Small End Research Articles

Study on Molecular Recognition of Pinocembrin with Methylated-β-Cyclodextrin

Abstract The inclusion behavior, inclusion capacity and inclusion mode of pinocembrin (PIN) with dimethyl-β-cyclodextrin (DM-β-CD) and trimethyl-β-cyclodextrin (TM-β-CD) were characterized by X-ray diffraction (XRD), thermal analysis, scanning electron microscopy (SEM), UV-visible spectral titration and molecular docking. The results showed that the packing ratio of PIN/DM-β-CD complex and PIN/TM-β-CD complex was 1:1. The water solubility of PIN increased by 817 times and 575 times in the inclusion complex with DM-β-CD and TM-β-CD, respectively. Molecular docking showed the PIN entered from the large end of the DM-β-CD molecule and penetrated through the cavity. The A and B rings of the PIN were respectively located at the big and small ends of the CD molecule. For the TM-β-CD, only A and C rings of the PIN entered the cavity of CD.

Origin of 1I/’Oumuamua. II. An Ejected Exo-Oort Cloud Object?

Abstract 1I/’Oumuamua is the first detected interstellar interloper. We test the hypothesis that it is representative of a background population of exo-Oort cloud objects ejected under the effect of post-main sequence mass loss and stellar encounters. We do this by comparing the cumulative number density of interstellar objects inferred from the detection of 1I/’Oumuamua to that expected from these two clearing processes. We consider the 0.08–8 M ⊙ mass range, take into account the dependencies with stellar mass, Galactocentric distance, and evolutionary state, and consider a wide range of size distributions for the ejected objects. Our conclusion is that 1I/’Oumuamua is likely not representative of this background population, even though there are large uncertainties in the masses and size distributions of the exo-Oort Clouds. We discuss whether the number density of free-floating, planetary-mass objects derived from gravitational microlensing surveys could be used as a discriminating measurement regarding 1I/’Oumuamua’s origin (given their potential common origin). We conclude that this is challenged by the mass limitation of the surveys and the resulting uncertainty of the mass distribution of the free floaters. The detection of interlopers may be one of the few observational constraints of the small end of this population, with the caveat that, as we conclude here and in Moro-Martín (2018), in the case of 1I/’Oumuamua, it might not be appropriate to assume this object is representative of an isotropic background population, which makes the derivation of a number density very challenging.

Measurements and Modeling of the Full Rain Drop Size Distribution

The raindrop size distribution (DSD) is fundamental for quantitative precipitation estimation (QPE) and in numerical modeling of microphysical processes. Conventional disdrometers cannot capture the small drop end, in particular the drizzle mode which controls collisional processes as well as evaporation. To overcome this limitation, the DSD measurements were made using (i) a high-resolution (50 microns) meteorological particle spectrometer to capture the small drop end, and (ii) a 2D video disdrometer for larger drops. Measurements were made in two climatically different regions, namely Greeley, Colorado, and Huntsville, Alabama. To model the DSDs, a formulation based on (a) double-moment normalization and (b) the generalized gamma (GG) model to describe the generic shape with two shape parameters was used. A total of 4550 three-minute DSDs were used to assess the size-resolved fidelity of this model by direct comparison with the measurements demonstrating the suitability of the GG distribution. The shape stability of the normalized DSD was demonstrated across different rain types and intensities. Finally, for a tropical storm case, the co-variabilities of the two main DSD parameters (normalized intercept and mass-weighted mean diameter) were compared with those derived from the dual-frequency precipitation radar onboard the global precipitation mission satellite.

Fractal behavior of the trajectories of the foot centers of pressure during pregnancy

The equilibrium of pregnant women is compromised because the falling risk increases as pregnancy progresses. The trajectories of the centers of pressure are related to equilibrium, gait and posture. The purpose of this work was to investigate the fractal behavior of the trajectories of the center of pressure of both feet in standing and walking pregnant women and how they evolve during pregnancy. By using instrumented insoles (F-Scan® system working at 40 Hz), the trajectories of the center of pressure of both feet were obtained for 71 women in the three trimesters of their pregnancy. The ‘detrended fluctuation analysis’, a technique designed to extract the fractal properties of a signal, was used to analyze the fractal behavior of both the x and y components of the measured trajectories. Specifically, the fractal characteristic exponents corresponding to the small and large end regions of the corresponding scaling functions were obtained and compared. No differences were found between the characteristic exponents obtained for x and y components nor from the signals found for left and right feet within the statistical uncertainties. In standing conditions all the exponents obtained remained almost constant, regardless of the elapsed pregnancy time, taking values around 0.5. In walking conditions, the small end exponents did not change with respect to those found in static conditions; on the contrary, the large-end exponents reduced as pregnancy progressed, reaching values of the order of −0.6 in the third trimester. The multi-scaling character of the walking signals could be related to the anteroposterior and medio-lateral displacement observed in previous experiments and that could be on the root of the development of musculoskeletal discomfort and a falling risk that increases with the pregnancy time.

A study on milling of super elasto-plastic titanium alloy with a small ball end mill tool

A study on milling of super elasto-plastic titanium alloy with a small ball end mill tool

Distributional consequences of technological change: Worker-level evidence

This paper explores the employment trajectories of workers exposed to technological change. Based on individual-level panel data from the UK, we first confirm that the share of middle-skilled routine workers has declined, while non-routine jobs in both high- and low-skilled occupations have increased, consistent with country-level patterns of job polarization. Next, we zoom in on the actual transition patterns of threatened routine workers. Despite the aggregate decline in routine work, most affected workers manage to remain in the labor market during the time they are in the study: about 64% “survive” in routine work, 24% switch to other (better or worse paying) jobs, almost 10% exit routine work via retirement and only a small minority end up unemployed. Based on this finding, the final part of our analysis studies the economic implications of remaining in a digitalizing occupational environment. We rely on an original approach that specifically captures the impact of information and communication technology at the industry level on labor market outcomes and find evidence for a digital Matthew effect: while outcomes are, on average, positive, it is first and foremost non-routine workers in cognitively demanding jobs that benefit from the penetration of new technologies in the workplace. In the conclusions, we discuss if labor market polarization is a likely source of intensified political conflict.

A study on milling of super elastic-plastic titanium alloy with a small ball end mill tool

A study on milling of super elastic-plastic titanium alloy with a small ball end mill tool

Are octahedral clusters missing on the carbon energy landscape?

We report a new class of carbon nanostructures at a lower sub-nano end of the size scale with a surprising stability, as compared to the well-known carbon fullerenes. The octahedral carbon clusters contain tetragonal rings, which, in spite of a common belief, prove to be an energy efficient means of plying graphene sheets to make three-dimensional spheroid shapes, similar to fullerenes. The two families of structures are shown to be competitive at small sizes (∼20 atoms) at room temperature, and for higher temperatures, at both small and large sizes (>200 atoms). Our calculations demonstrate that both vibrational and electronic spectra of these cluster families are similar, which thus might cloud their experimental identification. However, there is a sufficiently strong shift in vibrational frequencies below 160 and in the range of 600–800 cm−1, which should help to identify different types of carbon clusters experimentally. We propose octahedral clusters and other structures containing tetragonal rings as viable structural elements and building units in inorganic chemistry and materials science of carbon along with fullerenes.

Dynamic structural analysis of connecting rod through adaptive mesh refinement for different materials

In this research dynamic structural behavior of connecting rod made of three different materials has been investigated to choose best suitable and light weighted material for manufacturing of connecting rod without affecting its strength. So in this aspect dynamic structural behavior of connecting rod is analyzed through Finite Element Methods (FEM) by applying two different meshing schemes known as conventional and Adaptive Mesh Refinement (AMR) method. Simulation has been conducted by using ANSYS workbench module. Simulation results have been validated against experimental from literature. From the results of Dynamic structural analysis of connecting rod it is revealed that on the compressive loading maximum stresses occurred in the shank near small end and at its big end. Whereas in case of tensile loading maximum stresses occurred at the mid of inside surface near the smaller end. On the other hand maximum deformation occurs at big end of connecting rod for both compressive and tensile loads. Dynamic structural behavior comparison for connecting rod made of three different materials has also been carried out and it is observed from obtained results that Aluminum alloy experienced highest deformation followed by chromium steel alloy 410. Whereas lowest deformation was found in forged steel material. While comparison of stresses distribution, deformation and weight analysis results for connecting rod made from three different materials, it is concluded that chromium steel alloy 410 connecting rod is lighter in weight as compare to forged steel connecting rod and shown enough strength to sustain the maximum load as compare to aluminum alloy connecting rod. Therefore it is attributed that chromium steel alloy 410 would be better option than the aluminum alloy and forged steel for manufacturing of connecting rod. Furthermore, by comparing the meshing schemes, it is concluded that AMR method provide good results with less computational resources and within less CPU time.

Modelling of H2 production via sorption enhanced steam methane reforming at reduced pressures for small scale applications

The production of H2 via sorption enhanced steam reforming (SE-SMR) of CH4 using 18 wt % Ni/Al2O3 catalyst and CaO as a CO2-sorbent was simulated for an adiabatic packed bed reactor at the reduced pressures typical of small and medium scale gas producers and H2 end users. To investigate the behaviour of reactor model along the axial direction, the mass, energy and momentum balance equations were incorporated in the gPROMS modelbuilder®. The effect of operating conditions such as temperature, pressure, steam to carbon ration (S/C) and gas mass flow velocity (Gs) was studied under the low-pressure conditions (2–7 bar). Independent equilibrium based software, chemical equilibrium with application (CEA), was used to compare the simulation results with the equilibrium data. A good agreement was obtained in terms of CH4 conversion, H2 yield (wt. % of CH4 feed), purity of H2 and CO2 capture for the lowest (Gs) representing conditions close to equilibrium under a range of operating temperatures pressures, feed steam to carbon ratio. At Gs of 3.5 kg m−2s−1, 3 bar, 923 K and S/C of 3, CH4 conversion and H2 purity were up to 89% and 86% respectively compared to 44% and 63% in the conventional reforming process.

Learning from Couples Living with Sensory Loss

Learning from Couples Living with Sensory Loss

Innate Immunity Activation and RNAi Interplay in Citrus Exocortis Viroid-Tomato Pathosystem.

Although viroids are the smallest and simplest plant pathogens known, the molecular mechanisms underlying their pathogenesis remain unclear. To unravel these mechanisms, a dual approach was implemented consisting of in silico identification of potential tomato silencing targets of pospiviroids, and the experimental validation of these targets through the sequencing of small RNAs and RNA ends extracted from tomatoes infected with a severe isolate of Citrus exocortis viroid (CEVd). The generated RNA ends were also used to monitor the differentially-expressed genes. These analyses showed that when CEVd symptoms are well established: (i) CEVd are degraded by at least three Dicer-like (DCL) proteins and possibly by RNA-induced silencing complex (RISC), (ii) five different mRNAs are partially degraded through post-transcriptional gene silencing (PTGS), including argonaute 2a, which is further degraded in phasiRNAs, (iii) Dicer-like 2b and 2d are both upregulated and degraded in phasiRNAs, and (iv) CEVd infection induced a significant shift in gene expression allowing to explain the usual symptoms of pospiviroids on tomato and to demonstrate the constant activation of host innate immunity and systemic acquired resistance (SAR) by these pathogenic RNAs. Finally, based on in silico analysis, potential immunity receptor candidates of viroid-derived RNAs are suggested.

Novel Magnetic Compression Technique for Small Intestinal End to Side Anastomosis in Rats

Journal of the American College of Surgeons 227(4):p S110, October 2018. | DOI: 10.1016/j.jamcollsurg.2018.07.227

Rice hulls pellets as alternate solid fuel for energy generation

Rice is the staple diet of over half the population of the world at an estimated production volume of well over 800 million metric tonnes per month, the second largest produced cereal in the world. Rice grows from tropics to subtropical to warm temperature countries up to 400 S and 500 N of the equator. Four major environments are associated with rice growing as follows: irrigated, rain-fed lowlands, upland and flood prone. Fifty per cent of rice grown are consumed by China and India, and until a few years ago, the rice hulls (husks) resulting from hulling have been considered as agricultural waste and only used in a few small end applications. However, due to diligent research, the full potential of this valuable commodity is being realized and three significant products are being manufactured using this biomass – polymeric composite resins, polymeric lumber as an ideal substitute for natural wood, and more recently, rice hulls solid pellets as an alternative for diesel oil and coal as fuel for energy generation. While the first two are made from combinations of rice hulls flour and polymer resins, the last one is made by compression with suitable small quantities of additives primarily for adhesion. The dimensions and densities of these solid pellets can be varied to suit end applications and also to assist fuel feeding systems. When rice hulls solid pellets are used as fuel, they will generate ash in the combustion chamber and also flue ash which can be easily collected and both items can be successfully recycled. They can be used as filler for bricks, for roofing tiles, extraction of silica (>70%), fertilizer, chemical spill absorbents, filtration mediums and some others. The high content of silica in the ash will provide an enhanced moisture barrier for bricks and roofing tiles. A major end application is its usage as a component for the production of Portland cement. Rice hulls are also an ideal feedstock for producing bio-diesel, and for this purpose, thermochemical processes like pyrolysis and gasification can be used. This research study shows that rice hulls basically consisting of lignin polymer and 20% silica can be made into solid pellets and effectively used as an alternate fuel for petro-based diesel oil and coal for generation of energy. This emerging fuel from renewable sources can even replace the current usage of wooden pellets. Moreover, the resulting ash and flue ash from the combustion of rice hulls will have many viable end uses in industrial, commercial and chemical industries.

Efeitos da prática do suporte de peso corporal em crianças com paralisia cerebral: uma série de casos

INTRODUÇÃO: A paralisia cerebral (PC) é a causa mais comum de incapacidade motora na infância. Essa lesão cerebral pode resultar em comprometimentos neuromotores variados que, geralmente, estão associados à gravidade da sequela e a idade da criança. OBJETIVO: Avaliar a influência do Suporte de Peso Corporal (SPC) sobre a função motora e flexibilidade de crianças com paralisia cerebral. MÉTODO: Participaram do estudo sete crianças que não apresentavam o padrão de marcha, GMFCS nível IV e V, onde foi realizada a identificação do desempenho da função motora grossa por meio da Gross Motor Function Measure (GMFM), da flexibilidade por meio do teste Flexiteste,e do número de passos e distância percorrida antes e após um ano de tratamento com SPC em esteira ergométrica. Tendo assistência de dois terapeutas que auxiliavam em pontos chaves de joelho e tornozelo simulando o padrão de marcha da criança. As sessões foram realizadas uma vez por semana, durante 30 minutos. RESULTADO: O GMFM apresentou aumento das pontuações obtidas antes e após o tratamento, onde os itens deitar e rolar teve aumento de 14,09%, sentar teve aumento de 10,43%, engatinhar e ajoelhar teve, aumento de 7,27%, e por fim, o item em pé teve aumento de 8,10%. A variável flexibilidade apresentou diferença antes e após o tratamento, obtendo como flexibilidade inicial pequena e final médio negativa, com aumento de 7,85 pontos. Já o número de passos teve aumento de 175 passos e a distância percorrida de 132 metros CONCLUSÃO: The proposed SPC therapy in children with cerebral palsy proved to be efficient and could enhance motor performance, flexibility, number of steps and distance traveled.

Continuum study on the mechanics of ion-based carbon nanocones as gigahertz oscillators

There is a growing interest in the development of nanomechanical oscillators operating in the gigahertz range and beyond. This paper introduces a novel nano-oscillator based on a chloride ion inside an open carbon nanocone decorated by functional groups at both small and wide ends. Assuming that the carbon atoms and the electric charges of functional groups are evenly distributed over the surface and the two ends of nanocone, respectively, a continuum-based model is presented through which potential energy and interaction force are evaluated analytically. The van der Waals interactions between ion and nanocone are modeled by the 6–12 Lennard–Jones potential, while the electrostatic interactions between ion and two functional groups are modeled by the Coulomb potential. With respect to the proposed formulations, potential energy and interaction force distribution are presented by varying sign and magnitude of functional groups charge and geometrical parameters (size of small and wide ends of nanocone and its vertex angle). Using the fourth-order Runge–Kutta numerical integration scheme, the equation of motion is also solved to arrive at the time histories of separation distance and velocity of ion. An extensive study is performed to investigate the effects of sign and magnitude of functional groups charge, geometrical parameters, and initial conditions (initial separation distance and initial velocity) on the oscillatory behavior of ion-electrically charged open carbon nanocone oscillator. Numerical results demonstrate that the oscillation frequency of chloride ion inside an uncharged nanocone is respectively lower and higher than those generated inside a nanocone whose small end is decorated by positively and negatively charged functional groups. It is further shown that oscillation frequency is highly affected by the sign of electric charges distributed at the small end of nanocone.

Development of a Novel Continuous Filtration Unit for Pharmaceutical Process Development and Manufacturing

The lack of a commercial laboratory, pilot and small manufacturing scale dead end continuous filtration and drying unit it is a significant gap in the development of continuous pharmaceutical manufacturing processes for new active pharmaceutical ingredients (APIs). To move small-scale pharmaceutical isolation forward from traditional batch Nutsche filtration to continuous processing a continuous filter dryer prototype unit (CFD20) was developed in collaboration with Alconbury Weston Ltd. The performance of the prototype was evaluated by comparison with manual best practice exemplified using a modified Biotage VacMaster unit to gather data and process understanding for API filtration and washing. The ultimate objective was to link the chemical and physical attributes of an API slurry with equipment and processing parameters to improve API isolation processes. Filtration performance was characterized by assessing filtrate flow rate by application of Darcy's law, the impact on product crystal size distribution and product purity were investigated using classical analytical methods. The overall performance of the 2 units was similar, showing that the prototype CFD20 can match best manual lab practice for filtration and washing while allowing continuous processing and real-time data logging. This result is encouraging and the data gathered provides further insight to inform the development of CFD20.

Influence of tube geometry on the performance of standing-wave acoustic resonators.

A general and simple calculation method is presented to investigate the effects of tube shape on the resonant frequency and performance of a resonator. First, the resonant frequency of a variable cross-section resonator is modeled using a transfer matrix. Then, the amplification ratio of the pressure amplitude (ARPA), defined as the ratio of the pressure amplitude at the small end to that at the large end of the resonator, is used to evaluate its performance. The ARPA value for a variable cross-section resonator can be directly calculated from its resonant frequency. It is shown that the ARPA value is closely related to the compression ratio. However, its value is only determined by the resonator itself and is independent of the working conditions. Therefore, the ARPA index is potentially a more convenient tool for evaluating the performance of resonators compared with other indexes. Additionally, the presented method is validated by a comparison with analytical results and experimental data. Moreover, the harmonic frequencies for cylindrical, exponential, conical, half-cosine, 3/4 cosine, and Horn-Cone shape tubes are numerically investigated, in addition to the influence of the resonator shape on the resonance frequency and ARPA. Finally, optimal shape parameters for several types of resonators are suggested.

Machining Stress Analysis and Deformation Prediction of Connecting Rod Based on FEM and GRNN

The unequal distribution of residual stress caused by incorrect machining processes will probably distort the machined connecting rods of the diesel engines. Thus, the influence of the machining processes on the residual stress and distortion of the rod need to be studied. Firstly, the finite element model is established based on the geometry of the connecting rod. Based on the life and death unit method, the influence of material removal on the residual stress of the connecting rod is discussed. Secondly, an orthogonal test is designed. The variables of the test include the quenching temperature, tempering temperature, cooling speed and the sequence of the machining processes. The deformation of the connecting rod is analyzed and then predicted based on the generalized regression neural network. The results show that the minimum distortion is achieved when the quenching temperature is 860 °C, the tempering temperature is 620 °C, the cooling speed is 50 °C h−1, and the machining sequence is “drilling the small end hole-milling, the upper planes-sawing, the connecting rod-turning, and the big end hole”. The priority of the influence of the processes on the deformation of the connecting rod is ranked as follows: cooling speed, quenching temperature, tempering temperature, and process sequence. The tensile residual stress is produced inside the connecting rod by machining processes. The generalized regression neural network predicts the connecting rod deformation accurately and the average error is 8.1%.

Asymptotic analysis of the clamped-pinned elastica

Asymptotic solutions for the clamped-pinned elastica when the displacement of the pinned end is small (immediately after buckling) and when it approaches its limiting displacement (when the force in the rod tends to infinity) are presented. Simple leading order relationships describing the force as a function of the pinned end’s displacement are derived. Those approximate the force-displacement behaviour of the clamped-pinned elastica for small and limiting end displacements. All our results are valid for the clamped-pinned elastica in any mode.