Alternatively, a polymer-jacketed wire can be used to create a knuckle and subsequently advanced, followed by CrossBoss crossing of the final CTO segment. Hexa elements blast test.
Gear shift and brake cables often show the difference between a hastily assembled bike and one which has been assembled by a mechanic who cared what he or she was doing.Especially now that new handlebar designs seem to come along every week, a good mechanic must understand the theory of routing cables. One can no longer rely on a couple of rote 'rules of thumb' for routing cables correctly.Although people pay a lot of attention to what kind of derailers and brakes are fitted to a particular bicycle, good cable installation practices are more important than most differences between different brake and shift systems. The most expensive brakes and derailers will work poorly if there is excessive friction or play in their control cables. Even cheap brakes and derailers can usually be made to perform satisfactorily if care is used in installing the cables.The great majority of service problems with brakes and gears are the result of cable friction, not deficiencies in the levers, calipers or derailers.
How Cables Work. Cables used on bicycles are in two parts. The inner wire is made of twisted strands of steel. The outer is also made of flexible steel, usually wound in a helix. The inner wire runs down the middle of the housing.
Both parts are equally important: neither can work without the other.Isaac Newton said 'For every action, there is an equal and opposite reaction.' In the case of bicycle cables, this means that there cannot be a pull on an inner cable without an equal push on the housing. The housing gives the pull of the cable something to pull against.That's how the cable can apply force to one arm of a brake, and the housing, to the other arm. Looking at the brake, you will see that the cable pulls, and the housing pushes - equal and opposite.Or, think of a tug-of-war: The two teams are pulling on opposite ends of the rope, like the brake lever and the brake. The ground underneath is placed in compression, like the cable housing.To save weight, many bicycles substitute the bicycle frame for some sections of the housing.
This is done by attaching 'cable stops' to the frame or fork. A cable stop has a socket to receive an end of a cable housing, and a small hole or slot through which the inner cable can pass, but the housing can't. The 'push' of the housing is transferred to the frame, so the inner wire can run bare until it gets to another cable stop facing the other way, where the 'push' from the frame is transferred back to another length of housing.This 'bare cable' routing can be done anywhere that the cable runs in a straight line and doesn't have to bend.
Housing must be used from the handlebars to the frame, to accommodate the turning of the handlebars as the bicycle is steered. Housing must also be used where a cable moves the two arms of a brake in opposite directions. Sometimes, the inner wire is stationary and only the housing moves - see. Lengths of housing are also commonly used when the direction of pull of the cable must be changed. Types of Cable Housing Conventional Helical Housing.
At first glance, many people assume that cable housing is made of plastic. Actually, it is steel, and the plastic is a covering to protect it from moisture, and to keep it from scratching the paint of the bicycle.Traditional cable housing is a tightly-wrapped helix of steel wire, sort of like a small-diameter Slinky. It has no particular strength in tension (pulling) but it cannot be compressed because the coils of wire are tight against one another.Through the 1970's, the inner wire ran right through the steel helical housing, usually using grease for lubrication. Modern housing, however, has a plastic liner which surrounds the inner wire. This considerably reduces the friction.
Some high-end cable systems, such as the Gore-Tex 'Ride-On' cables, extend this liner even along the areas where there is no housing. These systems also have a special friction-reducing coating on the inner wires.
Compressionless 'Index-compatible' Housing. With the advent of indexed shifting combined with handlebar mounted shift levers, it developed that conventional housing was a source of imprecise shifting. This is because the effective length of the housing changes as it is bent. This is not a problem with brakes: Although sometimes it will be noted that rear brakes may drag slightly when the handlebars are turned all the way to one side, you can't turn the bars that far when the bike is actually in motion.The small variation in housing length was too much for reliable indexed shifting, however, so introduced ' housing, now widely copied by other manufacturers. This type of housing does not consist of a single helical-wound wire, but instead, it has a bundle of wires running pretty much straight along parallel to the housing. They are held in place by being sandwiched between the plastic housing liner and the plastic outer covering.' Compressionless' housing doesn't change length significantly as it is flexed, so the indexed shifter is able to communicate the correct setting to the derailer, even as the handlebars are turned, and the loops of cable housing bounce up and down due to bumps.Warning: Since compressionless housing relies on plastic to hold it together, it is not as strong as conventional spiral housing, and should never be used for brakes!
The loads applied to brake cables can easily cause compressionless housing to rupture and burst, causing a complete and sudden loss of brake function.Extra care must be used in routing compressionless housing because it is also less flexible than conventional housing. 'String of pearls' cable housing.
The German company manufactures cables with housings consisting of small, rigid, interlocking aluminum segments, with a low-friction plastic liner. When installed, the cable in its housing looks somewhat like a string of pearls. This system is index-compatible but allows much more flex than ordinary 'compressionless' index-compatible housing, and also can be used for brakes. The interlocking ends of the segments keep flex below the limit where the inner wire would be damaged. Nokon cables are very expensive but worth the price in demanding applications, especially where the cable must be flexed sharply. One important application is where a cable must pass the hinge of a folding bicycle.
There are other 'string of pearls' cable housings, but as of this writing they do not work as well as Nokon.Cutting Housing and Preparing the Ends. A very common source of excessive cable friction or 'sponginess' is improper cutting or failure to shape the ends of the cable properly. Helical HousingConventional helical housing can be cut with a good diagonal cutter or a shear cutter made for bicycle cables.
When you cut the housing, sometimes the cut will be clean, but other times, the last loop of the helix may get crushed down, partially blocking the passage that the inner cable must slide through. Usually, you can make a second cut and trim off the bent half-loop.Even when the housing is cut cleanly, the end is not square and perpendicular, due to the pitch of the helix. Careful mechanics will grind or file the end of the housing so that it is flat and flush. The best tool for this is a grinding wheel, but it can be done with a file if you don't have access to a grinding wheel.When you cut the housing, the end of the plastic liner also gets cut, and often gets squashed flat. You can use a scriber or a sharp awl to open it up and round it out. If you use a grinding wheel to dress the end of the housing, have your scriber right at hand so that you can open up the plastic liner immediately after grinding.
The heat from the grinding will partially melt the liner. By sticking the scriber in before the liner cools off, you can not only round out the end, but the shape of the scriber will actually flare the end a bit for a smoother transition. This cable housing is too long - there will be unnecessary friction and slop: This cable housing is correct: This cable housing is too short - when the brake is applied, the housing will not reach:. Right Front or Left Front?
The usual system is to have the rear brake controlled by the lever on the side of the bicycle that corresponds to the side of the road that it will be driven on, i.e., right in most of the world; left in the British Isles, Japan, and other places where they drive on the left.(The European Union, however, has standardized on having the right-hand lever control the front brake).Nobody knows exactly why this is. My theory is that it is based on the reasonable idea that you should be able to have your primary braking hand on the handlebars while making a turn signal with the appropriate hand - coupled with the erroneous idea that the rear brake is the primary brake.I prefer to set my own bicycles up with the front brake controlled by the right lever. This allows me to signal and stop at the same time, and also lets me use my stronger, more skillful hand for the more critical front brake. (I rarely use my rear brake.)Since this is the opposite of the prevailing national standard in the USA, I would never set up a bicycle this way for a customer without a specific request to do so. I have an which addresses these issues in more detail. Gear Cable Routing Over or Under the Bottom Bracket?. Over Up until the mid-1980's, the usual way to run gear cables was above the bottom bracket, either using short pieces of cable housing, or, more commonly, simple guides, either brazed on to the bottom-bracket shell, or clamped to the frame.
From the guide, the rear cable would run along the top of the right chainstay to a cable stop at the rear of the stay, for the final loop to the rear derailer.This worked quite well, until mountain bikes came on the scene and made granny gears a standard item. The problem was that the extended cage of a wide-range front derailer would interfere with the rear gear cable. Under The popular solution to this problem was to run the cable under the bottom-bracket shell, and move the chainstay cable stop to the underside of the chainstay. This had the added advantage of being cheaper-a simple plastic block bolted or riveted to the underside of the bottom-bracket shell took the place of a brazed-on or clamped-on set of guides. Most multi-speed bicycles are now made this way.Unfortunately, this routing tends to degrade shifting somewhat. Locating the chainstay cable stop down below creates a sharper curve for the final loop of housing, and also exposes the entrance to that loop to crud splashed up by the front wheel.
The bottom-bracket guide, whether over or under the bottom bracket, is also exposed to sprayed mud and crud from the front wheel.a particular problem for off-road cyclists. Top routing The third option, increasingly popular for mountain bikes, involves bypassing the bottom bracket altogether, and running both gear cables along the top tube.The rear runs down along the seatstay, and the front runs down the back of the seat tube. When this style first arose, in the early '90's, the front derailer was a problem, since existing front derailers were intended to be operated by a cable pulled from below.
Early top-routing schemes used brazed-on pulleys on the back of the seat tube, a rather mono-buttocked solution, in my opinion. This problem has been solved by the ready availability of 'top-pull' front derailers.Autoshifting. Most bicycles with handlebar-mounted shifters run the rear cable on the right, the front on the left. This causes some awkwardness in routing the length of housing from the shift lever to the frame stops. Due to the need to allow these housings to be long enough to permit the bars to be turned all the way back and forth, the housings often wind up making a reverse bend-for instance, the rear will go from the shifter, which is on the right, swing forward and cross over past the centerline of the bicycle, then back over to the right side of the top tube, before heading down the down tube. These extra bends increase friction, and the fairly forcible contact between the housing and the side of the top tube can damage the finish.A neat solution to this is to run the cables 'criss-cross' style: The rear runs from the lever, (on the right) around the top tube, and to the cable stop on the left side of the downtube! The front cable crosses over similarly from the left side of the handlebar to the right side of the down tube.The bare cables then cross one another under the middle of the downtube, making an 'X'.
The cables may touch where they cross, but they will do so very lightly, since they are both straight.the tiny bit of friction at this crossing is more than offset by the reduction in friction in the smoother-flowing cable housings.This technique does not work with over-the-bottom-bracket cable routing, but is doable with most newer bikes that have under-the-bottom-bracket cable routing and cable stops mounted toward the bottom side of the down tube.This site also contains an extensive Cable too Short? New cable too short? This problem can occur when you can't get a long cable for a tandem or when you need to re-use a front cable at the rear There are commercial cable splitters, for bicycles with separable frames.Two cable anchor bolts in a strip of metal drilled at both ends also will do the trick. In an emergency, two lengths of cable can be spliced together with a square knot. Bend each piece into a tight 'U' shape a couple of inches from the end, then loop them together to form the knot and pull hard on the cable with the lever to tighten it up. You may have to readjust it more than once. Highly flexible braided cable may need to be bent into a 'Z' shape so it can be knotted once more in order to hold.These Boots are made for Cabling.
In the old days, before the development of plastic-lined housing, it was necessary to coat the inner cable with light grease or heavy oil.Modern plastic-lined cables have made the use of grease inappropriate, because the viscosity of the grease makes for sluggish cable movement. This is a more critical concern with modern brake and gear systems that use weaker return springs, and with indexed shifting in general.Many manufacturers now recommend against using any lubrication on cables. It certainly should be avoided in the case of sealed systems such as Gore-Tex ®. Bicycles used in wet conditions, however, will often benefit by the application of a bit of oil, more as a rust-preventive than as a lubricant. The area of particular concern is the short loop of housing which carries the rear derailer cable around from the to the derailer.Some bicycles provide awkward cable routing which forces housing to enter cable stops/adjusting barrels at a fairly sharp angle. This is particularly common on rear brakes.
It often helps to put a bit of grease on the bit of cable that runs through such fittings. Hardware Lubrication. Much of the hardware associated with cables requires lubrication on assembly. Adjusting barrels must have lubrication on their threads, if they are to remain usable. Anchor-bolt threads should also be lubricated, lest the threads strip as you tighten them.Brake cable anchor bolts are the most important fasteners on a bicycle. They are small, and many of them have holes drilled through them, so it is easy to strip/break them, but.If you don't get the anchor bolts tight enough, the brakes will appear to work properly in normal use. Then, someday a bus will cut you off, and you will squeeze the brakes extra hard to make a panic stop.just when you need the brake to work their best, the cables will slip and the brakes will fail completely, with no warning.
How to test that cables are secure? Grab each brake lever in turn with both hands, and squeeze hard. Shift cables aren't subject to as much strain, but still, shift to the position with the cable tightest, and pull hard on the lever to check.Cable failure.
As just mentioned, cables can slip if not securely anchored. Housing can get bent; cables and housings can rust and seize up. These problems are obvious and call for replacement.Cables generally don't wear, but they can fail due to fatigue when bent back and forth repeatedly, the same way it is possible to break a paperclip. Cables usually break at an end or where they pass over a pulley. Usually there is no symptom until the cable parts: prevention is by replacing cables on a schedule, or at least checking them frequently. Carry spare cables!A pulley large enough to avoid fatiguing the cable would be at least a couple of inches across - impractical for shift levers. A handlebar-end shifter, as shown in the photo below, may give a warning: frayed cable strands may prick the cyclist's fingers, or impair shifting as they push against the housing end stop.A cable which has begun to fray due to repeated bendingof Sturmey-Archer internal-gear hubs have solved the fatigue problem for more than a century - and so, instead, Sturmey-Archer cables usually fail where they pass over the pulley sector in the shifter.A compact, lightweight pullchain isn't strong enough to resist the cable pull of a brake, and so a pivot at the cable end is needed instead.
The cable-end socket inside a drop-bar brake lever is free to rotate, and so the cable can align itself with the direction of its pull. Flat-bar levers generally rely on the cylindrical cable fitting to make this adjustment. Lubrication of the pivot is important.Many brakes and derailers attach the cable with an that does not allow the cable to align itself. This problem is generally worst with front derailers. Bending also occurs where a passes over the of a cantilever or centerpull brake.A shift-cable failure usually doesn't lead to a crash, but a brake-cable failure very easily can.
This is one reason that every bicycle other than a track-racing bicycle needs two independent braking systems. (The drivetrain of a fixed-gear bicycle does count as one, if the cyclist is skillful in using it for braking.)(David Gordon Wilson has written.) Take The Trouble To Do It Right.
Fast-spin technique.The Y-connector is held between the small finger and the palm of the left hand and the torque device is rotated using the index finger and thumb of both hands.The catheter can be spun by hand in either direction, rotating as fast as possible (until crossing or significant operator discomfort!). Faster spinning decreases friction and increases the likelihood of advancement and crossing. During catheter advancement it is important to keep the CrossBoss torquer device close (two finger-breadths) to the hemostatic valve, to prevent excessive forward movement of the CrossBoss. Failure of the CrossBoss to advance can be due to poor guide catheter support or a hard, calcified proximal cap. Potential solutions include: 1.Increase guide catheter support (for example by using a more supportive guide catheter, a side-branch anchor technique, or a guide catheter extension as described in detail in Chapter 3, Section 3.6).
2.In patients with hard, calcified proximal cap a stiff guidewire, such as the Confianza Pro 12, Hornet 14, or Astato 20 can be used to puncture the proximal cap (should not be advanced 5–10 mm to prevent vessel perforation). This wire should be immediately withdrawn and the CrossBoss advanced by itself, using the fast-spin technique. Alternatively, a polymer-jacketed wire can be used to create a knuckle and subsequently advanced, followed by CrossBoss crossing of the final CTO segment.
Myst 4 revelation. Peter Gabriel - Curtains (Myst IV Game) - Duration: 9:19. Rocha 76,013 views. Uru, Myst IV: Revelation & Myst V: End of Ages - Cyan Worlds Logo Ages of Myst. Unsubscribe from Ages of Myst? Cancel Unsubscribe. Subscribe Subscribed Unsubscribe 30. Part 30 of 30 in my Myst IV: Revelation walkthrough. (End Game) Be sure to change the quality to 720p to experience it how it should be. And so Myst IV comes to a tragic end.
3.Change to a guidewire crossing strategy. CrossBoss enters a side branch.Detection: Side-branch course of the CrossBoss catheter is detected by using imaging in various projections and contralateral injection. Side-branch course is suspected when the CrossBoss catheter is not dancing in sync with the CTO target vessel.Management: The CrossBoss catheter is retracted and redirected, usually using a knuckled polymer-jacketed guidewire or less commonly a stiff guidewire (such as the Gaia 2nd or Confianza Pro 12), which are less likely to enter the side branches.
CrossBoss Partially Crosses the Occlusion ( Fig. CrossBoss crosses into subintimal space distal to the distal cap.Reentry is optimally performed using the Stingray balloon (see Section 5.5) without reentry attempts with guidewires, as the latter may enlarge the area of dissection and cause large subintimal hematomas, which in turn can compress the distal true lumen, and hinder reentry attempts.The CrossBoss should be removed over a stiff, straight, nonlubricious guide wire, such as a Miracle 12, using the trapping technique to prevent wire movement and maintain distal position without enlarging the dissection. Example of true-to-true lumen crossing using the CrossBoss catheter. Previously failed chronic total occlusion of a right coronary artery ( arrows in A) with CrossBoss catheter tip ( arrows in B and C) crossing to the distal true lumen ( arrowheads in C), facilitating distal wire placement ( arrows in D), predilation, and final result (E). Reproduced with permission from Whitlow PL, Burke MN, Lombardi WL, et al. Use of a novel crossing and re-entry system in coronary chronic total occlusions that have failed standard crossing techniques: results of the FAST-CTOs (Facilitated Antegrade Steering Technique in Chronic Total Occlusions) trial. JACC Cardiovasc Interv 2012; 5:393–401.
The CrossBoss catheter ( Fig. 2.60) is a stiff, metallic, over-the-wire catheter with a 1 mm blunt, rounded, hydrophilic-coated distal tip that can advance through the occlusion when the catheter is rotated rapidly using a proximal torque device (fast-spin technique) ( Chapter 5 section 3). If the catheter enters the subintimal space, it creates a limited dissection plane making reentry into the distal true lumen easier. The risk of perforation is low provided that the CrossBoss catheter is not advanced into side branches. If the CTO is crossed subintimally, the Stingray LP balloon and guidewire can be used to assist with reentry into the distal true lumen, as described next. The CrossBoss catheter ( Figures 2.17 and 2.18) is a stiff, metallic, over-the-wire catheter with a 1-mm blunt, rounded, hydrophilic-coated distal tip that can advance through the occlusion when the catheter is rotated rapidly using a proximal torque device (“fast spin” technique) ( Chapter 5).
If the catheter enters the subintimal space, it creates a limited dissection plane making re-entry into the distal true lumen easier. The risk of perforation is low, provided that the CrossBoss catheter is not advanced into side branches. If the CTO is crossed subintimally, the Stingray balloon and guidewire can be used to assist with re-entry into the distal true lumen, as described below. Illustration of use of the CrossBoss catheter and the Stingray guidewire. Source: © 2013 Boston Scientific Corporation or its affiliates. All rights reserved. Used with permission of Boston Scientific Corporation.Step 2.
The CrossBoss catheter is rotated using a fast-spin technique and gentle forward pressure ( Figure 5.5B). The catheter can be spun by hand in either direction, rotating as fast as possible. It is important to keep the CrossBoss torque device close to the hemostatic valve, as this prevents excessive advancement of the CrossBoss.Step 3. After the CrossBoss advances forward, contralateral injection is performed to determine the distal CrossBoss position ( Figure 5.5C). What can go wrong?
A.CrossBoss fails to advance. I.Increase guide catheter support (e.g., by using a more supportive guide catheter, a side-branch anchor technique, or a guide catheter extension). Ii.In patients with hard, calcified proximal cap, a stiff guidewire is used to puncture the proximal cap (should not be advanced 5–10 mm to prevent vessel perforation).
This wire should be immediately withdrawn and the CrossBoss advanced by itself, using the fast-spin technique. Alternatively, a polymer-jacketed wire could be used to create a knuckle and subsequently advanced, followed by CrossBoss crossing of the final CTO segment. B.CrossBoss enters side branch. I.It is very important to detect this course of the CrossBoss catheter using imaging in various projections with contralateral injection, as continued CrossBoss advancement through a side branch can lead to perforation.
Ii.The CrossBoss catheter is retracted and redirected using a stiff guidewire (such as Confianza Pro 12) or a knuckle wire, which is less likely to enter the side branches. Iii.The CrossBoss catheter may also be advanced once it reaches the distal portion of the knuckle (“knuckle-Boss” technique). Example of true-to-true lumen crossing using the CrossBoss catheter.Previously failed CTO of a right coronary artery (arrows, A) with CrossBoss catheter tip (arrows, B and C) crossing to the distal true lumen (arrowheads, C), facilitating distal wire placement (arrows, D), predilation, and an excellent final result (E). Source: Reproduced with permission from Ref. 2.Rapid rotation in either or both directions is key while advancing the CrossBoss catheter, as it reduces friction between catheter and tissue.
Only gentle forward pressure should be applied. 3.Excellent guide support is critical for enhancing the CrossBoss catheter crossing success.
Example of disconnecting the injection syringe from the manifold (B) after antegrade subintimal crossing to prevent inadvertent contrast injection that could enlarge the subintimal space. 5.The torque device is usually attached 2–3 cm (three finger widths) proximal to the Y-connector, to limit potentially excessive forward movement of the CrossBoss catheter (so-called “CrossBoss jump”). As the CrossBoss catheter engages and penetrates tissue, at times the device stores torsional energy and has the propensity to jump during advancement and navigation. There are three possible outcomes after a CrossBoss jump: (1) CTO yield and advancement into the distal true lumen, (2) advancement into a side branch, or (3) exit from the vessel. This is why forward movement is best limited by having the torque device attached close to the Y-connector, thus limiting the length of catheter that may be introduced into the body. 6.The CrossBoss should be removed over a stiff, straight, non-lubricious guide wire, such as a Miracle 12, using the trapping technique to prevent wire movement and maintain distal position without enlarging the dissection. Such critiques were not just voiced by the legal profession, as physicians interested in medical jurisprudence rendered similar characterizations, predicated on the bias inherent in an adversarial system in which expert witnesses knew the source of their payment in advance.
As Harvard’s Frank W. Draper reported to the Boston Society for Medical Improvement in 1880:We know well what manner of man we may find in the typical American medical expert of modern times. He has been evolved out of the necessities of advocates and clients; he is the creature of his environment. In the first place, it goes without saying that he is partial; his partisanship is deliberate and inevitable. Without this controlling bias, he would be of little use in fulfilling the purposes to which he is employed. Sympathy, not less than selfish interest and professional pride, leads him to color his statements on the witness-stand according to the needs of his client; the points of evidence which are useful to his side are put prominently forward; other matters are faithfully omitted, misrepresented, or obscured. ( Draper, 1880, p.
While later physicians would emphasize the degree to which the personal equation—“a disturbing element in the mind of both physician and patient, of a variability defying the power of differential calculus” ( Herrick, 1895, p. 444)—rendered the inexact science of medicine prone to multiple interpretations, Draper placed the preponderance of blame in the courtroom on the adversarial system itself:I want to emphasize the fact that the behavior of the medical expert witness is the legitimate fruit of the conditions under which the modern practice of law is pursued. The physician in the sick-room does not exhibit the disposition here depicted; but place him under the novel and subtle influences of the court-room and he becomes another creature. ( Draper, 1880, p. 444)The solution, for Draper, was “the complete removal of the medical witness from the influences and temptations of partiality; he must be lifted far above the plane of bias” ( Draper, 1880, p.
Like-minded physicians made repeated attempts in the last decades of the nineteenth century to reform the expert witness system, often calling for commissions of independent, neutral experts assigned and paid for by the state ( Mohr, 1993, pp. 14 But such attempts were repeatedly rebuffed, as neutrality itself could be considered an unattainable ideal ( Irish, 1899). Instead, the adversarial system could itself be portrayed as part of the solution to such inherent bias, balancing and rendering evident the personal equations of competing witnesses. Related one physician to the Massachusetts Medico-Legal Society, nearly two decades after Draper’s report:Physicians are very prone to form all sorts of theories, and when once formed, they adhere to them with a pertinacity that would even do credit to members of the clerical profession. Hence, when we descend to the practical arena of the court room, these pet theories of ours are sure to come out and stand forth in clashing inconsistency with each other, and the strict honesty of the experts simply emphasizes the contradictions that appear. ( Irish, 1899, p. 300)The adversarial expert witness system thus remained entrenched in the American courtroom.
Decades later, in books written for the medical profession, we find the system defended as the “people’s method of settling disputes, a part of democratic self-government,” in contrast to the enforced dictates of seemingly neutral, state-determined committees ( Curran, 1965, p. Concerns with the role of payment in biasing witnesses were muted, with the prevailing equanimity regarding such potential bias evidenced by the egregiousness of the one condition considered capable of “destroy(ing)” the objectivity of the expert witness: “contingent fee contracts,” in which payment is predicated on a particular verdict ( Curran, 1965, p. Indeed, not only were blinded payments not suggested, but serendipitous blinding was to be corrected, if at all possible: “At times the doctor is actually without knowledge as to who is hiring him to testify in court. To avoid any misunderstanding it would be simple for the doctor to ask the lawyer ahead of time who is to be responsible for his time spent in court. This is a good custom and practice” ( Liebenson, 1961, pp. 29–30).By the 1990s, the matter would again be taken up in the pages of the New England Journal of Medicine, with the successors to Frank Draper continuing to advocate for neutral (and in this case, unpaid) panels of expert witnesses, echoing larger concerns about conflict of interest that had developed by this time.
As Tucson cardiologist Brendan Phibbs reflected on the persisting contradictions of the system: “This adversarial advocacy system is a dinosaur, incredibly expensive and slow and, in terms of determining scientific fact, a farce. One thinks of Kafka” ( Phibbs, 1997, p.
But leading medical expert witnesses such as Johns Hopkins’ Fred Berlin continued to defend the prevailing adversarial system as “affording all the opportunity to argue their case in court effectively with an expert witness of their own choosing” ( Berlin, 1998, p. Such a system persists in our country to this day, to the point where we find not calls for neutral witnesses, but rather books telling physicians how to become the “dangerous expert witness” who “puts fear into opposing counsel and knows how to defeat opposing counsel’s tactics and is capable of turning the tables on opposing counsel” ( Babitsky and Mangraviti, 2005, p. 15In all of this debate, it is surprising that as the medical profession considered blinding as a means of countering the “personal equation” and ensuring objectivity in clinical research, no one explicitly invoked such a parallel for the courtroom.
Objectivity, from the nineteenth century onward, has become a defining feature of orthodox medical self-identification (see, e.g., Warner, 1991). In the comparative study of two remedies offered by two different companies, we would scarcely ask for unblinded researchers funded by each company to study their remedies and clash over the results, but that is what we have permitted in the courtroom. 16 It is perhaps time to consider the blinding of expert witnesses themselves, as we continue to strive to offset the impact of the “personal equation.”.
Zelizer, in, 2001 1.3 Social RelationsThe full meaning of any monetary transaction, however, also depends on the relationship between the parties. Contrary to the view of money as a great equalizer, people actively distinguish transfers and media according to the social relations involved. Parent–child, priest–congregant, welfare official–aid recipient, legislator–constituent, courting couple—all these relations sometimes involve monetary payments, but each calls for a very different combination of media and transfer routines.Why do people make such distinctions? This pervasive differentiation of monetary media and transfers serves to support significant differences in the meaning and quality of people's commitments to each other. People work hard to maintain such distinctions: they care greatly about differentiating monies because payment systems are a powerful way in which they mark apart different social ties. Each of these ties has a different quality and each one therefore calls for different forms and rituals of payments. Long-time emigrants, for instance, distinguish carefully between money they send home to support their immediate families, contributions to their home churches, and money paid for taxes in their country of origin.That is why people will respond with anger, shock, or ridicule to the ‘misuse’ of monies for the wrong circumstances or social relations, such as offering a salary to a wife, a gift to a traffic policeman, or a tip to a friend.
People care deeply about making such distinctions; the wrong transfer challenges, confuses, or violates the definition of particular social relations. Mondschein MD, in, 2011 23 How can one indirectly estimate portal venous pressure to confirm the diagnosis of portal hypertension?Catheterization of a hepatic vein is performed via jugular or femoral vein access. The catheter is advanced until it obstructs a small hepatic vein branch, or a balloon occlusion catheter is inflated within the hepatic vein to obstruct its outflow. The wedged hepatic vein pressure is actually a measure of sinusoidal pressure, but allows for a reasonable indirect estimate of portal pressure.
A corrected sinusoidal pressure measurement is obtained by subtracting the measured free hepatic venous pressure from the wedged hepatic venous pressure. Corrected sinusoidal pressure measurements less than or equal to 5 mm Hg are considered normal. Measurements of 6 to 10 mm Hg are compatible with mild portal hypertension, and measurements greater than 10 mm Hg are compatible with more severe portal hypertension. Costas Tsioufis. Dimitris Tousoulis, in, 2018 GenderEvidence has demonstrated that within the age spectrum of 40–60 years old incidence of CVD and death attributed to atherosclerosis is at least twice as high in men compared to women. Menopause has been found to be the equalizer. These observations have raised a hypothesis regarding the atheroprotective role of female sex hormones.
Indeed, estrogens have been associated with increased high-density lipoprotein (HDL) and decreased low-density lipoprotein (LDL) levels, as well as diverse antioxidant, vasoprotective and antithrombotic effects. However, despite these correlations, research failed to demonstrate a beneficial cardiovascular effect of hormone replacement therapy after menopause 5–7. Aronow, in, 2016 Optical Coherence TomographyOptical coherence tomography (OCT) is a technology that uses near infrared light to produce images. It can be technically more challenging than IVUS to perform. Older OCT systems utilized an over the wire low-pressure occlusion balloon catheter with distal flush ports. Saline or lactated ringers were infused to clear the lumen of blood in order to limit signal attenuation.
Newer systems with accelerated pullback utilize a high-speed bolus dose of contrast to clear the vessel lumen of blood 28. Images are generated by measuring the echo time delay and intensity of light that is reflected from the arterial wall.
Higher band widths used in OCT result in higher image resolution as compared to IVUS. It also provides greatly improved contrast between the vessel wall and lumen. This allows for potentially better assessment of incomplete stent apposition, edge dissection, and thrombus presence. However, visualization of residual plaque behind the stent is viewed better with IVUS, which exhibits better tissue penetration 29.
While it may be easier with OCT to identify complications such as edge dissection, it is unclear if this has a clinical benefit. In a study of 73 patients who underwent OCT after stent implantation, there was a 25% incidence of edge dissection 29. Despite being able to identify the edge dissection, this finding did not lead to an increase in intrahospital events 30.OCT has also demonstrated promise in its ability to assess and treat in-stent restenosis 31.
Typically, in-stent stenosis with bare-metal stents demonstrates a homogenous tissue band with OCT, while in-stent stenosis with drug-eluting stents shows a layered heterogenous band. OCT can also allow for the detection of unstable features such as intracoronary thrombus or ruptured plaque, which can influence management 31. However, prospective trials are needed to determine whether more detection by OCT leads to improved outcomes.The major value of intracoronary imaging with OCT comes with its ability to guide PCI. In an observational study of 670 patients undergoing PCI, 335 patients had angiographic plus OCT guidance and 335 matched patients had angiographic guidance only 32.
The primary endpoint was the 1-year incidence of cardiac death or myocardial infarction. Angiographic plus OCT guidance was associated with a significantly reduced risk of cardiac death or myocardial infarction at extensive multivariable analysis adjusting for baseline and procedural differences between the two groups (odds ratio = 0.49; 95% CI, 0.25–0.96; p = 0.037) and at propensity-score adjusted analyses. Because of the improved resolution with OCT, OCT was proposed to be a better alternative to IVUS for the guidance of PCI. This observational study suggested that use of OCT can improve clinical outcomes of patients undergoing PCI 32.However, Habara et al. Showed that the use of OCT was associated with smaller stent expansion and more frequent residual reference segment stenosis when compared with IVUS guidance 33. The inferiority of OCT in this case was hypothesized to be due to difficulty in viewing the vessel border. OCT has demonstrated a lesser degree of interobserver variability, however, when compared with IVUS 34.
Despite these observations, OCT has not been extensively studied prospectively. In addition, its use of more contrast and requirement for total vessel ischemia has likely contributed to operator reluctance to use OCT. Lewis, in, 2001An increasingly accepted redefinition of ‘map’ has substantively expanded and temporally extended the history of cartography field. It is no longer presented as post-medieval Eurocentric, with brief references to earlier developments in several parts of Asia and a North American coda.
The field's concern is no longer exclusively or even primarily with maps as artifacts and modes of map production but has been expanded to embrace the social, cultural, and cognitive contexts in which maps functioned. The field diversified significantly during the last quarter of the twentieth century but no generally agreed temporal-cultural structure emerged. A four-stage one is used here. Mapmaking originated prehistorically in many parts of the world and was a characteristic of all traditional cultures when first contacted by the expanding urban-based ‘civilizations.’ Map referents were the terrestrial world (but rarely the maritime), celestial world, supposed worlds beyond those of direct experience and reliable report, and sundry combinations of these. Terrestrial mapmaking was a vernacular skill but other kinds of maps were made by tribal and shamanistic leaders.
The uses, variety, and quality of maps increased spectacularly but probably independently in most of the world's early urban societies. In post-medieval Europe maps became even more sophisticated. Their importance in religious contexts declined as their secular uses increased and diversified. Mapmaking became increasingly specialized and map consciousness even more widespread. By 1900 maps made in this tradition were characteristic of most of the world's nation-states and many colonial areas.
1950 modes of map production were increasingly influenced by technical developments within North America; particularly so after c. 1975 with the development of computer-based geographical information systems.