Linear Grooves Research Articles

Vertebral Distraction during Anterior Cervical Discectomy and Fusion Causes Postoperative Neck Pain

ObjectiveVertebral distraction is routinely performed during anterior cervical discectomy and fusion (ACDF). Overdistraction can injure the facet joints and may cause postoperative neck pain consequently. The purpose of this study was to investigate the clinical relevance of distraction force during ACDF.MethodsThis study included 24 consecutive patients with single level cervical disc disease undergoing single level ACDF. We measure the maximum torque just before the the arm of the Caspar retractor was suspended by the rachet mechanism by turning the lever on the movable arm using a torque meter. In order to turn the lever using the torque driver, we made a linear groove on the top of the lever. We compared the neck disability index (NDI) and visual analogue scale (VAS) scores between the high torque group (distraction force>6 kgf·cm) and the low torque group (distraction force≤6 kgf·cm) at routine postoperative intervals of 1, 3, 5 days and 1, 3, 6 months.ResultsThe VAS scores for posterior neck pain had a linear correlation with torque at postoperative 1st and 3rd days (y=0.99×-1.1, r2=0.82; y=0.77×-0.63, r2=0.73, respectively). VAS scores for posterior neck pain were lower in the low torque group than in the high torque group on both 1 and 3 days postoperatively (3.1±1.3, 2.6±1.0 compared with 6.0±0.6, 4.9±0.8, p<0.01). However, the difference in NDI scores was not statistically significant in all postoperative periods.ConclusionVertebral distraction may cause posterior neck pain in the immediate postoperative days. We recommend not to distract the intervertebral disc space excessively with a force of more than 6.0 kgf·cm.

Linear fibroblast alignment on sinusoidal wave micropatterns

Micrometer and nanometer grooved surfaces have been determined to influence cellular orientation, morphology, and migration through contact guidance. Cells typically elongate along the direction of an underlying groove and often migrate with guidance provided by constraints of the pattern. This phenomenon has been studied primarily using linear grooves, post, or well patterns. We investigated the behavior of mouse embryonic fibroblasts on non-linear, sinusoidal wave grooves created via electron beam lithography on a polymethyl methacrylate (PMMA) substrate that was spin-coated onto a positively charged glass surface. Three different wave patterns, with varying wavelengths and amplitudes, and two different line patterns were created. Cell orientation and adhesion was examined after 4, 24, and 48h after cell seeding. Attachment strength was studied via subjecting cells on substrates to centrifugal force following a 24-h incubation period. For all wave patterns studied, it was noted that cells did not reside within the groove, rather they were observed to cross over each groove, residing both inside and outside of each wave pattern, aligning linearly along the long axis of the pattern. For the linear patterns, we observed that cells tended to reside within the grooves, consistent with previous observations. The ability to add texture to a surface to manipulate cell adhesion strength and growth with only localized attachment, maintaining free space in curvilinear microtopography underlying the cell, may be a useful addition for tissue engineering and the fabrication of novel biomedical devices.

Can Continuum Thermodynamics Characterize Wenzel Wetting States of Water at the Nanometer Scale?

We address the question of how solid-liquid surface free energy is affected by nanometer scale roughness. We proceed through molecular dynamics calculations of the solid-liquid surface free energy of water in a collapsed wetting state on rough nonpolar surfaces characterized by an array of parallel linear grooves. We establish a continuum equation based on Wenzel and Cassie-Baxter approaches to predict the solid-liquid surface free energy variations of systems, where the vertical and horizontal surfaces of the groove have different interactions with water and where the groove geometry can be varied. We show that the molecular simulations results agree with the prediction of the continuum equation under the condition that the groove is wider than three water molecular diameters and deeper than one molecular diameter.

Diseases of the Nail Unit

The human nail is a complex unit that includes five major modified cutaneous structures: the nail matrix, nail bed, nail plate, nail folds, and cuticle (eponychium). This chapter discusses the function and structure of the five nail components and the pathophysiology affecting each. Also reviewed are nail findings associated with underlying systemic and dermatologic conditions: splinter hemorrhages, koilonychia, transverse nail-plate depressions (Beau’s lines), onycholysis, leukonychia, clubbing, nail-plate pitting, and longitudinal pigmented bands. Infections of the nail are discussed, which include bacterial paronychia, chronic paronychia, and onychomycosis. Figures illustrate the longitudinal section of the fingernail, multiple pigmented longitudinal bands, psoriasis involving the fingernail, late-stage lichen planus of the fingernail, transverse linear grooves, Pseudomonas aeruginosa causing a green nail, psoriasis of the nail, melanonychia striata, and a nail specimen for potassium hydroxide preparation. Tables describe antifungal treatment for toenail onychomycosis as well as selected dermatologic disorders that affect the nail unit. This chapter contains 50 references.

다공성 친바이오 나노섬유 극초단 레이저 가공특성 연구

Electrospun meshed poly-caprolactone PCL was patterned by femtosecond laser with linear grooves. As parametric variables, focus spot size, pulse energy, and scanning speed were varied to determine the affects on groove size and the characteristics of the electrospun fiber at the edges of these grooves. The femtosecond laser was seen to be an effective means for flexibly structuring the surface of ES PCL scaffolds and the width of the ablated grooves was well controlled by laser energy and focus spot size. The ablation threshold was measured to be 14.9J/cm<SUP>2 </SUP>which is a little higher than other polymers. These affects were attributed to optical multiple reflections inside nano-fibers. By the laser-induced plasma at higher pulse energies,<BR>some melting of fibers was observed.<BR>

Single Screw Extruder Characteristics on Friction and Heat Generated with the Barrel Carved Spiral Groove

To make single-screw extruder with extrusion pressure enough, through theory of friction-induced extrusion pressure，which has been generally accepted in the industry. The barrel designed modular structure, in the before barrel carved groove, to add the friction coefficient between barrel and solid material. It form extrusion pressure In this section by exponential increase. This papers analyze that use of spiral groove instead of linear grooves can effectively reduce the frictional heat generation.

Toothpaste lava from the Barren Island volcano (Andaman Sea)

Toothpaste lava is a basaltic lava flow type transitional between pahoehoe and aa and has been described from Paricutin, Kilauea and Etna volcanoes. Here we describe a spectacular example of toothpaste lava, forming part of a recent (possibly 1994–95) aa flow on the active volcano of Barren Island (Andaman Sea). This flow of subalkalic basalt shows abundant squeeze-ups of viscous toothpasate lava near its entry into the sea. The squeeze-ups are sheets and slabs, up to several meters across and tens of centimeters thick, extruded from boccas. They are often prominently curved, have striated upper surfaces with close-spaced, en echelon linear ridges and grooves, broad wave-like undulations perpendicular to the striations, and sometimes, clefts. Textural, geochemical, and Sr–Nd isotopic data on the squeeze-ups and the exposed aa flow core indicate very crystal-rich, viscous, and isotopically very homogeneous lava. We envisage that a greatly reduced speed of this viscous flow at the coastline, possibly aided by a shallowing of the basal slope, led to lateral spreading of the flow, which caused tension in its upper parts. This, with continued (albeit dwindling) lava supply at the back, led to widespread tearing of the flow surface and extrusion of the squeeze-ups. The larger slabs, while extruding in a plastic condition, curved under their own weight, whereas their surfaces experienced brittle deformation, forming the en echelon grooves. The extruded, detached, and rotated sheets and slabs were carried forward for some distance atop the very slowly advancing aa core, before the flow solidified.

The Vascular Groove Sign: A New CT Finding Associated With Osteoid Osteomas

We have observed that osteoid osteomas are frequently surrounded by thin curvilinear or serpiginous low-density grooves in the surrounding bone on CT examinations. We believe that these grooves represent prominent enlarged feeding arterioles, corresponding to recently published histologic findings. This study was performed to assess the sensitivity and specificity of this vascular groove sign for differentiating osteoid osteomas from other radiolucent bone lesions. The study group consisted of 42 patients with pathologically proven osteoid osteomas. The control group included 29 patients with radiolucent bone lesions other than osteoid osteomas. Two readers scored CT examinations of these lesions for the presence of the vascular groove sign, defined as one or more radiolucent linear or serpiginous grooves extending from the periosteal surface of bone down to the radiolucent tumor. Sensitivity and specificity values were calculated for each reader. Positive and negative predictive values, p values, and interobserver agreement values were calculated. The sensitivity of the vascular groove sign for detection of osteoid osteoma was 73.8% for reader 1 and 76.2% for reader 2, specificity was 96.6% for reader 1 and 89.7% for reader 2, positive predictive value was 96.9% for reader 1 and 91.4% for reader 2, and negative predictive value was 71.8% for reader 1 and 72.2% for reader 2. The p value was less than 0.0001 for both readers. The interobserver agreement was very good, with a kappa value of 0.85. The vascular groove sign is a moderately sensitive but highly specific sign for distinguishing osteoid osteomas from other radiolucent bone tumors on CT.

Ice keel seabed features in marine channels of the central Canadian Arctic Archipelago: evidence for former ice streams and iceberg scouring

The study area lies within the central part of the Canadian Arctic Archipelago; a region that was covered by the Laurentide Ice Sheet during the Late Wisconsinan glaciation and earlier. Multibeam imagery from widely spaced transects indicates the presence of linear groove and ridge features on the seabed at several localities in Peel Sound, Franklin Strait, northern Larsen Sound, and within M’Clintock Channel. These lineations resemble features in Antarctica and in several formerly glaciated regions that have been interpreted to be sole marks emplaced beneath fast-flowing ice streams. Based on these analogies, a similar origin is inferred for the lineations on the channel floors within the study area The lineations are oriented parallel to the channel axes and margins. They occur on all transects within the bathymetrically deeper area at the junction of Franklin Strait and Peel Sound. Northward in Peel Sound they occur extensively on the western and central transects, and more locally on the eastern transect. Their north-south orientation is normal to that of glacial flow features on Somerset Island and most of eastern Prince of Wales Island, which border Peel Sound to the east and west, respectively. The trend of the lineations is northeasterly (parallel to the channel axis) in Franklin Strait and mainly northerly in Larsen Sound and M’Clintock Channel. Elsewhere, the seabed imagery commonly displays scours of various sizes and orientations created by the keels of icebergs. Seabed sediments revealed by 3.5 kHz sub-bottom profiles are interpreted to consist primarily of ice-contact sediments, that in part are thinly mantled by draped water lain sediments. The age of the lineations has not been established. Possibly their formation was coincident with an ice stream in the M’Clintock Channel – eastern Victoria Island region, which formed an ice shelf in Viscount Melville Sound that grounded on southern Melville and Byam Martin islands at ca. 10.4–9.6 14C ka BP Alternatively, they could result from later glacial events.

Evolution of structural defects associated with electrical degradation in AlGaN/GaN high electron mobility transistors

We have investigated the surface morphology of electrically stressed AlGaN/GaN high electron mobility transistors using atomic force microscopy and scanning electron microscopy after removing the gate metallization by chemical etching. Changes in surface morphology were correlated with degradation in electrical characteristics. Linear grooves formed along the gate edges in the GaN cap layer for all electrically stressed devices. Beyond a critical voltage that corresponds to a sharp increase in the gate leakage current, pits formed on the surface at the gate edges. The density and size of the pits increase with stress voltage and time and correlate with degradation in the drain current and current collapse. We believe that high mechanical stress in the AlGaN layer due to high-voltage stressing is relieved by the formation of these defects which act as paths for gate leakage current and result in electron trapping and degradation in the transport properties of the channel underneath.

A lab-on-a-chip platform for studying the subcellular functional proteome of neuronal axons

Axons are long, slender processes extending from the cell bodies of neurons and play diverse and crucial roles in the development and function of nervous systems. Here, we describe the development of a chip device that can be used to produce large quantities of axons for proteomic and RNA analyses. On the chip surface, bundles of axons of rat hippocampal neurons in culture are guided to grow in areas distinct and distant from where their cell bodies reside. Fluorescence immunocytochemical studies have confirmed that the areas where these axons are guided to grow are occupied exclusively by axons and not by neuronal somatodendrites or astroglial cells. These axon-occupied parts are easily separated from the remainder of the chip and collected by breaking the chip along the well-positioned linear grooves made on the backside. One- and two-dimensional gel electrophoresis and Western blotting analyses reveal that the axons and whole cells differ in their protein compositions. RT-PCR analyses also indicate that the axons contain only a subset of neuronal RNAs. Furthermore, the chip device could be easily modified to address other issues concerning neuronal axons, such as the molecular composition of the axon substructure, the growth cone and shaft, the degeneration and regeneration processes associated with injured axons and the effects of extrinsic molecules, such as axon guidance cues and cell adhesion molecules, on the axon. With these diverse applications, the chip device described here will serve as a powerful platform for studying the functional proteome of neuronal axons.

A Re-Evaluation Of ‘Petroglyphs’ On Blue Tier, Northeast Tasmania

In 1957 several eminent scientists (‘the 1957 Blue Tier Expedition’) investigated unusual rock markings reported to be Aboriginal petroglyphs on Blue Tier in northeast Tasmania and concluded that some markings were the result of dissolution of granite by roots, some were made by the subaerial action of plants abrading granite, and others were made by miners and prospectors. However a recent publication has restated claims of an Aboriginal origin for the ‘petroglyphs’. As a result the markings were re-examined so that their genesis could be conclusively decided. The markings on Blue Tier are classified into eight types: (1) Rills; (2) Long Linear Grooves; (3) Circular Holes; (4) Inscriptions; (5) Oval Depressions; (6) Regularly Spaced Circular Depressions; (7) Short Linear Grooves; and (8) Small Circular Depressions. We conclude that Types 1, 2, 5, 7 and 8 markings are natural; Type 3 markings were drilled by prospectors or geologists; Type 4 markings were incised by miners or visitors; and Type 6 markings, which form a distinctive feature just below the crest of Australia Hill, were made by tin prospectors employed by the Mt Lyell Railway and Mining Company Limited. Therefore all markings on Blue Tier have been either produced by natural means (chiefly chemical weathering) or by geologists, prospectors and recent visitors. There is no evidence for the presence of Aboriginal petroglyphs on Blue Tier.

Bite marks on early Holocene Tursiops truncatus fossils from the North Sea indicate scavenging by rays (Chondrichthyes, Rajidae)

AbstractA number of Tursiops truncatus mandibles in the collection of fossil marine mammals in the Rotterdam Natural History Museum have marks consisting of several parallel linear grooves. These marks are also found on four atlas complexes, a scapula and on one vertebra. The hypothesis that they are bite marks and were caused by scavenging rays (Rajidae, Chondrichthyes) was tested with a real-life experiment using different shark and ray species, allowing them to scavenge on cow ribs as proxies for the dolphin bones. The bite marks of these animals were compared with the fossil marks and show that the fossil marks are most likely caused by scavenging rays.

Dermatological signs in South Asian women induced by sari and petticoat drawstrings

The sari, the elegant garment worn by Indian and many South Asian women, is associated with many cutaneous signs. With millions of South Asians settled all over the world, it is important for clinicians to be aware of the cutaneous associations of wearing a sari that is tied tightly around the waist with a drawstring. Lichenified linear hyperpigmented grooves, vitiligo, postinflammatory depigmentation, lichen planus and superficial cutaneous infections are some of the conditions seen in women wearing this garment. This review is one of the very few detailed reports of this widely worn garment and its dermatological associations.

How grooves reflect and confine surface plasmon polaritons

The reflection of surface plasmon polaritons by deep linear grooves structured into gold surfaces is investigated with numerical finite-difference-in-time-domain as well as boundary-element-method calculations. Groove widths of 25 and 100 nm are studied, with depths as large as 500 nm. The reflection depends strongly on wavelength, groove depth, and width. By systematically varying these parameters and studying the field profiles in the grooves as well as mode dispersion, we relate the resonances of the reflectivity to resonant coupling of propagating planar plasmon modes to cavity modes inside the grooves. By careful design of the groove width and depth the reflectivity can be tuned to values up to at least 30% for either a narrow or wide band of wavelengths.

APPLICATION OF FORENSIC SCIENCE TECHNIQUES TO TRACE FOSSILS ON DINOSAUR BONES FROM A QUARRY IN THE UPPER JURASSIC MORRISON FORMATION, NORTHEASTERN WYOMING

Trace fossils on sauropod skeletons from a quarry in fluvial deposits of the Morrison Formation, Wyoming, are used to reconstruct the taphonomic history of the dinosaur bone accumulation. Shallow pits; rosettes; hemispherical pits; thin, curvilinear, branching grooves; and U- to V-shaped linear grooves make up trace fossils found on sauropod skeletons. The traces were interpreted by comparisons to traces on modern bone. Rosettes are circular rings of modified bone and are likely an early stage in the production of shallow pits. They are interpreted as pupation chambers constructed in dried flesh in contact with sauropod bone. Hemispherical pits are circular with a U-shaped cross section and interpreted as dermestid pupation chambers completed in sauropod bone. Thin, curvilinear, branching grooves are semicircular in cross section, form irregular dendritic or looping patterns, and are interpreted as root etchings. U- to V-shaped linear grooves are interpreted as theropod or crocodilian bite marks. Skeletal articulation and condition and distribution of bone modification traces suggest the skeletons accumulated at this site over no more than 3.5 years, with the bulk of the skeletons contributed during the dry season in the final 3–6 months. Carcasses went through all stages of decomposition—including the dry stage, represented by shallow pits, rosettes, and hemispherical pits. Vertebrate scavengers and necrophagous arthropods fed on the carcasses during all decomposition stages prior to burial of the assemblage.

Femtosecond laser-induced formation of nanometer-width grooves on synthetic single-crystal diamond surfaces

We form periodic linear grooves in synthetic single-crystal diamond with femtosecond pulses at 800 nm. The grooves are 40 nm wide, 500 nm deep, up to 0.3 mm long, and have an average spacing of 146±7 nm. The grooves are perpendicular to the direction of the laser polarization and are formed below the threshold for ablation throughout the focal volume. The submicrometer periodicity is caused by interference between a laser-induced plasma and the incident laser beam, which locally enhances the field at the surface so the ablation threshold is exceeded. Using Raman spectroscopy we find that the structures retain the original diamond composition.

Determination of the head losses in metal body disc filters used in drip irrigation systems

The objective of this study was to determine the head losses in several type metal body disc filters manufactured by domestic companies. In order to meet the objective, three different filter designs (L, LT and Y type), each at four different inlet and outlet pipe diameters, were used to measure the head losses at different flow rates in the laboratory. A total of sixteen filters manufactured by three domestic companies (A, B and C) and two different disc elements (linear and curly) were taken into consideration in this study. A comparison of the different filter designs in terms of measured the head losses indicated that in all cases while the L type filters gave the highest head loss, the other two designs provided less head losses at the same flow rate. Furthermore, the head losses in C-LT type filters with curly groove shape discs were less than B-LT type filters with linear groove shape discs in comparing with the LT type filters produced by two different manufacturers even though the design and the size of the filter body were similar. The differences in the head loss can be clarified with the help of the results obtained from the structural characteristic of filtering elements. As a result, in drip irrigation systems, the use of Y and LT type disc filters with curly groove shaped discs are recommended in order to obtain less head losses and low energy requirements when compared with filters used in this study.

Switching Liquid Morphologies on Linear Grooves

The morphology of liquids confined to linear micrometer-sized grooves of triangular and rectangular cross section is studied for different substrate wettabilities. Depending on the wettability and exact geometry, either droplike morphologies or elongated liquid filaments represent the generic equilibrium structures on the substrate. Upon changing the apparent contact angle of aqueous drops by electrowetting, we are able to trigger the transition between elongated filaments and droplets. In the case of rectangular grooves, this transition allows us to advance liquid reversibly into the grooves while crossing a certain threshold contact angle. In triangular grooves, however, these elongated filaments undergo a dynamic instability when the contact angle returns to a value above the filling threshold. The different filling and drainage behavior is explained by specific aspects of the triangular and rectangular groove geometry.

Dewetting of Liquid Filaments in Wedge-Shaped Grooves

The dewetting of liquid filaments in linear grooves of a triangular cross section is studied experimentally and theoretically. Homogeneous filaments of glassy polystyrene (PS) are prepared in triangular grooves in a nonequilibrium state. At elevated temperatures, the molten PS restores its material contact angle with the substrate. Liquid filaments with a convex liquid-vapor interface decay into isolated droplets with a characteristic spacing depending on the wedge geometry, wettability, and filament width. This instability is driven by the interplay of local filament width and Laplace pressure and constitutes a wide class of 1D instabilities that also include the Rayleigh-Plateau instability as a special case. Our results show an accurately exponential buildup of the instability, suggesting that fluctuations have a minor influence in our system.