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87-455: In selecting the needle, thread, and suturing technique to use for a specific patient, a medical care provider must consider the tensile strength of the specific suture thread needed to efficiently hold the tissues together depending on the mechanical and shear forces acting on the wound as well as the thickness of the tissue being approximated. One must also consider the elasticity of the thread and ability to adapt to different tissues, as well as

174-401: A bave . Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs. Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers . Silk is one of the strongest natural fibers, but it loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even

261-476: A needle holder . The needle point is pressed into the flesh, advanced along the trajectory of the needle's curve until it emerges, and pulled through. The trailing thread is then tied into a knot, usually a square knot or surgeon's knot . Ideally, sutures bring together the wound edges, without causing indenting or blanching of the skin, since the blood supply may be impeded and thus increase infection and scarring. Ideally, sutured skin rolls slightly outward from

348-512: A tensometer at a constant strain (change in gauge length divided by initial gauge length) rate until the sample breaks. When testing some metals, indentation hardness correlates linearly with tensile strength. This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers. This practical correlation helps quality assurance in metalworking industries to extend well beyond

435-416: A bond to the underlying surface. The tissue adhesive has been shown to act as a barrier to microbial penetration as long as the adhesive film remains intact. Limitations of tissue adhesives include contraindications to use near the eyes and a mild learning curve on correct usage. They are also unsuitable for oozing or potentially contaminated wounds. In surgical incisions it does not work as well as sutures as

522-403: A given U.S.P. size differs depending on the suture material class. Many different techniques exist. The most common is the simple interrupted stitch ; it is indeed the simplest to perform and is called "interrupted" because the suture thread is cut between each individual stitch. The vertical and horizontal mattress stitch are also interrupted but are more complex and specialized for everting

609-627: A high degree of mechanical or shear force (tendons, certain skin location). They also supply the operator with greater ease of use due to less thread memory. Silk (polyfilament, Permahand, Ethicon; Sofsilk, Covidien) Synthetic materials include nylon , polypropylene and surgical steel all of which are monofilaments with great tensile strength. Nylon (monofilaments, Dermalon, Ethilon) Nylon (polyfilaments, Nurolon, Surgilon, Supramid) Braided polyester (polyfilament, Ethibond, Dagrofil, Synthofil, PremiCron, Synthofil) Polybutester (monofilament, Novafil) Surgical steel Suture sizes are defined by

696-424: A large satin waistcoat with flaps, were got up, of which the silk was perfect, but the lining entirely gone ... from the thread giving way ... No articles of dress of woollen cloth have yet been found.' Silk is a poor conductor of electricity and thus susceptible to static cling . Silk has a high emissivity for infrared light, making it feel cool to the touch. Unwashed silk chiffon may shrink up to 8% due to

783-738: A long history of a formative textile industry in ancient China, this find of silk textiles employing "complicated techniques" of weaving and dyeing provides direct evidence for silks dating before the Mawangdui -discovery and other silks dating to the Han dynasty (202 BC – 220 AD). Silk is described in a chapter of the Fan Shengzhi shu from the Western Han (202 BC – 9 AD). There is a surviving calendar for silk production in an Eastern Han (25–220 AD) document. The two other known works on silk from

870-542: A non-linear region, represented in figure 1 by point 2 (the "yield strength"), up to which deformations are completely recoverable upon removal of the load; that is, a specimen loaded elastically in tension will elongate, but will return to its original shape and size when unloaded. Beyond this elastic region, for ductile materials, such as steel, deformations are plastic . A plastically deformed specimen does not completely return to its original size and shape when unloaded. For many applications, plastic deformation

957-440: A number of small firms and cooperatives emerged. Among the most prominent of these was the cooperative utopian Northampton Association for Education and Industry, of which Sojourner Truth was a member. Following the destructive Mill River Flood of 1874 , one manufacturer, William Skinner , relocated his mill from Williamsburg to the then-new city of Holyoke . Over the next 50 years he and his sons would maintain relations between

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1044-417: A small amount, it remains stretched. It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty. One example of the durable nature of silk over other fabrics is demonstrated by the recovery in 1840 of silk garments from a wreck of 1782 : 'The most durable article found has been silk; for besides pieces of cloaks and lace, a pair of black satin breeches, and

1131-562: A swaged suture the thread is of narrower diameter than the needle, whereas it protrudes on both sides in an eyed needle. Being narrower, the thread in a swaged suture has less drag when passing through tissue than the needle, and, not protruding, is less likely to traumatize friable tissue, earning the combination the designation "atraumatic". There are several shapes of surgical needles. These include: The ski and canoe needle design allows curved needles to be straight enough to be used in laparoscopic surgery , where instruments are inserted into

1218-416: A white-colored silk thread with no mineral on the surface. The pupae are killed by either dipping them in boiling water before the adult moths emerge or by piercing them with a needle. These factors all contribute to the ability of the whole cocoon to be unravelled as one continuous thread, permitting a much stronger cloth to be woven from the silk. Wild silks also tend to be more difficult to dye than silk from

1305-468: Is pounds per square inch (lb/in or psi). Kilopounds per square inch (ksi, or sometimes kpsi) is equal to 1000 psi, and is commonly used in the United States, when measuring tensile strengths. Many materials can display linear elastic behavior , defined by a linear stress–strain relationship , as shown in figure 1 up to point 3. The elastic behavior of materials often extends into

1392-408: Is because the engineering stress is calculated assuming the original cross-sectional area before necking. The reversal point is the maximum stress on the engineering stress–strain curve, and the engineering stress coordinate of this point is the ultimate tensile strength, given by point 1. Ultimate tensile strength is not used in the design of ductile static members because design practices dictate

1479-509: Is composed mostly of beta-sheets , due to a 59-mer amino acid repeat sequence with some variations. The flat surfaces of the fibrils reflect light at many angles, giving silk a natural sheen. The cross-section from other silkworms can vary in shape and diameter: crescent-like for Anaphe and elongated wedge for tussah . Silkworm fibers are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like glue , to form

1566-547: Is concentrated in the Coimbatore , Erode , Bhagalpuri , Tiruppur , Salem , and Dharmapuri districts. Hyderabad , Andhra Pradesh , and Gobichettipalayam , Tamil Nadu , were the first locations to have automated silk reeling units in India. In the northeastern state of Assam , three different types of indigenous variety of silk are produced, collectively called Assam silk : Muga silk , Eri silk and Pat silk . Muga,

1653-566: Is defined as a stress, which is measured as force per unit area. For some non-homogeneous materials (or for assembled components) it can be reported just as a force or as a force per unit width. In the International System of Units (SI), the unit is the pascal (Pa) (or a multiple thereof, often megapascals (MPa), using the SI prefix mega ); or, equivalently to pascals, newtons per square metre (N/m ). A United States customary unit

1740-525: Is done with a needle and thread prior to sewing fabric. The advantage of this is that any combination of thread and needle may be chosen to suit the job at hand. Swaged (or "atraumatic") needles with sutures consist of a pre-packed eyeless needle already attached (by swaging) to a specific length of suture thread. This saves time, and eliminates the most difficult threading of very fine needles and sutures. Two additional benefits are reduced drag and less potential damage to friable tissue during suturing. In

1827-401: Is due to the triangular prism -like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles , thus producing different colors. Silk is produced by several insects; but, generally, only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other types of silk, which differ at the molecular level. Silk

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1914-509: Is forbidden. Modern attire has raised a number of issues, including, for instance, the permissibility of wearing silk neckties , which are masculine articles of clothing. In the Odyssey , 19.233, when Odysseus, while pretending to be someone else, is questioned by Penelope about her husband's clothing, he says that he wore a shirt "gleaming like the skin of a dried onion" (varies with translations, literal translation here) which could refer to

2001-444: Is generally used internally during surgery or to avoid further procedures for individuals with low likelihood of returning for suture removal. To-date, the available data indicates that the objective short-term wound outcomes are equivalent for absorbable and non-absorbable sutures, and there is equipoise amongst surgeons. Natural absorbable material includes plain catgut , chromic catgut and fast catgut which are all produced from

2088-649: Is mainly produced by the larvae of insects undergoing complete metamorphosis , but some insects, such as webspinners and raspy crickets , produce silk throughout their lives. Silk production also occurs in hymenoptera ( bees , wasps , and ants ), silverfish , caddisflies , mayflies , thrips , leafhoppers , beetles , lacewings , fleas , flies , and midges . Other types of arthropods produce silk, most notably various arachnids , such as spiders . The word silk comes from Old English : sioloc , from Latin : sericum and Ancient Greek : σηρικός , romanized :  sērikós , "silken", ultimately from

2175-584: Is now part of Malaysia , a second generation of silkworm was being imported as early as 1764 for the country's silk textile industry, especially songket . However, since the 1980s, Malaysia is no longer engaged in sericulture but does plant mulberry trees. In Vietnamese legend, silk appeared in the first millennium AD and is still being woven today. The process of silk production is known as sericulture . The entire production process of silk can be divided into several steps which are typically handled by different entities. Extracting raw silk starts by cultivating

2262-516: Is one that is supported by a pledget , that is, a small flat non-absorbent pad normally composed of polytetrafluoroethylene , used as buttresses under sutures when there is a possibility of sutures tearing through tissue. Topical cyanoacrylate adhesives (closely related to super glue), have been used in combination with, or as an alternative to, sutures in wound closure. The adhesive remains liquid until exposed to water or water-containing substances/tissue, after which it cures (polymerizes) and forms

2349-531: Is potentially large when compared with other natural fibers. A life-cycle assessment of Indian silk production shows that the production process has a large carbon and water footprint, mainly due to the fact that it is an animal-derived fiber and more inputs such as fertilizer and water are needed per unit of fiber produced. Silk fibers from the Bombyx mori silkworm have a triangular cross section with rounded corners, 5–10  μm wide. The fibroin-heavy chain

2436-953: Is quantified by the U.S.P. Needles Pull Specifications . Suture material is often broken down into absorbable thread versus non-absorbable thread, which is further delineated into synthetic fibers versus natural fibers. Another important distinction among suture material is whether it is monofilament or polyfilament (braided) Monofilament fibers have less tensile strength but create less tissue trauma and are more appropriate with delicate tissues where tissue trauma can be more significant such as small blood vessels. Polyfilament (braided) sutures are composed of multiple fibers and are generally greater in diameter with greater tensile strength, however, they tend to have greater tissue reaction and theoretically have more propensity to harbor bacteria. Absorbable sutures are either degraded via proteolysis or hydrolysis and should not be utilized on body tissue that would require greater than two months of tensile strength. It

2523-415: Is soaked in extremely cold water and bleached before dyeing to remove the natural yellow coloring of Thai silk yarn. To do this, skeins of silk thread are immersed in large tubs of hydrogen peroxide . Once washed and dried, the silk is woven on a traditional hand-operated loom. The Rajshahi Division of northern Bangladesh is the hub of the country's silk industry. There are three types of silk produced in

2610-478: Is still used today, mainly to secure surgical drains. [REDACTED] Media related to Surgical suture at Wikimedia Commons Tensile strength Ultimate tensile strength (also called UTS , tensile strength , TS , ultimate strength or F tu {\displaystyle F_{\text{tu}}} in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials,

2697-594: Is the presence of the silk protein fibroin in soil samples from two tombs at the neolithic site Jiahu in Henan , which date back about 8,500 years. The earliest surviving example of silk fabric dates from about 3630 BC, and was used as the wrapping for the body of a child at a Yangshao culture site in Qingtaicun near Xingyang , Henan. Legend gives credit for developing silk to a Chinese empress, Leizu (Hsi-Ling-Shih, Lei-Tzu). Silks were originally reserved for

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2784-479: Is the second largest producer of silk in the world after China. About 97% of the raw mulberry silk comes from six Indian states, namely, Andhra Pradesh , Karnataka , Jammu and Kashmir , Tamil Nadu , Bihar , and West Bengal . North Bangalore, the upcoming site of a $ 20 million "Silk City" Ramanagara and Mysore , contribute to a majority of silk production in Karnataka. In Tamil Nadu , mulberry cultivation

2871-459: Is unacceptable, and is used as the design limitation. After the yield point, ductile metals undergo a period of strain hardening, in which the stress increases again with increasing strain, and they begin to neck , as the cross-sectional area of the specimen decreases due to plastic flow. In a sufficiently ductile material, when necking becomes substantial, it causes a reversal of the engineering stress–strain curve (curve A, figure 2); this

2958-634: The Great Palace complex in Constantinople, and the cloth produced was used in imperial robes or in diplomacy, as gifts to foreign dignitaries. The remainder was sold at very high prices. Italy was the most important producer of silk during the Medieval age. The first center to introduce silk production to Italy was the city of Catanzaro during the 11th century in the region of Calabria . The silk of Catanzaro supplied almost all of Europe and

3045-730: The Torah , a scarlet cloth item called in Hebrew "sheni tola'at" שני תולעת – literally "crimson of the worm" – is described as being used in purification ceremonies, such as those following a leprosy outbreak (Leviticus 14), alongside cedar wood and hyssop ( za'atar ). Eminent scholar and leading medieval translator of Jewish sources and books of the Bible into Arabic , Rabbi Saadia Gaon , translates this phrase explicitly as "crimson silk" – חריר קרמז حرير قرمز. In Islamic teachings, Muslim men are forbidden to wear silk. Many religious jurists believe

3132-833: The United States Pharmacopeia (U.S.P.). Sutures were originally manufactured ranging in size from #1 to #6, with #1 being the smallest. A #4 suture would be roughly the diameter of a tennis racquet string. The manufacturing techniques, derived at the beginning from the production of musical strings, did not allow thinner diameters. As the procedures improved, #0 was added to the suture diameters, and later, thinner and thinner threads were manufactured, which were identified as #00 (#2-0 or #2/0) to #000000 (#6-0 or #6/0). Modern sutures range from #5 (heavy braided suture for orthopedics) to #11-0 (fine monofilament suture for ophthalmics). Atraumatic needles are manufactured in all shapes for most sizes. The actual diameter of thread for

3219-521: The Yayoi period . The silk industry was dominant from the 1930s to 1950s, but is less common now. Silk from East Asia had declined in importance after silkworms were smuggled from China to the Byzantine Empire. However, in 1845, an epidemic of flacherie among European silkworms devastated the silk industry there. This led to a demand for silk from China and Japan , where as late as

3306-464: The 10th century, the catgut suture along with the surgery needle were used in operations by Abulcasis . The gut suture was similar to that of strings for violins, guitars, and tennis racquets and it involved harvesting sheep or cow intestines . Catgut sometimes led to infection due to a lack of disinfection and sterilization of the material. Joseph Lister endorsed the routine sterilization of all suture threads. He first attempted sterilization with

3393-476: The 12th century. Other Italian cities involved in silk production were Genoa , Venice , and Florence . The Piedmont area of Northern Italy became a major silk producing area when water-powered silk throwing machines were developed. The Silk Exchange in Valencia from the 15th century—where previously in 1348 also perxal ( percale ) was traded as some kind of silk—illustrates the power and wealth of one of

3480-595: The 17th century. James I attempted to establish silk production in England, purchasing and planting 100,000 mulberry trees, some on land adjacent to Hampton Court Palace , but they were of a species unsuited to the silk worms, and the attempt failed. In 1732 John Guardivaglio set up a silk throwing enterprise at Logwood mill in Stockport ; in 1744, Burton Mill was erected in Macclesfield ; and in 1753 Old Mill

3567-402: The 1860s "carbolic catgut", and chromic catgut followed two decades later. Sterile catgut was finally achieved in 1906 with iodine treatment. The next great leap came in the twentieth century. The chemical industry drove production of the first synthetic thread in the early 1930s, which exploded into production of numerous absorbable and non-absorbable synthetics. The first synthetic absorbable

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3654-646: The American silk industry and its counterparts in Japan, and expanded their business to the point that by 1911, the Skinner Mill complex contained the largest silk mill under one roof in the world, and the brand Skinner Fabrics had become the largest manufacturer of silk satins internationally. Other efforts later in the 19th century would also bring the new silk industry to Paterson, New Jersey , with several firms hiring European-born textile workers and granting it

3741-591: The Chinese monopoly . Nonetheless, sericulture reached Korea with technological aid from China around 200 BC, the ancient Kingdom of Khotan by AD 50, and India by AD 140. In the ancient era, silk from China was the most lucrative and sought-after luxury item traded across the Eurasian continent, and many civilizations, such as the ancient Persians, benefited economically from trade. Archaeological evidence indicates that sericulture has been practiced since

3828-567: The Chinese word "sī" and other Asian sources—compare Mandarin sī "silk", Manchurian sirghe , Mongolian sirkek . The production of silk originated in China in the Neolithic period, although it would eventually reach other places of the world ( Yangshao culture, 4th millennium BC). Silk production remained confined to China until the Silk Road opened at some point during

3915-649: The Han period are lost. The first evidence of the long distance silk trade is the finding of silk in the hair of an Egyptian mummy of the 21st dynasty, c.1070 BC. The silk trade reached as far as the Indian subcontinent , the Middle East , Europe , and North Africa . This trade was so extensive that the major set of trade routes between Europe and Asia came to be known as the Silk Road . The emperors of China strove to keep knowledge of sericulture secret to maintain

4002-634: The Japanese silk industry and its position as the lead silk exporter of the world. Today, China exports the largest volume of raw silk in the world. Silk has a long history in India. It is known as Resham in eastern and north India, and Pattu in southern parts of India . Recent archaeological discoveries in Harappa and Chanhu-daro suggest that sericulture , employing wild silk threads from native silkworm species, existed in South Asia during

4089-530: The Middle East by Peter Gaddum . Wild silk taken from the nests of native caterpillars was used by the Aztecs to make containers and as paper. Silkworms were introduced to Oaxaca from Spain in the 1530s and the region profited from silk production until the early 17th century, when the king of Spain banned export to protect Spain's silk industry. Silk production for local consumption has continued until

4176-451: The abdominal cavity through narrow cannulas. Needles may also be classified by their point geometry; examples include: Finally, atraumatic needles may be permanently swaged to the suture or may be designed to come off the suture with a sharp straight tug. These "pop-offs" are commonly used for interrupted sutures, where each suture is only passed once and then tied. Sutures can withstand different amounts of force based on their size; this

4263-426: The body 7–10 days. Removal of sutures is traditionally achieved by using forceps to hold the suture thread steady and pointed scalpel blades or scissors to cut. For practical reasons the two instruments (forceps and scissors) are available in a sterile kit. In certain countries (e.g. US), these kits are available in sterile disposable trays because of the high cost of cleaning and re-sterilization. A pledgeted suture

4350-441: The case of compression, instead of tension, is called the compressive strength . Tensile strengths are rarely of any consequence in the design of ductile members, but they are important with brittle members. They are tabulated for common materials such as alloys , composite materials , ceramics , plastics, and wood. The ultimate tensile strength of a material is an intensive property ; therefore its value does not depend on

4437-706: The collagen extracted from bovine intestines. They are all polyfilaments which have different degradations times ranging from 3–28 days. This material is often used for body tissue with low mechanical or shearing force and rapid healing time. Synthetic absorbable material includes polyglactic acid, polyglycolic acid, poliglecaprone, polydioxanone, and polytrimethylene carbonate. Among these are monofilaments, polyfilaments and braided sutures. In general synthetic materials will keep tensile strength for longer due to less local tissue inflammation. These sutures hold greater tensile strength for longer periods of time and are not subject to degradation. They are appropriate for tissues with

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4524-486: The cultivated silkworm. A technique known as demineralizing allows the mineral layer around the cocoon of wild silk moths to be removed, leaving only variability in color as a barrier to creating a commercial silk industry based on wild silks in the parts of the world where wild silk moths thrive, such as in Africa and South America. Silk use in fabric was first developed in ancient China. The earliest evidence for silk

4611-945: The disadvantage of having to be stored in the refrigerator, were exothermic so they stung the patient, and the bond was brittle. Nowadays, the longer chain polymer, 2-octyl cyanoacrylate, is the preferred medical grade glue. It is available under various trade names, such as LiquiBand, SurgiSeal, FloraSeal, and Dermabond. These have the advantages of being more flexible, making a stronger bond, and being easier to use. The longer side chain types, for example octyl and butyl forms, also reduce tissue reaction. Through many millennia, various suture materials were used or proposed. Needles were made of bone or metals such as silver , copper , and aluminium bronze wire . Sutures were made of plant materials ( flax , hemp and cotton ) or animal material ( hair , tendons , arteries , muscle strips and nerves , silk , and catgut ). The earliest reports of surgical suture date to 3000 BC in ancient Egypt , and

4698-511: The domesticated varieties in colour and texture and are therefore less uniform; second, cocoons gathered in the wild have usually had the pupa emerge from them before being discovered so the silk thread that makes up the cocoon has been torn into shorter lengths; and third, many wild cocoons are covered in a mineral layer that prevents attempts to reel from them long strands of silk. Thus, the only way to obtain silk suitable for spinning into textiles in areas where commercial silks are not cultivated

4785-677: The early center of the silk industry in America, when the Cheney Brothers became the first in the United States to properly raise silkworms on an industrial scale; today the Cheney Brothers Historic District showcases their former mills. With the mulberry tree craze of that decade, other smaller producers began raising silkworms. This economy particularly gained traction in the vicinity of Northampton, Massachusetts and its neighboring Williamsburg , where

4872-411: The emperors of China for their own use and gifts to others, but spread gradually through Chinese culture and trade both geographically and socially, and then to many regions of Asia . Because of its texture and lustre, silk rapidly became a popular luxury fabric in the many areas accessible to Chinese merchants. Silk was in great demand, and became a staple of pre- industrial international trade . Silk

4959-500: The golden silk, and Eri are produced by silkworms that are native only to Assam. They have been reared since ancient times similar to other East and South-East Asian countries. Silk is produced year-round in Thailand by two types of silkworms, the cultured Bombycidae and wild Saturniidae. Most production is after the rice harvest in the southern and northeastern parts of the country. Women traditionally weave silk on hand looms and pass

5046-571: The great Mediterranean mercantile cities. Silk was produced in and exported from the province of Granada , Spain, especially the Alpujarras region, until the Moriscos , whose industry it was, were expelled from Granada in 1571. Since the 15th century, silk production in France has been centered around the city of Lyon where many mechanic tools for mass production were first introduced in

5133-458: The laboratory and universal testing machines . Silk Silk is a natural protein fiber , some forms of which can be woven into textiles . The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons . The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity ( sericulture ). The shimmering appearance of silk

5220-557: The largest silk exporter in the world. This increase in exports was mostly due to the economic reforms during the Meiji period and the decline of the Qing dynasty in China, which led to rapid industrialization of Japan whilst the Chinese industries stagnated. During World War II , embargoes against Japan had led to adoption of synthetic materials such as nylon , which led to the decline of

5307-460: The latter part of the 1st millennium BC, though China maintained its virtual monopoly over silk production for another thousand years. Several kinds of wild silk, produced by caterpillars other than the mulberry silkworm, have been known and spun in China , South Asia , and Europe since ancient times. However, the scale of production was always far smaller than for cultivated silks. There are several reasons for this: first, they differ from

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5394-467: The lustrous quality of silk fabric. Aristotle wrote of Coa vestis , a wild silk textile from Kos . Sea silk from certain large sea shells was also valued. The Roman Empire knew of and traded in silk, and Chinese silk was the most highly priced luxury good imported by them. During the reign of emperor Tiberius , sumptuary laws were passed that forbade men from wearing silk garments, but these proved ineffectual. The Historia Augusta mentions that

5481-405: The memory of the thread material which lends to ease of use for the operator. Different suture characteristics lend way to differing degrees of tissue reaction and the operator must select a suture that minimizes the tissue reaction while still keeping with appropriate tensile strength. Historically, surgeons used reusable needles with holes (called "eyes"), which must be threaded before use just as

5568-488: The nickname "Silk City" as another major center of production in the United States. World War II interrupted the silk trade from Asia, and silk prices increased dramatically. U.S. industry began to look for substitutes, which led to the use of synthetics such as nylon . Synthetic silks have also been made from lyocell , a type of cellulose fiber, and are often difficult to distinguish from real silk (see spider silk for more on synthetic silks). In Terengganu , which

5655-422: The nineteenth and early twentieth centuries, Japanese exports competed directly with Chinese in the international market in such low value-added, labor-intensive products as raw silk. Between 1850 and 1930, raw silk ranked as the leading export for both countries, accounting for 20%–40% of Japan's total exports and 20%–30% of China's. Between the 1890s and the 1930s, Japanese silk exports quadrupled, making Japan

5742-468: The oldest known suture is in a mummy from 1100 BC. A detailed description of a wound suture and the suture materials used in it is by the Indian sage and physician Sushruta , written in 500 BC. The Greek father of medicine, Hippocrates , described suture techniques, as did the later Roman Aulus Cornelius Celsus . The 2nd-century Roman physician Galen described sutures made of surgical gut or catgut . In

5829-586: The present day, sometimes spinning wild silk. King James I introduced silk-growing to the British colonies in America around 1619, ostensibly to discourage tobacco planting. The Shakers in Kentucky adopted the practice. The history of industrial silk in the United States is largely tied to several smaller urban centers in the Northeast region. Beginning in the 1830s, Manchester, Connecticut emerged as

5916-399: The reasoning behind the prohibition lies in avoiding clothing for men that can be considered feminine or extravagant. There are disputes regarding the amount of silk a fabric can consist of (e.g., whether a small decorative silk piece on a cotton caftan is permissible or not) for it to be lawful for men to wear, but the dominant opinion of most Muslim scholars is that the wearing of silk by men

6003-466: The region: mulberry, endi, and tassar. Bengali silk was a major item of international trade for centuries. It was known as Ganges silk in medieval Europe. Bengal was the leading exporter of silk between the 16th and 19th centuries. The 7th century CE murals of Afrasiyab in Samarkand , Sogdiana , show a Chinese Embassy carrying silk and a string of silkworm cocoons to the local Sogdian ruler. In

6090-439: The risk of a burst wound, and suggesting a SL:WL ratio of 4:1 or more in abdominal wounds. A later study suggested 6:1 as the optimal ratio in abdominal closure. In contrast to single layer suturing , two layer suturing generally involves suturing at a deeper level of a tissue followed by another layer of suturing at a more superficial level. For example, Cesarean section can be performed with single or double layer suturing of

6177-748: The silkworms on mulberry leaves. Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibres to be extracted and fed into the spinning reel. To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms. It takes about 5000 silkworms to make a pure silk kimono . The major silk producers are China (54%) and India (14%). Other statistics: Production in Int $ 1000 have been calculated based on 1999–2001 international prices Source: Food And Agricultural Organization of United Nations: Economic And Social Department: The Statistical Division The environmental impact of silk production

6264-505: The size of the test specimen. However, depending on the material, it may be dependent on other factors, such as the preparation of the specimen, the presence or otherwise of surface defects, and the temperature of the test environment and material. Some materials break very sharply, without plastic deformation , in what is called a brittle failure. Others, which are more ductile, including most metals, experience some plastic deformation and possibly necking before fracture. Tensile strength

6351-400: The skill on to their daughters, as weaving is considered to be a sign of maturity and eligibility for marriage. Thai silk textiles often use complicated patterns in various colours and styles. Most regions of Thailand have their own typical silks. A single thread filament is too thin to use on its own so women combine many threads to produce a thicker, usable fiber. They do this by hand-reeling

6438-412: The skin and distributing tension. The running or continuous stitch is quicker but risks failing if the suture is cut in just one place; the continuous locking stitch is in some ways a more secure version. The chest drain stitch and corner stitch are variations of the horizontal mattress. Other stitches or suturing techniques include: Sutures are placed by mounting a needle with attached suture into

6525-569: The third-century emperor Elagabalus was the first Roman to wear garments of pure silk, whereas it had been customary to wear fabrics of silk/cotton or silk/linen blends. Despite the popularity of silk, the secret of silk-making only reached Europe around AD 550, via the Byzantine Empire . Contemporary accounts state that monks working for the emperor Justinian I smuggled silkworm eggs to Constantinople from China inside hollow canes. All top-quality looms and weavers were located inside

6612-435: The threads onto a wooden spindle to produce a uniform strand of raw silk. The process takes around 40 hours to produce a half kilogram of silk. Many local operations use a reeling machine for this task, but some silk threads are still hand-reeled. The difference is that hand-reeled threads produce three grades of silk: two fine grades that are ideal for lightweight fabrics, and a thick grade for heavier material. The silk fabric

6699-727: The time of the Indus Valley civilisation (now in Pakistan and India) dating between 2450 BC and 2000 BC. Shelagh Vainker, a silk expert at the Ashmolean Museum in Oxford, who sees evidence for silk production in China "significantly earlier" than 2500–2000 BC, suggests, "people of the Indus civilization either harvested silkworm cocoons or traded with people who did, and that they knew a considerable amount about silk." India

6786-403: The ultimate tensile strength is close to the yield point , whereas in ductile materials, the ultimate tensile strength can be higher. The ultimate tensile strength is usually found by performing a tensile test and recording the engineering stress versus strain . The highest point of the stress–strain curve is the ultimate tensile strength and has units of stress. The equivalent point for

6873-450: The use of the yield stress . It is, however, used for quality control, because of the ease of testing. It is also used to roughly determine material types for unknown samples. The ultimate tensile strength is a common engineering parameter to design members made of brittle material because such materials have no yield point . Typically, the testing involves taking a small sample with a fixed cross-sectional area, and then pulling it with

6960-434: The uterine incision. Whereas some sutures are intended to be permanent, and others in specialized cases may be kept in place for an extended period of many weeks, as a rule sutures are a short-term device to allow healing of a trauma or wound. Different parts of the body heal at different speeds. Common time to remove stitches will vary: facial wounds 3–5 days; scalp wound 7–10 days; limbs 10–14 days; joints 14 days; trunk of

7047-440: The wound (eversion), and the depth and width of the sutured flesh is roughly equal. Placement varies based on the location, Skin and other soft tissue can lengthen significantly under strain. To accommodate this lengthening, continuous stitches must have an adequate amount of slack. Jenkin's rule was the first research result in this area, showing that the then-typical use of a suture-length to wound-length ratio of 2:1 increased

7134-428: The wounds often break open. Cyanoacrylate is the generic name for cyanoacrylate based fast-acting glues such as methyl-2-cyanoacrylate, ethyl-2-cyanoacrylate (commonly sold under trade names like Superglue and Krazy Glue) and n-butyl-cyanoacrylate. Skin glues like Indermil and Histoacryl were the first medical grade tissue adhesives to be used, and these are composed of n-butyl cyanoacrylate. These worked well but had

7221-685: Was also used as a surface for writing, especially during the Warring States period (475–221 BCE). The fabric was light, it survived the damp climate of the Yangtze region, absorbed ink well, and provided a white background for the text. In July 2007, archaeologists discovered intricately woven and dyed silk textiles in a tomb in Jiangxi province, dated to the Eastern Zhou dynasty roughly 2,500 years ago. Although historians have suspected

7308-585: Was based on polyvinyl alcohol in 1931. Polyesters were developed in the 1950s, and later the process of radiation sterilization was established for catgut and polyester. Polyglycolic acid was discovered in the 1960s and implemented in the 1970s. Today, most sutures are made of synthetic polymer fibers. Silk and, rarely, gut sutures are the only materials still in use from ancient times. In fact, gut sutures have been banned in Europe and Japan owing to concerns regarding bovine spongiform encephalopathy . Silk suture

7395-830: Was built in Congleton . These three towns remained the centre of the English silk throwing industry until silk throwing was replaced by silk waste spinning . British enterprise also established silk filature in Cyprus in 1928. In England in the mid-20th century, raw silk was produced at Lullingstone Castle in Kent. Silkworms were raised and reeled under the direction of Zoe Lady Hart Dyke , later moving to Ayot St Lawrence in Hertfordshire in 1956. During World War II , supplies of silk for UK parachute manufacture were secured from

7482-470: Was by tedious and labor-intensive carding . Some natural silk structures have been used without being unwound or spun. Spider webs were used as a wound dressing in ancient Greece and Rome, and as a base for painting from the 16th century. Caterpillar nests were pasted together to make a fabric in the Aztec Empire . Commercial silks originate from reared silkworm pupae, which are bred to produce

7569-619: Was sold in a large market fair in the port of Reggio Calabria , to Spanish, Venetian, Genovese, and Dutch merchants. Catanzaro became the lace capital of the world with a large silkworm breeding facility that produced all the laces and linens used in the Vatican. The city was world-famous for its fine fabrication of silks, velvets, damasks, and brocades. Another notable center was the Italian city-state of Lucca which largely financed itself through silk-production and silk-trading, beginning in

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