legs syndrome without other known risk factors of cardiovascular diseases were evaluated with regard to the intima-media thickness of the carotid artery by employing a high-resolution B-mode ultrasound study. The findings of the ultrasound study between the case and the control group were compared and statistically analyzed. Results: Intima-media thickness was revealed to be of a lower value in subjects with restless legs syndrome (0.79 ± 0.10) compared to the control group (0.88 ± 0.13). Also, our study showed that older age and the presence of hypertension directly correlates with intima-media thickness. Conclusion: It can be concluded that restless legs syndrome is associated with a lower intima-media thickness.