Oval Holes Research Articles

Residual stresses in welding circular and oval holes

Residual stresses in welding circular and oval holes

An anatomic study of the effects of dural puncture with different spinal needles.

The purpose of this study is to evaluate the effects of puncture of lumbar dura mater with needles of different sizes and with bevels of different shapes. After removal, the dura was punctured with different needles (22-, 25-, 27-, and 29-gauge Quincke, 24-gauge Sprotte, 22-gauge Whitacre, and 18-gauge Tuohy needles) and observed by stereomicroscope to examine the gross morphology. Histologic features were observed by light microscope using frozen and fixed samples stained with hematoxylin and eosin or specific methods (Masson and Weigert) to evidence elastic or collagen fibers. Puncture hole size was proportional to the size of the needle used. Quincke type needles determined oval or ellipsoidal holes; pencil-point needles determined more rounded holes. Dural retraction determined a reduction of the holes in all cases. Histologic examination revealed an irregular border of the hole, with sectioned as well as compressed fibers. The pattern of compressed but not sectioned fibers was observed more frequently in the samples punctured by pencil-point needles. This study confirms that the arrangement of dural fibers is not as uniform as previously thought. Histologic findings confirm the current opinion that pencil-point needles may be less traumatic than Quincke-type needles. The direction of the bevel of the needle does not appear to have great importance in determining the shape of the hole.

Photonic band structure: The case of oval holes

The photonic bands of a face-centered-cubic structure with a basis consisting of three intersecting cylinders with oval cross section are computed using the plane-wave method. The optimal band-gap size to midgap frequency ratio is found to be 12% larger than the case of circular holes for a refractive-index contrast of 3.6. A contour plot is computed that gives this ratio as a function of both the refractive-index contrast and the major diameter of the oval holes.

Internal Fixation with a Self-Compressing Plate and Lag Screw

For a number of years, self-compressing plates, with oval holes and using special drill guides, have been in use. Recently, the advantages offered by lag screw interfragmentary compression inserted through the plate have gained prominence. Often such screws are inserted in an inclined position toward the fracture plane for better efficiency. It has also become evident that inclined screws placed into oval holes undergo a displacement toward the fracture. Efforts to improve the effect of this technique have led to a new plate and screw interaction that is described herein. The result is versatility and efficiency of the fracture fixation.

Haemoperitoneum following gunshot wound of the thigh

We have reported here the case of a rupture of the extensor pollicis longus caused by the protruding end of a screw which was too long placed through a volarly situated plate to stabilize a Barton’s fracture. On the lateral radiograph of our patient’s wrist, it can be seen that the screw inserted through the oval hole of the buttress plate protrudes beyond the far cortex by two turns (Figure~b). This screw is usually inserted first to obtain temporary fixation of the plate to the volar aspect of the distal radius. The plate can then be slid distally or proximally to obtain optimum buttressing of the volarly displaced fragment of a Barton’s fracture. Insertion of further plate screws approximate the plate to the bone, thereby decreasing the distance from the plate to the drilled far cortex. When all screws have been inserted, it is therefore necessary to remove the initial screw, to repeat measurement of the length of the screw hole and insert a shorter screw. This step was most probably omitted in the case described here; instead, as the screw in the oval hole was tightened after insertion of other screws, it came to protrude beyond the far cortex where it produced a delayed attrition rupture of the extensor pollicis longus. References

Pathways between lymph vessels and sinuses in lymph nodes: a study in horses.

The pathways through which lymph flows from terminal afferent lymphatics to the lymph sinuses, and from the sinuses to initial efferent lymphatics, were studied in horse lymph nodes by using Microfil casts and electron microscopy. Terminal afferent lymphatics are continuous with the subcapsular sinus through oval holes, about 3 microns wide, along their length, and through larger openings near their end. Other terminal afferents penetrate into the node within trabeculae and are supported by processes across the lumen. They connect with trabecular and medullary sinuses through oval or round holes, generally 20-30 microns across. Some of these have processes, similar to the luminal strands of the adjacent sinuses, extending across them, apparently providing reinforcement. Initial efferent lymphatics receive lymph from medullary sinuses through holes which are similar to those in afferent lymphatics, though more common, especially near the origin of the vessel. Initial efferents within the medulla appear to be supported by the luminal strands of the surrounding medullary sinuses. It seems likely that these strands, like the trabeculae which surround the penetrating afferent lymphatics, may help to keep the lymphatic vessels open as the node swells while draining an area of infection.

Rasterelektronenoptische beobachtungen an frühen befallsstadien der kartoffelnaβfäule

Summary 1. By scanning electron microscopic observation the effects of an inoculation of potato parenchyma cells by Erwinia carotovora subsp. atroseptica were studied. 2. Immediately after inoculation the bacterial cells are irregularly distributed on the surface of the parenchyma cells. However, already 4 h p. i. the division of the bacteria is starting and small microcolonies are developing. 8 h p. i. a loose film of bacteria could be observed upon the parenchyma cells. 14-16 h later a thick more layer-cover of Erwinia cells has established itself. 3. As a result of secreting pectoiytic enzymes the development of a slime matrix could be observed, wherein the Erwinia cells are embedded; this slime layer contains many oval holes presumbly produced by bacteria cells as lysis zones. These structures were to detect firstly 24 h p. i. To the same time as a second effect of the enzyme attack a loose network of long filaments were to find. It is suggested, that it could be cellulose microfibrills solved out of pectin matrix, which represents the main component of the primary wall of the plant cells.

Evaluation of the dentinal bridge after pulpotomy andcalcium hydroxide dressing

The characteristics of the hard tissue bridge formed after pulpotomies and the dressing of the pulpal wound with a calcium hydroxide-camphorated p -monochlorophenol paste was evaluated in 13 young premolars with the use of a scanning electron microscope and methylene blue dye. The coronal surface of the bridge showed the presence of crystals of different sizes and shapes. The pulpal surface of the bridge was formed by the coalescence of calcospherites, showing the existence of numerous circular or oval holes of 20 to 250 μm diameter approximately. The permeability of the bridge was evaluated with the use of 2% methylene blue dye, showing an intense filtration of the dye through the aforementioned orifices.

Optimum design considerations for dual conductor bubble devices

A design for dual conductor, current-access bubble devices with 8-μm periods has been optimized with a numerical calculation method for bubble motion in a propagating magnetic field, generated around hole patterns in conductor layers. Magnetic bias field distributions are calculated for an oval hole chain in the conductor layers. Bubble motion equations are obtained with analytical field distribution functions approximating the calculated field distributions. Minimum drive current density J min for normal bubble propagation is determined by a solution to the equations. The hole shape has been optimized by the minimization of the drive power P min , the product of J min and conductor resistance, which is calculated from current distributions around the hole pattern. Optimum layer thickness have also been obtained for 8-μm period bubble devices. Both registration tolerance between the two conductor layers and bubble skew effects have been studied semiquantitatively on the basis of the equations of motion. The numerical calculation method developed here is found to be a highly effective means to optimize pattern design for smaller period devices.

Juvenile Retinal Detachment: Pan American Association of Ophthalmology and American Journal of Ophthalmology Lecture

In 20 patients with retinal detachments caused by the impact of a soccer ball, the interval between the injury and the diagnosis of retinal detachment was less than one month in ten cases and less than one week in four cases, suggesting that the retinal breaks occur at the time of injury. The most common breaks were superotemporal dialyses and round or oval holes. Macular damage was common. Nineteen of the 20 retinas were reattached surgically, Final visual acuities were 6/12 (20/40) or better in 12 cases, but worse than 6/60 (20/200) in five patients, all of whom had total long-standing retinal detachments or severe traumatic maculopathy. In 48 male patients with X-chromosome-linked juvenile retinoschisis, there was a high proportion with refractive errors. Vitreous veils occurred in 22 patients (47%) and macular lesions were the most common finding. In younger patients the small macular cysts were arranged in a radial pattern and separated by yellow septa. There were also fine radial folds in the internal limiting membrane in most cases. Peripheral retinoschisis was found in 19 patients (39.6%). In eight patients who underwent photocoagulation in one eye, the retinoschisis had not progressed in either eye after a mean follow-up period of 49 months. Retinal detachments occurred in five eyes (5.2%) of the youngest boys with extensive retinoschisis. In a series of 1,000 consecutive cases of rhegmatogenous retinal detachment, 9.8% were the result of nontraumatic retinal dialyses. Most o(97%) of the nontraumatic retinal dialyses occurred in the inferotemporal quadrant. Multiple dialyses occurred in 32% of the patients. In a series of 100 cases, the dialyses were bilateral in 37. A familial pattern was demonstrated in eight pedigrees. Surgery, including cryotherapy or diathermy, scleral infoldings, silicone implants, and drainage of subretinal fluid, reattached 97 of the retinas but the visual acuity results were often unsatisfactory.

Excavations at a Neolithic Causewayed Enclosure, Orsett, Essex, 1975

SummaryThe Causewayed Enclosure at Orsett, Essex, was trial trenched in 1975 to determine the state of site preservation and confirm its postulated Neolithic date and site sequence. The enclosure consisted of three incomplete circuits of discontinuous ditch with an associated timber palisade slot lying inside and concentric to the middle ditch. Within the interior was an oval post hole structure of a contemporary date. Quantities of Mildenhall style pottery and flint artifacts of the mid third millennium b.c. were recovered from the primary ditch silts and other features. A small quantity of Late Neolithic/Early Bronze Age wares came from the secondary ditch silts and the interior.Later phases on the site were represented by unenclosed Early Iron Age occupation, a Middle Iron Age sub-rectangular enclosure and Saxon ring-ditch burials.

On the Shear Buckling Strength of Perforated Plates and their Reinforcements

As one of the characteristics of ship hull structure, many holes are made on web plates for access and weight saving.Many studies have already been made to investigate the declining of the buckling strength by the perforation. Nevetheless, the shear buckling failure of such a structure has not ceased to exist.On this paper the instability of perforated plates having reinforcement is studied by means of FEM analysis and experimentation to determine the effect of stiffenings on the buckling strength. This study mainly deals with the simply supported plate with an oval hole subjected to shearing force. As for the reinforcing method, stiffener, spigot-plate and doubling are chosen.The conclusions drawn are as follows;1) As the reinforcing method, stiffener is most desirable in respect of elastic range.2) On the presumption of the representative ratio of thickness to breadth for the web plate, yielding will take place before the buckling failure.3) In case of the above, stiffener does not improve much the buckling strength and it is better to reinforce the perforated plate by doubling.

A new plate for internal fixation—the dynamic compression plate (DCP)

A system of internal fixation of fractures is presented in which two new principles are introduced simultaneously. Titanium is adopted as the material for the plates and screws by virtue of its corrosion resistance and because its elasticity is nearer to that of bone than is that of stainless steel. The second new principle is the provision of sloping cylind-rical oval holes in the plate, so that driving home the spherical-headed screws applies compression without the need for a separate compressor. A system of internal fixation of fractures is presented in which two new principles are introduced simultaneously. Titanium is adopted as the material for the plates and screws by virtue of its corrosion resistance and because its elasticity is nearer to that of bone than is that of stainless steel. The second new principle is the provision of sloping cylind-rical oval holes in the plate, so that driving home the spherical-headed screws applies compression without the need for a separate compressor.

STUDIES ON THE CONSTRUCTION AND FUNCTIONING OF MACHINES FOR FERTILIZER DISTRIBUTION

SUMMARY The researches were made on the machine of fertiliz er distribution MA 3,5, which has a capacity of 3,5 m 3 . It is used for transport and spreading solid chem ical fertilizers. It is tracted by tractor U 650 and is actioned from the p ower prize of tractor and from the right support wheels. This machine is formed of frame with catching equipment, bin, distribution equipment, transmision and mechanisms of adjustment and getting in function. The metal frame is supported by 2 pairs of wheels w ith tires, which afford a big mobility during work to the machine . . The distributor is of centrifugal type, formed of a horizontal disc with 6 pallets with adjusted position. Above the disc is found an adjus ting channel which conducts the material brought by the transporting band to the distributor . In the paper are presented the researches made with the adjustments of this machine, such as: the adjustment of the quantity of distrib uted material depending on the ha doze realized through the change of section of evacuatio n window with the shut off valve ; the adjustment of speed of transporting band through ch anging the transmission report between the motion wheel of machine and that of motion axe of transporting band; the adjustment of pallets on the distribution disc from the medium po sition through the oval holes depending on the distributed material; the adjustment of supply ing channel from above the distribution disc for a proper distribution from it and the disc wall . All these researches were made in order to improve the parameters of functioning of this machine , so that our agriculture to be compet itive with that of European Union.

Fenestrated muscle hook for retinal detachment surgery.

PASSAGE of a bridle stay suture beneath each rectus muscle insertion is done to control the eye in most operative procedures for retinal detachment. This report describes an instrument which has proven useful in the rapid passage of these sutures. Two modifications of the instrument have been fashioned from ordinary muscle hooks (Fig 1). In both the tip of the muscle hook was flattened to a thickness of about one third millimeter. In a right-angle model, an oval hole, 2×1 mm, was bored near the tip of the instrument to accommodate either a stay suture or a No. 40 silastic band (Fig 1). Another model with a 1 mm round hole at the slightly pointed tip was designed for the passage of stay sutures only. An S-shaped curve in the shank permits easier exposure of the instrument tip once it is passed beneath the muscle. A No. 4-0 stay suture

On Some Manuscripts in the Libraries of Kairouan and Tunis

THE Library of the Great Mosque in Kairouan is unique in several respects. Its manuscripts are still preserved in the room of Aglabid construction, attached to the qibla wall, in which the Library was established soon after 400 A.H. 1. Notwithstanding the depredations of time and of men, the Library still contains manuscripts which were deposited there when it was founded. Some of them even were written much earlier and are among the oldest Arabic manuscripts in existence 2. Most of them are written on parchment, and the sheets are sometimes of slightly irregular shape, or pierced by small oval holes, where considerations of economy had made it advisable to use a skin to the largest possible extent. The manuscripts written about the year 400 A.H. often show a feature which was pointed out to me by the Librarian, Sidi Othman Jrad, and which, to the best of my knowledge, has not been identified before: a whole line or part of a line is left empty in the middle of each page. Some of these manuscripts were written by a father for the benefit of his 3, a practice which is first attested by the example of 'Abd Alldh b. 'Abd al-Hakam (d. 27I), who copied the books of Sdfici for himself and for his son 4. Above all, the Library contains an almost incredible number of ancient works of the MMliki school the existence of which has been unknown so far 5; and a number of the manu-

New die simultaneously pierces two oval holes

New die simultaneously pierces two oval holes

Sideroret fra Vorså

The Steering Oar from Vorså In 1958 a well-preserved steering oar was fished up in the Kattegat off north Jutland near Vorså and was presented by the finder to tbe Bangsbo Museum at Frederikshavn. It comes from a stretch of coast where wrecks are frequently discovered. For example, in 1922 a wreck which should probably be dated to the 11th-12th centuries was investigated at the river Elling near Frederikshavn.The oar is of oak, very slender and well-formed (figs. 2 and 3). The blade measures 1.92 metres, and the total length is 2.80 metres. The width of the blade increases from 0.175 m. at the top to 0.375 m. at the bottom, where the aft edge forms a little "heel", while its thickness decreases from 10 cms. to 1.5 cms. The sections show that the oar blade is asymmetrically formed, the side towards the ship being almost flat while the other side is curved to a greater or less degree. The fore edge is sharp, while the aft edge is fairly square-cut. At the top there are two oval holes for attachment of the rudder bar, and at the thickest point there is a hole of 4.7 cms. diameter for the withe in which the steering oar was hung.This type of steering oar is known from illustrations and from previous discoveries, in particular the ships from Gokstad 5) and Oseberg 6). A close parallel is provided by a Swedish oar found in Östra Aros 7-8) (Fig. 4). Various modes of suspension have been proposed to explain the many holes and marks of wear on this oar. In the case of the Vorså oar the two holes for the rudder bar are explained by the fact that the oar could be used in two positions, almost vertical during deep-water sailing, or, for shallow-water sailing, turned around the withe into an oblique position where the lower edge of the oar came level with the keel. This feature suggests that the oar belonged to a merchant ship which could only with difficulty be manoevred by means of oars alone. The asymmetrical section resulted in the oar lying close in to the ship, so that wear on the withe in which it hung would be minimal.The form of the oar shows that it is Scandinavian, and probably of 9th-12th century in date. It is natural to place it in association with a number of discoveries made along the east coast of Jutland. A series of discoveries has here been made of Viking-Period artifacts of Norwegian origin, objects of soapstone, in particular bollards 14 ), and 12 axeheads assembled on a stick for ease of transport 16). These bear witness to busy sea-traffic from Norway to the trade centre of Hedeby by Denmark's former southern frontier. Wrecks of ships and isolated parts of ships from the same period found along this sailing route further support this picture, though it is more difficult in the case of the ships to establish with certainty whether they took part in this traffic.If the good opportunities for underwater archeological research in Denmark are exploited, it will undoubtedly be possible to recover much material which, together with the other discoveries of boats and ships in the country, will be able to provide a detailed picture of the development of ship building and seafaring in Scandinavia.Ole Crumlin Pedersen.

A New Eyeless Spider (Archerius: Theridiidae) from Shobudo Cave, Kochi Prefecture, Japan

Till now, about a score of cave-inhabiting spiders have already been reported from some caves in Japan by K. Kishida, J. Ishikawa, T. Komatsu, T. Uyemura, T. Habe, S. Nomura, S. Ueno and T. Yaginuma. Although in these spiders are sometimes found various stages of reduction of eyes, no eyeless spider has yet been recorded. Recently, however, the author had an oppotunity to examine a small spider, collected from a hollow in a limestone cave in Kochi Prefecture, which shows apparently a form for isolated dwelling in a dark cave by lacking eyes. In this paper is reported a new eyeless species of Archerius; which, however, has eyes in American species. The specific name was given in honour of Mr. Kiyoshi Nakahira who discove-red the present species. (_??_) Cephalothorax convex, longer than wide. Anterior part of the head roun-ded. Clypeus vertical. Eyes entirely wanting, and even their vestiges invisible, only a few hairs remaining. All grooves or furrows on carapace obsolete. Tarsus of palp without claw. Upper margin of fang furrow with three teeth, lower also with three but small. Sternum as long as broad. Maxillae wide, converging in front of labium. Labium fused to sternum.Legs 4. 1. 2. 3, scopulae and claw tufts wanting. Posterior legs with weak spines on each tibia. Tarsus longer than metatarsus. Tarsal claws three; upper claws with four extremely small teeth increasing distally in length. These teeth unrecognizable without careful observation. Serrated brisles as usually seen in Theridiidae, wanting, but hairs on the undersid-es of all tarsi and metatarsi weakly serrated. Abdomen long oval, with many reddish brown sclerotized spots with a hair on each, scattered closely on the en-tire dorsum. Anterior part of abdomen overlapping the hind part of thorax. A ventral scutum extending forward to encircle the pedicel, covers 2/3 of the vent-er, and with a pair of small oval holes of spiracles in anteriar part. Posterior tracheal spiracle transverse, a little advanced from spinnerets, and near to epi-gynum situated at the end of the scutum. Spinnerets sorrounded by mammillary wall. Colulus small but distinct. Total length 1.8mm. Colour: Body and appendages yellowish brown. Margin of sternum, ventral scu-tum and posterior tracheal spiracle reddish brown. Abdomen yellowish brown with many reddish brown spots. Locality and Date: Shobudo cave, Kochi Prefecture, Japan. (Collected by Mr. Nakahira, Aug. 8, 1958) Remarks: Present specier belongs to the genus Archerius which was establis-hed by H. W. Levi 1957, and is distinguished from Archerius mendocino LEVI by the absence of eyes, small colulus and the shape of eyigynum. The characteristics of present species indicates also those of Symphytognathidae which is sometimes treated as distinct family. The author has another species of which was identified by H. W. Levi, and wil be described by prof. OI in near future.

口内接近法による犬及猫に於ける下垂体剔出術

An improved technique for the hypophysectomy in dogs and cats is described. This is a modification of McLean's buccal method in dogs. The operation is performed under the barbiturate anaesthesia in dogs and by the subcutaneous injection of ether in cats. No assistant service is neccessary. The benzalkonium chloride solution is adopted to simplify the sterilization of instruments, gauze, cotton and operative field. Characteristic advantages of this technique are as follows. A clod of clay wrapped in a sterilized vinyl sheet is used conveniently for the head fixation. Three kinds of hooks are used snugly for drawing the tongue, for lateral retraction of the incised edges of the soft palate and of the freed edges of the mucoperiosteum of the sphenoid bone. A clear-cut oval hole is produced in the sphenoid bone by the dental points (No. 9 & 20). Accordingly the gauge and the mallet are -not neccessary throughout the perforation. Moreover the dental points will serve to prevent the bleeding in the diploe. A very small steel plate probe is convenient to separate the pituitary from the attachment to the diaphragma sellae. The stalk section before the suction of pituitary will protect the hypothalamus from injury. After the removal of the pituitary the defect hole is filled with penicillin. The nasopharyngeal mucous membrans is sutured and it is not neccessary to close the periosteum.In cats and puppies the haemorrhage in the diploe is generally rare, so that the operation will be very easy. In some dogs, however, the haemostasis during perforation may prove to be tedious, although it will not make the pituitary extirpation itself impossible. Even if operative procedures through the dura opening extend beyond 1 hour by some accidents, the danger of meningitis would be prevented by the local and systemic administration of penicillin.The average duration of this operation are about 1 hour or less, 1 to 2 hours and 3 hours or more, respectively, in cats, puppies and dogs. In view of the simplicity and the short duration of the operation and additionally rapid recovery, this technique would be most suitable in cats and puppies.