Differential Shift Research Articles

Molecular mechanisms and evolutionary robustness of a color switch in proteorhodopsins.

Proteorhodopsins are widely distributed photoreceptors from marine bacteria. Their discovery revealed a high degree of evolutionary adaptation to ambient light, resulting in blue- and green-absorbing variants that correlate with a conserved glutamine/leucine at position 105. On the basis of an integrated approach combining sensitivity-enhanced solid-state nuclear magnetic resonance (ssNMR) spectroscopy and linear-scaling quantum mechanics/molecular mechanics (QM/MM) methods, this single residue is shown to be responsible for a variety of synergistically coupled structural and electrostatic changes along the retinal polyene chain, ionone ring, and within the binding pocket. They collectively explain the observed color shift. Furthermore, analysis of the differences in chemical shift between nuclei within the same residues in green and blue proteorhodopsins also reveals a correlation with the respective degree of conservation. Our data show that the highly conserved color change mainly affects other highly conserved residues, illustrating a high degree of robustness of the color phenotype to sequence variation.

Transmembrane pH gradient imaging in rodent glioma models.

A unique feature of the tumor microenvironment is extracellular acidosis in relation to intracellular milieu. Metabolic reprogramming in tumors results in overproduction of H+ ions (and lactate), which are extruded from the cells to support tumor survival and progression. As a result, the transmembrane pH gradient (ΔpH), representing the difference between intracellular pH (pHi) and extracellular pH (pHe), is posited to be larger in tumors compared with normal tissue. Controlling the transmembrane pH difference has promise as a potential therapeutic target in cancer as it plays an important role in regulating drug delivery into cells. The current study shows successful development of an MRI/MRSI-based technique that provides ΔpH imaging at submillimeter resolution. We applied this technique to image ΔpH in rat brains with RG2 and U87 gliomas, as well as in mouse brains with GL261 gliomas. pHi was measured with Amine and Amide Concentration-Independent Detection (AACID), while pHe was measured with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS). The results indicate that pHi was slightly higher in tumors (7.40-7.43 in rats, 7.39-7.47 in mice) compared with normal brain (7.30-7.38 in rats, 7.32-7.36 in mice), while pHe was significantly lower in tumors (6.62-6.76 in rats, 6.74-6.84 in mice) compared with normal tissue (7.17-7.22 in rats, 7.20-7.21 in mice). As a result, ΔpH was higher in tumors (0.64-0.81 in rats, 0.62-0.65 in mice) compared with normal brain (0.13-0.16 in rats, 0.13-0.16 in mice). This work establishes an MRI/MRSI-based platform for ΔpH imaging at submillimeter resolution in gliomas.

Carbon-13 Radiofrequency Amplification by Stimulated Emission of Radiation of the Hyperpolarized Ketone and Hemiketal Forms of Allyl [1-13C]Pyruvate.

13C hyperpolarized pyruvate is an emerging MRI contrast agent for sensing molecular events in cancer and other diseases with aberrant metabolic pathways. This metabolic contrast agent can be produced via several hyperpolarization techniques. Despite remarkable success in research settings, widespread clinical adoption faces substantial roadblocks because the current sensing technology utilized to sense this contrast agent requires the excitation of 13C nuclear spins that also need to be synchronized with MRI field gradient pulses. Here, we demonstrate sensing of hyperpolarized allyl [1-13C]pyruvate via the stimulated emission of radiation that mitigates the requirements currently blocking broader adoption. Specifically, 13C Radiofrequency Amplification by Stimulated Emission of Radiation (13C RASER) was obtained after pairwise addition of parahydrogen to a pyruvate precursor, detected in a commercial inductive detector with a quality factor (Q) of 32 for sample concentrations as low as 0.125 M with 13C polarization of 4%. Moreover, parahydrogen-induced polarization allowed for the preparation of a mixture of ketone and hemiketal forms of hyperpolarized allyl [1-13C]pyruvate, which are separated by 10 ppm in 13C NMR spectra. This is a good model system to study the simultaneous 13C RASER signals of multiple 13C species. This system models the metabolic production of hyperpolarized [1-13C]lactate from hyperpolarized [1-13C]pyruvate, which has a similar chemical shift difference. Our results show that 13C RASER signals can be obtained from both species simultaneously when the emission threshold is exceeded for both species. On the other hand, when the emission threshold is exceeded only for one of the hyperpolarized species, 13C stimulated emission is confined to this species only, therefore enabling the background-free detection of individual hyperpolarized 13C signals. The reported results pave the way to novel sensing approaches of 13C hyperpolarized pyruvate, potentially unlocking hyperpolarized 13C MRI on virtually any MRI system─an attractive vision for the future molecular imaging and diagnostics.

Rectal deformation management with IGRT in prostate radiotherapy: Can it be managed with rigid alignment alone?

It is challenging to achieve appropriate target coverage of the prostate with Image Guided Radiation Therapy (IGRT) while simultaneously constraining rectal doses within planned values when there is significant variability in rectal filling and shape. We investigated if rectum planning goals can be fulfilled using rigid CBCT-based on-board alignment to account for interfraction rectal deformations. Delivered rectal doses corresponding to prostate alignment ("PR") and anterior rectum alignment ("AR") for 239 daily treatments from 13 patients are reported. Rectal doses were estimated by rigidly mapping the planned dose on the daily CT derived from the daily CBCT according to respective alignment shifts. Rectum V95% (rV95%) was used for analyses. Compared to "PR", "AR" alignment increased rV95% for an average of 34.4% across all patients. rV95% (cc) averaged over all fractions was significant from planning values for 10/13 patients for "PR" and for 9/13 for "AR". 3/13 patients had reproducible anatomy. Of patients with non-reproducible anatomy, three had dosimetrically more favorable, while seven had less favorable anatomies. Most shift differences (82.3%) between the "PR" and "AR" alignments larger than 2mm resulted in rV95% changes larger than 2 cc. Most shift differences (82.2%) of 2mm or less between the "PR" and "AR" alignments resulted in rV95% changes less than 2 cc. The average percentage of fractions among patients in which anterior or posterior shifts for "AR" and "PR" alignment was larger than the PTV margins was 9.1% (0.0%-37.5%) and 1.3% (0%-10%). Rectal deformation and subsequent inconsistent interfraction separation between prostate and rectal wall translate into anatomical changes that cannot always be mitigated with rigid alignment. If systematic differences exist due to a non-reproducible planning anatomy, attempts to restore the planned rectal doses through anterior rectum alignment produce rather small improvements and may result in unacceptable target underdosage.

Intra-serotypic antigenic diversity of dengue virus serotype 3 in Thailand during 2004-2015.

In addition to the well-known differences among the four dengue serotypes, intra-serotypic antigenic diversity has been proposed to play a role in viral evolution and epidemic fluctuation. A replacement of genotype II by genotype III of dengue virus serotype 3 (DENV3) occurred in Thailand during 2007-2014, raising questions about the role of intra-serotypic antigenic differences in this genotype shift. We characterized the antigenic difference of DENV3 of genotypes II and III in Thailand, utilizing a neutralizing antibody assay with DENV3 vaccine sera and monotypic DENV3 sera. Although there was significant antigenic diversity among the DENV3, it did not clearly associate with the genotype. Our data therefore do not support the role of intra-serotypic antigenic difference in the genotype replacement. Amino acid alignment showed that eight positions are potentially associated with diversity between distinct antigenic subgroups. Most of these amino acids were found in envelope domain II. Some positions (aa81, aa124, and aa172) were located on the surface of virus particles, probably involving the neutralization sensitivity. Notably, the strains of both genotypes II and III showed clear antigenic differences from the vaccine genotype I strain. Whether this differencewill affect vaccine efficacy requires further studies.

Beyond slow two-state protein conformational exchange using CEST: applications to three-state protein interconversion on the millisecond timescale.

Although NMR spectroscopy is routinely used to study the conformational dynamics of biomolecules, robust analyses of the data are challenged in cases where exchange is more complex than two-state, such as when a 'visible' major conformer exchanges with two 'invisible' minor states on the millisecond timescale. It is becoming increasingly clear that chemical exchange saturation transfer (CEST) NMR experiments that were initially developed to study systems undergoing slow interconversion are also sensitive to intermediate-fast timescale biomolecular conformational exchange. Here we investigate the utility of the amide 15N CEST experiment to characterise protein three-state exchange occurring on the millisecond timescale by studying the interconversion between the folded (F) state of the FF domain from human HYPA/FBP11 (WT FF) and two of its folding intermediates I1 and I2. Although 15N CPMG experiments are consistent with the F state interconverting with a single minor state on the millisecond timescale, 15N CEST data clearly establish an exchange process between F and a pair of minor states. A unique three-state exchange model cannot be obtained by analysis of 15N CEST data recorded at a single temperature. However, including the relative sign of the difference in the chemical shifts of the two minor states based on a simple two-state analysis of CEST data recorded at multiple temperatures, results in a robust three-state model in which the F, I1 and I2 states interconvert with each other on the millisecond timescale ( ~ 550s-1, ~ 1200s-1, ~ 5000s-1), with I1 and I2 sparsely populated at ~ 0.15% and ~ 0.35%, respectively, at 15°C. A computationally demanding grid-search of exchange parameter space is not required to extract the best-fit exchange parameters from the CEST data. The utility of the CEST experiment, thus, extends well beyond studies of conformers in slow exchange on the NMR chemical shift timescale, to include systems with interconversion rates on the order of thousands/second.

The impact of vaccine hesitancy on psychological impairment among healthcare workers in a Total Worker Health© approach.

Vaccination practice is a well-known individual protective measure for biological risk in healthcare. During the COVID-19 pandemic vaccine hesitancy has grown among healthcare workers (HCWs). The study aims to investigate how vaccine hesitancy influences the psychological burden experienced by healthcare workers. This study aimed to explore attitudes of HCWs in acceptance or refusal of vaccinations related to the risk of psychological impairment (PI) and describe the associated occupational factors, during the seasonal flu/COVID-19 vaccination campaign of 2022-2023. 302 HCWs were enrolled in the study. A questionnaire was self-administered, including two scales on the risk of psychological impairment (Psychological Injury Risk Indicator, PIRI) and vaccine hesitancy (Adult Vaccine Hesitancy Scale, AVHS). PIRI scores revealed that 29.8% of participants were at risk of PI. Differences in sex, age, occupational seniority, professional category, and night shifts were found between HCWs at risk of PI and those not at risk. Females registered a four-fold higher risk than males (85.6% vs. 14.4%, χ2 = 4.450, p < 0.05). Nurses were the highest risk category, followed by physicians and technicians (54.4% vs. 30.0% vs. 12.2%, χ2 = 14.463, p < 0.001). 41.7% of participants received the flu vaccination, and 98.9% received the COVID-19 vaccine. HCWs were prone to being vaccinated to protect patients and family members. Conversely, vaccine refusal was attributed to the perception of flu vaccines as not beneficial and COVID-19 contagion at low risk. The latter was more frequently reported for HCWs at risk of PI (16.7% vs. 4.7%, χ2 = 11.882, p = 0.001). Finally, hesitant HCWs were at higher risk of psychological impairment than others. HCWs expressed vaccine acceptance considering their social role in the community as protectors. However, the underestimation of the risk of severity of COVID-19 was more relevant among HCWs at risk of PI than others. Psychological aspects need to be considered by healthcare providers when fighting vaccine hesitancy.

Machine learning-based correction for spin-orbit coupling effects in NMR chemical shift calculations.

As one of the most powerful analytical methods for molecular and solid-state structure elucidation, NMR spectroscopy is an integral part of chemical laboratories associated with a great research interest in its computational simulation. Particularly when heavy atoms are present, a relativistic treatment is essential in the calculations as these influence also the nearby light atoms. In this work, we present a Δ-machine learning method that approximates the contribution to 13C and 1H NMR chemical shifts that stems from spin-orbit (SO) coupling effects. It is built on computed reference data at the spin-orbit zeroth-order regular approximation (ZORA) DFT level for a set of 6388 structures with 38 740 13C and 64 436 1H NMR chemical shifts. The scope of the methods covers the 17 most important heavy p-block elements that exhibit heavy atom on the light atom (HALA) effects to covalently bound carbon or hydrogen atoms. Evaluated on the test data set, the approach is able to recover roughly 85% of the SO contribution for 13C and 70% for 1H from a scalar-relativistic PBE0/ZORA-def2-TZVP calculation at virtually no extra computational costs. Moreover, the method is transferable to other baseline DFT methods even without retraining the model and performs well for realistic organotin and -lead compounds. Finally, we show that using a combination of the new approach with our previous Δ-ML method for correlation contributions to NMR chemical shifts, the mean absolute NMR shift deviations from non-relativistic DFT calculations to experimental values can be halved.

Virtual clinical trial-based study for clinical evaluation of projection-reduced low-dose cone-beam CT for image guided radiotherapy.

Repeated cone-beam CT (CBCT) scans for image-guided radiotherapy (IGRT) increase the health risk of radiation-induced malignancies. Patient-enrolled studies to optimize scan protocols are inadequate. We proposed a virtual clinical trial-based approach to evaluate projection-reduced low-dose CBCT for IGRT. A total of 71 patients were virtually enrolled with 26 head, 23 thorax and 22 pelvis scans. Projection numbers of full-dose CBCT scans were reduced to 1/2, 1/4, and 1/8 of the original to simulate low-dose scans. Contrast-to-noise ratio (CNR) values in fat and muscle were measured in the full-dose and low-dose images. CBCT images were registered to planning CT to derive 6-degree-of-freedom couch shifts. Registration errors were statistically analyzed with the Wilcoxon paired signed-rank test. As projection numbers were reduced, CNR values descended and the magnitude of registration errors increased. The mean CNR values of full-dose and half-dose CBCT were >3.0. For full-dose and low-dose CBCT (i.e. 1/2, 1/4 and 1/8 full-dose), the mean registration errors were< ± 0.4 mm in translational directions (LAT, LNG, VRT) and ±0.2 degree in rotational directions (Pitch, Roll, Yaw); the mean magnitude of registration errors were< 1 mm in translation and< 0.5 degree in rotation. The couch shift differences between full-dose and low-dose CBCT were not statistically significant (p>0.05) in all the directions. The results indicate that while the impact of dose-reduction on CBCT couch shifts is not significant, the impact on CNR values is significant. Further validation on optimizing CBCT imaging dose is required.

Redox-Mediated Enantioselective Interactions in Chiral Metallopolymers Possessing Supramolecular Chirality

Synthetic chiral platforms can be a powerful platform for enantioselective interactions, especially when coupled with redox-mediated electrochemical processes. Redox metallopolymers represent a distinct class of versatile functional materials and have been extensively studied for a wide scope of applications such as membranes, self-assembly, hydrogels, and redox-mediated ion separation. However, many studies have focused on molecularly-selective binding and release of achiral molecules, with limited studies on chirality strategies for enantioselective interactions. Chiral organic anions comprise an important class of biologically-relevant molecules, and their separation and sensing have received intense attention. Here, we introduce new chiral redox-polymers with chiral ferrocene (Fc) building blocks, that can serve as an electro-responsive enantioselective platform for a variety of amino acids and pharmaceutical carboxylates, taking advantage of supramolecular chirality for enhancing electrochemical recognition. Two chiral redox-metallopolymers were designed and synthesized based on Ugi’s amine-inspired chiral monomers containing an amide (poly-1) or amine group (poly-2), and their enantioselective recognitions toward amino acids and pharmaceutical carboxylates were investigated by redox potential shifts using square wave voltammetry. The half potential shift of both poly-(S)-1 and poly-(S)-2 increased more with increasing D-tryptophan concentration than the other enantiomer, L-tryptophan, while the half potential of poly-(R)-1 and poly-(R)-2 shifted more with L-tryptophan than with D-tryptophan, proving the enantioselective interaction of both redox-metallopolymers. Nuclear Overhauser Effect spectroscopy (2D NOESY) and solid-state circular dichroism revealed the emergence of supramolecular chirality of the polymers resulting from the intramolecular interaction between the ferrocene and the alkyl group in the backbone, and the steric hindrance of the ferrocene within the polymer. The half-peak potential shift demonstrated the remarkable enhancement of enantioselective recognition with tryptophan (Trp) and naproxen, provided by the chiral polymers possessing the supramolecular chirality over the single-site, chiral building block itself. For instance, the two (S) polymers showed the potential shift difference 2.4-2.8 times higher than the corresponding monomers upon the binding of Trp enantiomers. The enantioselective potential shift of the chiral metallopolymer electrodes could determine enantiomeric excess (%ee) of Trp over the range of 0–100%ee. Investigation on solvent polarity and pH effect revealed that the enantioselective mechanism of the chiral redox polymers was attributed to the subtle balance between hydrogen bonding and π-π interaction. We also identified the importance of aromatic groups on the analytes for increasing enantioselectivity of the chiral redox polymers. This work highlights the potential of chiral redox-metallopolymers as platforms for electrochemically-modulated enantioselective processes toward a variety of amino acids and pharmaceutical carboxylates. Figure 1

Differences in shift and work-related patterns between metropolitan and regional/rural healthcare shift workers and the occupational health and safety risks.

To explore if there are differences in shift patterns and work-related factors between metropolitan and regional/rural healthcare shift workers and their risk of poor sleep and mental health. Furthermore, explore whether these factors impact on medical errors, workplace and car/near car accidents. A cross-sectional study. An anonymous online survey of healthcare shift workers in Australia. A total of 403 nurses, midwives and paramedics completed the survey. Sample characteristics, employment location, shift work-related features, sleep and mental health measurements, workplace accidents, medical errors and car/near car accident post shift. Regional/rural healthcare shift workers were significantly older, had more years' experience, worked more nights, on-call and hours per week. Those in metropolitan areas took significantly longer (minutes) to travel to work, had higher levels of anxiety, increased risk of shift work disorder, reported significantly more workplace accidents and were more likely to have a car/near car accident when commuting home post shift. Both groups reported ~25% having a medical error in the past year. Workplace accidents were related to more on-call shifts and poor sleep quality. Medical errors were associated with fewer years' experience, more evening shifts and increased stress. Car accidents were associated with metropolitan location and increased depression. Differences in work-related factors between metropolitan and regional/rural healthcare shift workers were observed. Some of these factors contributed to occupational health and safety risks. Further exploration is needed to understand how to reduce occupational health and safety risks, and improve employee and patient safety both in both regional/rural and metropolitan areas.

Treatment of Class II Malocclusion With Orthodontic Microimplant Anchorage

IntroductionThe objective of the study was to compare the effects of orthodontic microimplant anchorage (MIA) and conventional extraoral arch anchorage (EAA) on tooth structure and oral inflammatory response in patients with Class II Division I malocclusion. MethodsA total of 104 patients with Class II malocclusion were enrolled and were randomly assigned to receive MIA or EAA treatments. Clinical efficacy was assessed at 6 months after treatment by measuring molar shift, convex distance, and hinge angle difference between maxillary and mandibular incisors. X-ray was performed for tissue evaluations. The levels of cell adhesion molecule-1 (CAM-1), matrix metalloproteinase-2 (MMP-2), and proinflammatory cytokines in gingival sulcus fluid were measured using enzyme-linked immunosorbent assay to assess inflammatory responses to the implants. ResultsOur study demonstrated superior efficacy of MIA compared to EAA in terms of overall efficacy, molar shift, convex distance between upper and middle incisors, as well as hinge angle difference between upper and middle incisors. MIA also showed greater efficacy in reducing tissue fix-point measurements, including saddle point–nasal root point–superior alveolar seat point (SNA), alveolar seat point–nasal root point–inferior alveolar seat point (ANB), overlying (OJ), and overbite (OB). ConclusionsMIA is a novel orthodontic treatment that showed stronger efficacy in inducing molar shift and correcting soft/hard tissue positions, whilst generating suppressed inflammatory responses. Our study could have significant implications for practice in the orthodontic treatment of Class II malocclusion.

Solvents Influence 1H NMR Chemical Shifts and Complete 1H and 13C NMR Spectral Assignments for Florfenicol

Florfenicol (FFC) is an important and widely used veterinary drug, and its structure has been characterized by nuclear magnetic resonance (NMR) spectroscopy. The study aimed to investigate the influences of solvent type, solvent concentration, and temperature on the chemical shifts of the 1H NMR of FFC. The results showed that different types of solvents significantly affected the chemical shifts, especially the chemical shifts of 2-H, 3-H, 5-H, and the active protons. When DMSO-d 6 is used as the solvent, there is no significant difference in the chemical shifts of FFC with a concentration ranging from 20 to 250 mmol/L; however, as the temperature increases, the chemical shifts of the active protons move to a higher field. Besides, the NMR spectroscopic data and structural analysis of FFC were refined by 1H, 13C, distortionless enhancement by polarization transfer-135 (DEPT-135), 1H–1H correlation spectroscopy (1H–1H COSY), phase-sensitive gradient heteronuclear singular quantum correlation (gHSQC), and heteronuclear multiple bond correlation (gHMBC) NMR spectroscopy using DMSO-d 6 as a solvent. The study will help with qualitative and quantitative analysis of FFC in the future.

Skin-like and highly elastic optical fiber strain sensor based on a knot-bend shape for human motion monitoring.

A simply designed, highly sensitive, stretchable, compact wearable, and skin-like optical fiber sensing instrument is designed and demonstrated for joint motion monitoring. The fiber sensing scheme comprises only a section of single-mode fiber (SMF) deformed in the knot-like configuration, which performs as a Mach-Zehnder interferometer (MZI) based on a modal coupling mechanism between the core and cladding modes of the deformed SMF section. This proposed optical fiber sensor based on a knot-like configuration is mounted onto wearable woven fabric and then garments on the limbs of a healthy human's body. As the flexion angle of the human limb is varied, the interference fringe coding based on the spectral shift difference of the periodical transmission spectra is perceived. The proposed wearable optical fiber sensor exhibits excellent sensitivities from around -0.431 to -0.614n m/∘ realized for elbow and knee joint flexion between a range of motion around 0°-90°. Additionally, this sensor also displays high repeatability and stability and a fast response time of 1.4ms, combined with a small standard deviation of about 2.585%. The proposed sensor device possesses manufacturing simplicity, high processing accuracy, lightness, and elasticity, as well as certain improvements over other goniometers and optical fiber sensors. These attributes of the proposed sensor prove its applicability for human joint angle monitoring.

Difference in seasonal shift of spatial homogenization between taxonomic and functional structure in demersal fish communities

Under climate change and anthropogenic activities, the homogenization of fish communities shows spatial and temporal shifts and threatens biodiversity and ecosystem functioning, but little effort has been made to assess the seasonal shift of spatial homogenization in marine demersal fish, which hinders effective management. In the present study, we investigated the spatial patterns of demersal fish communities and their seasonal changes in the shelf sea of Shandong Peninsula in northeast China based on the four seasonal surveys. Our findings showed that both season and region were important factors in the distributions of biodiversity and the community structure of demersal fish. Spatial homogenization of taxonomic structure and functional structure exhibited inconsistent changes with season. Compared with taxonomic structure, functional structure exhibited relatively lower spatial homogenization in all seasons. Our results suggest that the density of survey stations for demersal fish resource investigation in the study area should be conducted in at least four regions and considering seasonality. This study highlights a need to understand spatial homogenization and its seasonal changes in demersal fish in both taxonomic and functional approaches, which could give insight into biodiversity and resource state and be conducive to improving the efficiency of resource investigation and management.

Nordic hamstring exercises in functional knee rehabilitation after anterior cruciate ligament reconstruction: a prospective, randomised, controlled study

To study the effect of using Nordic hamstring exercise method on muscle strength and knee joint stability of patients after ACL reconstruction. 60 patients admitted to our hospital for ACL reconstruction were randomly divided into a test group (n = 30, applying Nordic hamstring exercise) and a control group (n = 30, applying conventional rehabilitation training methods), and the difference in the circumference of the thighs of the patients in the two groups was analysed after training, and the peak torque (PT), total torque (PT), and flexion and extension strength were measured by using the Biodex system3 Multi-joint Isokinetic Testing System at knee joints with an angular velocity of 60°/s and 120°/s. The peak torque (PT), total work (TW), and average peak torque (AVG PT) were measured by extension and flexion strength at angular velocity, and the Lysholm Knee Score was used to assess the knee function of 60 patients. There was no difference in the difference in thigh circumference between the two groups before surgery (P > 0.05); the difference in thigh circumference between the patients in the test group at 12 and 24 weeks after surgery was (− 0.35 ± 0.22) cm and (0.12 ± 0.03) cm, respectively, which were higher than those in the control group, (− 0.51 ± 0.15) cm and (− 0.41 ± 0.34) cm (P < 0.05). At the 12th and 24th postoperative weeks, the popliteal muscle strength of both groups was improved compared with that before surgery; among them, by comparing the popliteal peak moments with different angular velocities, the ratio of popliteal peak moment on the affected side/peak moment on the healthy side of the popliteal muscle of the experimental group was significantly higher than that of the control group, and the difference was significant (P < 0.05), but there was still a gap compared with that of the healthy side. The Lachmen test and the anterior drawer test were negative in the test and control groups at the 24th postoperative week of review, and the anterior tibial shift was < 5 mm in the KT-1000 test, and the difference in the anterior shift was < 3 mm compared with the healthy side, and there was no significant difference between the two groups. By Nordic hamstring exercise can make patients after knee ACL reconstruction reduce patient pain, accelerate the recovery of knee function, improve the swelling of the lower limb, reach the level of flexor strength of the healthy side within 24 weeks, and can increase the stability of the knee joint.

Abstract 211: Comparing Early and Late Window 3mm Trevo Stent Retriever Performance in Medium Vessel Occlusion Thrombectomy

Introduction Endovascular thrombectomy has been shown to be beneficial for select patients with medium vessel occlusion ischemic strokes. Newer mechanical thrombectomy devices have designs to facilitate navigation of the medium and distal cerebrovasculature. In this single‐center study, we aim to compare the performance of 3mm Trevo NXT stent retrievers (Stryker, Kalamazoo, MI) for medium vessel occlusion mechanical thrombectomy for patients treated within either the early (&lt;6 hour) or late (&gt;6 hour) treatment window. Methods A retrospective review was conducted of acute ischemic stroke patients with medium vessel occlusions (i.e., M2‐M4, ACA, and PCA) who underwent thrombectomy over 5 years (2018‐2022) at a single comprehensive stroke center. Classification into early or late window was defined as time from last known well to groin puncture less than 6 hours or greater than 6 hours, respectively. Primary efficacy outcome included successful recanalization (modified thrombolysis in cerebral infarction [mTICI]&gt;=2B) using 3mm Trevo NXT on either first pass or rescue pass (i.e., after initial pass failure with another device). Primary safety outcome is rate of complications associated with the stent retriever. Primary clinical outcome was National Institutes of Health Stroke Scale (NIHSS) shift between admission and discharge. Results Of 81 patients with medium vessel occlusion ischemic strokes, 38 patients (44.7% female, median age of 73.5 years [IQR 66‐82], median initial NIHSS 13 [IQR 8‐23]) underwent thrombectomy with 3mm Trevo NXT. Stent retriever‐assisted aspiration (versus stent retriever only) was performed in 31/38 (81.6%) patients. Successful recanalization with stent retriever was achieved in 28/38 (73.7%) of patients. There was no significant difference in rate of recanalization between early and late window thrombectomy (16/22 [72.7%] early window vs. 12/16 [75%] late window, p=0.8752). The lack of significant difference in recanalization rate was consistent with stent retriever use during first pass (11/14 [78.6%] early window vs. 9/10 [90%] late window, p=0.6146) and as rescue (5/8 [62.5%] early window vs. 3/6 [50%] late window, p=0.6400). There was no significant difference in the rate of stent retriever complications between early and late windows (1/16 [6.3%] early vs. 0/22 [0%] late, p=0.4211). There was no significant difference in median NIHSS shift from admission to discharge ( ‐6 [IQR ‐16 ‐ 9] early window vs. ‐3 [IQR ‐5 ‐ 4] late window, p=0.3666). Conclusion In both early and late window medium vessel occlusion thrombectomy, the 3mm Trevo NXT as first line and rescue intervention performs comparably and adequately. Future multicenter studies will further characterize novel stent retriever performance in medium vessel occlusion thrombectomies.

A retrospective comparison of setup accuracy from CBCT and SGRT data in breast cancer patients

IntroductionBoth cone-beam computed tomography (CBCT) and surface-guided radiotherapy (SGRT) are used for breast patient positioning verification before treatment delivery. SGRT may reduce treatment time and imaging dose by potentially reduce the number of CBCT needed. The aim of this study was to compare the displacements resulting in positioning from the Image Guided Radiation Therapy (IGRT) 3D and SGRT methods and to design a clinical workflow for SGRT implementation in breast radiotherapy to establish an imaging strategy based on the data obtained. MethodsFor this study 128 breast cancer patients treated with 42.5 Gy in 16 fractions using 3D conformal radiotherapy with free breathing technique were enroled. A total of 366 CBCT images were evaluated for patient setup verification and compared with SGRT. Image registrations between planning CT images and CBCT images were performed in mutual agreement and in online mode by three health professionals. Student's paired t‐test was used to compare the absolute difference in vector shift, measured in mm, for each orthogonal axis (x, y, z) between SGRT and CBCT methods. The multidisciplinary team evaluated a review of the original clinical workflow for SGRT implementation and data about patients treated with the updated workflow were reported. ResultsComparison of the shifts obtained with IGRT and SGRT for each orthogonal axis (for the x-axes the average displacement was 0.9 ± 0.7 mm, y = 1.1 ± 0.8 mm and z = 1.0 ± 0.7 mm) revealed no significant statistical differences (p > 0.05). Using the updated workflow the difference between SGRT and IGRT displacements was <3 mm in 91.4 % of patients with a reduction in total treatment time of approximately 20 %, due to the reduce frequency of the CBCT images acquisition and matching. ConclusionsThis study has shown that IGRT and SGRT agree in positioning patients with breast cancer within a millimetre tolerance. SGRT can be used for patient positioning, with the advantages of reducing radiation exposure and shorter overall treatment time.

An exploratory study of brain temperature and choline abnormalities in temporal lobe epilepsy patients with depressive symptoms.

Epilepsy and depression share neurobiological origins, and evidence suggests a possible bidirectional relationship that remains poorly understood. This exploratory, cross-sectional study aimed to investigate this relationship by employing magnetic resonance spectroscopic imaging (MRSI) and thermometry (MRSI-t) in patients with temporal lobe epilepsy (TLE) with comorbid depressive symptoms and control participants. This is the first study to combine MRSI and MRSI-t to examine brain temperature and choline abnormalities in regions implicated in seizure onset and depression. Twenty-six patients with TLE and 26 controls completed questionnaires and underwent imaging at 3T. Volumetric echo-planar MRSI/MRSI-t data were processed within the Metabolite Imaging and Data Analysis System (MIDAS). Choline (CHO) was quantified as a ratio over creatine (CRE; CHO/CRE). Brain temperature (TCRE ) was calculated based on the chemical shift difference of H2 O relative to CRE's stable location on the ppm spectrum. The Hospital Anxiety and Depression Scale measured anxiety and depressive symptoms. The Chalfont Seizure Severity Scale measured seizure severity in patients with TLE. Two sets of voxelwise independent sample t tests examined group differences in CHO/CRE and TCRE maps. Voxel-based multimodal canonical correlation analysis (mCCA) linked both datasets to investigate if, how, and where CHO/CRE and TCRE abnormalities were correlated in TLE participants and controls. Compared to controls, patients with TLE reported more depressive symptoms (P = 0.04) and showed CHO/CRE and TCRE elevations in left temporal and bilateral frontal regions implicated in seizure onset and depressive disorders (pFWE < 0.05). For the TLE group, CHO/CRE levels in temporal and frontal cortices were associated with elevated TCRE in bilateral frontal and temporal gyri (r = 0.96), and decreased TCRE in bilateral fronto-parietal regions (r = -0.95). Abnormalities in TCRE and CHO/CRE were observed in seizure-producing areas and in regions implicated in depression. These preliminary findings suggest that common metabolic changes may underlie TLE and depression. Our results suggest further investigations into the proposed bidirectional mechanisms underlying this relationship are warranted.

Influence of a Capsular Tension Ring on Capsular Bag Behavior of a Plate Haptic Intraocular Lens: An Intraindividual Randomized Trial

PurposeTo evaluate the influence of a capsular tension ring (CTR) on rotational stability, decentration, tilt and axial stability of a 11.0mm plate haptic intraocular lens (IOL) DesignIntraindividual, randomized, double masked, controlled, clinical trial. ParticipantsPatients scheduled for sequential same day bilateral cataract surgery. MethodsAll patients were randomized to receive a CTR and a plate haptic IOL in one eye and a plate haptic IOL in the fellow eye only. IOL axis assessment was performed at the end of surgery (EOS), 1 hour (1h), 1 week (1w), 1 month (1m) and 6 months (6m) using a high precision evaluation method. Decentration and tilt of the crystalline and pseudophakic lenses were assessed preoperatively, at 1w and 6m using an anterior segment OCT (AS-OCT). Main outcome measuresRotational stability from EOS to 6m and at all follow up visits. Decentration and tilt at 6m. Differences in axial shift between 1w and 6m. ResultsOne hundred and thirty eyes of 65 patients were included in the study. Absolute rotation from EOS to 6m was 2.8°±3.9° and 3.2°±5.3° for the CTR and control groups, respectively (p=0.613). IOL decentration and IOL tilt at 6m were 0.29±0.1mm and 0.24±0.1mm and 6.7°±2.8° and 5.6°±1.6° for the CTR and control groups, respectively (p=0.058, p<0.01). A posterior IOL shift of 0.31±0.31 mm and 0.19±0.14 mm was observed in the CTR and control groups, respectively. ConclusionsConcomitant implantation of a CTR and a plate haptic IOL did not improve the overall rotational stability of the IOL compared to the control group. A negative effect of the CTR on decentration, tilt and axial stability was observed. The simultaneous use of a CTR and a plate haptic IOL in the absence of zonular weakness at the time of cataract surgery should be considered with caution.