Perpendicular Cut Research Articles

Plane Potential Field Outside a Symmetric T-Shaped Profile

We consider a new plane problem of the potential theory outside a symmetric T-shaped profile. In view of the symmetry of the profile, we reduce the analyzed problem to a mixed boundary-value problem in a half plane with perpendicular cut whose solution is constructed by the method of partial domains with the use of polar coordinates and the Mellin integral transformation. The original problem is reduced to a system of two Wiener–Hopf equations whose solution is reduced to a completely regular infinite system of linear algebraic equations. The solution of the infinite system is approximately found by the method of reduction. The obtained explicit expressions for the unknown harmonic function make it possible to efficiently determine its values for all possible values of the arguments.

Cultivation of one-year poplar plants rooted in autumn and spring with the use of different methods of cutting planting material

Purpose. Study of the peculiarities of growing one-year cutting seedlings of four cultivars of the black poplar under the conditions of the Right Bank Forest Steppe using cuttings with a perpendicular and oblique section.
 Methods. Field, laboratory, statistical.
 Results. Cuttings of cultivars ‘Dorskamp’, ‘I-45/51’, ‘Robusta’ and Toropohrytskyi’s poplar 20 cm long were planted in November and early April for three years. The cuttings for rooting were cut from one-year-old shoots using secateurs, with cuts (i) perpendicular to the axis of the shoots and (ii) an angle of 45º. In an average of 3 years, autumn planting of the varieties ‘I-45/51’ (by 6%) and ‘Robusta’ (by 25%) showed better rooting of cuttings with perpendicular cuts. Cuttings of ‘Dorskamp’ variety with oblique cuts rooted by 11 % and Toropohrytskyi’s poplar by 7% better. When planted in spring, the rooting index of cuttings with a perpendicular cut in the ‘Dorskamp’ variety was 24% higher, in ‘I-45/51’ by 30% higher, and in ‘Robusta’ variety 54 % higher. Cuttings with an oblique cut rooted better in Toropohrytskyi’s poplar (by 20 %). The height of the rooted cuttings was the largest for autumn planting of the same variety (192.9 cm). Also, cuttings with an oblique cut had an advantage in height in the variety ‘Dorskamp’ (by 12%). In the varieties ‘I-45/51’ and ‘Robusta’, cuttings with a perpendicular cut had a higher height by 16 and 5 %, respectively. For spring planting, plants of the ‘Dorskamp’ variety had a maximum height, both when using cuttings with a perpendicular cut (197.9 cm), and with an oblique cut (195.6 cm). Plants of the ‘I-45/51’ variety with a perpendicular cut had a height of 149.1 cm and oblique 126.5 cm. In ‘Robusta’, cuttings with an oblique cut were 8% smaller. The cuttings of Toropohrytskyi’s poplar at both planting seasons were taller than cuttings with an oblique cut.
 Conclusions. The effectiveness of using cuttings with a perpendicular or oblique cut depends on the cultivar of poplar, the timing of planting and the weather conditions during vegetation season. In the conditions of the Right Bank Forest Steppe, for the cultivation of Toropohrytskyi’s poplar, it is recommended to use autumn planting of cuttings with an oblique cut. Cuttings of the varieties ‘I-45/51’ and ‘Robusta’ should be planted in autumn using a perpendicular cut, and ‘Dorskamp’ with the same cut, but in spring.

Striations in molecular clouds: streamers or MHD waves?

Dust continuum and molecular observations of the low column density parts of molecular clouds have revealed the presence of elongated structures which appear to be well aligned with the magnetic field. These so-called striations are usually assumed to be streams that flow towards or away from denser regions. We perform ideal magnetohydrodynamic (MHD) simulations adopting four models that could account for the formation of such structures. In the first two models striations are created by velocity gradients between ambient, parallel streamlines along magnetic field lines. In the third model striations are formed as a result of a Kelvin-Helmholtz instability perpendicular to field lines. Finally, in the fourth model striations are formed from the nonlinear coupling of MHD waves due to density inhomogeneities. We assess the validity of each scenario by comparing the results from our simulations with previous observational studies and results obtained from the analysis of CO (J = 1 - 0) observations from the Taurus molecular cloud. We find that the first three models cannot reproduce the density contrast and the properties of the spatial power spectrum of a perpendicular cut to the long axes of striations. We conclude that the nonlinear coupling of MHD waves is the most probable formation mechanism of striations.

The “midsulcus line” as a landmark for tibial resection during total knee arthroplasty

BackgroundProper tibial alignment is an important goal of total knee arthroplasty. Most surgeons agree that tibial coronal alignment should be within three degrees of neutral mechanical alignment. The “midsulcus line” is a line drawn along the sulcus of the tibial spines, and then the line is continued in the sagittal plane and extended onto the anterior tibia where it intersects the tibial tubercle approximately 3 to 4mm lateral to the tubercle's medial border. The tibial cut was then made perpendicular to this line. The aim of our study was to assess, using CT scans, whether this line provided a consistent guide for planning the tibial cut in total knee arthroplasty. MethodsWe reviewed the CT scans of the knees of 107 patients with osteoarthritis who had undergone a CT scan for planning of custom cutting guides. The midsulcus line was drawn on all scans. ResultsWe found that in 105 of 107 knees, a perpendicular cut to this tibial landmark would have delivered a cut surface within three degrees of neutral mechanical alignment. ConclusionsThe midsulcus line is a reliable landmark for planning the tibial resection in total knee arthroplasty. Level of EvidenceIII

Eye Bank-Prepared Femtosecond Laser-Assisted Automated Descemet Membrane Endothelial Grafts.

The aim of this study was to investigate the use of a femtosecond laser (FL) in the eye bank preparation of corneas for Descemet membrane (DM) automated endothelial keratoplasty (fDMAEK) and to compare endothelial cell death in graft preparations between fDMAEK, Descemet stripping endothelial keratoplasty (DSEK), and DM endothelial keratoplasty (DMEK). Twenty cadaveric tissues were used to test the fDMAEK method. A 9.0-mm-diameter lamellar incision was made using the FL with a 6.0-mm perpendicular anterior ring cut that enabled a stromal rim by acting as a venting incision for bubble expansion. DM was pneumodissected off the central 6.0 mm of the tissue. The fDMAEK grafts were trephined and stained with a viability dye, calcein AM. The entire stained endothelial surface was digitally captured and the endothelial cell loss (ECL) was calculated using trainable segmentation software. For comparison, a series of 6 DSEK grafts and 8 DMEK grafts were created and analyzed. Six of 20 tissues (30%) were lost during fDMAEK preparation. In the 14 successful tissues, the average ECL was 30.4% [95% confidence interval (CI), 25.3-35.6] compared with 21.1% (95% CI, 13.2-28.9, P = 0.09) in the 6 DSEK grafts and 22.5% (95% CI, 18.0-27.0, P = 0.04) in the 8 DMEK grafts. FLs are useful in preparing DMAEK tissue at the eye bank and may promote predictable and precise big bubbles and stromal rims. The fDMAEK preparation success improved with experience and laser adjustments. In fDMAEK, the ECL is higher than was previously reported in DMEK and DSEK, likely due to greater tissue manipulation, although not significantly higher than DSEK controls.

Osteotomía oblicua distal del primer metatarsiano en la cirugía del hallux rigidus. Valoración radiológica del descenso y acortamiento

Distal first metatarsal osteotomies have been indicated in the surgical treatment of mild to moderate hallux rigidus. Its purpose is to decrease the metatarsal head but at the expense of a shortening of the same, which can sometimes produce transfer metatarsalgia. In our center we perform a modification of an oblique distal osteotomy, in order to control and prevent excessive shortening of the first metatarsal. The aim of this study is to perform a radiographic evaluation of the decrease and shortening made with this technique.We reviewed 32 cases (27 patients) undergoing hallux rigidus distal metatarsal osteotomy with no other metatarsal osteotomies associated with a year minimum follow-up. The distal osteotomy consists on a first oblique cut and it starts distally on the dorsum of the first metatarsal head with a variable angle of 10–30°; and second dorsal perpendicular cut to complete the osteotomy. The hallux rigidus were classified according to Coughlin and Shurnas. In the preoperative and postoperative radiographs at one year follow-up the intermetatarsal angle (IMTA), metatarsal-phalangeal angle (MTPA), shortening and lowering of the first metatarsal were assessed.3 cases were grade I, 10 as II and 19 were classified as III. The IMTA and MTPA were respectively 9.78° and 17.° preoperatively and 5.88° and 4.91° per year. The average shortening was 3.66 mm and the lowering 1.91mm.This modified osteotomy looks for a three-dimensional reconstruction in the treatment of hallux rigidus. The advantages are to be a stable extraarticular osteotomy, which allows properly lowering the first metatarsal head with controlled shortening of the radius, giving a rotational stability to the metatarsal head.

Influência do sistema de corte basal de miniestacas na propagação clonal de híbrido de Eucalyptus urophylla x Eucalyptus globulus subsp. maidenii

A técnica de miniestaquia permitiu o estabelecimento de florestas clonais em larga escala. Porém, pouco se avançou no seu manejo em viveiro para genótipos recalcitrantes. Assim, esse estudo teve como objetivo avaliar a influência do sistema de cortes na base de miniestacas na produção de mudas de um clone híbrido de Eucalyptus urophylla x Eucalyptus globulus subsp. maidenii. Desta forma, foram realizadas três avaliações: 1) sobrevivência aos 30 dias em casa de vegetação; 2) enraizamento aos 45 dias em casa de sombra; e 3) aproveitamento final aos 60 dias na área de rustificação. O índice de enraizamento foi determinado com base no percentual de sobrevivência. O delineamento experimental utilizado foi em blocos casualizados constituído de três tratamentos: 1) miniestacas com corte na base perpendicular (testemunha); 2) miniestacas com corte na base em bisel (corte diagonal) e 3) miniestacas cortadas perpendicularmente, com três incisões longitudinais na base. Foram avaliadas quatro blocos de 228 plantas por bloco. Os resultados de enraizamento foram superiores a 80% nos melhores tratamentos e indicam que a propagação do clone via miniestaquia é viável, não apresentando comportamento recalcitrante. Os sistemas de corte basal das miniestaca em bisel e as incisões não favoreceram a formação de raízes.

Theoretical Risk of Anterior Femoral Cortex Notching in Total Knee Arthroplasty Using a Navigation System

Two important requirements for navigation systems in total knee arthroplasty (TKA), perpendicular cut from the distal femoral condyle to the femoral mechanical axis and prevention of notching of the anterior femoral cortex, might be difficult to meet simultaneously. The potential risk of notching was investigated using three-dimensional (3D) computed tomography data of 50 entire lower extremities of 50 female Japanese candidates for TKA and a 3D template system. Navigation systems for TKA carry the potentially higher risk of notching of the anterior femoral cortex (34% to 51%) than conventional technique (11%) (P<0.001). More anterior setting of the reference point for navigation systems on the distal femur and more external setting of the femoral component were risk factors for notching (P<0.001).

Evolution of crystallographic grain orientation and anisotropic properties of (K0.5Na0.5)NbO3 ceramics using BaTiO3 templates by reactive templated grain growth

Platelike BaTiO3 (BT) templates were used for the first time to fabricate (001) textured K0.5Na0.5NbO3 (KNN) piezoelectric ceramics. Plakelike BT templates with a thickness of 1–1.5μm and a mean diameter of 10–15μm were synthesized by the topochemical microcrystal conversion method using Bi4Ti3O12 as precursor particles. A systematic investigation was conducted on illustrating the texture development and microstructure evolution as a function of heat-treatment conditions. It was found that the KNN–BT solid solution was formed between BT templates and matrix materials. The increase of sintering temperature and time induced an orthorhombic–tetragonal phase transition. And it was indicated that the dominant mechanism of texture development could be the abnormal grain growth in the textured KNN ceramics. A (001) orientation degree of 80% was achieved at 1130°C for 24h. The textured ceramics showed anisotropic electrical properties in the direction of parallel and perpendicular to the casting plane. The orthorhombic–tetragonal polymorphic phase transition To–t, the tetragonal–cubic ferroelectric phase transition TC, the dielectric constant εr and the remnant polarization Pr values for the perpendicular cut specimens were lower than the parallel cuts. The excellent electric properties at the parallel cuts were found to be the dielectric constant εr=810, the piezoelectric charge constant d33=163pC/N, and the electromechanical coupling factor kp=0.37.

Formation and evolution mechanisms of transmission dips in a compound metallic grating with perpendicular cut

The transmission properties are investigated of a compound metallic grating in which each period is comprised of two slits but only one is engraved with a perpendicular cut are investigated. Based on Fabry–Parot (FP) resonances and phase resonances, the formation and evolution mechanisms of transmission dips are analyzed. We show that there is a corresponding relationship between the depth of transmission dips and the phase difference of magnetic fields in adjacent slits. In particular, the absorption intensity is powerfully enhanced as phase resonances take place and absorption peaks corresponding to transmission dips exhibit blue-shift or red-shift with an increase in depth of the perpendicular cut. We also show that the variation of transmission peaks and bandwidth of transmission dips can be interpreted by a compound of the transmission spectra of two corresponding simple gratings.

Warriors from the East. Skeletal evidence of warfare from a Lombard-Avar cemetery in Central Italy (Campochiaro, Molise, 6th–8th Century AD)

The early mediaeval cemetery of Campochiaro is located in Molise (Central Italy) and dates to the 6th–8th centuries AD. It consists of two inhumation areas: one at Morrione and the other at Vicenne. This site is important because of the contemporary presence of locals, Lombards and Avars of the steppes. Campochiaro was probably an outpost against the Byzantine army settled in southern Italy. Since no signs of a stable settlement or built-up area have been found, it seems the cemetery can be attributed to a semi-nomadic group. Many graves contained a man and his horse with the harness complex and typical Avar stirrups. The military nature of this settlement is shown by ostearchaeological evidence of warfare and violence on three skeletal individuals: n. 20, n. 102 and n. 108. Two of them exhibit lesions of the cranial vault probably produced by shock weapons in the fashion of the Byzantine armies: a spiked mace and a battle-axe. The cicatrisation of the wounds and the bony neo-formation suggest that the individuals survived these injuries for a long time. The third individual suffered from leprosy. He shows a long perpendicular cut in the left section of the frontal bone. The wound is clean and, because it is without traces of bony neo-formation, was probably a peri-mortem blow landed with a sharp weapon. The wound was not mortal, because it was very slight and probably produced only a slash. As ritual or magical practises and/or damage produced during the excavation or by the action of roots in the earth can be excluded, this individual was perhaps really a leper warrior who died in combat.

Response of engineered cartilage to mechanical insult depends on construct maturity

Injury to articular cartilage leads to degenerative changes resulting in a loss of mechanical and biochemical properties. In engineered cartilage, the injury response of developing constructs is unclear. To characterize the cellular response of tissue-engineered constructs cultured in chemically-defined medium after mechanical insult, either by compression-induced cracking, or by cutting, as a function of construct maturity. Primary immature bovine articular chondrocytes (4-6 weeks) were encapsulated in agarose hydrogel (2%, 30 millioncells/mL) and cultured in chemically-defined medium supplemented with Transforming growth factor (TGF)-β3 (10ng/mL, first 2 weeks). At early (5 days) and late (35 days) times in culture, subsets of constructs were exposed to mechanical overload to produce a crack in the tissue or were exposed to a sharp wound with a perpendicular cut. Constructs were returned to culture and allowed to recover in static conditions. Mechanical and biochemical properties were evaluated at 2-week intervals to day 70, and cellular viability was assessed at 2-week intervals to day 85. Constructs injured early in culture recovered their mechanical stiffness back to control values, regardless of the mode of injury. Later in culture, when constructs exhibited properties similar to those of native cartilage, compression-induced cracking catastrophically damaged the bulk matrix of the tissue and resulted in permanent mechanical failure with persistent cell death. No such detrimental outcomes were observed with cutting. Biochemical content was similar across all groups irrespective of mode or time of injury. Unlike native cartilage, engineered cartilage constructs exhibit a reparative capacity when the bulk integrity of the developing tissue is preserved after injury.

Trapping of surface-plasmon polaritons in a subwavelength cut

We study a transverse magnetic wave propagation in a subwavelength metallic slit which is modified by a perpendicular cut. The surface-plasmon polaritons (SPPs) can be trapped in the perpendicular cut by tuning the length or width of the cut. Moreover, the period of the resonance states corresponds to the difference of the cut's length Δ L which is 450 nm. An analytical solution for the resonance condition of the structure is derived by the cavity theory, which is consistent with the numerical simulation by using the finite difference time domain (FDTD) method.

Stratal attributes and evolution of asymmetric inner- and outer-bend levee deposits associated with an ancient deep-water channel-levee complex within the Isaac Formation, southern Canada

Isaac Channel 3 is a rare outcrop example of a perpendicular cut through a sinuous deep-water channel, and also where levee deposits formed on opposite sides of the channel are well exposed. Strata flanking the outer- and inner-bend margin of the channel show important differences in lithofacies, architecture and association with channel-fill strata. Proximal outer-bend levee deposits are sand-rich (N:G up to 0.68) and comprise medium- to thick-bedded, T a–d turbidites interstratified with thinly-bedded, T cd turbidites. The thicker-bedded deposits show lateral variation in grain size and thickness over hundreds of meters whereas thin-bedded strata thin and fine negligibly over similar distances. The distal outer-bend levee (up to 700 m laterally away from the channel) consists predominantly of thin-bedded turbidites interstratified with up to 5 m thick coarse-grained splay deposits. In contrast to the outer-bend, the inner-bend levee deposits are significantly more mud-rich (N:G as low as 0.15) and consist mostly of thin-bedded, T cd turbidites with less common thicker-bedded, T a–d turbidites. Lateral thinning and fining trends associated with these less common thicker-bedded deposits occur more rapidly than their outer-bend counterparts. Erosion associated with lateral migration of the channel axis produced a sharp contact along the outer-bend channel margin causing coarse-grained channel-fill deposits to be in erosional contact with levee deposits. This suggests that the crest of the outer-bend levee was elevated above the channel floor and produced a channel margin upon which channel-fill strata onlapped. Positive topography is interpreted to have developed by overspilling processes that deposited abundant sand on the outer-bend levee while the majority of the flow continued through the channel bend and bypassed to areas further downslope. In contrast, some thick-bedded, amalgamated channel-fill deposits in the axial channel area grade laterally over 140 m into thinly-bedded turbidites on the inner-bend levee. The lack of channel-fill on lap relationships implies that topography along the inner bend was sufficiently subtle that at least some flows were able to expand laterally and over the overbank area without becoming separated from the main throughgoing channel flow. Stratal relationships observed in Isaac Channel Complex 3 suggests three main episodes of channel-levee growth that were each initiated by a period of increased levee relief followed by channel filling and distal levee deposition. This consistent depositional history points to the regular variations, in both time and space, of sediment transport and deposition in a deep-marine sinuous channel-levee system.

Effect of Arc Current Ultrasonic-Frequency Pulsation on Plasma Cut Quality

The present work proposes a novel plasma cutting system using the ultrasonic frequency pulsed arc, and then experimentally investigates the effect of pulse process parameters on cut quality in the frequencies of 20-60 kHz. It is shown that kerf widths, bevel angle, straightness and dross attached level decrease obviously with the appropriate increases in the frequency and amplitude of pulse current. Furthermore, cutting heat affected zone narrows and cut hardness drops clearly in the pulsed cutting. This current pulsation can thus improve plasma cut quality remarkably, and finally leads to a narrower, flatter and more perpendicular cut of better remachinability. Experimental results simultaneously demonstrate that the effectiveness of the ultrasonic-frequency pulsed cutting process developed at the low current of arc.

Submerged Speleothemes - Expect the Unexpected. Examples from the Eastern Adriatic Coast (Croatia)

With the intention of reconstructing Late Pleistocene – Holocene sea-level changes along the Eastern Adriatic coast, a series of speleothems were collected from several submerged caves and pits, in order to constrain periods of their deposition and ceased growth related to sea-level fluctuations. For that purpose, stalagmites provide more reliable records than stalactites, due to their successive layers deposited perpendicularly to the growth direction. Therefore, stalagmites have been collected preferably. But, two of 17 speleothems displayed unexpected interior morphology – speleothem L-1 collected at the depth of 1.5 m in Medvjeđa spilja Cave on Lošinj Island, and speleothem M-25 from Pit near Iški Mrtovnjak Islet collected at the depth of 25 m. Both of the samples were taken from the cave floor, in the growth position of the stalagmite. But the insight into the perpendicular cut with evident central tube revealed their true (stalactitic) origin and additional confirmations were obtained by longitudinal cut and U-Th and 14C dating. Just as the causes of their breakdowns were probably different, so were their falls; speleothem M 25 (together with several other speleothems around it) stuck in the marine sediment in its primary position, while L-1 turned upside-down and even continued crystallizing during the lower sea level. These events are possible in the continental caves, as well. Evidently, it is much easier to recognize and avoid these problems in air-filled caves than in the submarine ones where the speleothems are almost always covered with marine overgrowth, which disguises their outer morphology. Additionally, the bases of the stalagmites are also sometimes covered with marine sediment, which makes correct estimation rather difficult.

How Precise is the Determination of Rotational Alignment of the Femoral Prosthesis in Total Knee Arthroplasty: An In Vivo Study

Correct rotation of the femoral component is critical in avoiding patellar instability in total knee arthroplasty. This study attempted to compare the precision of 4 commonly used methods (transepicondylar axis [TEA], 3° external rotation [ER] from posterior condylar line [PCL], perpendicular cut to Leo Whiteside line [WSL], and balanced flexion gap [GAP]) in determining the rotational alignment of the femoral prosthesis in an in vivo setting. The ranges of error were as follows: (1) TEA, 28° (17° internal rotation [IR] to 11° ER); (2) PCL, 27° (13° IR to 14° ER); (3) WSL, 32° (17° IR to 15° ER); (4) GAP, 26° (14° IR to 12° ER). If an error of more than 5° from neutral alignment is defined as an outlier, 56% in TEA, 72% in PCL, 60% in WSL, and 20% in GAP methods would fall in the outlier zone.

Use of an Electrochemically Etched Platinum Microelectrode for Ascorbic Acid Mapping in Oranges

A positionable platinum microelectrode fabricated by electrochemical etching was used to monitor the concentration of ascorbic acid in fruits and vegetables. Studies carried out with ascorbate oxidase confirmed the suitability of the amperometric sensor to measure selectively the ascorbic acid content. The results obtained with the proposed method for ascorbic acid determination in orange juices compared well with those found by iodimetry with coulometrically generated iodine. The standard deviation calculated by measuring limiting current values in voltammograms was found to be 3% (n = 150). The sensor allowed the evaluation of the spatial distribution of ascorbic acid concentration in oranges by in-situ measurements. Ascorbic acid concentration maps show that in a perpendicular cut the concentration is higher near the peel to the center of the fruit. In a parallel cut, the concentration increases with the distance to the stem. A correlation between the ripening stage and the ascorbic acid concentration was also observed from electrochemical measurements, the content being higher in mature fruits.

Observations of the proximal tibia in total knee arthroplasty.

Relatively little has been written concerning the proximal tibia in total knee arthroplasty. Few authors have looked at landmarks and guidelines for tibial tray preparation and tibial tray orientation. The current study showed that a line drawn 1 mm medial to the medial border of the tibial tubercle and going through the midsulcus of the tibial spines (the midsulcus line) provided a reproducible landmark for the tibia, and when a perpendicular cut was made relative to this line, 46 of 50 knees were cut in appropriate alignment. In addition, it has been said that the tibial tray should be rotated externally to approximately the medial 1/3 of the tubercle to maximize function. The current study showed that when the tibia is allowed to float in a functional position relative to the femoral implant, the tibial external rotation was only 2 mm lateral from the medial age of the tibial tubercle; this is far less than the medial 1/3 of the tubercle and close to the starting point of the midsulcus line.

Identification of the primary auditory field in archival human brain tissue via immunocytochemistry of parvalbumin

Using parvalbumin (PV)-immunocytochemistry, we identified the human primary auditory field (PAF) for the first time. The first gyrus of the right Heschl was identified, and a serial perpendicular cut to the gyrus was made. PV-immunoreactive neuropils delineated four zones, as have been described in monkeys. Unlike with conventional staining, zone 1, characterized by intense immunostaining, corresponded to the koniocortex (PAF), while zone 2, characterized by moderate immunostaining around zone 1, to the parakoniocortex. PV-immunocytochemistry was a useful way to identify PAF in formaline-fixed archival human brain tissue.