Narrow End Research Articles

TiO2 NANOTUBES FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE

Titanium dioxide remains one of the most studied semiconductor for photocatalytic applications due to its low cost production, reduced toxicity, ability to break down the organic pollutants and possibility to achieve complete mineralization. In this work, we report on results of the photocatalytic activity of titanium dioxide nanotubes fabricated by electrochemical anodization technique in an electrolyte solution containing a mixture of hydrofluoric acid, ethylene glycol and phosphoric acid. The morphology and crystallinity of the obtained nanotubes were investigated by means of electron microscopy and it was found that nanotubes have a constant outer diameter of 200 nm and an internal conical shape where the diameter gradually decreases from 120 nm at the wide end to 50 nm at the narrow end. The transmission electron microscopy investigation defined two different phases of titanium dioxide obtained after annealing of amorphous TiO2 in air at 650 °C and 850 °C. Photocatalytic activity of the samples have been evaluated in methylene blue solution in the presence of dispersed nanotubes under visible and UV irradiation by means of UV/Vis spectroscopy. Anatase phase TiO2 shows the best performance degrading 85 % of dye in 25 min under UV illumination, while rutile phase with anatase inclusions shows the best results with a 50 % decay of dye concentration in 25 min under visible light illumination.

Initial-position-driven opposite directional transport of a water droplet on a wedge-shaped groove.

The transport direction of water droplets on a functionalized surface is of great significance due to its wide applications in microfluidics technology. The prevailing view is that a water droplet on a wedge-shaped groove always moves towards the wider end. In this paper, however, molecular dynamics simulations show that a water droplet can move towards the narrower end if placed at specific positions. It is found that the direction of water droplet transport on a grooved surface is related to its initial position. The water droplet moves towards the wider end only when it is placed near the wider end initially. If the water droplet is placed near the narrower end, it will move in the opposite direction. The novel phenomenon is attributed to the opposite interactions of the groove substrate and the groove upper layers with water droplets. Two effective models are proposed to exploit the physical origin of different transport directions of water droplets on a wedge-shaped groove surface. The study provides an insight into the design of nanostructured surfaces to effectively control the droplet motion.

Bringing the desert to the Nile: Some thoughts on a Predynastic terracotta model

This article draws attention to an artefact in the Royal Ontario Museum in Canada, that has thus far received little attention despite having been in their archive for nearly a century. The object (ROM 900.2.45) is a heavily reconstructed ter-racotta rectangular-based model with openings to one side and on top. Painted and incised figures decorate the sides of the object. This paper presents a fresh approach regarding this particular artefact by addressing three issues that are intended to provide an insight into the symbolism of desert and Nile hunting. Firstly, I discuss its identification as a “house”, proposing instead that it may well resemble a Predynastic boat cabin. Secondly, I discuss the iconographic interpre-tation, showing that the scene painted in its “narrow end A” is not a depiction of goats feeding their young, but rather a hunting scene. While this claim has been suggested by other Egyptologists as well, it is still possible to bring some new ideas to the discussion. Finally, I compare these findings with the available evidence and research conducted in the last few years to test this approach and propose an alternative interpretation to both the terracotta model and its painted scenes. This object can provide more information about a much-discussed topic : the apparent contradiction between desert hunting and river navigation.

Molecular evidence and morphological aspects of Transversotrema licinum, Phyllodistomum hoggettae, and re-description of Gyliauchen volubilis (Digenea) from the Red Sea.

During a recent survey on digenean parasites infecting marine fish captured from water located along the Red Sea off Gizan Coasts, Saudi Arabia, thirty-two (29.09%) out of 110 fish were naturally infected with three different species of digenean parasites. The taxonomical status of the recovered worms was confirmed by light microscopy and molecular analysis. Transversotrema licinum infecting the Haffara seabream Rhabdosargus haffara possessed a transversely elongated body with eyespots and the anterior body margin with delineated velum along with its entire breadth. Oral sucker was absent, and eyespots were paired anterior to or at the level of ventral sucker. Phyllodistomum hoggettae from the urinary bladder of the Arabian Nagil Plectropomus areolatus was differentiated by its elongated body, narrow anterior end widened as going posteriorly with prominent marginal undulations in the hindbody. Gyliauchen volubilis infecting the marbled spinefoot Siganus rivulatus, was with fleshy body, conical, tapered anteriorly, convex dorsally, and concave ventrally. Prepharynx was very long and convoluted and had occupied the greater part of the anterior half of the body. Multiple sequence alignment and phylogeny were based on maximum likelihood analysis for the ITS–2 and 28S rDNA for Transversotrema licinum and Phyllodistomum hoggettae were constructed, respectively. They were compared to species within their families and further deposited into the Genebank under accession numbers MG 722711 and MG722710, respectively.

Quasi-Living Copolymerization of Aryl Isocyanates and Epoxides.

Nontraditional polyurethane (PU) has been successfully synthesized by anionic copolymerization of some typical aryl isocyanates and epoxides with ammonium halide onium salt (Lewis base) as the initiator and triisobutylaluminum (Lewis acid) as the activator and the synergistic coordinator. In contrast to the traditional step-growth approach, this chain-growth copolymerization can maintain the anionic propagation site and exhibit some living features with a high activity, by which the copolymers synthesized have narrow molecular weight distributions and discrete end groups. The copolymer is primarily constituted by a urethane linkage, and the byproducts of isocyanurate trimer and oxazolidinone can be effectively suppressed as the polymerization proceeds. Density functional theory (DFT) calculations were also performed to support the proposed reaction mechanism.

Effectiveness of Ureteric Reimplantation on Non-Refluxing Obstructive Congenital Megaureter

Background: One in ten thousand children born with megaureter. A significant portion of this groups are of obstructed variety and the rest are refluxing ureter. It can cause obstructions and back pressure renal damage. Early diagnosis and treatment can stop deterioration of renal function and prevent complications like renal failure. Definitive treatment is uretero-neocystostomy with or without tailoring the ureter. Objective: Objective of this study was to observe the effectiveness of ureteric reimplantation on non-refluxing obstructive congenital megaureter. To achieve this objective we had observed serum creatinine level pre and postoperatively and assessed structural changes in kidney by ultrasonogram, IVU, MCU and RGP pre and postoperatively. We also observed the split renal function and split GFR of the affected kidney both pre and post operatively. Methods: This was a cross-sectional observational study. This study comprise of 35 cases of congenital non-refluxing obstructed megaureter, who were admitted in BIRDEM General Hospital and multiple other hospitals in Dhaka city from July 2013 to December 2014. Diagnosis was made by intravenous urography (IVU) reveling a dilated lower third or entire ureter with narrow tapering lower end. Obstruction was also confirmed by diuretic Tc99m DTPA scan. A voiding cystourethrogram was obtained to exclude VUR. Those with poor renal function were evaluated by ultrasonography, DTPA scan and retrograde ureteropyelography. Results: Of 35 patients, 20 were male and 15 were female. Age range 2 to 19 years. All patients underwent ureteric reimplantation, with tailoring in 15 cases. Post-operative mean serum creatinine was 0.99±0.34 which showed improvement. Split function in DTPA renogram and split GFR of patient with POM in the affected right side also showed improvement (29.49±4.02 and 29.64±4.86) as well as affected in left side (27.77±4.18 and 28.02±5.31). Conclusion: Ureteral tailoring with an extravesical ureteral reimplantation can be performed safely and effectively for primary obstructive megaureter. It is found that, ureteroneocystostomy ensured free renal drainage and preserved renal function as well as prevented complications and further deterioration. Bangladesh Journal of Urology, Vol. 21, No. 1, January 2018 p 20-24

Restoration of two great auk (Pinguinus impennis) eggs: Bourman Labrey's egg and the Scarborough egg

Most of the approximately 75 known eggs of the extinct great auk ( Pinguinus impennis) are in public museums, with a few in private collections. A small number of these eggs has sustained damage, either at the time of collection or subsequently, and two of these eggs are known to have been repaired. The two eggs suffered rather different types of damage and were subsequently restored using different techniques. The first, known as Bourman Labrey's egg, sustained extensive damage sometime prior to the 1840s, when the shell was broken into numerous pieces. This egg was repaired by William Yarrell in the 1840s, and when it was restored again in 2018, it was discovered that Yarrell's restoration had involved the use of an elaborate cardboard armature. This egg is currently in a private collection. The second egg, known as the Scarborough egg, bequeathed to the Scarborough Museum in 1877, was damaged (by unknown causes) and repaired, probably by the then curator at Scarborough, W. J. Clarke, in 1906. This egg was damaged when one or more pieces were broken adjacent to the blowhole at the narrow end (where there was some pre-existing damage). The media reports at the time exaggerated the extent of the damage, suggesting that the egg was broken almost in two. Possible reasons for this exaggeration are discussed. Recent examination using a black light and ultraviolet (UV) revealed that the eggshell had once borne the words, “a Penguin's Egg”, that were subsequently removed by scraping.

Gunn threshold voltage characterization in GaAs devices with wedge-shaped tapering

We fabricate gallium arsenide-based devices with a wedge-shaped tapering region connected to a rectangular-shaped region and measure the threshold voltage required to trigger the Gunn effect. The threshold voltage reduction is attributed to the focusing of the electric field toward the narrower end of the device and is effective when the device has a steep enough tapering. We also model the electric field profile for the tapered devices using an intuitive graphical approach and the finite element method and provide estimates for the threshold voltages of tapered devices. Finally, we compare the estimates to the measured values and provide possible reasons for the discrepancies. We believe the capability of threshold voltage reduction with the wedge-shaped tapering design could be useful in device applications.

The invasive land flatworm Obama nungara (Platyhelminthes: Geoplanidae) reaches a natural environment in the oceanic island of São Miguel (Açores).

During an entomological sampling trip in the island of São Miguel (Açores, Portugal) on 02-11-2019 by José Rafael González-López, one specimen of the invasive flatworm Obama nungara Carbayo et al. 2016 was found under a rock (Fig. 1A). The specimen was photographed in situ and identified by its external morphology based on its large and broad leaf-like body with nearly parallel body margins, narrow and rounded anterior end, rounded posterior end, and dorsal pigmentation consisting of a light brown ground color covered with dark longitudinal and irregular stripes, and ventral surface grayish-white. Recent studies (Justine et al. 2020; Negrete et al. 2020) showed the reliability of photograph-based identification of O. nungara specimens. It is the sixth island where this species has been found (after Guernsey, Great Britain, Ireland, Corsica, and Madeira).

Menopause and Midlife Aging in Cross-Cultural Perspective: Findings from Ethnographic Research in China.

Based on longitudinal mixed methods ethnographic research conducted in China from the mid-1990s to 2018, this article argues that Chinese lay language use divides what Americans and Canadians refer to as "menopause" into two distinct though overlapping concepts of the narrow juejing or end of menstruation and the broader non-gender-specific gengnianqi or "transition between middle and old age." While comparison with research done by Lock in Japan shows that Japanese language uses a similar set of two overlapping yet distinct terms called heikei and könenki, there are important differences between Chinese and Japanese views and experiences of female midlife amidst the similarities. While views and experiences of juejing in China are very similar to notions of heikei in Japan, gengnianqi is quite different from könenki. Like in Japan, the end of menstruation tends to be welcomed by women in China. Also like in Japan, midlife women in China had a lower prevalence of hot flashes than that found in the US and Canada. Also similar to Japan, Chinese women rarely associate hot flashes with embarrassment. However, unlike in the Japanese sample, the Chinese women reported a higher rate of irritability than even the American and Canadian samples. Contrasting with könenki, which is primarly associated with bodily aches and self-restraint in Japan, gengnianqi is commonly viewed as a time of vulnerability to irritable outbursts which must be allowed, though managed carefully. Overall, I show how menopause and midlife aging as concepts and as lived experiences are subject to variation related to differences in language, cultural ideas and practices, local biologies, and culturally-mediated generational experiences of historical change.

Directed motion of two-component droplets on wedge-shaped composite copper surfaces without back-end pinning

The motion of three-phase contact line of a droplet is always halted by the contact angle hysteresis on a common solid surface. In this work, the Ag/Cu surface and Cu(OH)2/Cu surface with water contact angle of 25.0° were fabricated and found favorable for two-component droplet moving. The droplet, water with propylene glycol in irregular shape could restore to a circle (top view) on these prepared surfaces. Inspired by the shape restoration, the directed motion of two-component droplet without back-end pinning was achieved on both the wedge-shaped Ag/Cu and Cu(OH)2/Cu composite surfaces. The two-component droplet moves in a way of the front-end spreading with the subsequent back-end shrinking. The needle-like Cu(OH)2 microstructure is more conducive to the front-end spreading, while the spheroidal Ag particles on Cu substrate is in favor of the back-end shrinking. In addition, the segmented Ag@Cu(OH)2/Cu wedge-shaped composite surfaces with Ag film on the narrow end of the track and Cu(OH)2 on the wide end could enhance the droplet moving. Finally, a micro-chemical reactor was designed capable of driving two dispersed droplets to move in a specific direction, converge, and then react with each other.

Spontaneous and unidirectional transportation of underwater bubbles on superhydrophobic dual rails

Superhydrophobic/superhydrophilic surfaces (SBS/SLS) with excellent water repellency/adhesion are important in both academic research and industrial settings owing to their intriguing functions in tiny droplet and gas bubble manipulation. However, most manipulation strategies involving SBS/SLS are limited to their large-area fabrication or sophisticated morphology designs, which distinctly hinders their practical uses. In this paper, we design and fabricate superhydrophobic polydimethylsiloxane narrowing dual rails (SNDRs) beneath a superhydrophilic stainless steel sheet by one-step femtosecond laser ablation. Our SNDR tracks are capable of transporting gas bubbles in various volumes from wide end to narrow end spontaneously and unidirectionally underwater, even when they are bent. The mechanical analysis for diverse geometrical dual-rail configurations in bubble transportation performance is further discussed. Finally, we experimentally demonstrate the intriguing capability of lossless mixing of gas bubbles at a designed volume ratio on a multiple SNDR combination. This approach is facile and flexible, and will find broad potential applications such as intelligent bubble transport, mixing, and controllable chemical reactions in interfacial science and microfluidics.

Fast and Wide CMEs without Observed >20 MeV Protons

Abstract Statistical studies have found a close association between large solar energetic particle (SEP) events and fast and wide coronal mass ejections (CMEs). However, not all fast and wide CMEs have an associated SEP event. From the Coordinated Data Analysis Web catalog of CMEs observed by the Solar and Heliospheric Observatory (SOHO) between 2009 January 1 and 2014 September 30, we select fast (plane-of-sky speed >1000 km s−1) and wide (plane-of-sky angular width >120°) CMEs and determine whether >20 MeV protons were detected by either SOHO or the Solar TErrestrial RElations Observatory (STEREO-A or STEREO-B). Among the 123 selected CMEs, only 11 did not produce a >20 MeV proton intensity increase at any of the three spacecraft. We use multispacecraft coronagraph observations to reevaluate the speeds and widths of the CMEs. The 11 CMEs without observed >20 MeV protons tend to be in the narrow and slow end of the distribution of the selected CMEs. We consider several factors that might play a role in the nonobservation of high-energy particles in these events, including (1) the ambiguous determination of the CME parameters, (2) the inefficiency of the particle sources to produce >20 MeV protons, (3) the lack of magnetic connection between particle sources and any spacecraft, and (4) the lack of particles accelerated and released during the parent solar eruptions. Whereas the extent of the high Mach number regions formed in front of the CME is limited, the characteristic that seems to distinguish those fast and wide CMEs that lack observed >20 MeV protons is a deficit in the release of particles during the solar eruptions.

Study of Variations in the Morphology of Liver in the Nepalese Cadavers

Backgrounds: Liver is the largest viscera, located in the right hypochondrium, epigastrium and left hypochondrium of the abdominal cavity. It is a wedge-shaped organ with its narrow end pointed towards the left. It is convex in the front, to the right, above, and behind, and is somewhat concave inferiorly, where it is moulded to the shapes of the adjacent viscera. Even though the surface is smoothly continuous, liver is customarily apportioned by the anatomists into a larger right and a smaller left lobe by the line of attachment of the falciform ligament anteriorly and the fissure for ligamentum teres and ligamentum venosum on inferior surface. Materials and Methods: The present study was conducted on 50 formalin fixed livers and gall bladders during routine labex of undergraduate students in the dissection hall of Anatomy department of Nobel Medical College Teaching Hospitals, Biratnagar, Nepal in the period of 3 years starting from June 2016 to May 2019. Each of the specimens was studied for morphological variations. Results: In the present study the livers with normal architectures were considered normal. Out of 50 liver specimens, 21 were normal without any gross anomalies with normal architecture. The remaining 29 specimens showed some short of accessory fissures and lobes on the different lobes of the liver. Out of 29 specimens in 2 specimens lingular process was observed arising from the left lobe. Hypoplastic left lobes was also observed in 2 specimens. Conclusions: Knowledge of morphological variations like atrophy, agenesis, presence of accessory lobes and fissures, presence of intrahepatic gall bladder and absence of normal fissure and lobe can cause diagnostic error in interpretation for the anatomists, radiologists and surgeons.

EFFECT OF REVERSIBLE ADDITION-FRAGMENTATION CHAIN TRANSFER EMULSION STYRENE–BUTADIENE RUBBER ON THE PROPERTIES OF SILICA COMPOUNDS

ABSTRACT In recent years, solution styrene–butadiene rubber (SSBR), which has a narrow molecular weight distribution, controllable microstructure, and chain end functionality, is mainly used as base rubber for passenger car tire tread compounds. However, SSBR has a lower molecular weight than that of emulsion SBR (ESBR) because it is difficult to increase the molecular weight of SSBR. In contrast, ESBR can easily increase the molecular weight; however, it has a broad molecular weight distribution. The reversible addition-fragmentation chain transfer (RAFT) polymerization technique is applicable to the emulsion polymerization. Polymers with narrow molecular weight distributions can be obtained by the RAFT polymerization because the RAFT agent prevents the coupling reaction of the growing chain radicals. In this case, ESBR having a narrow molecular weight distribution, which is an advantage of SSBR, and a high molecular weight, which is an advantage of ESBR, can be synthesized. Therefore, we synthesized RAFT ESBR and fabricated its compounds with silica filler. We confirmed that the physical properties of the RAFT ESBR silica compound are different from those of the ESBR silica compound. In addition to the narrow molecular weight distribution of the RAFT ESBR, the trithiocarbonyl group of the RAFT agent in the RAFT ESBR chain molecules affects the physical properties.

Cercetări efectuate la Băile Figa în anii 2016–2019 și considerații privind deslușirea valențelor unui peisaj salin hibrid / Research carried out at Băile Figa during 2016–2019 Revealing the potential of a hybrid saltscape

Cercetări efectuate la Băile Figa în anii 2016–2019 și considerații privind deslușirea valențelor unui peisaj salin hibrid / Research carried out at Băile Figa during 2016–2019 Revealing the potential of a hybrid saltscape

Cryo-EM structures of apo and antagonist-bound human Cav3.1

Among the ten subtypes of mammalian voltage-gated calcium (Cav) channels, Cav3.1-Cav3.3 constitute the T-type, or the low-voltage-activated, subfamily, the abnormal activities of which are associated with epilepsy, psychiatric disorders and pain1-5. Here we report the cryo-electron microscopy structures of human Cav3.1 alone and in complex with a highly Cav3-selective blocker, Z9446,7, at resolutions of 3.3Å and 3.1Å, respectively. The arch-shaped Z944 molecule reclines in the central cavity of the pore domain, with the wide end inserting into the fenestration on the interface between repeats II and III, and the narrow end hanging above the intracellular gate like a plug. The structures provide the framework for comparative investigation of the distinct channel properties of different Cav subfamilies.

How do complementarity and discount choices interact with latitude of price acceptance in price bundling?

Purpose This paper aims to examine three important questions: What would be the effects of pricing at the lower end of a wide vs narrow latitude of price acceptance (LPA) on consumer choice of the bundle? How would the nature of a bundle frame (i.e. discount on bundle vs discount on components) and discount frame (i.e. discount as absolute off vs discount as percentage off) influence the preference given to a price level that is at the wide or narrow end of the LPA? Would the effect be significantly different if the bundle components were complementary vs if they were non-complementary? Design/methodology/approach The authors carried out two studies using between-subject experimental design. In Study 1, the authors used 2 (LPA: wide/narrow) × 2 (complementarity: yes/no) × 2 (bundle frame: together/separate) design, and in Study 2, the authors replaced bundle frame with discount frame (i.e. absolute off/percentage off). Findings The authors find that the LPA effect is likely to outweigh the complementarity effect; however, a combined effect of complementarity and bundle frame is stronger than the LPA effect. Also, for a wide (narrow) LPA product bundle, absolute off (percentage off) discount frame is more attractive. Practical implications Managers should use bundling strategy with complementary products having wider LPA. In case of wide LPA and complementary products, both together and separate frame could be the best bundling strategy while in case of narrow LPA and complementary products, together frame could be the best bundling strategy. Originality/value The main contribution relates to the role LPA plays in consumer evaluation of a bundle offer and its interaction with complementarity and discount frame. The authors apply the range hypothesis principles (i.e. price-attractiveness judgments are based on a comparison of market prices to the endpoints of a range of evoked prices) in the bundling context and extend the earlier work in the area of complementarity and discount frame.

Phyllosticta capitalensis Causes Leaf Spot on Tea Plant (Camellia sinensis) in China

<i>Phyllosticta capitalensis</i> Causes Leaf Spot on Tea Plant (<i>Camellia sinensis</i>) in China

Optimizing the anchoring structure for a super large cable-net structure with improved fatigue resistance

During its operation, the vast cable-net structure of China’s Five-hundred-meter Aperture Spherical radio Telescope is subject to super high stress amplitude (up to 500 MPa) that the current anchoring structure is unable to bear. As a solution to this problem, this article presents an optimized anchoring structure that includes a main anchor cup and an auxiliary anchor cup. Typically used to compose Five-hundred-meter Aperture Spherical radio Telescope’s cable-net structure, the S3-type cable is selected as the subject of analysis. In addition to anchoring limit and fatigue tests, a finite element analysis is conducted using the software ANSYS to set up a one-sixth three-dimensional high-precision numerical model to examine the contact–slip relationship between the steel wires and the chill casting. The following combination of structural parameters is found for an optimized design of the S3-type cable anchoring structure: auxiliary cup internal inclination angle, 3°; friction coefficient between anchor cup and chill casting, 0.12; and elastic modulus of the chill casting, 36 GPa. This optimal structural setting eliminates fretting wear in the main cup section; instead, fretting wear most likely occurs at the narrow end of the auxiliary anchor cup. When the structure bears the maximum working load, the slip amplitude between the chill casting and the tendons is 25 μm at the narrow end of the auxiliary anchor cup, and the radial compressive stress of the steel wire is −20 MPa. It is determined that this innovative anchoring structure with the S3-type cable boasts excellent static and dynamic load-bearing qualities with the elastic modulus of the cable remaining almost unchanged during the testing processes, which indicates that this anchorage meets the highly demanding requirements of the Five-hundred-meter Aperture Spherical radio Telescope project and offers a prototype to facilitate future anchoring enhancing efforts.