Silver Pin Research Articles

Fixation Performance of Bioabsorbable Zn-6Ag Pins for Osteosynthesis.

Bioabsorbable implants have become the focus of the latest research for new bone implant materials. With favorable characteristics such as compatible mechanical characteristics, no long-term side effects, and even osteogenesis enhancing properties they seem to be the future of osteosynthesis. Besides these characteristics, they must perform on the same level as traditional implant materials regarding their mechanical support for bone healing. A particular focus in the research for bioabsorbable implants has been on metal alloys, as these have particularly good mechanical properties such as excellent maximum force and high stability. This study focused on the shear strength of new bioabsorbable zinc and magnesium pins in comparison to traditional implants such as K-wires and cancellous bone screws in bone-implant connections. During quasi-static and fatigue loading experiments, magnesium pins (MAGNEZIX, Syntellix AG, Hannover, Germany) and new zinc silver pins (Zn-6Ag) by Limedion (Limedion GmbH., Mannheim, Germany) were compared with conventional osteosynthetic materials. The pins made of the new bioabsorbable alloys withstood the cyclic loads to the same extent as the conventional osteosynthesis materials. In the quasi-static loading, it was shown that the novel Zn-6Ag from Limedion has the same shear strength as the magnesium pin from Syntellix, which is already in clinical use. In addition, the zinc pin showed significantly better shear strength compared to osteosynthesis with K-wires (p < 0.05).

Role of coatings and materials of external fixation pins on the rates of pin tract infection: A systematic review and meta-analysis.

BACKGROUNDInfection at the pin tract is a frequent and feared complication of external fixators (EF). The type of pin material and coatings have been regarded as possibly influencing infection rates. Over the last 20 years, few prospective clinical studies and systematic reviews addressed the role of coated pins on the rate of pin site infection in human clinical studies.AIMTo assess the EF literature over the past 20 years on the clinical benefits of pins manufactured from varied materials and coating systems and their possible role in pin tract infection rates. METHODSWe performed a systematic review according to the PRISMA and PICOS guidelines using four scientific platforms: PubMed, LiLacs, SciELO, and Cochrane. We searched the literature for related publications over the past 20 years. RESULTSA literature search yielded 29 articles, among which seven met the inclusion criteria. These studies compared stainless-steel pins and pins coated with hydroxyapatite (HA), titanium and silver. The pin tract infection definitions were arbitrary and not standardized among studies. Most studies included a low number of patients in the analysis and used a short follow-up time. Three meta-analyses were carried out, comparing stainless steel vs silver pins, stainless steel vs HA-coated pins, and titanium vs HA-coated pins. None of this analysis resulted in statistically significant differences in pin tract infection rates. CONCLUSIONCurrently, no clinical evidence supports the advantage of EF pins manufactured with materials other than stainless steel or coated over uncoated pins in reducing the rates of pin tract infections. A standardized definition of pin tract infection in external fixation is still lacking.

Structure and antibacterial properties of Ag and N doped titanium dioxide coatings containing Ti2.85O4N phase, prepared by magnetron sputtering and annealing

Study reports on structure and antibacterial properties of the Ag and N doped TiO2 coatings. The coatings were deposited on glass by direct current reactive magnetron sputtering. A titanium target with silver pins was sputtered in an Ar/O2/N2 atmosphere. The reactive gases flow ratio was varied. The TiO2:Ag,N coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy (TEM, SEM), atomic force microscopy (AFM). The microbiological tests (S. aureus) of the coatings were also shown. The coatings consisting of crystalline Ag nanoparticles in an amorphous matrix were then annealed (500 °C/1 h) for crystallization. After the heat treatment, the coatings consisted of the Ti2.85O4N, anatase, rutile and silver phases. The crystallites of the formed phases were sized below 20 nm. This mixture of phases provided improved antibacterial properties activated by visible light.

Late Neolithic/Early Bronze Age metallurgical practices at Limenaria, Thasos: evidence for silver and copper production

Excavations at Limenaria in southwestern Thasos brought to light a significant amount of finds associated with metallurgical activities of the Final Neolithic and Early Bronze Age. The recovered evidence includes copper alloy artifacts, one silver pin, copper slags, a crucible fragment, pieces of shallow bowl lead silicates and litharge-resembling cupels, and numerous fragments of hematite/limonite lumps, some containing secondary cupriferous minerals, mainly malachite and azurite. With the exception of the complete artifacts, a representative sample of the finds (approx. 40) was studied by applying instrumental analytical methods. The analytical results strongly suggest that the metalworkers utilized exclusively the local mineral resources for copper and silver production. They demonstrated significant skill and succeeded in extracting metallic copper from the locally available polymetallic (and poor in cupriferous secondary ores) mineral resources, and expanded their practice in crucible working (for copper alloying with arsenic). The technological traits so far recognized appear to be closer to the Aegean pyro-metallurgical practices rather than their northern counterparts in the Balkans.

Kirkemosegård – Et offerfund med smykker fra ældre germansk jernalder

Kirkemosegård – Et offerfund med smykker fra ældre germansk jernalder

Endoscopic ultrasound-guided fine-needle marking of lymph nodes

No previous studies have evaluated the ability of endoscopic ultrasonography to describe the anatomic location of lymph nodes on the basis of a node-to-node comparison. The aim of this study was to assess the feasibility and safety of a new endoscopic ultrasound (EUS)-guided fine-needle technique for marking lymph nodes. Twenty-five patients with suspected or confirmed malignancies of the upper gastrointestinal tract were prospectively included. EUS-guided fine-needle marking (EUS-FNM) was performed with a silver pin with a diameter that allowed it to fit into a 19-gauge needle. The position of the pin was verified by EUS. End points were the ability to identify and isolate the marked lymph node during surgery and a comparison between the location of the pin as suggested by EUS and the actual location found in the resected specimen. Twenty-three lymph nodes were marked. Nineteen intended surgical isolations were performed. The lymph nodes were isolated in the resection specimens in 18 patients (95 %). In 2 out of 20 cases the pin was not localized by laparoscopic ultrasonography. In 89 % of the cases the marked lymph node was in the same location as described by EUS. One pin (5 %) was not retrieved. In three cases, a small hematoma was observed. There was no sign of long-term complications. EUS-FNM with a silver pin in lymph nodes is feasible and safe. EUS-FNM seems to be a suitable tool for evaluating lymph nodes on the basis of a node-to-node comparison.

P62/SQSTM1 Binds Directly to Atg8/LC3 to Facilitate Degradation of Ubiquitinated Protein Aggregates by Autophagy

Protein degradation by basal constitutive autophagy is important to avoid accumulation of polyubiquitinated protein aggregates and development of neurodegenerative diseases. The polyubiquitin-binding protein p62/SQSTM1 is degraded by autophagy. It is found in cellular inclusion bodies together with polyubiquitinated proteins and in cytosolic protein aggregates that accumulate in various chronic, toxic, and degenerative diseases. Here we show for the first time a direct interaction between p62 and the autophagic effector proteins LC3A and -B and the related gamma-aminobutyrate receptor-associated protein and gamma-aminobutyrate receptor-associated-like proteins. The binding is mediated by a 22-residue sequence of p62 containing an evolutionarily conserved motif. To monitor the autophagic sequestration of p62- and LC3-positive bodies, we developed a novel pH-sensitive fluorescent tag consisting of a tandem fusion of the red, acid-insensitive mCherry and the acid-sensitive green fluorescent proteins. This approach revealed that p62- and LC3-positive bodies are degraded in autolysosomes. Strikingly, even rather large p62-positive inclusion bodies (2 microm diameter) become degraded by autophagy. The specific interaction between p62 and LC3, requiring the motif we have mapped, is instrumental in mediating autophagic degradation of the p62-positive bodies. We also demonstrate that the previously reported aggresome-like induced structures containing ubiquitinated proteins in cytosolic bodies are dependent on p62 for their formation. In fact, p62 bodies and these structures are indistinguishable. Taken together, our results clearly suggest that p62 is required both for the formation and the degradation of polyubiquitin-containing bodies by autophagy.

Gold and Silver Pins from Urartu: Typology and Methods of Manufacture

Gold and Silver Pins from Urartu: Typology and Methods of Manufacture

Gold and Silver Pins from Urartu: Typology and Methods of Manufacture

Suite a l'exposition consacree par le musee de Jerusalem a la metallurgie urartienne, cet article presente des epingles sculptees en or et en argent

Wear of Silver-Graphite Brushes Against Various Ring Materials at High-Current Densities

A study has been carried out to evaluate noble metals for potential use as ring materials for high-speed high-current applications. A pin-on-disk friction apparatus was constructed so as to allow sliding tests to be carried out at high speeds and high-current densities in controlled environments. The pin material was a silver-graphite brush composite while the flat material was one of the elemental metals nickel, copper, silver, gold, platinum, palladium, rhodium, ruthenium, rhenium, or iridium. The pressure was 0.2 N/mm2, the current density was 0.8 A/mm2, and the sliding speed was 4 m/s. The friction, wear, and electrical resistance were determined in wet CO2 and dry air. In general, and surprisingly, materials which give high friction give low wear although, in fact, both the friction and the electrical resistance values covered a narrow range. The wear results are not in agreement with earlier data obtained during tests of silver pins sliding against the same metals at much lower loads, speeds, and electrical current densities, in which case the low wear metals were those with low metallurgical compatibility against silver, or else metals with a hexagonal crystal structure. In these new tests, the wear behavior at high speeds and high-current densities with silver-graphite brushes obeys essentially the same compatibility relationships, but referred to the graphite. The best performance in terms of low wear was provided by the metals rhodium, palladium, and platinum.

Mechanical tests of smooth silver-plated retention pins in amalgam.

Retention and stress concentration factors can be improved if a good mechanical bond exists between smooth retention pins and an amalgam restoration. It is shown that, by silver-plating pins and by using a rubbing technique during condensation of the amalgam, a good mechanical bond is produced. Mechanical tests of this bond show that its shear strength is adequate to withstand the stresses likely to be produced by occlusal forces. The form of the tests was: (a) torsion, to demonstrate the performance of the bond in shear and (b) push-through, to provide stress distributions more closely allied to those found under clinical conditions. Plain stainless steel and plated stainless steel pins were compared for their performance and sterling silver pins were used for checking the validity of the torsion test methods. It is concluded from these tests that, with the plating and "rubbing" techniques mentioned, a good mechanical bond is produced which is likely to have value in clinical dentistry.

Preparation of thin cryo-sections for electron probe analysis of calcifying cartilage.

Conventional methods of fixation, dehydration, embedding and wet-sectioning can produce artefacts in the chemical composition of mineralizing tissues. Cryoultramicrotomy was adopted for a more reliable approach to electron probe analysis of initial apatite formation in calcifying cartilage. Fresh rabbit epiphyseal cartilage was mounted on silver pins, frozen by immersion in liquid nitrogen, and sectioned with the specimen temperature at 133 K and the knife temperature at 273 K. Dry cryo-sections (30-70 nm in thickness) were manipulated on to coated grids and examined the same day. These cryo-sections showed good morphological and cytoplasmic detail, with large areas relatively free of ice-crystal damage. Sections stained either with osmium vapour or negatively stained with silicotungstic acid showed areas with well-preserved mitochondria with granules and endoplasmic reticulum. Unstained sections also showed dense granules (50-120 nm in diameter) in the mitochondria of chondrocytes and preliminary electron probe analysis of these has indicated a Ca/P mass ratio of approximately 1.14. In the longitudinal septa, about 2 micrometer away from the chondrocytes, matrix-vesicle-like particles could be seen with crystal needles inside them. Micro-analysis of two of these gave a Ca/P mass ratio of 1.73 and 2.68. Cryo-ultramicrotomy appears to confirm a number of conclusions derived from conventional ultrastructural study of growth cartilage and suggests for the first time how amorphous calcium phosphate and crystalline apatite can be shown to exist in different organelles in the same cryo-section of the tissue.

Silver pins: Their influence on the strength and adaptation of amalgam

Silver pins: Their influence on the strength and adaptation of amalgam

Possible factors influencing the demonstration of post-tetanic potentiation of the H-reflex as studied in the cat

A study of possible factors influencing the demonstration of post-tetanic potentiation (PTP) of H-reflexes was performed in cats and kittens. Monosynaptic reflexes were elicited by surface stimulation of mixed nerves and recorded either by surface electrodes or silver pins in the muscles. The results were controlled by appropriate nerve sections and stimulation of bared nerve trunks and recording from peripheral nerves or roots. It was found that the sensory fibers have a lower threshold than the motor fibers, which explains why the H-reflex is obtained before th M-response. Tetanization of a peripheral nerve lead to changes in threshold which were not restricted to the region of stimulation when testing with submaximal stimulus strength. Since that has to be used to demonstrate H-reflexes, the M-response is reduced and accordingly the antidromic volley up the motor fibers. The H-reflex may then appear enhanced after a tetanization because it is counteracted by a smaller antidromic volley. These mechanisms can lead to the appearance of a “false” PTP. It is concluded that the only safe way to demonstrate a PTP of the H-reflex is to use test stimuli weak enough not to set up any M-response.

‘Numerous Years of Joyful Life’ from Mycenae

We must bear in mind two fundamental facts, which are basic to the theme of this paper: first, that Egypt more than any other land has influenced the Minoan-Mycenaean civilisation, and second, that the free adaptation and fusion of Egyptian motives is a typical phenomenon of Aegean art and mentality.Something has already been written about Egyptian influence in the art of the Shaft Graves of Mycenae. I hope to show, in a forthcoming paper, that this connection is even greater, extending its influence not only in art (in just that point the influence is not great), but also and especially in material matters and in deep religious and funerary ideas. Here we will discuss a very well known and ‘curious’ object of early Mycenaean art, the gold and silver pin from the Third Shaft Grave (Fig. 1).

Resistance and Capacity of Stimulated and Unstimulated Muscle at Varying Electric Current Frequency Related to Chronaxie.

The relation of chronaxie to the frequency of alternating electric currents capable of stimulating muscle is shown in the following table. The alternating current was derived from a General Radio Company oscillator, No. 377, and silver pin electrodes 5 mm. apart coated with AgCl by electrolyzing 1% NaCl with 6 volts for 10 seconds. These were stuck into the muscle and the chronaxie was determined by the condenser method.The above table indicates that the threshold of duration of current from oscillator is about 0.05 of the chronaxie in case of fish and frog. With the crab and scallop the results are uncertain owing to the uncertainty of the determination of such long chronaxies by the condenser method. Since the energy required to stimulate is at a minimum at the chronaxie, it seems best to use muscles with short chronaxies for measuring the conductivity of the muscle with the stimulating current (using telephone for detection), so that the muscle will become stimulated in a small fraction of a cycle.Lapi...

Observations on spinal and decerebrate knee-jerks, with special reference to their inhibition by single break-shocks

The present communication deals with certain differences observed in knee-jerk reflexes when elicited from decerebrate animals (i) with intact spinal cord, and (ii) with the spinal cord separated from the higher centres by section in the thoracic region, and further with their different behaviour to inhibition produced by single break-shocks. Sherrington was the first to show that the knee-jerk was inhibitable like other spinal reflexes (32, 35), and the work of Jolly (23), of Snyder (39), of Dodge (9) and of Viets (40a) contributed further to the recognition of the jerk as a true reflex phenomenon.Method.—The isometric myograph of high vibration frequency, previously described (16, 18, 20, 21) has been used throughout with a string galvanometer (new Cambridge pattern) arranged in the same optical system. As before, the reflex has been elicited by a finger tap on the tendon or by tapping the table with the finger or light hammer (Waller, 41). Control records such as that shown in fig. 1, A, have shown that the taps so elicited are constant (in height) within 5 per cent. The animals used have been cats, decerebrated at the inter-collicular level by the trephine method under deep anæsthesia, and allowed to recover. When they are made “ spinal,” the level of transection has been usually between the last thoracic and the first lumbar root. The section was made under anæsthesia sometimes before, sometimes after, decerebration. In some cases the preparations have been used “ decerebrate,” and after some hours have been made spinal. In one case a decapitate preparation was used. In a small number of cases the cord had been severed by aseptic operation a few days previously. For inhibiting the jerk a single break induction shock has been used, delivered in all cases to an ipsilateral afferent nerve. The leads from the muscle for recording the electrical responses were two silver pins, coated with chloride, one in the tendon, the other in the belly of rectus femoris.

Electrical responses of extensor muscles during postural (myotatic) contraction

Liddell and Sherrington (22) have observed that an anti-gravity muscle of decerebrate and thalamic animals responds to relatively slow stretches by active contraction, and it has been concluded that these myotatic reflexes are in large measure responsible for the postural tonus of muscles (29). As the behaviour of the electrical responses during such stretch reflexes has not been previously examined, we have obtained simultaneous mechanical and electrical records of the responses of the quadriceps extensor of cats to stretching, and we propose in this communication to describe the results.Method. —A myograph of high natural frequency (1,600 per second) in the same optical system as the galvanometer has been employed as previously described (13, 15, 17). Two silver pins coated with chloride have been used as leads, one inserted into the tendon, the other inserted into the belly of rectus femoris. The falling table described by Liddell and Sherrington (22) has been used for slow stretches. Cats decerebrated under deep anæsthesia by the trephine method and allowed to recover have been used throughout. All muscles (except the one used) of both hind limbs were immobilised by nerve section and resection of tendons. The knee-jerks studied were usually elicited by tapping the tendon with the finger, but sometimes also by tapping the table, which, although heavy and rigid, yielded probably 1/40 mm., thereby stretching the muscle and eliciting the reflex.

Tombs of Hellenic Date at Praesos

Professor Bosanquet has kindly asked me to publish the contents of the following tombs found on the east side of the gravel ridge, west of the road from Vavelloi (modern village) to ancient Praesos. The description of the objects is derived in the main from notes made at the time of excavation by Mr. J. H. Marshall in 1901 (cf. B.S.A. viii. pp. 231 ff.). I have added remarks on some of the ornaments (chiefly in gold and silver) which were discovered.Tomb 2.—Small b.-f. kylix.Tomb 3 (unbuilt).—Corinthian vase with four projecting handles; two pyxides, one broken.Tomb 6 (unbuilt).—Burnt b.-f. fragments; amphora of common ware; two toilet vases, red clay, sepia slip; small common juglet with two handles.Tomb 8 (burnt).—Bones; a few beads; b.-f. toilet vase; jug with high neck, of common ware.Tomb 9 (roughly built).—Two silver pins (one illustrated below, Fig. 4, on the r.; long-necked amphora with high shoulder handles, intact (25·8 cm. high); toilet vase with rounded sides; shell; iron axe above tomb, which was 1 m. deep.Tomb 10 (built of square blocks; floor ·71 m. down).—Silver ring; b.-f. fragments; common vase fragments, some incised with cross-hatchings; flat vase, like upper part of toilet vase, in bright red clay with sepia slip.Tomb 12 (roughly outlined and covered with irregular slabs; cremation).—Beads; burnt silver pins (?); part of iron strigil; fragments of b.-f. toilet vase; bronze ring and more beads near the tomb, probably belonging to it.

56. Note on the Silver Pin Found at Dhlo-Dhlo by Mr. Randall-MacIver.

56. Note on the Silver Pin Found at Dhlo-Dhlo by Mr. Randall-MacIver.