Average Conformation Research Articles

Descriptive management of suspected acute cystitis in adult patients by French general practitioners during remote consultation

ObjectivesThe main objective of this study was to analyze French general practitioners’ (GP) online prescriptions for suspected acute cystitis using a single nationwide teleconsultation platform. Patients and MethodsFirst, a descriptive study of management for suspected cystitis was conducted from the 1st of January to the 31st of December 2020. After which, following pedagogical intervention, a pre/post descriptive analysis of the antibiotics prescribed was carried out. ResultsSome 496,041 teleconsultations (TCs) were carried out in 2020 on the Qare platform. Among them, 15,089 TCs for cystitis with ICD-10 encoding (N30) were analyzed. Fosfomycin trometamol was the most prescribed antibiotic (n = 10297, 69%), while fluoroquinolones (n = 1568, 10.6%) were the second. Urine test strip was prescribed in 3157 (20%) and urine culture in 7033 (47%) of the TCs. July-August 2020 and July-August 2021 were compared and while a significant drop in fluoroquinolone prescriptions and a major increase in Fosfomycin trometamol were observed, there was no change in the prescriptions of urine culture. An average antibiotic conformity rate of 61.5% was observed before the intervention, and 68.8% afterwards. ConclusionsCystitis is a recurrent reason for remote consultation. The study demonstrated sizable over-prescription of urine culture, ultrasound, and fluoroquinolones. Intervention should be improved and strengthened to guarantee continuous training and awareness of GP's on appropriate cystitis prescriptions in telemedicine.

Direct observation of conformations of a high-mobility n-type low-bandgap copolymer in solutions and solid films.

The aggregation morphologies of conjugated polymers in solutions and solid films are important for their optoelectronic applications. Due to the amorphous state of the polymers, it remains a great challenge to determine their conformations in either liquids or solids. Herein, a ps/fs synchronized 2D IR technique is applied to investigate the molecular conformations of a high-mobility n-type low-bandgap copolymer, N2200, dissolved in CHCl3 and CCl4, and in solid films cast from both solutions by the vibrational cross-angle method. In CCl4, the polymer forms more aggregates and folds more and the backbone dihedral angle of C-C(NDI)/C-S(Thiophene) of its average conformation is about 10° more distorted than that in CHCl3 and the most stable conformation for a free molecule. Anti-intuitively, the solid films cast from both solutions have the same molecular conformation, and the conformation is similar to that of the polar CHCl3 rather than the conformation of the less polar CCl4. The results imply that the interaction between the polymer backbones is probably stronger than its interaction with CCl4, which can naturally guide the rearrangement of polymer chains during the evaporation of solvent molecules. This work also implies that the balance and competition between the polymer/polymer interaction and the polymer/solvent interaction seem to be the dominant factors responsible for what morphology can form in a solid film cast from solution. It is not always true that different molecular conformations must exist in solid films grown from different solutions with different polarity or different extents of aggregates with different conformations.

PENERAPAN TOTAL QUALITY MANAGEMENT (TQM) DAN MANAGEMENT PROJECT DALAM MENINGKATKAN KUALITAS DAN KINERJA PADA PT. KIMIA FARMA, TBK

The quality and performance of a given pharmaceutical company determines the success of competition in meeting patient satisfaction and is one of the important things that determines business development strategy and maintains the quality of the pharmaceutical company itself. Total Quality Management (TQM) is amanagement system used to improve service quality and help achieve targets set by an organization. This research is an observational study using interviews through questionnaires conducted at 40 Kimia Farma pharmacy outlets in Batam with the aim of analyzing the implementation of Total Quality Management in the city of pharmacy services. In determining the development strategy of PT. Kimia Farma Tbk, conducted a Focus Group Discussion (FGD) to analyze the internal and external factors of Kimia Farma with a SWOT analysis. The results of the evaluation carried out by performance analysis showed an average performance value of 4.05 and an average importance value of 4.31 and an average conformity level of all components of 93.87%. So it can be said that the application of Total Quality Management at PT. Kimia Farma Tbk has been running well. The development strategy that can be carried out based on the SWOT analysis is the SO (Strengths-Oportunity) strategy to optimize the available resources and maximizethe success of existing opportunities in order to improve the performance of PT. Kimia Farma Tbk

BPRS Performance Evaluation Using Importance-Performance Analysis (IPA)

BPRS (Bank Pembiayaan Rakyat Syariah) is a bank that conducts its business activities based on Sharia procedures. However, its assets and financing are still relatively small compared to commercial banks. One of the reasons for this is that BPRS is limited in providing services for payment transactions. Therefore, it is important to evaluate the performance and customer satisfaction levels of BPRS. This study aims to measure the efficiency of BPRS performance using the Importance Performance Analysis (IPA) method. The research was conducted at PT. BPRS Bhakti Sumekar, a BPRS owned by the Regency Government of Sumenep. The results of this measurement can be used to evaluate the performance of BPRS Bhakti Sumekar in facing challenges and opportunities as well as for policy making considering its huge impact on the community. The results showed an average Conformity Level (TKi) of 99.57%, indicating that the performance of each attribute has met customer expectations but still requires improvement. The Customer Satisfaction Index (CSI) value resulting from this study was 75.45%, indicating that customer satisfaction with BPRS Bhakti Sumekar as a whole can be considered as satisfied. This customer satisfaction is based on the CSI interpretation table, which shows that the value obtained in this study falls in the range of 66% - 80.99%. This suggests that the performance of BPRS Bhakti Sumekar has almost reached customer expectations, leading to a high level of customer satisfaction.

Ligand-observed in-tube NMR in natural products research: A review on enzymatic biotransformations, protein–ligand interactions, and in-cell NMR spectroscopy

Natural product-observed NMR methods have considerably expanded the potentialities for in-tube NMR monitoring of complex enzymatic biotransformations and investigation of protein-natural product interactions even in living cells. We review, herein, the significant advantages of ligand-observed in-situ NMR monitoring of enzymatic biotransformations without restoring to laborious and time-consuming chromatographic methods. Emphasis will be given to the potentialities of the use of the NMR bioreactor: (i) to investigate through saturation transfer difference (STD), the capacity of natural products to serve as enzyme substrates, (ii) to monitor multiple biotransformation products of natural products with the use of immobilized enzymes and (iii) to investigate interactions of biotransformed products with protein targets. The use of STD and its variants, transfer effect Noes for PHArmacophore Mapping (INPHARMA) NMR, in conjunction with computational methods, can provide excellent tools in investigating competitive binding modes even in proteins with multiple binding sites. The method has been successfully applied in the study of unsaturated free fatty acids (UFFAs)-serum albumin complexes in which the location and conformational states of UFFAs could not be determined accurately, despite numerous X-ray structural studies, due to conformational averaging. This combined method, thus, may find promising applications in the field of protein-natural product recognition research. The emerging concept of in-cell NMR and recent applications will be discussed since they can provide atomic level insights into natural product-protein interactions in living cells without the need of isotope labelled techniques.

A modified Darcy’s law for viscoelastic flows of highly dilute polymer solutions through porous media

Viscoelastic flows of polymer solutions in complex geometries can generate a strong localization of stress within small regions of the fluid and the formation of birefringent strands. In porous media , these localized structures of stress drive preferential flow paths and increase global dissipation. Modeling the impact of such effects at Darcy or larger scales is a daunting task—one of the reasons being the lack of approaches using homogenization theories to help figure out both the correct form of the averaged transport equations and the relevant set of effective parameters. Here we homogenize the incompressible Oldroyd-B equations at zero Reynolds number to obtain a Darcy scale model that captures the effect of localized polymeric stress. This model consists of an advection—reaction transport equation for the average conformation tensor along with a form of Darcy’s law that contains an additional forcing term associated with structures of localized stress. The derivation is based upon a limit of high dilution, a regime where the Oldroyd-B model can be transformed into a sequence of linear problems using asymptotic developments. We validate our approach in test cases corresponding to flows in a channel and through arrays of circles. Besides providing a new model for viscoelastic flows in porous media , our work also shows that modeling viscoelastic flows through porous media is not simply a matter of determining an apparent permeability tensor—the homogenized model cannot be easily reduced to a simple form of Darcy’s law—but rather requires the development of specific homogenized models that capture the coupling between the transport of the polymeric stress and momentum. • The Oldroyd-B equations are homogenized using asymptotics and volume averaging. • We derive a Darcy-scale model for viscoelastic flow in porous media. • Our model couples a form of Darcy’s law with transport of the conformation tensor. • Our model captures the effect of stress localization at pore-scale on the average flow. • The notion of effective permeability alone seems to be insufficient for viscoelastic flows.

Microsecond MD Simulations to Explore the Structural and Energetic Differences between the Human RXRα-PPARγ vs. RXRα-PPARγ-DNA.

The heterodimeric complex between retinoic X receptor alpha (RXRα) and peroxisome proliferator-activated receptor gamma (PPARγ) is one of the most important and predominant regulatory systems, controlling lipid metabolism by binding to specific DNA promoter regions. X-ray and molecular dynamics (MD) simulations have revealed the average conformation adopted by the RXRα-PPARγ heterodimer bound to DNA, providing information about how multiple domains communicate to regulate receptor properties. However, knowledge of the energetic basis of the protein-ligand and protein-protein interactions is still lacking. Here we explore the structural and energetic mechanism of RXRα-PPARγ heterodimer bound or unbound to DNA and forming complex with co-crystallized ligands (rosiglitazone and 9-cis-retinoic acid) through microsecond MD simulations, molecular mechanics generalized Born surface area binding free energy calculations, principal component analysis, the free energy landscape, and correlated motion analysis. Our results suggest that DNA binding alters correlated motions and conformational mobility within RXRα–PPARγ system that impact the dimerization and the binding affinity on both receptors. Intradomain correlated motions denotes a stronger correlation map for RXRα-PPARγ-DNA than RXRα-PPARγ, involving residues at the ligand binding site. In addition, our results also corroborated the greater role of PPARγ in regulation of the free and bound DNA state.

Experiments and Modeling of Flow-Enhanced Nucleation in LLDPE.

A computational and experimental framework for quantifying flow-enhanced nucleation (FEN) in polymers is presented and demonstrated for an industrial-grade linear low-density polyethylene (LLDPE). Experimentally, kinetic measurements of isothermal crystallization were performed by using fast-scanning calorimetry (FSC) for melts that were presheared at various strain rates. The effect of shear on the average conformation tensor of the melt was modeled with the discrete slip-link model (DSM). The conformation tensor was then related to the acceleration in nucleation kinetics by using an expression previously validated with nonequilibrium molecular dynamics (NEMD). The expression is based on the nematic order tensor of Kuhn segments, which can be obtained from the conformation tensor of entanglement strands. The single adjustable parameter of the model was determined by fitting to the experimental FSC data. This expression accurately describes FEN for the LLDPE, representing a significant advancement toward the development of a fully integrated processing model for crystallizable polymers.

Reconstruction of a Synchronous Scrambler Based on Average Check Conformity

Channel coding technology is indispensable in digital communication systems. In noncooperative contexts, the identification of the channel codes of the synchronous scrambler is essential. In this paper, a new algorithm that directly uses a soft decision sequence for blind reconstruction of the synchronous scrambler is proposed. First, considering imbalanced signal sources and the principle of scrambling and descrambling the synchronous scrambler, the error-containing equation of the synchronous scrambler is established. Second, the average check conformity is introduced to complete the check relationship detection. Then, based on the statistical characteristics of the average check conformity, the corresponding discrimination threshold is established, and the reconstruction of the feedback polynomial of the synchronous scrambler is completed by traversing the possible primitive polynomials. Finally, the verification equation is determined by the method of subsection optimization, which greatly reduces the number of initial states that need to be traversed; this is critical for scramblers with high-order feedback polynomials (i.e., when the order of the feedback polynomial is greater than 15). Simulations show that the algorithm can effectively reconstruct the synchronous scrambler under imbalanced signal sources. Moreover, the proposed algorithm offers improved performance with about 1–2 dB gain at low signal-to-noise ratios compared with existing methods, and its computational complexity is reasonable.

PARENTS’ SATISFACTION WITH MEASLES RUBELLA IMMUNIZATION SERVICES FOR SCHOOLERS DURING THE COVID-19 PANDEMIC

Background: Measles Rubella (MR) immunization coverage for schoolers in Semarang City decreased to 92.7% in 2020 due to the COVID-19 pandemic. However, in practice, many parents still complain about MR immunization services for schoolers. Aims: This study aimed to determine parental satisfaction with MR immunization services during the COVID-19 pandemic. Methods: This quantitative study used a cross-sectional approach. Purposive and proportional sampling was used to select 102 samples. Data collection was done through questionnaire, and data were analyzed using the chi-square test and importance-performance analysis test. Results: The lowest suitability dimension level was tangibility (81.52%), followed by responsiveness (86.6%). The reliability dimension had the highest average conformity level (92.87%). The priority items for improvement were related to health workers’ compliance with the use of complete personal protective equipment (PPE), spacious immunization service rooms, registration officers’ responsiveness in giving directions, punctual immunizations distribution, polite and friendly registration services officers, as well as health workers’ initiative to remind parents about health protocols. Bivariate analysis showed there was no relationship between respondents’ characteristics and their satisfaction level. Conclusion: Parental satisfaction with MR immunization services for schoolers did not match their expectations; therefore, it is necessary to improve future immunization services.

Structural Characterization of the Full-Length Anti-CD20 Antibody Rituximab.

Rituximab, a murine–human chimera, is the first monoclonal antibody (mAb) developed as a therapeutic agent to target CD20 protein. Its Fab domain and its interaction with CD20 have been extensively studied and high-resolution atomic models obtained by X-ray diffraction or cryo-electron microscopy are available. However, the structure of the full-length antibody is still missing as the inherent protein flexibility hampers the formation of well-diffracting crystals and the reconstruction of 3D microscope images. The global structure of rituximab from its dilute solution is here elucidated by small-angle X-ray scattering (SAXS). The limited data resolution achievable by this technique has been compensated by intensive computational modelling that led to develop a new and effective procedure to characterize the average mAb conformation as well as that of the single domains. SAXS data indicated that rituximab adopts an asymmetric average conformation in solution, with a radius of gyration and a maximum linear dimension of 52 Å and 197 Å, respectively. The asymmetry is mainly due to an uneven arrangement of the two Fab units with respect to the central stem (the Fc domain) and reflects in a different conformation of the individual units. As a result, the Fab elbow angle, which is a crucial determinant for antigen recognition and binding, was found to be larger (169°) in the more distant Fab unit than that in the less distant one (143°). The whole flexibility of the antibody has been found to strongly depend on the relative inter-domain orientations, with one of the Fab arms playing a major role. The average structure and the amount of flexibility has been studied in the presence of different buffers and additives, and monitored at increasing temperature, up to the complete unfolding of the antibody. Overall, the structural characterization of rituximab can help in designing next-generation anti-CD20 antibodies and finding more efficient routes for rituximab production at industrial level.

Distribution of Charged Residues Affects the Average Size and Shape of Intrinsically Disordered Proteins.

Intrinsically disordered proteins (IDPs) are ensembles of interconverting conformers whose conformational properties are governed by several physico-chemical factors, including their amino acid composition and the arrangement of oppositely charged residues within the primary structure. In this work, we investigate the effects of charge patterning on the average compactness and shape of three model IDPs with different proline content. We model IDP ensemble conformations as ellipsoids, whose size and shape are calculated by combining data from size-exclusion chromatography and native mass spectrometry. For each model IDP, we analyzed the wild-type protein and two synthetic variants with permuted positions of charged residues, where positive and negative amino acids are either evenly distributed or segregated. We found that charge clustering induces remodeling of the conformational ensemble, promoting compaction and/or increasing spherical shape. Our data illustrate that the average shape and volume of the ensembles depend on the charge distribution. The potential effect of other factors, such as chain length, number of proline residues, and secondary structure content, is also discussed. This methodological approach is a straightforward way to model IDP average conformation and decipher the salient sequence attributes influencing IDP structural properties.

Effect of the simulated half leaf width of a multileaf collimator on volumetric modulated arc therapy plan quality in hippocampal avoidance whole-brain radiotherapy.

PurposeWhole‐brain radiotherapy (WBRT) is commonly used in patients with multiple brain metastases. Compared with conventional WBRT, hippocampal avoidance WBRT (HA‐WBRT) more favorably preserves cognitive function and the quality of life. The hippocampal volume is considerably small (approximately 3.3 cm3). Therefore, downsizing the leaf width of a multileaf collimator (MLC) may provide higher spatial resolution and better plan quality. Volumetric modulated arc therapy (VMAT) could simulate the half MLC leaf width through couch shifting between arcs. This study investigated changes in VMAT quality for HA‐WBRT with a simulated fine MLC leaf width.MethodsWe included 18 patients with brain metastasis. All target and avoidance structures were contoured by an experienced radiation oncologist. The prescribed dose was 30 Gy in 10 fractions. For each patient, three different treatment plans were generated for comparison: VMAT with couch‐shift, VMAT without couch‐shift, and TomoTherapy. All treatment plans fulfilled Radiation Therapy Oncology Group (RTOG) 0933 criteria for HA‐WBRT. The Wilcoxon paired signed‐rank test was used to compare different treatment plans.ResultsVMAT with couch‐shift had the better average conformity index (0.823) with statistically significant difference compared to VMAT without couch‐shift (0.810). VMAT with couch‐shift (0.219) had a more favorable average homogeneity index (HI) than did VMAT without couch‐shift (0.230), although the difference was not significant. TomoTherapy had an optimal average HI of 0.070. In terms of the hippocampus, all three treatment plans met the RTOG 0933 criteria. VMAT with couch‐shift had a lower average D max (15.2 Gy) than did VMAT without couch‐shift (15.3 Gy, p = 0.071) and TomoTherapy (15.5 Gy, p = 0.133). The average D 100% of hippocampus was the same for both VMAT with and without couch‐shift (8.5 Gy); however, TomoTherapy had a lower average D 100% value of 7.9 Gy. The treatment delivery time was similar between VMAT with and without couch‐shift (average, 375.0 and 369.6 s, respectively). TomoTherapy required a long average delivery time of 1489.9 s.ConclusionThe plan quality of VMAT for HA‐WBRT was improved by using the couch‐shift technique to simulate the half MLC leaf width. However, the improvement was not statistically significant except conformity index. The downsizing effect decreased with the use of the sophisticated grade of VMAT. TomoTherapy offered superior plan quality but required the longest delivery time.

Mg2+-dependent conformational equilibria in CorA and an integrated view on transport regulation.

The CorA family of proteins regulates the homeostasis of divalent metal ions in many bacteria, archaea, and eukaryotic mitochondria, making it an important target in the investigation of the mechanisms of transport and its functional regulation. Although numerous structures of open and closed channels are now available for the CorA family, the mechanism of the transport regulation remains elusive. Here, we investigated the conformational distribution and associated dynamic behaviour of the pentameric Mg2+ channel CorA at room temperature using small-angle neutron scattering (SANS) in combination with molecular dynamics (MD) simulations and solid-state nuclear magnetic resonance spectroscopy (NMR). We find that neither the Mg2+-bound closed structure nor the Mg2+-free open forms are sufficient to explain the average conformation of CorA. Our data support the presence of conformational equilibria between multiple states, and we further find a variation in the behaviour of the backbone dynamics with and without Mg2+. We propose that CorA must be in a dynamic equilibrium between different non-conducting states, both symmetric and asymmetric, regardless of bound Mg2+ but that conducting states become more populated in Mg2+-free conditions. These properties are regulated by backbone dynamics and are key to understanding the functional regulation of CorA.

Signal from the noise: A mixed graphical and quantitative process mining approach to evaluate care pathways applied to emergency stroke care

ObjectiveMapping real-world practice patterns vs. deviations from intended guidelines and protocols is necessary to identify and improve the quality of care for emergent medical conditions like acute ischemic stroke. Most status-quo process identification relies on expert opinion or direct observation, which can be biased or limited in scalability. We propose a mixed graphical and quantitative process mining approach to Electronic Health Record (EHR) event log data as a unique opportunity not only to more easily identify practice patterns, but also to compare real-world care processes and measure their conformance or variability. MaterialsData was obtained from the event log of a major EHR vendor (Epic) for Stanford Health Care Hospital patients aged 18 years and older presenting to the ED from January 1, 2010 through December 31, 2018 and receiving tPA (tissue plasminogen activator) within 4.5 h of presentation. MethodsWe developed an unsupervised process-mining algorithm to create a process map from clinical event logs. The method first identifies the most common events across the cohort. Then, all possible ordered events are recorded, and a summarized vector of nodes (events) and edges (events occurring in series) are mapped by their timing and probability. The highest probability ordered pairs are used to identify the most common path. We define measures for individual pathways conformity and average conformity across all encounters. ResultsAutomatically generated process mining graphs, and specifically it’s the most common path, mimicked our institutions recommended “code stroke” clinical pathway. The average conformity score for our cohort was 0.36 (i.e. paths had an average of 36% overlap with all possible paths), with a range from high of 0.64 and low of 0.20. DiscussionThis method allows for unsupervised visualization of the current state of common processes as well as their most common path, which can then be used to calculate the conformity of individual pathways through this process. These results may be used to evaluate the consistency of quality care at a given institution. It may also be extended to other common processes like sepsis or myocardial infarction care or even those which currently lack standardized clinical pathways. ConclusionOur mixed graphical and quantitative process mining approach represents an essential data analysis step to improve complex care processes by automatically generating qualitative and quantitative process measures from existing event log data which can then be used to target quality improvement initiatives.

Swelling of asymmetric pom-pom polymers in dilute solutions

In this paper we continue our recent analysis [K. Haydukivska et al., J. Mol. Liq., 2021, 328, 115456] of complex molecules with two branching points at both ends of the linear backbone with f1 and f2 side arms starting from them, known as the pom-pom polymers. Here, we analyze the asymmetric case, f1 ≠ f2, by applying both the analytical approach, based on the direct polymer renormalization, and computer simulations using both dissipative particle dynamics and Monte Carlo methods. We study the role played by the molecular asymmetry of average polymer conformations, considering the infinite dilution regime and good solvent conditions.The quantitative estimates are reported for the set of universal size and shape characteristics of such molecules and for their individual branches, all the functions of f1 and f2. In particular, we evaluate the size ratio of the gyration radii of symmetric and asymmetric pom-pom topologies with the same molecular weight and quantitatively reveal an increase of the effective size of a molecule caused by its asymmetry. We also introduce and analyse the asymmetry factor and estimate the shift of the center of mass caused by the presence of side stars, which can serve as another characteristic of the asymmetry of pom-pom structure.

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

Feasibility and Patient Tolerance of Proton Based Stereotactic Body Radiotherapy

<h3>Purpose/Objective(s)</h3> Proton-based stereotactic body radiotherapy (SBRT) may provide a dosimetric benefit vs photon SBRT in certain cases, seeking to reduce toxicity risks or facilitate reirradiation, though data are limited. We assessed the feasibility and patient tolerance of proton SBRT for palliation and ablation. <h3>Materials/Methods</h3> From Sep. 2019 to Dec. 2020, 58 patients were simulated for proton SBRT to 68 lesions. Acute toxicities were prospectively recorded using CTCAE grading without attribution, and patient-reported outcomes were assessed prior to and at completion of treatment using the MD Anderson Symptom Inventory (MDASI) and EQ-5D5L visual analogue score (VAS). <h3>Results</h3> 52 of 58 patients (90%) received SBRT treatment. Treatment was not initiated in 6 patients due insurance denial (n = 1), change in treatment plan (n = 1), interval disease progression (n = 1), transition to hospice (n = 2), or death (n = 1). Fractionation varied by indication and disease site with a median of 5 fractions and a median fractional dose of 8 Gy. Proton range uncertainty (RU) was ± 3.5% in soft tissue and ± 5% in lung. For bone or immobile lesions, a target equivalent to a standard photon SBRT PTV was defined and optimized with RU. For mobile targets, 4D CT was used to define an ITV for robust optimization, typically with 5 mm positional uncertainty + RU, using a PTV Evaluation for assessment of comparable SBRT plan metrics. Among 27 patients with 4D CT assessment of target motion, 20 (74%) were treated with beam-gated breath hold, 4 (15%) with abdominal compression, and 3 (11%) free breathing. Cone beam CT (CBCT) was used for image guidance at each fraction. Average conformity index was 1.06 and average number of treatment fields per target was 4 (range of 2-8). The median treatment time per fraction was 41 minutes (range 18-171 mins). There was a significant difference in treatment time for patients requiring breath hold (67 vs 47 mins, <i>P</i> = 0.006). Five patients (10%) required adaptive replanning due to set up uncertainties (n = 3) or tumor growth (n = 2). 11 patients (21%) had concurrent systemic therapy. 21 patients (40%) had no observable acute toxicity associated with treatment. Maximum recorded toxicities, related or unrelated to SBRT treatment, were grade 1 in 25 patients (48%), grade 2 (fatigue, depression, anorexia, proctitis) in 5 patients (10%), and grade 3 (dysphagia and hoarseness) in 1 patient (2%). Comparing pretreatment to end of treatment timepoints, there was a significant improvement in the mean VAS (68 to 76, <i>P</i> = 0.027, n = 33), with no significant change in the mean MDASI symptom (1.8, 1.8) or interference (2.2, 2.3) scores. <h3>Conclusion</h3> Proton-based SBRT was feasible and well-tolerated with no decrement in patient reported outcomes and a mean 8 point improvement in VAS at the conclusion of SBRT. Further follow-up is necessary for tumor control and late effects analysis.

HyperArc VMAT SRT for Locally Recurrent Previously-Irradiated Head and Neck Cancers: Plan Quality, Treatment Delivery Accuracy and Efficiency

To demonstrate the feasibility and efficacy of HyperArc VMAT treatments for locally recurrent, locally advanced or previously irradiated head and neck cancers treated with stereotactic radiotherapy (SRT).First, an anthropomorphic head phantom from the MD Anderson's IROC credentialing laboratory containing a 1.9 cm diameter spherical target and in vivo-dosimetry system was imaged, planned and irradiated (25 Gy in 1 fraction) using HyperArc VMAT module with 10MV-FFF beam. Second, RANDO head phantom was imaged, planned and irradiated (35 Gy in 5 fractions) by generating eight HyperArc VMAT plans (4 right, 4 left neck tumors) at different anatomical locations (C1-C4). Average tumor volume was 21.7 cc (13.0-32.3 cc). Distance to isocenter from the central marker of the Encompass device down to neck was 25.8 cm (23.8-28.0 cm) and 24.3 cm (22.0-27.1 cm) for the left and right neck tumors and 9 cm (in) from the both lateral markers that defined the patient protection zone. Third, two head and neck cancer patients with recurrent large mass of 56 cc (4.8 cm, diameter) on right maxillary sinus and 159 cc (6.7 cm, diameter) on right ethmoid sinus were imaged, planned and treated (35 Gy in 5 fractions) with HyperArc SRT. Plan quality, treatment delivery accuracy and efficiency were reported.Phantom irradiation results met all the compliance criteria set forth by the IROC for HyperArc SRS. For end-to-end tests, the average conformity index, Paddick conformation number, gradient and heterogeneity indices, and dose to 2 cm away from the target were 1.08 ± 0.05 (1.02-1.14), 0.85 ± 0.02 (0.83-0.89), 2.71 ± 0.27 (2.28-2.92), 0.14 ± 0.02 (0.11-0.17) and 23.5 ± 1.5% (21.4-25.0%). Average maximal dose to skin and spinal cord was 12.8 ± 3.5 Gy (9.2-16.7 Gy) and 4.6 ± 0.8 Gy (4.0-5.6 Gy). Mean values of modulation factor, beam on time and treatment time was 2.96 ± 0.5 (2.39-3.78), 3.1 ± 0.2 min (2.67-3.78 min), and 13.96 ± 0.50 min (13.39-14.78 min) with no collision issue. Pretreatment portal dosimetry quality assurance results demonstrated a high pass rate of 99.1 ± 1.6% for clinical gamma passing criteria of 2%/2 mm. Similar results were found on the patient's plans including highly conformal target coverage, sharp dose fall-off (50% dose fall-off within 5 mm from the target) and sparing adjacent critical organs including spinal cord (< 5 Gy). Perfect pitch couch correction average was < 1.5 mm and 2o. Beam on time was about 3.02 min, and patient's treatment completed within 15 min treatment slot.For recurrent head and neck SRT treatments, HyperArc VMAT provided highly conformal dose distribution, rapid dose fall-off, excellent sparing of adjacent critical organs, highly precise and accurate treatment that could be delivered to as low as C4 level. It could potentially allow HyperArc SRT to glomus tumors to those patients who may not tolerate frame-based SRS. Clinical follow up of these patients is ongoing to confirm the therapeutic benefits of this novel and attractive head and neck SRT.D. Pokhrel: None. M.E. Bernard: None. D. Lockhart: None. J. Jeremiah: None. D. Fabian: None. M.R. Kudrimoti: None.

Shape Analysis of Energy Polydisperse Polymers

AbstractThe equilibrium properties of an energy polydisperse chain, in which the interaction strengths between the monomers are drawn from a log‐normal distribution, at small polydispersity value are investigated by means of computer simulations. We perform coarse‐grained molecular dynamics simulations in an implicit solvent condition, and a comparative study with that of the corresponding homopolymers is carried out. In this study, we focus our attention in understanding the behavior of average instantaneous conformations, characterized through various shape parameters for both energy polydisperse and homopolymer chains as a function of temperature (T). It is found that the energy polydisperse chain has relatively low value of θ‐temperature (Tθ), at which polymer assumes ideal conformation. In particular, we investigate the conformational changes across Tθ and found that for T at/above Tθ the behavior is independent of the chain type and length, whereas for T below Tθ, strong dependence on the chain length is observed. To understand the detailed statistics, we also compare the distributions of chain sizes as well as eigenvalues of the gyration tensor.