A tutorial on the CARE III approach to reliability modeling

The CARE 3 reliability model for aircraft avionics and control systems is described by utilizing a number of examples which frequently use state-of-the-art mathematical modeling techniques as a basis for their exposition. Behavioral decomposition followed by aggregration were used in an attempt to deal with reliability models with a large number of states. A comprehensive set of models of the fault-handling processes in a typical fault-tolerant system was used. These models were semi-Markov in nature, thus removing the usual restrictions of exponential holding times within the coverage model. The aggregate model is a non-homogeneous Markov chain, thus allowing the times to failure to posses Weibull-like distributions. Because of the departures from traditional models, the solution method employed is that of Kolmogorov integral equations, which are evaluated numerically

Nanocrystalline Zr3Al Made through Amorphization by Repeated Cold Rolling and Followed by Crystallization

The intermetallic compound Zr3Al is severely deformed by the method of repeated cold rolling. By X-ray diffraction it is shown that this leads to amorphization. TEM investigations reveal that a homogeneously distributed debris of very small nanocrystals is present in the amorphous matrix that is not resolved by X-ray diffraction. After heating to 773 K, the crystallization of the amorphous structure leads to a fully nanocrystalline structure of small grains (10 - 20 nm in diameter) of the non-equilibrium Zr2Al phase. It is concluded that the debris retained in the amorphous phase acts as nuclei. After heating to 973 K the grains grow to about 100 nm in diameter and the compound Zr3Al starts to form, that is corresponding to the alloy composition

The efficacy of Quick Care cleaning regimen on Menicon SF-P rigid gas permeable lenses: An in-vitro study

The goal of this study was to determine the efficacy of Ciba\u27s QuickCARE System on Menicon SF-P rigid gas permeable lenses. An in-vitro study was designed to examine any parameter changes on Menicon SF-P lenses while using QuickCARE. Twenty-five lenses with identical parameters were cleaned for a simulated time of six months. Twenty lenses were cleaned with Ciba\u27s QuickCARE System, two with Allergan\u27s Wet \u27n Soak Plus Care System, two with QuickCARE Finishing Solution only, and one lens was stored in QuickCARE Finishing Solution with no mechanical cleaning. Half of the lenses were scooped out of the storage cases and half were poured out of the caseS. The lenses were assessed at 1 week, 1 month, 3 monthS and 6 month intervals for any changes is base curve, power, center thickness, diameter and surface integrity. No significant parameter changes occurred for diameter, power, center thickness, and base curve. However, surface integrity changes were statistically significant with pouring the lens from the case being better than scooping the lens from the case

Potential Extracorporeal Membrane Oxygenation Use for Increased Survival of In-Hospital Cardiac Arrests

Abstract This study sought to analyze and better understand the different etiologies of in-hospital cardiac arrest (IHCA), to determine the short and long term outcomes for these patients, to review and look for trends within the “code blue” data, and to identify patients who may benefit from an advanced and aggressive cardiopulmonary support system like extracorporeal membrane oxygenation (ECMO) during the cardiopulmonary resuscitation (CPR) process. A retrospective study of 182 patient charts and resuscitation records from the years 2011-2012 was completed with patients ranging in age from 24-70 years with a median age of 58. The most significant results found were an IHCA 30 day survival rate/survival rate to discharge of 28% and that at least 44 patients may have benefitted from ECMO-CPR. Though this study includes only a very small sample size and two years of data, it is significant because it highlights places where implicating a new resuscitation process for select IHCA patients could directly save lives. It warrants further research into implementing ECMO-CPR within the Lehigh Valley Health Network and continued analysis of the current data on “code blues” and CPR protocol. Introduction In-hospital cardiac arrest (IHCA) is a relatively uncommon event but is very resource intensive and associated with a poor outcome including a low rate of survival. Cardiac arrest in the hospital setting can be the result of a variety of etiologies. The progression of cardiopulmonary resuscitation (CPR) for these arrests can vary greatly between patients. Many factors including initial cardiac rhythm, duration of CPR, quality of CPR, and cause of the arrest account for these differences and the end prognosis for the patient.1 Even when given optimal care, survival rates for IHCA are still with the majority of patients are unable to regain proper and lasting circulation to discharge. Analyzing in-hospital cardiac arrest data allows the Lehigh Valley Health Network to review their cardiopulmonary resuscitation protocols and pinpoint trends and differences within the data. This information can highlight areas of possible improvement in patient outcomes and care. As technology continues to advance, more options are slowly becoming available to improve prognoses of IHCA patients. Extracorporeal membrane oxygenation (ECMO) is a highly aggressive and advanced cardiopulmonary support system that can benefit select patients who cannot be successfully resuscitated through traditional cardiopulmonary resuscitation. Essentially, veno-arterial ECMO works similarly to the cardiopulmonary bypass machines utilized during open heart surgeries. The blood is drained from the patient and oxygenated outside of the body before it is returned to circulation. This temporarily allows for adequate bodily perfusion in patients whose hearts will not pump properly. Because ECMO is an expensive and only temporary solution for patients in refractory cardiac arrest, selection is restricted to those who have ‘reversible’ causes of cardiac arrest. ECMO offers valuable time for the pathologies behind the cardiac arrest to be evaluated and treated.2 Studies have shown that ECMO is most effective for these patients as well as patients whose arrests were witnessed and had immediate CPR intervention, which is why it is more of an option for IHCA versus out-of hospital cardiac arrests.1,3 One study found the rate of survival of ECMO-CPR for IHCA patients was 42% and out of hospital cardiac arrest only 15%.1 Patient gender, age, and body weight have not been found to be statistically significant factors in survival rates of ECMO-CPR.3 Introducing ECMO-CPR for select IHCA patients in the Lehigh Valley Health Network is a realistic way to produce positive outcomes for patients who would otherwise face grave prognoses and better the overall survival statistics for IHCA in the network. Methodology This was a retrospective study involving the 182 patients in 2011 and 2012 between the ages of 18 and 70 within the Lehigh Valley Health Network for which a “code blue” was called for a cardiac arrest. Data was examined for each patient from their medical charts, electronic medical records, and resuscitation records that are filled out for each “code blue” incidence. The overall exclusion criteria were an age 70 years or an existing do not resuscitate (DNR) before the code took place. A database was made using Microsoft Access to compile and condense relevant information for each included patient. This information included demographics, medical history, date of the cardiac arrest, cause of the cardiac arrest, initial cardiac rhythm, location within the hospital, reason the code was terminated, if there was a return of circulation (\u3e20minutes), if multiple cardiac arrests were experienced in the day, if the patient became DNR after coding, and if the patient survived to 30 days and 1 year following the arrest with or without good neurological condition. Some gender differences in IHCA within the hospital were explored, with statistics being analyzed using a Fischer’s Exact Test. All included patients were used for each analysis, except for analysis of initial cardiac rhythms where nine patients had to be excluded because of unrecorded or unknown initial rhythms. When identifying patients who may have benefitted from ECMO, additional exclusion criteria used were: previous severe neurological damage, intracranial hemorrhage, cardiac arrest of traumatic origin, uncontrolled bleeding, terminal malignancy, irreversible organ failure (like hepatic failure), original unwitnessed out of hospital cardiac arrest, severe COPD, and severe PVD.2 Criteria for cardiopulmonary resuscitation with ECMO is relatively selective because ECMO-CPR is by nature much more involved, invasive, and expensive than traditional CPR. Patients recognized for possible ECMO benefit were then sorted by the etiology of their cardiac arrest. Results The results in Table 1 (see Appendix A) show that of the 182 patients suffering IHCA in 2011-2012 within the outlined age range, only 51 (28%) survived at least 30 days following their arrest despite 106 (58%) gaining some kind of return of circulation (ROC) greater than 20 minutes. 24 patients who had ROC became DNR following their first code and subsequently passed away soon after, while 35 patients who had ROC had repeat codes with only 2 surviving. The average age of all survivors to 30 days was 53 years with a range of 24-70 years, and the average duration of CPR for survivors was 15.5 minutes with a standard deviation of about 14.5 minutes and a range of About 59% of all of the IHCA patients were male and the remaining 41% female. Surprisingly, there was a difference in survival seen between male and female patients with rates of 23% and 35% respectively (Table 1). Rates of the initial cardiac rhythms at arrest between males and females were also found to be different but not significantly so (Figure 2). Survival rates varied for each initial rhythm with ventricular fibrillation or ventricular tachycardia arrests having a survival rate of almost 50%, statistically significantly (p values After reviewing comorbid conditions and causes of cardiac arrest, 44(about 34%) of the 131 patients who did not survive with traditional CPR were found to have likely benefitted from ECMO-CPR (Table 3). A variety of causes of cardiac arrest are represented within this population (Figure 3), the most common being acute coronary syndrome, pulmonary embolism, cardiomyopathy, and sepsis. Conclusion The results show a few noteworthy trends within the IHCA data for 2011-2012 including gender differences in survival, survival rates in patients who code multiple times, and patients who may have benefitted from ECMO-CPR and the causes of their arrests. The differences in survival rates between the genders in the two years have a few possible explanations. First, the small sample size and limited age range examined could have skewed the data. Secondly, there was a significantly smaller ratio of percentage of males versus females that went into ventricular fibrillation or ventricular tachycardia arrests than previous studies have found. This study found only 24% of male and 22% of female in-hospital cardiac arrests had an initial ventricular tachycardia/ventricular fibrillation rhythm, while other studies have found men to have a statistically significant larger percentage of arrests originating in this type of rhythm.4 Since an initial rhythm of ventricular fibrillation or tachycardia is well documented to have the highest rate of survival, this helps to explain the difference in survival found between the genders. This study confirmed the greater survival rate for this rhythm, with 55% of men and 43% of women surviving 30 days post arrest. From looking at the results of this study, patients who suffered repeat cardiac arrests within the same day appear to have very grave prognoses. Less than 6% of these patients survive 30 days, excluding the additional 24 patients that were DNR after their first arrest and subsequently coded. Further studies incorporating additionally years of data and data from additional hospital systems would be able to confirm if this is a consistent trend. Of the 131 patients that did not survive to 30 days post their IHCA, 44 would have been included as good candidates for ECMO-CPR per criteria listed above. Survival rates to discharge for patients undergoing ECMO-CPR for IHCA vary between studies but are most often found to be around 30-42%.1,2 Conservatively this indicates that about 13-18 patients could have been saved in 2011-2012 and increased the overall IHCA survival rate for the two years from 28% to 35-39%. This shows that introducing ECMO-CPR for select IHCA patients in the Lehigh Valley Health Network is a realistic way to produce positive outcomes for patients who would otherwise face grave prognoses and better the overall survival statistics for IHCA in the network. The study has quite a few limitations. It cannot be broadly applied due to the small sample size of only 182 total patients with only 2 years of IHCA data, limited age range of patients reviewed, and because only statistics from a single hospital system were examined. However, the findings outlined above suggest that further research of IHCA patients within the Lehigh Valley Health Network and into adopting ECMO-CPR protocols is at least warranted. Appendix

Surgical Treatment of Multiple Vein Graft Aneurysms in 72 Year Old Man

Abstract The rarity of saphenous vein graft aneurysms following coronary artery bypass graft surgery presents an interesting case, as seen in a 72 year-old gentleman who underwent his third bypass surgery for an aneurysmal graft. Information regarding the case was gathered using the Lehigh Valley Health Network medical databases. The 8 cm aneurysmal portion of the graft was resected successfully and replaced with a CryoVein. Following surgery the patient had relief of symptoms and recovered well. It was determined that the patient had two true aneurysms present, making surgery a necessity in this specific case. Introduction Saphenous vein graft (SVG) aneurysms following coronary artery bypass grafting (CABG) are rare but fatal complications that frequently require surgical repair.1 We address a rare surgical case regarding an individual requiring a third sternotomy involving two SVG aneurysms with thrombus, 22 years following CABG. Information was gathered retrospectively using the LVHN database. Case Report In November of 2013, a 72 year-old man, a former smoker with a previous history of hypertension, hyperlipidemia, coronary artery disease, myocardial infarction, and coronary artery bypass graft surgery, was readmitted for a third sternotomy to resect a giant vein graft aneurysm forming on the right coronary artery (RCA) graft that had grown to a diameter of 8 cm. An additional aneurysm of 5 cm was also present on the circumflex vein graft. The patient had undergone coronary artery bypass graft (CABG) surgery in 1991, with his first redo CABG occurring in 2007. At that time, the vein graft aneurysm measured 4 cm but was not resected during the second bypass graft procedure to the left anterior descending (LAD) and circumflex arteries. Five years later, in 2013, the patient returned after a syncope episode and presented at the hospital with an enlarged aneurysm of the RCA vein graft, measuring 8 cm and a 5 cm aneurysm of the circumflex vein graft. A transesophageal echocardiogram (TEE) was performed, showing the presence of the aneurysms and as a result, inflow obstruction from the inferior and superior vena cava due to small atrial chamber size. The patient was scheduled for surgery in November and discharged from the hospital. At the time of surgery, the patient received general anesthesia, and a skin incision was made right below the clavicle to expose the axillary artery, through which the patient was heparinized. An 8 mm Hemashield conduit was anastomosed onto the right axillary artery and connected to the arterial line. A left groin incision was made to expose the femoral vein on the left side. This vein was cannulated with a 24 French venous cannula from Edwards Medical Supplies Inc. The patient was opened through a median sternotomy with an oscillating saw following the removal of previous surgical wires. A retractor was inserted into the mediastinum after the substernal structure was dissected. Upon opening, the vein graft aneurysm from the RCA was clearly visible and easily palpated. The aneurysm was first dissected off of adhesions, pleural tissue, and the right atrium. The ascending aorta was partly visible at this time, but it was a fairly short view. A segment of 3 to 4 cm of vein graft that was not aneurysmal was identified prior to the extremely aneurysmal portion. A right angle dissector was used to get around the normal caliber of the vein graft. The dissection continued along with the aneurysm out along the diaphragmatic surface of the heart, where the native RCA became visible on top of the vein graft aneurysm. The aneurysm had grown over the years causing tenting and migration of the native RCA to occur. There was clear anastomosis and it was followed, causing movement further distally into the heart itself. The distal PDA that appeared to be of reasonable caliber was dissected out. At this time the CryoVein was prepared, and the vein was incised to shape it. Using a beating heart on-pump technique, the distal PDA was opened with a 1.5 mm shunt for bleeding control, and the vein was anastomosed to the arteriotomy. The vein graft was sized to the original vein graft of the RCA and was clamped proximally. A punch hole was made in the vein graft for proximal anastomosis. With the vein graft still clamped, the proximal neck of the vein graft aneurysm was cut into and disconnected from the normal segment of the old vein graft. After sewing over the cut end of the old graft, it could then be laid into the vein graft aneurysm after removing all thrombus and grommet material. The entire venous graft aneurysm was compressed and most of the aneurysmal wall was resected. There was a second aneurysm of the vein graft by the diaphragmatic surface of approximately 4 to 5 cm in diameter. This was resected in its entirety and disconnected from the native coronary artery. The native coronary artery was completely occluded and so the artery was clipped and divided. The patient was then weaned off of cardiopulmonary bypass without difficulties, protamine was given, cannulas removed and hemostasis was achieved. Following surgery the patient did have pneumomedtastinum that resolved and a resolved left pleural effusion as a result of surgery over the five- day period before discharge. Upon discharge the patient had an improved blood pressure and was recovering well. Discussion After CABG, aneurysms of SVGs are a rare complication that can occur from a few days to over 21 years after surgery.2 Aneurysms can present as either true aneurysms or pseudoaneurysms. A relative distinction has been determined, that true aneurysms typically present as late complications of bypass surgery,3 while pseudoaneurysms may occur early after initial surgery at the anastomotic site.4 It has been determined that our patient developed two true aneurysms following both bypass graft procedures. True aneurysms have been found to occur more commonly in the body of the graft, present more than 5 years following bypass and are a result of vein graft necrosis, hypertension, trauma at harvest or implantation, or progressive atherosclerosis and thrombosis.5 Our patient presented with a single syncope episode, which is a common symptom presenting with SVG.2 CT and CT with contrast were used to show the extent of the aneurysm and its relation to and impact on surrounding structures. In a study from the Annals of Thoracic Surgery using 15 patients’ data, 25% had SVG aneurysms to the right coronary artery graft and 19% had the same to the circumflex coronary artery graft, which were the second and third highest locations of aneurysmal sites.6 In the same study, patients with previous histories of myocardial infarctions and hyperlipidemia were more at risk to develop SVG aneurysms,6 which were previous health factors for our patient. True aneurysms have been found to commonly form in the body of the vein graft as a result of chronic degeneration by vascular injury from hyperlipidemia and progression of atherosclerosis.7,8 With complications presenting as a result of compression from the aneurysmal graft, surgical intervention for this patient was required. Surgical correction was necessary due to previous heart history, multiple aneurysms, possibility for rupture, and presence of thrombus within the aneurysm. Aneurysms of SVGs are frequently unknown until symptoms arise or the discovery is made coincidentally with other medical testing. Patients with increased risk factors for SVG aneurysms should follow-up with physicians around the 10-year mark post surgery to check for aneurysm formation. References: 1Drummer E, Furey K, Hollmann J. Rupture of a saphenous vein bypass graft during coronary angioplasty. Br Heart J. 1987;58:78-81. 2Mayglothling J, Thomas MP, Nyzio JB, et al. Aneurysm of aortocoronary saphenous vein graft: case report and literature review. Heart Surg Forum. 2004;55:587-588. 3Liang BT, Antman EM, Taus R, et al. Atherosclerotic aneurysms of aortocoronary vein grafts. Am J Cardio. 1988;61:185-188. 4Le Breton H, Pavin D, Langanay T, et al. Aneurysm and pseudoaneurysms of saphenous vein coronary arter bypass grafts. Heart. 1998;79:505-508. 5Bramlet DA, Behar VS, Ideker RE. Aneurysm of a saphenous vein bypass graft associated with aneurysms of native coronary arteries. Cathet Cardiovasc Diagn. 1982;8:489-4. 6Sareyyupoglu, B, Schaff HV, Ucar I, et al. Surgical treatment of saphenous vein graft aneurysms after coronary artery revascularization. Ann Thorac Surg. 2009;88:1801-1805. 7Poll LW, Sadra B, Rühlow S, et al. Thrombosis of a large saphenous vein graft aneurysm leading to acute myocardial infarction 21 years after coronary artery bypass grafting: role of cardiac multi-slice computed tomography. Interact CardioVasc and Thorac Surg. 2011;12:284-286. 8Kalimi R, Palazzo RS, Graver LM. Giant aneurysm of saphenous vein graft to coronary artery compressing right atrium. Ann Thorac Surg. 1999;68:1433-1437

Robust Receptive Vocabulary Instruction for Students With Significant Cognitive Disabilities Who Use AAC

Robust vocabulary instruction is an important part of comprehensive English language arts (ELA) instruction. Vocabulary instruction supports students in learning the meaning of words to build a receptive vocabulary that they can rely on to comprehend the words they read and hear. Many students with significant cognitive disabilities (SCD) and complex communication needs (CCN) struggle to read or understand grade-level words, concepts, and texts. Explicit vocabulary instruction can play an important role in addressing this area of need. Addressing the vocabulary needs of students with SCD and CCN in a comprehensive way calls for a greater investment of instructional time to build their receptive vocabulary and conceptual understandings of new vocabulary. It calls for leveraging the high frequency expressive vocabulary students are likely to have available on their augmentative and alternative communication (AAC) systems to make meaningful connections and demonstrate their understanding of new vocabulary. The aim is successful comprehension across ELA and other academic domains through a robust and expanding receptive vocabulary that extends beyond the words commonly programmed onto AAC systems. Finally, vocabulary instruction should be one part of a comprehensive approach to ELA instruction, with substantial time and effort also devoted to reading and writing instruction so that one day students with SCD and CCN can use spelling and writing to bridge the gap between the words they know and the words they have access to use expressively

Introduction to the Special Issue on the 2011 Tohoku Earthquake and Tsunami

The 11 March 2011 Tohoku earthquake (05:46:24 UTC) involved a massive rupture of the plate‐boundary fault along which the Pacific plate thrusts under northeastern Honshu, Japan. It was the fourth‐largest recorded earthquake, with seismic‐moment estimates of 3–5×10^(22)  N•m (M_w 9.0). The event produced widespread strong ground shaking in northern Honshu; in some locations ground accelerations exceeded 2g. Rupture extended ∼200  km along dip, spanning the entire width of the seismogenic zone from the Japan trench to below the Honshu coastline, and the aftershock‐zone length extended ∼500  km along strike of the subduction zone. The average fault slip over the entire rupture area was ∼10  m, but some estimates indicate ∼25  m of slip located around the hypocentral region and extraordinary slip of up to 60–80 m in the shallow megathrust extending to the trench. The faulting‐generated seafloor deformation produced a devastating tsunami that resulted in 5–10‐km inundation of the coastal plains, runup of up to 40 m along the Sanriku coastline, and catastrophic failure of the backup power systems at the Fukushima Daiichi nuclear power station, which precipitated a reactor meltdown and radiation release. About 18,131 lives appear to have been lost, 2829 people are still missing, and 6194 people were injured (as reported 28 September 2012 by the Fire and Disaster Management Agency of Japan) and over a half million were displaced, mainly due to the tsunami impact on coastal towns, where tsunami heights significantly exceeded harbor tsunami walls and coastal berms

Deforestation: Correlations, Possible Causes and Some Implications

Changes in national forest areas during 1990-2000 are contrasted with other variables to illustrate correlations and provoke discussion about possible causes. Twenty-five statistically-significant correlations (including rural population, life expectancy, GDP, literacy, commerce, agriculture, poverty and inflation) are illustrated and a statistical model suggests that good governance, alternative employment opportunities, and payments for environmental services may be effective in combating deforestation. The data suggest that a global forest convention may need to be supported by substantial and carefully-targeted development assistance to foster good governance