Slight Tilt Research Articles

Defecatory Dysfunction and the Pelvic Floor

Defecatory dysfunction is infrequently considered a gynaecological problem. However, obstructed defecation (OD) more commonly affects women than men and is associated with pelvic floor dysfunction. Therefore, we set out to write a review from a urogynaecologists’ prospective focusing on OD as it relates to the pelvic floor. Literature on this topic remains sparse and the studies tend to have a low sample size. It is clear that OD is associated with pelvic floor dysfunction including urinary incontinence and structural dysfunction; however, it is less clear which is the primary pathology. Management of OD needs to be considered in treatment of pelvic floor dysfunctions. OD effects 14% of the general population. Ninety percent of the patients with OD will have a rectocele, enterocele or even intussusception. The pathophysiology is multifactorial and still not fully comprehended. Aetiology of constipation is classified as primary or secondary. The former includes slow transit or normal constipation and defecation disorders. The latter includes constipation caused by medications, diet and medical conditions. The Rome IV criteria are used to define functional constipation globally. Defecation disorders of the pelvic floor are categorised as structural disorders, pudendal neuropathy and dyssynergic defecation. First-line management includes treating the primary causes, dietary modification and laxatives. We stress the importance of posture whilst defecating is of utmost importance. A full squatting position with a slight forward tilt results in the broadening of the anorectal angle thereby facilitating emptying. Biofeedback therapy is still considered first-line treatment for dyssynergic defecation. Finally, surgical management of advanced stage prolapse is often unavoidable but is not a cure of OD. The increasing use of translabial ultrasound as a diagnostic modality will hopefully help facilitate research in this area.

An Electrostatic MEMS Translational Scanner with Large Out-of-Plane Stroke for Remote Axial-Scanning in Multi-Photon Microscopy

We present an electrostatic microelectromechanical systems (MEMS) resonant scanner with large out-of-plane translational stroke for fast axial-scanning in a multi-photon microscope system for real-time vertical cross-sectional imaging. The scanner has a compact footprint with dimensions of 2.1 mm × 2.1 mm × 0.44 mm, and employs a novel lever-based compliant mechanism to enable large vertical displacements of a reflective mirror with slight tilt angles. Test results show that by using parametrical resonance, the scanner can provide a fast out-of-plane translational motion with ≥400 μm displacement and ≤0.14° tilt angle over a wide frequency range of ~390 Hz at ambient pressure. By employing this MEMS translational scanner and a biaxial MEMS mirror for lateral scanning, vertical cross-sectional imaging with a beam axial-scanning range of 200 μm and a frame rate of ~5–10 Hz is enabled in a remote scan multi-photon fluorescence imaging system.

The effect of column tilt on flow homogeneity and particle agitation in a liquid fluidized bed

The motion of particles in a solid-liquid fluidized bed was experimentally studied by video tracking of marked particles in a matched refractive index medium. In this study, two fluidized states are compared, one carefully aligned in the vertical direction ensuring a homogeneous fluidisation and another one with a non-homogeneous fluidisation regime that results from a slight tilt of the fluidisation column of 0.3° with respect to the vertical. As a result of the misalignment, large recirculation loops develop within the bed in a well-defined spatial region. It is found that in that range of solid fraction (between 0.3 and 0.4), the inhomogeneous motion of the particles leads to significant differences in velocity fluctuations as well as in self-diffusion coefficient of the particles in the vertical direction, whereas the fluidisation height remains unaffected. At lower (less than 0.2) or higher (higher than 0.5) concentration, particle agitation characteristics are almost unchanged in the vertical direction.

Z-plasty for severe gluteal muscle contracture in children.

To review the records of 363 patients with severe gluteal muscle contracture to determine its mechanism, underlying pathology, and treatment outcome. Records of 136 males and 227 females aged 5 to 18 (mean, 12.2) years who underwent Z-plasty for bilateral (n=347) or unilateral (n=16) severe gluteal muscle contracture were reviewed. Severe gluteal muscle contracture was classified as typical (n=52) or special (n=311). The typical type is associated with symptoms of positive out-toe gait, Ober sign, back-extending test, cross-leg test, squatting with knee side-by-side test, and hip dysfunction. It is further subdivided into mild (n=0), moderate (n=40), or severe (n=12). The special type is associated with additional symptoms of pelvic tilt and leg length discrepancy (<2 cm in 181 hips, 2-4 cm in 82 hips, and >4 cm in 48 hips). 311 hips had pelvic tilt and 47 hips had lumbar compensatory scoliosis. Treatment outcome was assessed at 6 months. Hip functional score was assessed at the final follow-up. The mean hospitalisation period was 11 days. After a mean follow-up of 1.5 years, the mean hip functional score improved from 8.03 to 11.69; improvement was higher in children (age 5-13 years) than in adolescents (age 14-18 years) [3.7 vs. 2.9, p<0.001]. At 6 months, outcome was excellent in 280 hips, good in 80, fair in 3 hips, and poor in 0. The 3 hips with fair outcome had persistent slight pelvic tilt and swaying gait. Two of them had preoperative leg length discrepancy >4 cm, and intra-operatively the contracture band severely affected the joint capsule. The third patient did not comply with postoperative exercises. Surgical treatment for severe gluteal muscle contracture achieved good outcome.

TRIO Platform: A Novel Low Profile In vivo Imaging Support and Restraint System for Mice.

High resolution, in vivo optical imaging of the mouse brain over time often requires anesthesia, which necessitates maintaining the animal's body temperature and level of anesthesia, as well as securing the head in an optimal, stable position. Controlling each parameter usually requires using multiple systems. Assembling multiple components into the small space on a standard microscope stage can be difficult and some commercially available parts simply do not fit. Furthermore, it is time-consuming to position an animal in the identical position over multiple imaging sessions for longitudinal studies. This is especially true when using an implanted gradient index (GRIN) lens for deep brain imaging. The multiphoton laser beam must be parallel with the shaft of the lens because even a slight tilt of the lens can degrade image quality. In response to these challenges, we have designed a compact, integrated in vivo imaging support system to overcome the problems created by using separate systems during optical imaging in mice. It is a single platform that provides (1) sturdy head fixation, (2) an integrated gas anesthesia mask, and (3) safe warm water heating. This THREE-IN-ONE (TRIO) Platform has a small footprint and a low profile that positions a mouse's head only 20 mm above the microscope stage. This height is about one half to one third the height of most commercially available immobilization devices. We have successfully employed this system, using isoflurane in over 40 imaging sessions with an average of 2 h per session with no leaks or other malfunctions. Due to its smaller size, the TRIO Platform can be used with a wider range of upright microscopes and stages. Most of the components were designed in SOLIDWORKS® and fabricated using a 3D printer. This additive manufacturing approach also readily permits size modifications for creating systems for other small animals.

Extending the Hydrophobic Mismatch Concept to Amphiphilic Membranolytic Peptides.

A series of nine amphiphilic, pore-forming α-helical KIA peptides (KIAGKIA repeats) with lengths between 14 and 28 residues were studied by solid-state (15)N NMR to determine their alignment in oriented lipid bilayers. In a 2:1 mixture of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) with its corresponding 1-myristoyl-2-hydroxy-sn-glycero-3-phosphocholine (lyso-MPC), which has a highly positive spontaneous curvature, the helix tilt angle was found to vary steadily with peptide length. The shortest peptide was aligned transmembrane and upright, while the longer ones successively became tilted away from the membrane normal. This behavior is in agreement with the hydrophobic matching concept, conceived so far only for hydrophobic helices. In 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine, with a negative spontaneous curvature, all KIA peptides remained flat on the bilayer surface, while the cylindrical DMPC lipids permitted a slight tilt. Peptide insertion thus depends critically on the intrinsic lipid curvature, and helix orientation is then fine-tuned by membrane thickness. A refined toroidal pore model is proposed.

Thermal Expansion and Second Harmonic Generation Response of the Tungsten Bronze Pb2AgNb5O15.

The incorporation of transition metal element Ag was performed to explore negative thermal expansion (NTE) materials with tetragonal tungsten bronze (TTB) structures. In this study, the structure and thermal expansion behaviors of a polar TTB oxide, Pb2AgNb5O15 (PAN), were systematically investigated by high-resolution synchrotron powder diffraction, high-resolution neutron powder diffraction, transmission electron microscope (TEM), and high-temperature X-ray diffractions. The TEM and Rietveld refinements revealed that the compound PAN displays (√2a(TTB), √2b(TTB), 2c(TTB))-type superstructure. This superstructure within the a-b plane is caused by the ordering of A-site cations, while the doubling of the c axis is mainly induced by a slight tilt distortion of the NbO6 octahedra. The transition metal Ag has larger spontaneous polarization displacements than Pb, but the Pb-O covalence seems to be weakened compared to the potassium counterpart Pb2KNb5O15 (PKN), which may account for the similar Curie temperature and uniaxial NTE behavior for PAN and PKN. Powder second harmonic generation (SHG) measurement indicates that PAN displays a moderate SHG response of ∼0.2 × LiNbO3 (or ∼100 × α-SiO2) under 1064 nm laser radiation. The magnitudes of the local dipole moments in NbO6 and PbOx polyhedra were quantified using bond-valence approach. We show that the SHG response stems from the superposition of dipole moments of both the PbO(x) and NbO6 polyhedra.

Thermal convection in inclined cylindrical containers

By means of direct numerical simulations (DNS) we investigate the effect of a tilt angle ${\it\beta}$, $0\leqslant {\it\beta}\leqslant {\rm\pi}/2$, of a Rayleigh–Bénard convection (RBC) cell of aspect ratio 1, on the Nusselt number $\mathit{Nu}$ and Reynolds number $\mathit{Re}$. The considered Rayleigh numbers $\mathit{Ra}$ range from $10^{6}$ to $10^{8}$, the Prandtl numbers range from 0.1 to 100 and the total number of the studied cases is 108. We show that the $\mathit{Nu}\,({\it\beta})/\mathit{Nu}(0)$ dependence is not universal and is strongly influenced by a combination of $\mathit{Ra}$ and $\mathit{Pr}$. Thus, with a small inclination ${\it\beta}$ of the RBC cell, the Nusselt number can decrease or increase, compared to that in the RBC case, for large and small $\mathit{Pr}$, respectively. A slight cell tilt may not only stabilize the plane of the large-scale circulation (LSC) but can also enforce an LSC for cases when the preferred state in the perfect RBC case is not an LSC but a more complicated multiple-roll state. Close to ${\it\beta}={\rm\pi}/2$, $\mathit{Nu}$ and $\mathit{Re}$ decrease with increasing ${\it\beta}$ in all considered cases. Generally, the $\mathit{Nu}({\it\beta})/\mathit{Nu}(0)$ dependence is a complicated, non-monotonic function of ${\it\beta}$.

Detection and correction of wavefront errors caused by slight reference tilt in two-step phase-shifting digital holography.

A simple and convenient method, without the need for any additional optical devices and measurements, is suggested to improve the quality of the reconstructed object wavefront in two-step phase-shifting digital holography by decreasing the errors caused by reference beam tilt, which often occurs in practice and subsequently introduces phase distortion in the reconstructed wave. The effects of reference beam tilt in two-step generalized interferometry is analyzed theoretically, showing that this tilt incurs no error either on the extracted phase shift or on the retrieved real object wave amplitude on the recording plane, but causes great deformation of the recovered object wavefront. A corresponding error detection and correction approach is proposed, and the formulas to calculate the tilt angle and correct the wavefront are deduced. A series of computer simulations to find and remove the wavefront errors caused by reference beam tilt demonstrate the effectiveness of this method.

String gas cosmology after Planck

We review the status of string gas cosmology (SGC) after the 2015 Planck data release. SGC predicts an almost scale-invariant spectrum of cosmological perturbations with a slight red tilt, like the simplest inflationary models. It also predicts a scale-invariant spectrum of gravitational waves with a slight blue tilt, unlike inflationary models which predict a red tilt of the gravitational wave spectrum. SGC yields two consistency relations which determine the tensor to scalar ratio and the slope of the gravitational wave spectrum given the amplitude and tilt of the scalar spectrum. We show that these consistency relations are in good agreement with the Planck data. We discuss future observations which will be able to differentiate between the predictions of inflation and those of SGC.

The position of deuterium in HOD—NNO as determined by structural and nuclear quadrupole coupling constants

Rotational spectra of the weakly bound H2O-N2O complex and its HOD-N2O isotopologue in a supersonic jet are reported. Rotational constants of the singly substituted deuterium in water and each singly substituted nitrogen-15 are presented. Combinations of isotopic data and high level ab initio calculations place the water in a similar position to those of the isoelectronic H2O-CO2 complex, with a slight tilt of the OH towards the NNO axis. The deuterium nuclear quadrupole coupling constant places the deuterium on the O-H axis quasi-parallel to the NNO axis.

Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah, USA – integrating fieldwork, ground-penetrating radar and airborne imagery analysis

Abstract. The grabens of Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground-penetrating radar (GPR) surveys in combination with field observations and analysis of high-resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m, suggest a highly dilatant fault geometry. Sinkholes observed in the field as well as in airborne imagery give insights in local dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that either the grabens in Canyonlands National Park are older than previously assumed or that sedimentation rates were much higher in the Pleistocene.

Conformational gating dynamics in the GluCl anion-selective chloride channel.

Cys-loop receptors are central to propagation of signals in the nervous system. The gating of the membrane-spanning pore is triggered by structural rearrangements in the agonist-binding site, located some 50 Å away from the pore. A sequential conformational change, propagating from the ligand-binding site to the pore, has been proposed to govern gating in all Cys-loop receptors. Here, we identify structural and dynamic components of the conformational gating in the eukaryotic glutamate-gated chloride channel (GluCl) by means of molecular dynamics (MD) simulations with and without the l-glutamate agonist bound. A significant increase in pore opening and accompanying hydration is observed in the presence of glutamate. Potential of mean force calculations reveal that the barrier for ion passage drops from 15 kcal/mol to 5-10 kcal/mol with the agonist bound. This appears to be explained by agonist binding that leads to significant changes in the intersubunit hydrogen-bonding pattern, which induce a slight tilt of the extracellular domain relative to the transmembrane domain in the simulations. This rearrangement is subtle, but correspond to the direction of the quaternary twist observed as a key difference between open and closed X-ray structures. While the full reversible gating is still a much slower process, the observed structural dynamics sheds new light on the early stages of how the agonist influences the extracellular domain, how the extracellular domain interacts with the transmembrane domain, and how changes in the transmembrane domain alter the free energy of ion passage.

A ΛCDM bounce scenario

We study a contracting universe composed of cold dark matter and radiation, and with a positive cosmological constant. As is well known from standard cosmological perturbation theory, under the assumption of initial quantum vacuum fluctuations the Fourier modes of the comoving curvature perturbation that exit the (sound) Hubble radius in such a contracting universe at a time of matter-domination will be nearly scale-invariant. Furthermore, the modes that exit the (sound) Hubble radius when the effective equation of state is slightly negative due to the cosmological constant will have a slight red tilt, in agreement with observations. We assume that loop quantum cosmology captures the correct high-curvature dynamics of the space-time, and this ensures that the big-bang singularity is resolved and is replaced by a bounce. We calculate the evolution of the perturbations through the bounce and find that they remain nearly scale-invariant. We also show that the amplitude of the scalar perturbations in this cosmology depends on a combination of the sound speed of cold dark matter, the Hubble rate in the contracting branch at the time of equality of the energy densities of cold dark matter and radiation, and the curvature scale that the loop quantum cosmology bounce occurs at. Importantly, as this scenario predicts a positive running of the scalar index, observations can potentially differentiate between it and inflationary models. Finally, for a small sound speed of cold dark matter, this scenario predicts a small tensor-to-scalar ratio.

Fundamental Study on a New Thin Oil-film Recovery Device Based on the MHD Method

The MHD maritime oil spill recovery method has many advantages in tackling the marine thin oil-film. The existing device, in which the MHD channel is arranged horizontally, can’t operate successfully under wave conditions and the oil and air bubbles can’t move through the MHD channel smoothly. A new method with the MHD channel arranged with a slight tilt angle is proposed to improve the effect of the thin oil-film recovery. In this paper, the hydrodynamic characteristics of the seawater and air two-phase flow under the action of electromagnetic force with the MHD channel arranged obliquely were studied numerically and the results show that the static pressure decreases gradually from the MHD channel's inlet to the outlet. The flow rate decreases slightly as the tilt angle increases. The pressure rise and the effective power increase slightly as the tilt angle increases.

1D self-assembly of chemisorbed thymine on Cu(110) driven by dispersion forces.

Adsorption of thymine on a defined Cu(110) surface was studied using reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and scanning tunnelling microscopy (STM). In addition, density functional theory (DFT) calculations were undertaken in order to further understand the energetics of adsorption and self-assembly. The combination of RAIRS, TPD, and DFT results indicates that an upright, three-point-bonded adsorption configuration is adopted by the deprotonated thymine at room temperature. DFT calculations show that the upright configuration adopted by individual molecules arises as a direct result of strong O-Cu and N-Cu bonds between the molecule and the surface. STM data reveal that this upright thymine motif self-assembles into 1D chains, which are surprisingly oriented along the open-packed [001] direction of the metal surface and orthogonal to the alignment of the functional groups that are normally implicated in H-bonding interactions. DFT modelling of this system reveals that the molecular organisation is actually driven by dispersion interactions, which cause a slight tilt of the molecule and provide the major driving force for assembly into dimers and 1D chains. The relative orientations and distances of neighbouring molecules are amenable for π-π stacking, suggesting that this is an important contributor in the self-assembly process.

The reaction of dimethyldioxirane with 1,3-cyclohexadiene and 1,3-cyclooctadiene: monoepoxidation kinetics and computational modeling

Abstract The reaction of dimethyldioxirane (1) with excess 1,3-cyclohexadiene (2a) and 1,3-cyclooctadiene (2b) in dried acetone yielded the corresponding monoepoxides in excellent yield. Second-order rate constants for monoepoxidation were determined using UV methodology. The k2 value for the monoepoxidation of 1,3-cyclohexadiene was found to be 1.14±0.06 m -1 s-1, whereas that for the monoepoxidation of 1,3-cycloctadiene was 0.31±0.03 m -1 s-1. Basic density functional calculations at the B3LYP/6-31G level were employed to model the monoepoxidations. As expected, the calculations were consistent with a concerted, electrophilic process with a spiro-transition state. As found for the epoxidation of simple alkenes, the calculated transition-state geometry showed a slight asynchronous tilt of the dioxirane plane relative to that of the remaining alkene portion of the diene and a slight tilt back from the face of the diene. Relative reactivities (relative k2 values) were determined using the difference in the calculated electronic activation energies and were consistent with the experimental relative k2 values without the need to correct for the medium (solvent). Reactivity differences for epoxidation can be quickly predicted by this approach as long as there are reasonable structural similarities between the substrates.

Tengiz Field Sector Model for IOR/EOR Process Evaluation

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 170605, ’A Sector Model for IOR/EOR Process Evaluation,’ by Shie-Way Wang, Batima Yeskaiyr, SPE, and Chuck Walker, Tengizchevroil, prepared for the 2014 SPE Annual Technical Conference and Exhibition, Amsterdam, 27-29 October. The paper has not been peer reviewed. This work presents a methodology to construct a sector model for the Tengiz field that covers one-sixth of the field area to evaluate improved-/ enhanced-oil-recovery (IOR/EOR) processes to increase oil recovery through the life of the field. The method takes into account boundary flux, edge wells, and compositional effects to replicate full-field-model performance and subsequently generate alternative predictions. This model matches production/injection data of existing wells and the anticipated performance of future wells in the full-field model. Introduction The Tengiz field is a giant carbonate oil field onshore western Kazakhstan at the northern end of the Caspian Sea’s eastern shoreline. Tengiz is a stratigraphic trap consisting of a carbonate buildup with a large central platform area (10×15 km) with a raised rim area (up to 2 km wide). The Tengiz reservoir has mesa-like geometry overall—flat topped and steep sided. The top of the platform has a slight regional tilt (less than 1° to the south). The sides of the platform generally dip approximately 25° on all flanks. Production has been mainly from primary pressure depletion through oil expansion. Sour-gas injection was implemented in 2007 to address pressure decline and improve recovery efficiency. In general, the platform lacks fractures and is best suited for gas injection, whereas the slope is suitable for depletion drive because of high fracture density. Because gas injection is limited to the platform region, the main objective of this study is to investigate the best pressure-maintenance or IOR/EOR method to apply to the fractured slope region. Sector Model The area of the field modeled with the sector model was selected to include geological regions, material-balance regions, and displacement processes that are representative of Tengiz as a whole. The model incorporates 15.2% of the field surface area and has platform and slope regions within its boundary. Fig. 1 shows that the sector model includes (a) two five-spot existing sour-gas-injection patterns (green-line-pattern area) and (b) seven future-growth-project and sour-gas-injection patterns in the central platform region (black-line-pattern area). This sector model has 127 wells divided into two groups. The first group has 62 future and existing producers and eight injectors associated with base business operations. The second group has 57 potential future infill wells for long-term IOR/EOR development plans.

Morphometry and fabric orientation of trabecular bone in human craniofacial regions (918.17)

Variation in primate craniofacial form has been attributed to orofacial function. Strain gage experiments show that during orofacial function the zygoma is subjected to high strain relative to the browridge. Trabecular bone morphometry and orientation are reflective of function, but trabecular bone in these regions has been unexplored. This study uses µCT to quantify the morphometric properties of trabecular bone, anisotropy, and fabric orientation in the human browridge and zygoma. We hypothesize that zygomatic trabecular bone will have significantly greater bone volume fraction and anisotropy relative to the browridge as an adaption to larger, more unidirectional loads. Primary orientations of trabecular bone will differ by region consistent with their function.No significant differences were found between the browridge and zygoma in BVF (0.38 vs. 0.31), and DA (1.65 vs. 1.85), but SMI was significantly lower in the browridge (0.075; honeycomb‐like vs. SMI=1.0752; ideal plate‐like, p&lt;0.034). Orientation was highly significantly different between regions. The zygoma is made up of mediolaterally oriented plates with a slight inferosuperior tilt, while trabecular bone in the browridge is made of denser sagittally oriented plates.Both regions may be more similar in overall elasticity than predicted, but further analysis needs to test the combined effects of differences in individual features. Orientation of trabeculae in the zygoma appears to be consistent with what would be predicted based on orofacial strain patterns.Grant Funding Source: NSF BCS 0725141

A surface flattening mechanism of a heteroepitaxial film consisting of faceted non-flat top twins: [11¯3¯]-oriented GaN films grown on m-plane sapphire substrates

We carried out experiments and computational simulations in order to answer a yet unanswered question about a surface flattening mechanism of a [11¯03¯]-oriented GaN film consisting of faceted non-flat top twins. Our results revealed that an overgrowth of one variant of twins over the other, which was manifested only at a thickness larger than a few microns due to a slight asymmetric crystallographic tilt (1.0° ± 0.4°) of twins, played a key role in a surface flattening mechanism. In addition, we experimentally demonstrated that GaN grown on a SiO2-patterned m-plane sapphire substrate had no asymmetric tilt and that no surface flattening occurred.