Brownian motion of an ellipsoid

We studied the Brownian motion of isolated ellipsoidal particles in water confined to two dimensions and elucidated the effects of coupling between rotational and translational motion. By using digital video microscopy, we quantified the crossover from short-time anisotropic to long-time isotropic diffusion and directly measured probability distributions functions for displacements. We confirmed and interpreted our measurements by using Langevin theory and numerical simulations. Our theory and observations provide insights into fundamental diffusive processes, which are potentially useful for understanding transport in membranes and for understanding the motions of anisotropic macromolecules.

Premelting at Defects Within Bulk Colloidal Crystals

Premelting is the localized loss of crystalline order at surfaces and defects at temperatures below the bulk melting transition. It can be thought of as the nucleation of the melting process. Premelting has been observed at the surfaces of crystals but not within. We report observations of premelting at grain boundaries and dislocations within bulk colloidal crystals using real-time video microscopy. The crystals are equilibrium close-packed, three-dimensional colloidal structures made from thermally responsive microgel spheres. Particle tracking reveals increased disorder in crystalline regions bordering defects, the amount of which depends on the type of defect, distance from the defect, and particle volume fraction. Our observations suggest that interfacial free energy is the crucial parameter for premelting in colloidal and atomic-scale crystals.

Melting of two-dimensional tunable-diameter colloidal crystals

Melting of two-dimensional colloidal crystals is studied by video microscopy. The samples were composed of microgel spheres whose diameters could be temperature tuned, and whose pair potentials were measured to be short ranged and repulsive. We observed two-step melting from the crystal to a hexatic phase and from the hexatic to the liquid phase as a function of the temperature-tunable volume fraction. The translational and orientational susceptibilities enabled us to definitively determine the phase transition points, avoiding ambiguities inherent in other analyses and resolving a "dislocation precursor stage" in the solid phase that some of the traditional analyses may incorrectly associate with the hexatic phase. A prefreezing stage of the liquid with ordered patches was also found.

Capillary interactions between anisotropic colloidal particles

We report on the behavior of micron-sized prolate ellipsoids trapped at an oil-water interface. The particles experience strong, anisotropic, and long-ranged attractive capillary interactions which greatly exceed the thermal energy k(B)T. Depending on surface chemistry, the particles aggregate into open structures or chains. Using video microscopy, we extract the pair interaction potential between ellipsoids and show it exhibits a power law behavior over the length scales probed. Our observations can be explained using recent calculations, if we describe the interfacial ellipsoids as capillary quadrupoles.

Melting of colloidal crystal films

We study melting mechanisms in single and polycrystalline colloidal films composed of diameter-tunable microgel spheres with short-ranged repulsive interactions and confined between two glass walls. Thick films (>4 layers), thin-films (≤4 layers), and monolayers exhibit different melting behaviors. Thick films melt from grain boundaries in polycrystalline solid films and from film-wall interfaces in single-crystal films; a liquid-solid coexistence regime is observed in thick films but vanishes at a critical thickness of 4 layers. Thin solid films (2 to 4 layers) melt into the liquid phase in one step from both grain boundaries and from within crystalline domains. Monolayers melt in two steps with a middle hexatic phase.

Nematic nanotube gels

We report the creation of nematic nanotube gels containing large domains of isolated, oriented, half-micron-long, single-wall carbon nanotubes (SWNTs). We make them by homogeneously dispersing surfactant coated SWNTs at low concentration in an N-isopropyl acrylamide gel and then inducing a volume-compression transition. These gels exhibit hallmark properties of a nematic: birefrigence, anisotropy in optical absorption, and disclination defects. We also investigate the isotropic-to-nematic transition of these gels, and we describe the physical properties of their ensuing nematic state, including a novel buckling of sample walls. Finally, we provide a simple model to explain our observations.

Helical packings and phase transformations of soft spheres in cylinders

The phase behavior of helical packings of thermoresponsive microspheres inside glass capillaries is studied as a function of the volume fraction. Stable packings with long-range orientational order appear to evolve abruptly to disordered states as the particle volume fraction is reduced, consistent with recent hard-sphere simulations. We quantify this transition using correlations and susceptibilities of the orientational order parameter psi6. The emergence of coexisting metastable packings, as well as coexisting ordered and disordered states, is also observed. These findings support the notion of phase-transition-like behavior in quasi-one-dimensional systems.

Melting of lamellar phases in temperature sensitive colloid-polymer suspensions

We prepare a novel suspension composed of rodlike fd virus and thermosensitive polymer poly(N-isopropylacrylamide) whose phase diagram is temperature and concentration dependent. The system exhibits a rich variety of stable and metastable phases, and provides a unique opportunity to directly observe melting of lamellar phases and single lamellae. Typically, lamellar phases swell with increasing temperature before melting into the nematic phase. The highly swollen lamellae can be superheated as a result of topological nucleation barriers that slow the formation of the nematic phase.

Melting of multilayer colloidal crystals confined between two walls

Video microscopy is employed to study the melting behaviors of multilayer colloidal crystals composed of diameter-tunable microgel spheres confined between two walls. We systematically explore film thickness effects on the melting process and on the phase behaviors of single crystal and polycrystalline films. Thick films (>4 layers) are observed to melt heterogeneously, while thin films (≤4 layers) melt homogeneously, even for polycrystalline films. Grain-boundary melting dominates other types of melting processes in polycrystalline films thicker than 12 layers. The heterogeneous melting from dislocations is found to coexist with grain-boundary melting in films between 5- and 12-layers. In dislocation melting, liquid nucleates at dislocations and forms lakelike domains embedded in the larger crystalline matrix; the "lakes" are observed to diffuse, interact, merge with each other, and eventually merge with large strips of liquid melted from grain boundaries. Thin film melting is qualitatively different: thin films homogeneously melt by generating many small defects which need not nucleate at grain boundaries or dislocations. For three- and four-layer thin films, different layers are observed to have the same melting point, but surface layers melt faster than bulk layers. Within our resolution, two- to four-layer films appear to melt in one step, while monolayers melt in two steps with an intermediate hexatic phase.

Abstract P2-14-13: Single institute data to assess timing of surgery post neoadjuvant in breast cancer patients

Background: This study aims to analyze the impact of the time taken from the completion of neoadjuvant chemotherapy to surgery on patients' outcomes in terms of pathological response, overall survival and disease-free survival. There is no specific guideline for timing of the surgery. This study presents the experience of our institute's unique and large data of locally advanced breast cancer patients who received neoadjuvant systemic therapy.

Methods: This retrospective study evaluated patients diagnosed with Stage II and III breast cancer patients who received neoadjuvant chemotherapy, which was FEC and Taxotere +/-Herceptin depending on Her2 status of disease. Evaluation of the treatment outcome was based on the time interval between completion of neoadjuvant chemotherapy and surgery. Patients were selected from the time frame of January 2004 to December 2014. The effect of time interval was studied using two types of stratification. First stratification included time interval less than 4 weeks, 4-6 weeks and more than 6 weeks. Second stratification included patients with time interval <4 weeks, 4-7 weeks, and ≥8 weeks. Patients were also evaluated on the basis of receptor status ER, PR and Her2, and their outcomes.

Results: A total of 611 patients were identified. The patients were divided into two cohorts for better analysis. The first cohort showed 94 patients (15.4%) who had surgery within 4 weeks of their last dose of neoadjuvant chemotherapy, 378 (61.9%) within 4-6 weeks, and 139 (22.7%) ≥6 weeks. For the second cohort 94 patients (15.4%) had surgery within 4 weeks, 424 (69.4%) within 4-7 weeks, and 93 (15.2%) ≥ 8 weeks. Median OS and median DFS is not reached. OS at 5 years was 89.6% and DFS at 5 years was 74%. In both cohorts, OS and DFS were not significant when stratified to timing of surgery but the trend of DFS, although not statistically significant, was poor when patients had surgery more than 6 and 8 weeks. When patients were assessed on pathologic response stratified with timing of surgery, about 15% of patients had surgery ≥8 weeks, only 12.9% of those had complete pathological response compare to patients whose surgery was 6-7 weeks and complete pathologic response was 26% (p=0.02). In terms of receptor status, (ER-/HER-2+) patients had a statistically significant decrease in complete pathologic response if surgery was ≥8 weeks. However, ER+/HER-2-, (ER+/HER-2+), ER-/HER-2- had no difference in complete pathological response.

Conclusion: The above data indicates that our patients showed improved complete pathologic response if the surgery was performed within 8-weeks, especially for (ER-/HER-2+) patients. All patients post neoadjuvant had better OS and DFS trends if the surgery was performed between 4-6 weeks. The data suggests that early surgery helps complete pathologic response, and the necessary measures must be taken to identify any obstacles leading to delay in surgery and eliminating these obstacles.

Citation Format: Suleman K, Haque E, Mushtaq AH, Badran A, Alsayed A, Ajarim D, Twegieri T, Almalik O, Jastaniyah NT, Elhassan T, Alkhayal W. Single institute data to assess timing of surgery post neoadjuvant in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-14-13.

Overall symptom severity as a patient-reported outcome measure for chronic rhinosinusitis: what it reflects and how to measure it

BACKGROUND

The objective of this study was to identify how - and to what extent - overall symptom severity (OSS) score reflects individual chronic rhinosinusitis (CRS) symptoms and whether it can be measured using alternatives to the standard visual analog scale (VAS).

METHODS

CRS patients from four sites across three continents rated their OSS scores, severities of nasal obstruction, nasal drainage, decreased sense of smell, facial pain/pressure and sleep disturbance using a standard VAS, VAS with labeled tick marks at every 1 centimeter, and by writing down their OSS on a scale of 0 - 100 (which was divided by 10), all of which lead to severity scores ranging from 0 - 10 in 0.1 intervals. Quality of life was measured using the SNOT-22 and EQ-5D VAS.

RESULTS

In 311 CRS patients, OSS score was significantly correlated with SNOT-22 and EQ-5D VAS. OSS score was most greatly associated with the mean of all individual symptom severity scores. From individual CRS symptoms, OSS was most greatly associated with nasal obstruction followed by nasal drainage and facial pain/pressure severities. These results held true for participants with and without nasal polyps. Measurement of OSS and individual symptom severity scores using a standard VAS, tick-marked VAS, and write-in option had near-perfect consistency.

CONCLUSIONS

We demonstrate for the first time that OSS largely reflects the mean of individual CRS symptom severities, although OSS is=== most weighted by nasal obstruction severity. OSS and individual symptom severity scores can be measured using a standard VAS, tick-marked VAS or write-in prompt with near-perfect consistency.

The broad spectrum of clinical manifestations observed in three patients with L2 hydroxyglutaric aciduria spans from febrile seizures to complex dystonia

L-2 hydroxyglutaric aciduria (L-2-HGA) is a rare autosomal recessive progressive, organic aciduria which presents with a wide variety of clinical manifestations. Diagnosis is complex and necessitates an increase in clinical suspicion of the disease to obtain the necessary diagnostic tests and thus early administration of appropriate management. In this case series, we are reporting three cases of patients with L-2-HGA who presented with a variety of clinical manifestations. All patients presented with a constellation of symptoms including febrile seizures, hyperactivity and intellectual difficulties. One case had an unusual presentation of cervical dystonia in early adulthood. Another case had a homozygous variant, L2HGDH: NM_024884.3: c.368 A > G p. (Tyr123Cys) classified as variant of uncertain significance (VUS) at that time but recently has been reclassified as likely pathogenic variant in clin var. Furthermore, brain MRI of two patients depicted characteristic signs consistent with L-2-HGA. The findings include, symmetrical confluent high T2/FLAIR signal intensity of the white matter involving the subcortical U fibers and deep white matter with sparing of the immediate periventricular white matter, internal capsules and corpus callosum. There was also symmetric abnormal T2 signal intensity of the caudate nuclei, lentiform nucleus as well as the dentate nuclei of the cerebellum. Overall, only few cases with similar genetic mutation have been documented in the literature and were of Saudi origin. The aim of the study is to highlight the clinico-radiological features of L-2-HGA to aid in early, prompt diagnosis, and thus appropriate follow up and management of the disease with riboflavin, levocarnitine and a low-lysine diet.