Abstract OT3-20-03: Refusal of Breast Surgery in Breast Cancer Patients With cCR After Neoadjuvant Systemic Therapy and Vacuum-assisted Biopsy (VAB) and SLNB Confirmed pCR. An interim report of the prospective non-randomized trial. NCT04293796

Introduction The aim of the study was to prove efficacy and safety of de-escalation of traditional breast surgery in BC patients who develop cCR after neoadjuvant systemic therapy. Refusal of surgery was offered to exceptional responders after vacuum-assisted tumor bed biopsy and sentinel lymph node biopsy confirmed absence of residual disease (pCR). Materials and methods A single-center prospective study was run in the NMRC n.a. N.N. Petrov. Starting from August of 2020, 35 patients with early сT1-2N0-1M0 (stage Ia-IIb) triple-negative and HER2-positive (both ER+ and ER-) unifocal tumours without DCIS in core-biopsy specimen enrolled in the study. Primary lesions were marked with a single clip in the centre. In cases with nodal involvement (cN1) the affected lymph nodes were also clipped. Patients with triple-negative breast cancer received 4 cycles of AC q21d followed by 12 cycles of weekly paclitaxel and carboplatin AUC 2.0. HER2-positive patients received 4 cycles of AC followed by 4 cycles of docetaxel combined with trastuzumab and pertuzumab q21d. Breast US, mammography and SPECT were used at baseline and at response evaluation. Vacuum-assisted biopsy was performed with 7G needle and US-guidance in the OR simultaneously with the SLNB. VAB protocol included retrieval of the tumor clip as first stage. Subsequently surrounding tissues were sampled, and markers were placed to guide radiotherapy. In case residual tumor was found patients received standard breast-conserving surgery. In case the sentinel lymph nodes were found to be positive, standard level II axillary clearance was performed. HER2-positive patients with pCR confirmed by VAB and SLNB received adjuvant trastuzumab up to one year. HER2-positive patients with residual breast or nodal involvement received trastuzumab emtansine up to one year. In case ER+, all patients received appropriate endocrine-therapy. In case of residual in-breast or nodal involvement patients with triple-negative breast cancer received standart capecitabine. Results The interim analysis included 25 patients in both groups. The median follow-up of disease-free survival for patients is 12 months. In the triple-negative group 12 patients achieved cCR. All patients went on to receive VAB and SLNB. After VAB and SLNB pCR was confirmed 11 patients (91.7%). 1 patient had invasive residual tumor with less than 5% cellularity. FNR in this group was 8.3% (1/12). Patient with invasive residual tumor received standard breast-conserving surgery. All the patients in the TNBC group were also found to be (sn)ypN0. In the HER2-positive group cCR was achieved 13 patients. All patients went on to receive VAB and SLNB. After VAB and SLNB pCR was confirmed 10 patients (77%). 3 patients had invasive residual tumor with less than 5% cellularity. FNR in this group was 23% (3/13). Patients with invasive residual tumor received standard breast-conserving surgery. All HER2-positive patients were found to be (sn)ypN0. One patient with HER2-positive subtype experienced a local reccurence in the postoperative zone 16 months after surgery. Initially, this patient achieved cCR and undergone VAB with SLNB. On final pathomorphologic examination isolated focuses of DCIS were found (ypTisN0). Standard breast-conserving surgery was performed and histologically only DCIS was found. This patient recieved 1-year of Trastuzumab and standard radiotherapy with boost. After the histologic confirmation of local reccurence patient underwent nipple-sparring mastectomy with reconstruction and nowadays she is recieveing therapy with trastuzumab emtansine (T-DM1). Conclusion All visualization modalities fail to provide reliable information on the true rate of pCR. Contemporary systemic therapy regimens after accurate selection of patients, following the inclusion criteria, allows to achieve pCR in 75-90%, thereby reducing the risk of FNR after VAB. The trial continues to enroll patients and further follow-up is needed.

Citation Format: Petr Krivorotko, Sergey Yerechshenko, Alexander Emelyanov, Ekaterina Busko, Tengiz Tabagua, Viktoria Mortada, Konstantin Zernov, Alexander Komyakhov, Kirill Nikolaev, Elena Zhiltsova, Larisa Gigolaeva, Roman Pesotsky, Diana Enaldieva, Yana Bondarchuk, Nikolay Amirov, Valentin Channov, Sergey Novikov, Zhanna Bryantseva, Anna Artemyeva, Viktoriya Smirnova, Tatiana Semiglazova, Alexey Belyaev, Vladimir Semiglazov. Refusal of Breast Surgery in Breast Cancer Patients With cCR After Neoadjuvant Systemic Therapy and Vacuum-assisted Biopsy (VAB) and SLNB Confirmed pCR. An interim report of the prospective non-randomized trial. NCT04293796. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-20-03.

Band Structure, Phonon Spectrum and Thermoelectric Properties of Ag3CuS2

Sulfides and selenides of copper and silver have been intensively studied, particularly as potentially efficient thermoelectrics. Ag3CuS2 (jalpaite) is a related material. However very little is known about its physical properties. It has been found that the compound undergoes several structural phase transitions, having the tetrahedral structural modification I41/amd at room temperature. In this work, its band structure, phonon spectrum and thermoelectric properties were studied theoretically and experimentally. Seebeck coefficient, electrical conductivity and thermal conductivity were measured in a broad temperature range from room temperature to 600 K. These are the first experimental data on transport properties of jalpaite. Ab initio calculations of the band structure and Seebeck coefficient were carried out taking into account energy dependence of the relaxation time typical for the scattering of charge carriers by phonons. The results of the calculations qualitatively agree with the experiment and yield large values of the Seebeck coefficient characteristic for lightly doped semiconductor. The influence of intrinsic defects (vacancies) on the transport properties was studied. It was shown that the formation of silver vacancies is the most probable and leads to an increase of hole concentration. Using the temperature dependent effective potential method, the phonon spectrum and thermal conductivity at room temperature were calculated. The measurements yield low lattice thermal conductivity value of 0.5 W/(m K) at 300 K, which is associated with the complex crystal structure of the material. The calculated room temperature values of the lattice thermal conductivity were also small (0.14-0.2 W/(m K)).

Tailoring of the Distribution of SERS-Active Silver Nanoparticles by Post-Deposition Low-Energy Ion Beam Irradiation

The possibility of controlled scalable nanostructuring of surfaces by the formation of the plasmonic nanoparticles is very important for the development of sensors, solar cells, etc. In this work, the formation of the ensembles of silver nanoparticles on silicon and glass substrates by the magnetron deposition technique and the subsequent low-energy Ar⁺ ion irradiation was studied. The possibility of controlling the sizes, shapes and aerial density of the nanoparticles by the variation of the deposition and irradiation parameters was systematically investigated. Scanning electron microscopy studies of the samples deposited and irradiated in different conditions allowed for analysis of the morphological features of the nanoparticles and the distribution of their sizes and allowed for determination of the optimal parameters for the formation of the plasmonic-active structures. Additionally, the plasmonic properties of the resulting nanoparticles were characterized by means of linear spectroscopy and surface-enhanced Raman spectroscopy. Hereby, in this work, we demonstrate the possibility of the fabrication of silver nanoparticles with a widely varied range of average sizes and aerial density by means of a post-deposition ion irradiation technique to form nanostructured surfaces which can be applied in sensing technologies and surface-enhanced Raman spectroscopy (SERS).

Charge transport in the spatially correlated exponential random energy landscape: effect of the nonpositive correlation function

Charge transport in amorphous semiconductors having spatially correlated exponential density of states (DOS) has been considered for the arbitrary behavior of the correlation function of random energies. Average carrier velocity is exactly calculated for the quasi-equilibrium (nondispersive) transport regime. For the symmetric exponential DOS with exponential tails for low and high energies and nonpositive correlation function the temperature of the transition to the dispersive transport regime depends on correlation properties and becomes greater than the traditional estimation based on the DOS decay energy kT = U₀. Another new feature of the transport in the landscape having nonpositive correlation function is the decrease of the mobility with the field in the low field region and development of the universal mobility field dependence for stronger fields.

Topological phase singularities in atomically thin high-refractive-index materials

Atomically thin transition metal dichalcogenides (TMDCs) present a promising platform for numerous photonic applications due to excitonic spectral features, possibility to tune their constants by external gating, doping, or light, and mechanical stability. Utilization of such materials for sensing or optical modulation purposes would require a clever optical design, as by itself the 2D materials can offer only a small optical phase delay - consequence of the atomic thickness. To address this issue, we combine films of 2D semiconductors which exhibit excitonic lines with the Fabry-Perot resonators of the standard commercial SiO2/Si substrate, in order to realize topological phase singularities in reflection. Around these singularities, reflection spectra demonstrate rapid phase changes while the structure behaves as a perfect absorber. Furthermore, we demonstrate that such topological phase singularities are ubiquitous for the entire class of atomically thin TMDCs and other high-refractive-index materials, making it a powerful tool for phase engineering in flat optics. As a practical demonstration, we employ PdSe2 topological phase singularities for a refractive index sensor and demonstrate its superior phase sensitivity compared to typical surface plasmon resonance sensors.

Abstract P3-18-09: Refusal of breast surgery in breast cancer patients with clinical complete response (cCR) after neoadjuvant systemic therapy and vacuum-assisted biopsy (VAB) and sentinel lymph node biopsy (SLNB) confirmed pathological complete response (pCR). A first report of the prospective non-randomized trial results. NCT04293796

Introduction The aim of the study was to prove efficacy and safety of refusal of traditional breast surgery in BC patients who develop cCR after neoadjuvant chemotherapy. Refusal of surgery was offered to exceptional responders after vacuum-assisted tumor bed biopsy and sentinel lymph node biopsy confirmed absence of residual disease (pCR). Materials and methods A single-center prospective study was run in the NMRC n.a. N.N. Petrov. Starting from August of 2020 20 patients with early сT1-2N0-1M0 (stage Ia-IIb) triple-negative and HER2-positive (both ER+ and ER-) unifocal tumours without in situ component in core-biopsy specimen enrolled in the study. Primary lesions were marked with a single clip in the centre. In cases with nodal involvement (cN1) the affected lymph nodes were also clipped. Patients with triple-negative breast cancer received 4 cycles of AC q21d followed by 12 cycles of weekly paclitaxel and carboplatinum AUC 2.0. HER2-positive patients received 4 cycles of AC followed by 4 cycles of docetaxel combined with trastuzumab and pertuzumab q21d. Breast US, mammography and SPECT were used at baseline and at response evaluation. Vacuum-assisted biopsy was performed with 7G needle and US-guidance in the OR simultaneously with the SLNB under general anesthesia. VAB protocol included retrieval of the tumor clip as first stage. Subsequently surrounding tissues were sampled, and markers were placed to guide radiotherapy. In case residual tumor was found patients received standard breast-conserving surgery. In case the sentinel lymph nodes were found to be positive, standard level II axillary clearance was performed. HER2-positive patients with pCR confirmed by VAB and SLNB received adjuvant trastuzumab up to one year. HER2-positive patients with residual breast or nodal involvement received trastuzumab-emtanzine up to one year. In case ER-positive, all patients received appropriate endocrine-therapy. In case of residual in-breast or nodal involvement patients with triple-negative breast cancer received 6 cycles of capecitabine. Results cCR was achieved in 8 of 10 patients in the HER2-positive group. VAB and SLNB were performed in 7 cases and confirmed pCR in 5 patients. 2 had residual in-breast disease with <10% cellularity. One patient with cCR requested standard surgical approach that confirmed pCR. 2 patients failed to obtain cCR. Both received standard surgery. In one of the cases no residual disease was found, in another one - a residual in-breast tumor was found at section. All HER2-positive patients were found to be sn ypN0. In the triple-negative group cCR was achieved in 6 of 10 patients. 4 patients went on to receive VAB and SLNB. After VAB and SLNB pCR was confirmed in three of them. 1 patient had residual tumor with less than 5% cellularity. Two patients with cCR after NAT opted for standard surgery. In both cases pCR was confirmed. 4 patients with clinically detectable residual in-breast tumor received standard surgery. All turned out to have pCR. All the patients in the TNBC group were also found to be sn ypN0.ConclusionVisualization modalities fail to provide reliable information on the true rate of pCR. Contemporary systemic therapy regimens provide the rate of pCR up to 60-70%. In all cases of NAT tumor bed marking at baseline is an essential procedure to guide future interventions and confirm their success. Discrepancies between radiologic assessment and true rates of pCR are a substrate for further search for the techniques that would challenge the role of surgery in exceptional responders developing cCR. The trial continues to enrol patients.

Citation Format: Petr Krivorotko, Sergey Yerechshenko, Alexander Emelyanov, Ekaterina Busko, Alexander Bessonov, Viktoriya Gukova, Alexander Komyahov, Elena Zhiltsova, Kirill Nikolaev, Tengiz Tabagua, Larisa Gigolaeva, Roman Pesotsky, Sergey Novikov, Zhanna Bryantseva, Anna Artemyeva, Viktoriya Smirnova, Vladimir Kushnarev, Alexey Belyaev, Tatiana Semiglazova, Vladimir Semiglazov. Refusal of breast surgery in breast cancer patients with clinical complete response (cCR) after neoadjuvant systemic therapy and vacuum-assisted biopsy (VAB) and sentinel lymph node biopsy (SLNB) confirmed pathological complete response (pCR). A first report of the prospective non-randomized trial results. NCT04293796 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-09.

Comparison of diagnostic characteristics between sentinel lymph node biopsy (SLNB) and radio-guide elective neck dissection (RGEND) in patients with T1-2N0 oral tongue cancer

e18037

Background: Elective neck dissection remains the standard treatment for cN0 oral cancer due to the high incidence of occult lymph node (LN) metastases. Sentinel lymph node biopsy (SNB) might be a less morbid alternative to neck dissection. Diagnostic value of SLNB depends on the number of sampled LNs. We aimed to compare the diagnostic features of SNB and RGEND in patients with T1-2N0 oral tongue cancer. Methods: A prospective study was conducted in patients with cT1-2N0M0 oral tongue squamous cell carcinoma treated between January 2016 and December 2020. The procedure included SLNB ollowed by immediate extent ipsilateral neck dissection. SLNB included accumulated radiotracer LNs, which located close to the primary tumor. RGEND included LNs accumulated radiotracer with all LNs located at the same level. Pathology assessment was performed and diagnostic characteristics were compared between SLNB and RGEND. Results: A total of 38 patients were enrolled. The mean age was 55.7±13,1. Twenty-four patients had unilateral lymph flow and 14 had bilateral. Sentinel LNs were located at levels IIa-III. Occult metastases were found in 15,8% (n = 6) of patients. The median number of LNs in the sample was 3 (IQR: 1-5). The sensitivities of SLNB and RGEND were 50% (95%CI: 15.7 - 84.3) and 100% (95%CI: 54.7-100), respectively, p-value = 0.001. Specificity was similar among groups: 100% (95%CI: 88-100) and 100% (95%CI: 89.1-100. SLNB had accuracy of 89.5% (95%CI: 77.2 - 97), and RGEND 100% (95% CI: 90.7-100), p-value = 0.001. Positive predictive value (PPV) was similar among groups. Negative predictive value (NPV) was 88.2% (95% CI: 78.9 - 93.7) in SLNB and 100% (95%CI: 91-100) in RGEND groups. p-value = 0.001. Conclusions: SLNB and RGEND have high rates of specificity, accuracy, PPV, and NPV, regardless of sampling size. RGEND has the highest sensitivity in patients with cT1-2N0 oral tongue cancer.

Preoperative stereotactic ablative body radiotherapy with postoperative conventional irradiation of soft tissue sarcomas: Protocol overview with a preliminary safety report

e23546

Background: Preoperative radiotherapy in patients with soft tissue sarcomas is characterized by important advantages: high precision of dose delivery, reduction of tumour volume and implantation potential, induction of immunologic response. Postoperative irradiation is associated with a reduced risk of complication, and a comprehensive radiotherapy planning in accordance with the pathologic report. Combination of pre- and postoperative irradiation gives the opportunity to use the best of both methods. Methods: from 06.2018 to 01.2021 24 patients with soft tissue sarcomas of extremities were included in the protocol (NCT04330456) and 14 cases with at least 12 months follow-up were eligible for analysis. Preoperative stereotactic ablative body radiotherapy (SBRT) was performed as 5 fraction of 7 Gy with dose reduction (5 fractions of 5 Gy) on the margins of the tumor. Postoperative radiotherapy started 5-8 weeks after the surgery and was performed as standard compartmental irradiation in 25 fractions of 2Gy. Complications were determined according to CTCAE and wound complication scales. Results: Preoperative SBRT and subsequent radical resection with tumor free surgical margins were performed in all 14 cases. Primary wound closure was mentioned in all patients. Postoperative radiotherapy started 51.8 days (range 33-99 days) days after the surgery. With a relatively short follow-up of 21.5 (13-30) months, we recorded 2 cases (14%) of severe complications (Canadian sarcoma group criteria), and there were no local recurrences. Conclusions: Our preliminary results demonstrate that the combination of preoperative SBRT and postoperative conventional radiotherapy is feasible and does not increase the risk of postoperative complications. Clinical trial information: NCT04330456.

Two-dimensional bimolecular recombination in amorphous organic semiconductors

We consider the two-dimensional bimolecular recombination of charge carriers in amorphous organic semiconductors having the lamellar structure. We calculate the dependence of the effective recombination rate constant on the carrier density taking into account the correlated nature of the energetic disorder typical for organic semiconductors. The resulting recombination kinetics demonstrates a very rich variety of behaviors depending on the correlation properties of the particular semiconductor and relevant charge density range.

SPECT-CT localization of axillary sentinel lymph nodes for radiotherapy of early breast cancer

Purpose

To evaluate the opportunities of single photon emission tomography/computerized tomography (SPECT-CT) for localization of axillary sentinel lymph nodes (ASLNs) and subsequent radiotherapy planning in women with early breast cancer.

Material and methods

Individual topography of ASLN was determined in 151 women with clinical T1-2N0M0 breast cancer. SPECT-CT visualization of ASLNs was initiated 120 min after intra-peritumoral injection of 99mTc-radiocolloids. Doses absorbed by virtual ASLNs after the whole breast irradiation with standard and extended tangential fields were calculated on a treatment planning station.

Results

SPECT-CT demonstrated a large variability of ASLN localization. They were detected in the central subgroup in 94 (61%) patients, in pectoral - in 77 (51%), and in interpectoral - in 4 (3%) patients. Sentinel lymph nodes "lying on the chest" were revealed in 35 (23%) cases.We found that with standard tangential fields coverage of ASLNs was obtained only in 20% of evaluated women. Extended tangential fields can effectively irradiate ASLNs localized in all axillary sub-regions with the exception of ASLNs "lying on the chest".

Conclusion

SPECT-CT mapping of ASLNs in women with cT1-2N0M0 breast cancer reveals their variable localization. This information can be important for planning of radiation treatment in women that underwent breast conserving surgery without an axillary surgery.

Pulsed Laser Deposition of Nanostructured MoS3/np-Mo//WO3-y Hybrid Catalyst for Enhanced (Photo) Electrochemical Hydrogen Evolution

Pulsed laser ablation of MoS₂ and WO₃ targets at appropriate pressures of background gas (Ar, air) were used for the preparation of new hybrid nanostructured catalytic films for hydrogen production in an acid solution. The films consisted of a nanostructured WO_3−y underlayer that was covered with composite MoS₃/np-Mo nanocatalyst. The use of dry air with pressures of 40 and 80 Pa allowed the formation of porous WO_3−y films with cauliflower- and web-like morphology, respectively. The ablation of the MoS₂ target in Ar gas at a pressure of 16 Pa resulted in the formation of amorphous MoS₃ films and spherical Mo nanoparticles. The hybrid MoS₃/np-Mo//WO_3−y films deposited on transparent conducting substrates possessed the enhanced (photo)electrocatalytic performance in comparison with that of any pristine one (MoS₃/np-Mo or WO_3−y films) with the same loading. Modeling by the kinetic Monte Carlo method indicated that the change in morphology of the deposited WO_3−y films could be caused by the transition of ballistic deposition to diffusion limited aggregation of structural units (atoms/clusters) under background gas pressure growth. The factors and mechanisms contributing to the enhancement of the electrocatalytic activity of hybrid nanostructured films and facilitating the effective photo-activation of hydrogen evolution in these films are considered.

Abstract P3-03-39: Sentinel lymph node biopsy after surgery with removal of the primary tumor

Nowadays, sentinel lymph node biopsy (SLNB) is one of the basic methods for

diagnosing the lesion of regional lymph nodes (LN) and it is recommended by

experts as a standard method in determining the prevalence of the disease in breast

cancer patients (BC).

The aim of the study was the possibility of sentinel lymph node biopsy after

surgery with removal of the primary tumor.

Materials and methods

The study was conducted in the N.N. Petrov's National Medical Center of

Oncology from 2013 to 2018. SLNB was performed in patients who had a primary

tumorectomy in another medical institution. The study included patients with the

stage cN0. Radionuclide imaging of the sentinel lymph nodes (SLN) was

performed in 37 patients with breast cancer. The injection of radiopharmaceuticals

in postoperative scar was performed before the biopsy. Median of the period

between the operations was 21 days (14 to 30 days).

Results

After injection, the image of SLN was obtained in 91.9% (34 of 37) of patients.

During the operation, 1-5 sentinel lymph nodes were visualized. The lesion of the

sentinel lymph nodes (N+) was detected in 21.6% (8) patients, N0 in 78.4% (29)

patients, respectively.

There is no data for locoregional relapse for the period of observation from 2014 to

nowadays.

Conclusions

The obtained results are comparable with the results of sentinel lymph node biopsy

in primary patients with breast cancer stage cN0. This indicates the possibility of

biopsy after surgery with removal of the primary tumor.

Citation Format: Zhiltsova E, Krivorotko P, Dashayan G, Emelyanov A, Tabagua T, Bessonov A, Ivanova O, Kanaev S, Novikov S, Krzivickiyi P, Komayachov A, Nikolaev K, Gigolaeva L, Zernov K, Semiglazov V. Sentinel lymph node biopsy after surgery with removal of the primary tumor [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 P3-03-39.

Hierarchical self-assembly of gold nanoparticles into patterned plasmonic nanostructures

The integration of nanoparticle superstructures into daily life applications faces major challenges including the simplification of the self-assembly process, reduced cost, and scalability. It is, however, often difficult to improve on one aspect without losing on another. We present in this paper a benchtop method that allows patterning a macroscopic substrate with gold nanoparticle supercrystals in a one-step process. The method allows parallelization, and patterned substrates can be made with high-throughput. The self-assembly of a variety of building blocks into crystalline superstructures takes place upon solvent evaporation, and their precise placement over millimeter scale areas is induced by confinement of the colloidal suspension in micron-sized cavities. We mainly focus on gold nanorods and demonstrate their hierarchical organization up to the device scale. The height of the formed nanorod supercrystals can be tuned by simply varying nanorod concentration, so that the topography of the substrate and the resulting optical properties can be readily modulated. The crystalline order of the nanorods results in homogeneous and high electric field enhancements over the assemblies, which is demonstrated by surface-enhanced Raman scattering spectroscopy.

Decoupling a Cooper-pair box to enhance the lifetime to 0.2 ms

We present results on a circuit QED experiment in which a separate transmission line is used to address a quasilumped element superconducting microwave resonator which is in turn coupled to an Al/AlO(x)/Al Cooper-pair box charge qubit. With our device, we find a strong correlation between the lifetime of the qubit and the inverse of the coupling between the qubit and the transmission line. At the smallest coupling we measured, the lifetime of the Cooper-pair box was T₁=200 μs, which represents more than a twentyfold improvement in the lifetime of the Cooper-pair box compared with previous results. These results imply that the loss tangent in the AlO(x) junction barrier must be less than about 4×10⁻⁸ at 4.5 GHz, about 4 orders of magnitude less than reported in larger area Al/AlO(x)/Al tunnel junctions.

Hydrodynamic interactions in ribbon channels: from quasi-one-dimensional to quasi-two-dimensional behavior

We present a study of the dynamics of confined suspensions whose dimensionality is intermediate between quasi-one-dimensional and quasi-two-dimensional (q2D) using microfluidic channels of various widths. The crossover between the two limiting behaviors is found to occur to different extent for different dynamic correlations between a pair of particles. In particular, the transverse coupling diffusion coefficient of particle pairs significantly deviates from its q2D form even in surprisingly wide channels.

Collaborative development of predictive toxicology applications

OpenTox provides an interoperable, standards-based Framework for the support of predictive toxicology data management, algorithms, modelling, validation and reporting. It is relevant to satisfying the chemical safety assessment requirements of the REACH legislation as it supports access to experimental data, (Quantitative) Structure-Activity Relationship models, and toxicological information through an integrating platform that adheres to regulatory requirements and OECD validation principles. Initial research defined the essential components of the Framework including the approach to data access, schema and management, use of controlled vocabularies and ontologies, architecture, web service and communications protocols, and selection and integration of algorithms for predictive modelling. OpenTox provides end-user oriented tools to non-computational specialists, risk assessors, and toxicological experts in addition to Application Programming Interfaces (APIs) for developers of new applications. OpenTox actively supports public standards for data representation, interfaces, vocabularies and ontologies, Open Source approaches to core platform components, and community-based collaboration approaches, so as to progress system interoperability goals.The OpenTox Framework includes APIs and services for compounds, datasets, features, algorithms, models, ontologies, tasks, validation, and reporting which may be combined into multiple applications satisfying a variety of different user needs. OpenTox applications are based on a set of distributed, interoperable OpenTox API-compliant REST web services. The OpenTox approach to ontology allows for efficient mapping of complementary data coming from different datasets into a unifying structure having a shared terminology and representation.Two initial OpenTox applications are presented as an illustration of the potential impact of OpenTox for high-quality and consistent structure-activity relationship modelling of REACH-relevant endpoints: ToxPredict which predicts and reports on toxicities for endpoints for an input chemical structure, and ToxCreate which builds and validates a predictive toxicity model based on an input toxicology dataset. Because of the extensible nature of the standardised Framework design, barriers of interoperability between applications and content are removed, as the user may combine data, models and validation from multiple sources in a dependable and time-effective way.

Structure of quasi-one-dimensional ribbon colloid suspensions

We report the results of an experimental study of a colloid fluid confined to a quasi-one-dimensional (q1D) ribbon channel as a function of channel width and colloid density. Our findings confirm the principal predictions of previous theoretical studies of such systems. These are (1) that the density distribution of the liquid transverse to the ribbon channel exhibits stratification; (2) that even at the highest density the order along the strata, as measured by the longitudinal pair correlation function, is characteristic of a liquid; and (3) the q1D pair correlation functions in different strata exhibit anisotropic behavior resembling that found in a Monte Carlo simulation for the in-plane pair correlation function of a hard sphere fluid in a planar slit.

Long-range electrostatic forces on the surfaces of aluminum oxide and silica oxide

The morphology and electrical microstructure of different anodic oxide films on aluminum and thermic oxide on surface p-type silica (KDB/100) were studied using atomic force microscopy and scanning capacitance microscopy. It was shown that the small basic element in the texture of both thin (0.05 microm) and thick (0.8 microm) oxide films represents a disklike element ('grain') approximately 200x200x30 nm in size. For films with a rough surface relief, the capacitance (and consequently, the surface potential) shows strong fluctuations in the vicinity of coarse (approximately 5-8 microm) pores. Because of this, the image of the surface obtained using atomic force microscopy does not coincide with that obtained by scanning capacitance microscopy (the opposite contrast effect). The manifestation of the opposite contrast correlates with an increase in the surface potential of the anodic oxide films measured by an independent method. A series of experiments under atmospheric conditions at different distances from the end of the cantilever to the surface of anodic oxide films showed that the influence of the surface field is detectable at long distances (up to 0.7 microm). It was shown that at a test temperature of 120 degrees C, the opposite contrast disappears: the images obtained in the semicontact (atomic force microscopy) and non-contact (scanning capacitance microscopy) modes coincide with each other. The results obtained suggest a relationship between the formation of electrostatic nanosized irregularities at the surface of oxide films and the sorption of water molecules under atmospheric conditions.