Distinct Planes Research Articles

Study of Ce3+-substitution induced defects restructuring in BiFeO3 by positron annihilation and other supportive methods

The results of Ce3+-substitution in place of Bi3+ in BiFeO3 nanocrystallites are reported in this work. Although Bi1-xCexFeO3 (x = 0, 0.025, …, 0.175) was formed with distinct crystallographic planes of X-ray diffraction, no structural transformation was observed unlike in the case of other lanthanide ion substitution of Bi3+ ions as reported earlier. The nanocrystallite sizes and the lattice parameters decreased during the increase of substitution. Transmission electron microscopic images also revealed the nanostructure formation and the decrease of the particle sizes. Energy dispersive X-ray analysis revealed appreciable incorporation of Ce into the BiFeO3 lattice. The measured band gap energies decreased owing to the creation of acceptor levels by Ce3+ ions. Distinct peaks in the X-ray photoelectron spectra at the expected binding energies indicated the presence of the two oxidation states Ce3+ and Ce4+. Positron annihilation studies proved the formation of interfacial defects with increase in substitution. Majority of the positrons diffused to the surfaces of the nanocrystallites and the mean lifetime of positrons increased. Coincidence Doppler broadened spectra, however, indicated positron trapping in the interfacial defects of the oxides of Ce and Bi overriding the annihilations of positrons at the surfaces in the range x = 0.075 to 0.125.

Influence of lithology and bedding orientation on failure behavior of “D” shaped tunnel

To explore the influence of lithology on the failure behavior of layered tunnel, true triaxial compression experiments were undertaken on cubical phyllite and yellow sandstone samples containing a “D” shaped hole. The failure progress of the hole sidewalls was monitored and captured using a miniature camera. The results reveal that the initial vertical failure stress of the phyllite samples presents a “U” shaped change as the bedding angle increases. At the bedding angle of 45°, compared with the initial vertical failure stress of the yellow sandstone tunnel, that of the phyllite tunnel is lower, resulting in larger rock fragments and deeper V-shaped grooves. The failure pattern of the phyllite tunnel is primarily manifested as extensive shear sliding failure, and the failure is more severe. The failure of the yellow sandstone tunnel is primarily characterized by the sequential laminar fracturing along the maximum principal stress direction, predominantly manifesting as tensile failure. The primary factors influencing the failure of two types of layered rocks are the significant variations in the clay mineral content within the rocks. For the phyllite, it contains nearly one-third of montmorillonite (a clay mineral). This results in the formation of weak bedding planes within surrounding rocks, which induces shear slip failures along these bedding planes. In contrast, the yellow sandstone has a lower clay mineral content, leading to the absence of distinct weak bedding planes within the surrounding rock. In this case, bedding planes present ignorable effect on the surrounding rock.

Polypoidal Choroidal Vasculopathy: Evaluation Based on 3-Dimensional Reconstruction of OCT Angiography

Three-dimensional (3D) reconstruction using swept-source OCT angiography (SS-OCTA) can provide insights into the nature and structure of polypoidal choroidal vasculopathy (PCV) and its component parts, the polypoidal lesion (PL) and the branching neovascular network (BNN). This study aims to describe novel observations of PCV using 3D reconstruction of SS-OCTA, and to compare these observations with similar images of type I macular neovascularization (MNV) typical neovascular age-related macular degeneration (nAMD). Clinical case series. Patients with PCV in either eye from clinical studies conducted in a tertiary retina center. Images with prespecified SS-OCTA imaging protocol were obtained and reconstructed in 3D. Forty neovascularization lesions (30 PCV and 10 typical nAMD) based on SS-OCTA were analyzed. The following 3 specific features were evaluated: (1) the pattern of flow signal within the PLs as either homogenous or showing internal vascular architecture; (2) the configuration of the BNN as hypermature, mature, or immature; and (3) the spatial arrangement of the PLs in relation to the BNN. Comparisons were made between PCV and typical nAMD. All PLs exhibited internal vascular architecture in the form of coil-like loops and none exhibited homogenous flow. Small focal nodules were present within this internal vascular architecture in 70% of PLs. Branching neovascular networks exhibited a hypermature/mature configuration (100 vs. 50%, P < 0.01) and were associated with thicker choroid compared with typical nAMD type 1 MNV (238.7 ± 104.3 vs. 155.6 ± 49.2, P= 0.02). The BNN and PL were located at distinct anteroposterior planes in 81% of the eyes. We identified proliferating vasculature in both the PL and the BNN. Comparison of the configuration suggests that the BNN represents a more chronic and inactive lesion than the PL. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Treatment of intramedullary spinal cord tumors: a modified Delphi technique of the North American Spine Society Section of Spine Oncology.

Intramedullary spinal cord tumors (IMSCTs) are rare tumors with heterogeneous presentations and natural histories that complicate their management. Standardized guidelines are lacking on when to surgically intervene and the appropriate aggressiveness of resection, especially given the risk of new neurological deficits following resection of infiltrative tumors. Here, the authors present the results of a modified Delphi method using input from surgeons experienced with IMSCT removal to construct a framework for the operative management of IMSCTs based on the clinical, radiographic, and tumor-specific characteristics. A modified Delphi technique was conducted using a group of 14 neurosurgeons experienced in IMSCT resection. Three rounds of written correspondence, surveys, and videoconferencing were carried out. Participants were queried about clinical and radiographic criteria used to determine operative candidacy and guide decision-making. Members then completed a final survey indicating their choice of observation or surgery, choice of resection strategy, and decision to perform duraplasty, in response to a set of patient- and tumor-specific characteristics. Consensus was defined as ≥ 80% agreement, while responses with 70%-79% agreement were defined as agreement. Thirty-six total characteristics were assessed. There was consensus favoring surgical intervention for patients with new-onset myelopathy (86% agreement), chronic myelopathy (86%), or progression from mild to disabling numbness (86%), but disagreement for patients with mild numbness or chronic paraplegia. Age was not a determinant of operative candidacy except among frail patients, who were deemed more suitable for observation (93%). Well-circumscribed (93%) or posteriorly located tumors reaching the surface (86%) were consensus surgical lesions, and participants agreed that the presence of syringomyelia (71%) and peritumoral T2 signal change (79%) were favorable indications for surgery. There was consensus that complete loss of transcranial motor evoked potentials with a 50% decrease in the D-wave amplitude should halt further resection (93%). Preoperative symptoms seldom influenced choice of resection strategy, while a distinct cleavage plane (100%) or visible tumor-cord margins (100%) strongly favored gross-total resection. The authors present a modified Delphi technique highlighting areas of consensus and agreement regarding surgical management of IMSCTs. Although not intended as a substitute for individual clinical decision-making, the results can help guide care of these patients. Additionally, areas of controversy meriting further investigation are highlighted.

Constitutive modeling of orthotropic nonlinear mechanical behavior of hardened 3D printed concrete

3D printing of concrete is a promising construction technology, offering the potential to build geometrically complex structures without the use of cost-intensive formwork. The layer-wise deposit of filaments during the 3D printing process results in an intrinsic orthotropic mechanical behavior in the hardened state. Beyond that, the material behavior of 3D printed concrete (3DPC) is governed by a highly nonlinear behavior, characterized by irreversible deformations, strain hardening, strain softening and a degradation of the material stiffness. In this contribution, a new constitutive model for describing the orthotropic and highly nonlinear material behavior of 3DPC will be presented. It is formulated by the extension of a well-established isotropic damage plasticity model for concrete to orthotropic material behavior by linear mapping of the stress tensor into a fictitious isotropic configuration. The performance of the new model will be evaluated by finite element simulations of three-point bending tests of 3DPC samples, performed for different orientations of the loading direction relative to the printing direction and comparison with experimental results. In addition, the applicability of the model to replicate the mechanical behavior of 3DPC, manufactured by the alternative 3D printing process of binder jetting of cementitious powders, will be demonstrated by 3D finite element simulations of an arch structure with varying orientations of the loading direction relative to the layering. Overall, the proposed model provides a computationally efficient modeling approach for large-scale finite element simulations of 3DPC structures, being a promising alternative to complex and computationally expensive finite element models considering distinct interfacial planes.

Artificial Intelligence for context-aware surgical guidance in complex robot-assisted oncological procedures: An exploratory feasibility study

IntroductionComplex oncological procedures pose various surgical challenges including dissection in distinct tissue planes and preservation of vulnerable anatomical structures throughout different surgical phases. In rectal surgery, violation of dissection planes increases the risk of local recurrence and autonomous nerve damage resulting in incontinence and sexual dysfunction. This work explores the feasibility of phase recognition and target structure segmentation in robot-assisted rectal resection (RARR) using machine learning. Materials and methodsA total of 57 RARR were recorded and subsets of these were annotated with respect to surgical phases and exact locations of target structures (anatomical structures, tissue types, static structures, and dissection areas). For surgical phase recognition, three machine learning models were trained: LSTM, MSTCN, and Trans-SVNet. Based on pixel-wise annotations of target structures in 9037 images, individual segmentation models based on DeepLabv3 were trained. Model performance was evaluated using F1 score, Intersection-over-Union (IoU), accuracy, precision, recall, and specificity. ResultsThe best results for phase recognition were achieved with the MSTCN model (F1 score: 0.82 ± 0.01, accuracy: 0.84 ± 0.03). Mean IoUs for target structure segmentation ranged from 0.14 ± 0.22 to 0.80 ± 0.14 for organs and tissue types and from 0.11 ± 0.11 to 0.44 ± 0.30 for dissection areas. Image quality, distorting factors (i.e. blood, smoke), and technical challenges (i.e. lack of depth perception) considerably impacted segmentation performance. ConclusionMachine learning-based phase recognition and segmentation of selected target structures are feasible in RARR. In the future, such functionalities could be integrated into a context-aware surgical guidance system for rectal surgery.

Combined use of right ventricular coupling and pulmonary arterial elastance as a comprehensive stratification approach for right ventricular function.

Right ventricular (RV)-pulmonary arterial uncoupling is the consequence of increased afterload and/or decreased RV contractility. However, the combination of arterial elastance (Ea) and end-systolic elastance (Ees)/Ea ratio to assess RV function is unclear. We hypothesized that the combination of both could comprehensively assess RV function and refine risk stratification. The median Ees/Ea ratio (0.80) and Ea (0.59mmHg/mL) were used to classify 124 advanced heart failure patients into four groups. RV systolic pressure differential was defined as end-systolic pressure (ESP) minus beginning-systolic pressure (BSP). Patients among different subsets showed dissimilar New York Heart Association functional class (V=0.303, P=0.010), distinct tricuspid annular plane systolic excursion/ pulmonary artery systolic pressure (mm/mmHg) (0.65 vs. 0.44 vs. 0.32 vs. 0.26, P<0.001), and diverse prevalence of pulmonary hypertension (33.3% vs. 35% vs. 90% vs. 97.6%, P<0.001). By multivariate analysis, Ees/Ea ratio (hazard ratio [HR] 0.225, P=0.004) and Ea (HR 2.194, P=0.003) were independently associated with event-free survival. Patients with Ees/Ea ratio >0.80 and Ea <0.59mmHg/mL had better outcomes (P<0.05). In patients with Ees/Ea ratio >0.80, those with Ea ≥0.59mmHg/mL had a higher adverse outcome risk (P<0.05). Ees/Ea ratio ≤0.80 was associated with adverse outcomes, even when Ea was <0.59mmHg/mL (P<0.05). Approximately 86% of patients with ESP-BSP >5mmHg had an Ees/Ea ratio ≤0.80 and/or an Ea ≥0.59mmHg/mL (V=0.336, P=0.001). Combined use of Ees/Ea ratio and Ea could be a comprehensive approach to assessing RV function and predicting outcomes. An exploratory analysis demonstrated that Ees/Ea ratio and Ea might be roughly estimated based on RV systolic pressure differential.

Quantifying whole bladder biomechanics using the novel pentaplanar reflected image macroscopy system.

Optimal bladder compliance is essential to urinary bladder storage and voiding functions. Calculated as the change in filling volume per change in pressure, bladder compliance is used clinically to characterize changes in bladder wall biomechanical properties that associate with lower urinary tract dysfunction. But because this method calculates compliance without regard to wall structure or wall volume, it gives little insight into the mechanical properties of the bladder wall during filling. Thus, we developed Pentaplanar Reflected Image Macroscopy (PRIM): a novel ex vivo imaging method to accurately calculate bladder wall stress and stretch in real time during bladder filling. The PRIM system simultaneously records intravesical pressure, infused volume, and an image of the bladder in five distinct visual planes. Wall thickness and volume were then measured and used to calculate stress and stretch during filling. As predicted, wall stress was nonlinear; only when intravesical pressure exceeded ~ 15mmHg did bladder wall stress rapidly increase with respect to stretch. This method of calculating compliance as stress vs stretch also showed that the mechanical properties of the bladder wall remain similar in bladders of varying capacity. This study demonstrates how wall tension, stress and stretch can be measured, quantified, and used to accurately define bladder wall biomechanics in terms of actual material properties and not pressure/volume changes. This method is especially useful for determining how changes in bladder biomechanics are altered in pathologies where profound bladder wall remodeling occurs, such as diabetes and spinal cord injury.

Abstract 3582: Differentiation of niraparib and olaparib brain penetration in a mouse brain metastatic tumor model

Abstract Purpose: There remains an unmet need to provide effective treatment therapy for patients with primary and metastatic brain tumors; lack of drug penetration across the blood brain barrier (BBB) is a key factor. Synthetic lethality remains an attractive mechanism in treating brain tumors post radiotherapy. Here, we evaluated brain penetration and distribution of niraparib and olaparib in a mouse brain tumor model. Experimental: Female mice (CrTac:NCr-Foxn1nu; 6 w/o) received 2.5E5 luciferase transfected human breast cancer line (MDA 231-BRM2-831) via intracardiac injection. Mice were imaged twice/week using bioluminescence imaging (BLI) to monitor tumor growth. On day 35, mice with brain metastases (BM) were treated via oral gavage once daily for 5 days with either niraparib (35 mg/kg, n=4 BM, n=3 control), olaparib (50 mg/kg, n=3 BM, n=3 control), or vehicle (n=3 control). Terminal blood samples and brains were collected 2 hr post final dose. Serial tissue sections were collected for MALDI-IMS, H&amp;E and IHC staining from 5 distinct horizontal planes in the brain. Tissue collected between each imaging plane was homogenized for LC-MS bioanalysis. Summary of Data: In vivo BLI imaging was used to identify mice with BM and tumor presence was confirmed ex vivo using IHC. Quantitative MALDI IMS of coronal brain sections collected from mice administered niraparib showed consistent concentrations distributed throughout the brain parenchyma with locally higher concentrations detected from tumor regions. Table 1 summarizes the LC-MS bioanalysis concentrations in plasma and bulk brain homogenates and brain section concentrations detected by MALDI IMS. The estimated mean unbound brain-to-plasma partition coefficient (Kp,uu,brain) was 3.0x and 5.6x higher for niraparib compared to olaparib in control and BM mice, respectively. Conclusions: Herein, we demonstrated that niraparib has a higher brain penetration and distribution compared to olaparib in both control mice and mice with BM. Summary of Quantification Results Displayed as Total Conc. with Adjusted Free Conc. in Parentheses Compound Group Terminal Plasma Mean (ng/mL) LC-MS Bulk Brain Homogenate Mean (ng/g) MALDI IMS Brain Section Mean (ng/g) Kp,uu Brain Niraparib Control 3847 (769) 658 (111) 532 (89) 0.18 Niraparib BM 2535 (507) 543 (91) 473 (80) 0.14 Niraparib Vehicle BLQ BLQ Olaparib Control 226 (68) 6 (2) BLQ 0.06 Olaparib BM 119 (36) 5 (2) BLQ 0.03 Olaparib Vehicle BLQ BLQ Citation Format: Mark Reid Groseclose, Jeremy Barry, Tinamarie Skedzielewski, Gerald McDermott, Chakravarthi Balabhadrapatruni, Bill Benson, Yongle Pang, David K. Lim, Hoang Tran, Mike Ringenberg, Keyur Gada, Amine Aziez, Elaine Paul, Hasan Alsaid. Differentiation of niraparib and olaparib brain penetration in a mouse brain metastatic tumor model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3582.

Molecular Insights into the Effect of Crystal Planes on Droplet Wetting

Dynamic wetting by liquids on solid surfaces depends on several aspects such as surface energy, roughness, and interfacial tension, among many others. Copper (Cu), gold (Au), aluminum (Al), and silicon (Si) are a few of the most important metals that are used extensively as substrates in various industrial and biomedical applications. Metals are etched frequently on different crystal planes for fabrication purposes. Etching exposes distinct crystal planes that may come in contact with the liquids when used for different applications. The interaction of the crystal planes with the liquid that comes in contact with the solid dictates the wetting behavior of the surface. This necessitates the importance of understanding how various crystal planes of the same metals behave under similar conditions. Herein, three specific crystal planes, namely, (1 0 0), (1 1 0), and (1 1 1), are investigated at a molecular scale for the above-mentioned metals. The dynamic contact angle and contact diameter trends revealed that the relatively hydrophobic surfaces (Cu, Si) tend to reach their equilibrium contact angle faster compared to the hydrophilic substrates (Al, Au). Molecular kinetic theory is used to estimate the three-phase contact line friction which is found to be higher for (1 1 1) planes. Further, a consistent potential energy distribution variation is observed for the crystal lattice of (1 0 0), (1 1 0), and (1 1 1). These findings can be used as a guideline to determine the factors needed to completely describe a dynamic wetting phenomenon of the droplet over the different crystal planes. The understanding will be of great use in deciding experimental strategies where fabricated different crystal planes would be required to have a liquid contact.

Direct Calculation of the Interfacial Free Energy between NaCl Crystal and Its Aqueous Solution at the Solubility Limit.

Salty water is the most abundant electrolyte aqueous mixture on Earth, however, very little is known about the NaCl-saturated solution interfacial free energy (γ_{s}). Here, we provide the first direct estimation of γ_{s} for several NaCl crystallographic planes by means of the mold integration technique, a highly efficient computational method to evaluate interfacial free energies with anisotropic crystal resolution. Making use of the JC-SPC/E model, one of the most benchmarked force fields for NaCl water solutions, we measure γ_{s} of four different crystal planes, (100), (110), (111), and (112[over ¯]) with the saturated solution at normal conditions. We find high anisotropy between the different crystal orientations with values ranging from 100 to 150 mJ m^{-2}, and the average value of the distinct planes being γ[over ¯]_{s}=137(20) mJ m^{-2}. This value for the coexistence interfacial free energy is in reasonable agreement with previous extrapolations from nucleation studies. Our Letter represents a milestone in the computational calculation of interfacial free energies between ionic crystals and aqueous solutions.

Analysis of the formation mechanism of ceramic grains and mechanical properties of Mo2FeB2-based cermets by valence electron structure

The valence electron structures (VES) of Mo2FeB2-based cermets were constructed based on the empirical electron theory of solids and molecules (EET). The formation mechanism of grains and the influence of grain morphologies on the mechanical properties of the materials were explained in accordance with the calculated phase structure formation factors (S') and the interface electron structure (σN: the number of atom state groups, ∆ρ': electron density difference, and ρ': electron density), respectively. The results indicated that the morphologies of the Mo2FeB2 hard phase grains were reflected by the S' value of the distinct crystal planes. The progressive decrease in the Mo/B atomic ratio aggravated the differences between the S(210)' and S(001)' values and promoted the preferential growth of the hard phase grains along the [001] direction. This resulted in an increase in the (210)/(100) interface area, with the grains gradually forming an elongated structure. However, it was noticed that as the ratio of Mo to B increased, the value of |S(210)' − S(001)'| gradually tended toward 0, which allowed the elongated hard phase grains to transform into quasi-equiaxial grains. In addition, the maximum decrease in the σN value recorded was over 2500 when the Mo to B ratio increased continuously, indicating that the bonding strength at the (210)/(100) interface between the hard and binder phases was better at low Mo/B atomic ratios than at high Mo/B atomic ratios. This helped improve the fracture toughness and transverse rupture strength of the Mo2FeB2-based cermets.

Reciprocal Phase Transition Electro‐Optic Modulation

AbstractElectro‐optic (EO) modulation is a well‐known and essential topic in the field of communications and sensing, while ultrahigh modulation efficiency is unprecedentedly desired in the current green and data era. However, dramatically increasing the modulation efficiency is difficult in conventional mechanisms, being intrinsically limited by the monotonic mapping relationship between the electrical driving signal and modulated optical signal. To break this bottleneck, a new mechanism termed phase‐transition EO modulation is revealed from the reciprocal transition between two distinct phase planes arising from the Hopf bifurcation, being driven by a transient electrical signal to cross the critical point. A monolithically integrated mode‐locked laser is implemented as a prototype, strikingly achieving an ultrahigh modulation energy efficiency of 3.06 fJ bit−1 improved by about four orders of magnitude and a contrast ratio exceeding 50 dB. The prototype is experimentally implemented for radio‐over‐fiber communication and acoustic sensing. This work indicates a significant advance on the state‐of‐the‐art EO modulation technology and opens a new avenue for green communication and ubiquitous sensing applications.

MULTIPLE SOLITONS, BIFURCATIONS, CHAOTIC PATTERNS AND FISSION/FUSION, ROGUE WAVES SOLUTIONS OF TWO-COMPONENT EXTENDED (2+1)-D ITÔ CALCULUS SYSTEM

The exploration of nonlinear phenomena entails the representation of intricate systems with space-time variables, and across this line, Itô calculus, as the stochastic calculus version of the change pertaining to the variables formula and chain rules, involves the second derivative of f, coming from the property that Brownian motion has non-zero quadratic variation. To this end, the extended ([Formula: see text])-dimensional two-component Itô equation, as an applicable mathematical tool employed in this study for enhancing our understanding of the complex dynamics inherent in multidimensional physical systems, serves the purpose of modeling and understanding dynamic phenomena pervading various disciplines. For modeling complex phenomena, fractional differential equations (FDEs), ordinary differential equations (ODEs), partial differential equations (PDEs) as well as the other ones provide benefits in terms of accuracy and tractability. Accordingly, our study provides the analysis of the two-component nonlinear extended ([Formula: see text])-dimensional Itô equation using the Hirota bilinear method to derive multiple soliton solutions, including novel variations along with their dispersion coefficients, which shed light into the intriguing attributes of the Itô equation. The investigation further encompasses diverse soliton types, such as the general first-order soliton, second-order soliton with fission and bifurcation, third-order soliton, and fourth-order soliton with fission and bifurcation. Besides these, the study also explores the rogue wave and lump solutions by varying parameters across distinct planes. Consequently, these results validate the characteristics and utility of the two-component nonlinear extended ([Formula: see text])-dimensional Itô equation and its relevance to related systems. The novel findings based on the Itô calculus systems revealed, through the analyses, theoretical and experimental aspects in combination with the graphical presentation of the parameter effects on solitons in line with the analyses obtained. These have enhanced the understanding of the dynamics of intricate attributes governed by the two-component nonlinear extended ([Formula: see text])-dimensional Itô equation, particularly concerning chaotic patterns, fission and bifurcation soliton nonlinear complexities.

Design of Guided Bending Bellows Actuators for Soft Hand Function Rehabilitation Gloves

This study developed a soft pneumatic glove actuated by elliptical cross-sectional guided bending bellows to augment finger-knuckle rehabilitation for patients with hand dysfunction. The guided bending bellows actuators (GBBAs) are made of thermoplastic elastomer (TPE) materials, demonstrating the necessary air tightness as a pneumatic actuator. The GBBAs could produce different moments of inertia when increasing internal air pressure drives the GBBAs bending along distinct symmetry planes and exhibits anisotropic kinematic bending performance. Actuated by GBBAs, wearable soft rehabilitation gloves can be used for daily rehabilitation training of hand dysfunction to enhance the range of motion of the finger joint. To control each finger of the gloves independently to achieve the function of manipulating gestures, a multi-channel pneumatic control system is designed, and each air circuit is equipped with an air-pressure sensor to make adjustments based on feedback. Compared with general soft robotic exoskeleton gloves currently used for hand dysfunction, the GBBAs actuated soft gloves have the advantage of enhancing the rehabilitation strength, finger movement range, and multi-action coordination applied with guided bending bellows actuators.

Characterising bed-parallel slip during gravity-driven deformation

Despite the recognition that bed-parallel slip (BPS) must operate during gravity-driven deformation of basinal sediments, there is a general paucity of detailed outcrop-based observations to characterise and detect such a process. We therefore present detailed timing relationships between BPS and steeper dip-slip faults that were both created during seismically-triggered downslope-directed movement of sediments. Using the late Pleistocene Lisan Formation that was deposited around the Dead Sea Basin as our case study, we show that ‘sub-seismic’ decametric scale BPS planes may pre-date, post-date, or operate coevally with steeper faults generated as sediments slip downslope towards the depocentre. Older BPS can be recognised by sediment injections and minor folds and fractures, whereas younger BPS displaces marker faults downslope towards the basin. BPS operating coevally with steeper faults results in complex overprinting and development of fault-bound lenses. BPS that forms along single surfaces in the footwall of normal faults becomes separated into two distinct planes in the downthrown hangingwall block, indicating broadly coeval development. Adjacent BPS planes that operate synchronously result in synthetic and antithetic faults that ‘hard-link’ and transfer displacement between BPS planes. Attenuated bedding between segments of BPS that overlap and terminate next to one another suggests that ‘soft-linkage’ also forms between coeval BPS planes. Displacement-length relationships of measured BPS planes plot in the same range as recorded for normal faults, although BPS with larger displacements have relatively ‘short’ lengths, suggesting that complete BPS planes are missing due to limitations of outcrop size. Although the lack of displaced bedding across BPS makes it largely invisible on seismic sections across large-scale gravity-driven systems, it does potentially contribute towards the apparent inbalance between net extension and contraction observed in many sections across mass transport deposits. In addition, the realisation that BPS interacts with dip-slip faults to create repeated and missing sections that are particularly focussed along earlier deformed horizons and turbidites, has implications for palaeoseismic studies that assume broadly continuous stratigraphy.

Instantaneous 4D micro-particle image velocimetry (µPIV) via multifocal microscopy (MUM)

Multifocal microscopy (MUM), a technique to capture multiple fields of view (FOVs) from distinct axial planes simultaneously and on one camera, was used to perform micro-particle image velocimetry (µPIV) to reconstruct velocity and shear stress fields imposed by a liquid flowing around a cell. A diffraction based multifocal relay was used to capture images from three different planes with 630 nm axial spacing from which the axial positions of the flow-tracing particles were calculated using the image sharpness metric. It was shown that MUM can achieve an accuracy on the calculated velocity of around (0.52 ± 0.19) µm/s. Using fixed cells, MUM imaged the flow perturbations at sub-cellular level, which showed characteristics similar to those observed in the literature. Using live cells as an exemplar, MUM observed the effect of changing cell morphology on the local flow during perfusion. Compared to standard confocal laser scanning microscope, MUM offers a clear advantage in acquisition speed for µPIV (over 300 times faster). This is an important characteristic for rapidly evolving biological systems where there is the necessity to monitor in real time entire volumes to correlate the sample responses to the external forces.

Synthesis of Hydroxyapatite (HAp)-Zirconia Nanocomposite Powder and Evaluation of Its Biocompatibility: An In Vitro Study

A potential material for dental restorations and bone replacements is calcium phosphate (CaP)-based ceramic material. Nevertheless, its limited ability to withstand thermal processing and weak mechanical strength prevents it from being used in hard tissue engineering. Hydroxyapatite has been extensively used as a CaP-based biomaterial in prosthetic applications. On the other hand, zirconia is an inorganic material that combines outstanding mechanical capabilities with bioinert characteristics. In the present investigation, we demonstrated the reinforcement of zirconia in biomimetic hydroxyapatite (HAp) using a specially designed stir-type hydrothermal reactor to improve the biocompatibility and mechanical stability of bare hydroxyapatite. X-ray diffraction (XRD) analysis showed distinct peak shifts around 31° and 60°, which confirmed the formation of a nanocrystalline HAp-Zirconia composite without any intermediate phases. The size of the synthesized nanocomposite was found to be 30 nm using TEM. Further, the d-spacing value calculated from high-resolution transmission electron microscope (HRTEM) images corresponded to the distinct planes of the HAp (211) and zirconia (311) phases, respectively, in the composite powder. The in vitro cytotoxicity study revealed excellent biocompatibility with MG-63 human osteoblasts. Hence, the zirconia reinforced hydroxyapatite (HZ1) prepared in the present work could be utilized as a successful approach in a variety of hard tissue engineering applications.

All-optical inter-layers functional connectivity investigation in the mouse retina

SummaryWe developed a multi-unit microscope for all-optical inter-layers circuits interrogation. The system performs two-photon (2P) functional imaging and 2P multiplexed holographic optogenetics at axially distinct planes. We demonstrated the capability of the system to map, in the mouse retina, the functional connectivity between rod bipolar cells (RBCs) and ganglion cells (GCs) by activating single or defined groups of RBCs while recording the evoked response in the GC layer with cell-type specificity and single-cell resolution. We then used a logistic model to probe the functional connectivity between cell types by deriving the “cellular receptive field” describing how RBCs impact each GC type. With the capability to simultaneously image and control neuronal activity at axially distinct planes, the system enables a precise interrogation of multi-layered circuits. Understanding this information transfer is a promising avenue to dissect complex neural circuits and understand the neural basis of computations.

Ultrastructural Analysis of Er:YAG Lased Bovine Dentin Contaminated by Cariogenic Bacteria.

Objective: The purpose of this study is to investigate the crystal structure of bacteria-contaminated bovine dentin after Er:YAG laser irradiation at various energy densities from macroscale, microscale, and nanoscale. Background: Er:YAG laser can change the morphology and chemical components of dentin. Few preliminary researchers investigate the laser effect on crystal in dentin tissue. Methods: Twenty dentin specimens from bovine incisors were cocultured with S. mutans (UA 159) and divided into four groups with diverse Er:YAG laser irradiation energy (0, 6.37, 12.73, 19.11 J/cm2). The ultrastructure of dentin before and after laser irradiation was investigated with nanoanalytical electron microscopy. X-ray diffraction provided the information of lattice parameters in dentin. The morphology of dentin was observed by scanning electron microscopy. High-resolution transmission electron microscope images and selected-area electron diffraction patterns were obtained for characterizing crystal domain size, structure, and microenvironment of dentin. Results: The combination of these methods disclosed that there exist mineralized, demineralized, and remineralized dentin in the bacteria-invaded dentin and can be feasibly recognized using morphological features. Laser treatments influence hydroxyapatite (HAp) crystals in dentin tissue in different ways: needle HAp in mineralized dentin tissue keeps intact with laser irradiation of no higher than 19.11 J/cm2; laser irradiation improves the crystallinity of lamella HAp by domain growth and rearranges its growth orientations. Conclusions: We report an unprecedented presence of remineralization zone consisting of lamella HAp crystals with distinct high-index planes. These findings have broad implications on the role of laser operation in driving biomineralization and shed new insights into a possible relationship between laser irradiation and remineralization.