Classical guitar intonation and compensation: The well-tempered guitar.

An intuitive model of classical guitar intonation is presented that includes the effects of the resonant length of the fretted string, linear mass density, tension, and bending stiffness. An expression is derived for the vibration frequencies of a stiff string using asymmetric boundary conditions at the saddle and the fret. Based on logarithmic frequency differences ("cents") that decouple these physical effects, Taylor series expansions are introduced that exhibit clearly the origins of frequency deviations of fretted notes from the corresponding 12-tone equal temperament (12-TET) values. A simple in situ technique is demonstrated for measurement of the changes in frequency of open strings arising from small adjustments in length, and a simple procedure is proposed that any interested guitarist can use to estimate the corresponding frequency shifts due to tension and bending stiffness for their own guitars and string sets. Based on these results, a least-squares fit method is employed to select values of saddle and nut setbacks that map fretted frequencies-for a particular string set and guitar-almost perfectly onto their 12-TET targets. A general approach to tempering an "off-the-shelf" guitar is shown to further reduce the tonal errors inherent in any fretted musical instrument.

Investigation of dosimetric properties of CaSO4:Mn phosphor prepared using slow evaporation route.

The objective of this work was to investigate the luminescent properties of CaSO4:Mn synthesized by slow evaporation route. The crystalline structure, morphology, thermal and optical properties of the phosphors were characterized by X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM), photoluminescence (PL) and thermogravimetric analysis (TGA). Moreover, using thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques, the dosimetric properties of the phosphors, such as emission spectra, glow curve reproducibility, dose-response linearity, fading of the luminescent signal, variation of the TL intensity with the heating rate, OSL decay curves, correlation between TL and OSL emissions and minimum detectable dose (MDD) were comprehensively investigated. For dosimetric analyses, the samples were irradiated with doses from 169 mGy to 10 Gy. The emission band fits with the characteristic line of the Mn2+ emission features, ascribed to 6A1→4T1 transition. CaSO4:Mn pellets present a TL glow curve with a single typical peak centered around 494 nm, an OSL decay curve with predominance of a fast decay component, and a MDD on the order of mGy. The luminescent signals showed to be linear and reproducible in the studied dose range. The trapping centers located between 0.83 eV and 1.07 eV were revealed for different heating rates in the TL study. The high TL sensitivity of CaSO4:Mn was proven when comparing with commercially available dosimeters. The luminescent signals exhibit a smaller fading than described in the literature for CaSO4:Mn produced by other methods.

Luminescence characterization of BioGlass undoped and doped with europium and silver ions.

The objective of this study was to investigate the properties of BioGlass, with and without doping with europium and silver, with a specific focus on its potential application in thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimetry. The structural and optical characteristics of the samples were also analyzed using techniques such as X-ray diffraction (XRD), optical absorption (OA), and fluorescence spectroscopy (FL). An XRD analysis confirmed the amorphous phase of the BioGlass. OA and FL spectra were obtained at room temperature, and characteristic bands of dopant ions were observed which confirmed the incorporation of the Eu3+ ions and silver nanoparticles Ag(NP) ion into the BioGlass. The OSL decay curves exhibited a characteristic exponential behavior, with a notable presence of fast and medium decay components; this suggests that the charge traps within the BioGlass samples possess a high photoionization cross section when exposed to blue LEDs, which are commonly used as the light source in OSL readers. Different TL glow peaks with varying shapes of the glow curve were observed when the dopant, the co-dopant, and the concentration of silver were altered in the samples. The TL kinetic parameters were determined, such as the order value, activation energy, and frequency factor, and the OSL parameters for the compound were also analyzed, including an exponential fit to the curves. Based on these initial results, we conclude that BioGlass has the potential for use in radiation dosimetry.

'Bundle busters': who is at risk of exceeding the target payment and can they be optimized?

AIMS: The Bundled Payments for Care Improvement (BPCI) initiative has identified pathways for improving the value of care. However, patient-specific modifiable and non-modifiable risk factors may increase costs beyond the target payment. We sought to identify risk factors for exceeding our institution's target payment, the so-called 'bundle busters'. PATIENTS AND METHODS: Using our data warehouse and Centers for Medicare and Medicaid Services (CMS) data we identified all 412 patients who underwent total joint arthroplasty and qualified for our institution's BPCI model, between July 2015 and May 2017. Episodes where CMS payments exceeded the target payment were considered 'busters' (n = 123). Risk ratios (RRs) were calculated using a modified Poisson regression analysis. RESULTS: An increased risk of exceeding the target payment was significantly associated with increasing age (adjusted RR 1.04, 95% confidence interval (CI) 1.01 to 1.06) and body mass index (adjusted RR 1.03, 95% CI 1.003 to 1.06). Eight comorbid risk factors were also identified (all p < 0.05), only two of which were considered to be potentially modifiable (diabetes with complications and preoperative anaemia). An American Society of Anesthesiologist physical status classification system (ASA) score ≥ 3 (adjusted RR 2.3, 95% CI 1.67 to 3.18) and Charlson Comorbidity Index (CCI) ≥ 3 (adjusted RR 1.94, 95% CI 1.45 to 2.60) were risk factors for bundle busting. CONCLUSION: Non-modifiable preoperative risk factors can increase costs and exceed the target payment. Future bundled payment models should incorporate the stratification of risk. Cite this article: Bone Joint J 2019;101-B(7 Supple C):64-69.

Correction of mildly dysplastic hips with periacetabular osteotomy demonstrates promising outcomes, achievement of correction goals, and excellent five-year survivorship.

AIMS: The aim of this study was to compare patient-reported outcome measures (PROMs), radiological measurements, and total hip arthroplasty (THA)-free survival in patients who underwent periacetabular osteotomy (PAO) for mild, moderate, or severe developmental dysplasia of the hip. PATIENTS AND METHODS: We performed a retrospective study involving 336 patients (420 hips) who underwent PAO by a single surgeon at an academic centre. After exclusions, 124 patients (149 hips) were included. The preoperative lateral centre-edge angle (LCEA) was used to classify the severity of dysplasia: 18° to 25° was considered mild (n = 20), 10° to 17° moderate (n = 66), and < 10° severe (n = 63). There was no difference in patient characteristics between the groups (all, p > 0.05). Pre- and postoperative radiological measurements were made. The National Institute of Health's Patient Reported Outcomes Measurement Information System (PROMIS) outcome measures (physical function computerized adaptive test (PF CAT), Global Physical and Mental Health Scores) were collected. Failure was defined as conversion to THA or PF CAT scores < 40, and was assessed with Kaplan-Meier analysis. The mean follow-up was five years (2 to 10) ending in either failure or the latest contact with the patient. RESULTS: There was no significant difference in PROMs for moderate (p = 0.167) or severe (p = 0.708) groups compared with the mild dysplasia group. The numerical pain scores were between 2 and 3 units in all groups at the final follow-up (all, p > 0.05). There was no significant difference (all, p > 0.05) in the proportion of patients achieving target correction for the LCEA between groups. The mean correction was 12° in the mild, 15° in the moderate (p = 0.135), and 23° in the severe group (p < 0.001). Failure-free survival at five years was 100% for mild, 79% for moderate, and 92% for severely dysplastic hips (p = 0.225). CONCLUSION: Although requiring less correction than hips with moderate or severe dysplasia, we found PAO for mild dysplasia to be associated with promising PROMs, consistent with that of the general United States population, and excellent survivorship at five years. Future studies should compare these results with the outcome after arthroscopy of the hip in patients with mild dysplasia. Cite this article: Bone Joint J 2019;101-B(6 Supple B):16-22.

Ten-year survivorship of primary total hip arthroplasty in patients 30 years of age or younger.

Aims: For this retrospective cohort study, patients aged ≤ 30 years (very young) who underwent total hip arthroplasty (THA) were compared with patients aged ≥ 60 years (elderly) to evaluate the rate of revision arthroplasty, implant survival, the indications for revision, the complications, and the patient-reported outcomes. Patients and Methods: We retrospectively reviewed all patients who underwent primary THA between January 2000 and May 2015 from our institutional database. A total of 145 very young and 1359 elderly patients were reviewed. The mean follow-up was 5.3 years (1 to 18). Logistic generalized estimating equations were used to compare characteristics and the revision rate. Survival was evaluated using Kaplan-Meier curves and hazard rates were created using Cox regression. Results: The overall revision rate was 11% (16/145) in the very young and 3.83% (52/1359) in the elderly groups (odds ratio (OR) 2.58, 95% confidence interval (CI) 1.43 to 4.63). After adjusting for the American Society of Anesthesiologists (ASA) score, gender, and a history of previous surgery in a time-to-event model, the risk of revision remained greater in the very young (adjusted hazard ratio (HR) 2.48, 95% CI 1.34 to 4.58). Survival at ten years was 82% (95% CI, 71 to 89) in the very young and 96% (95% CI, 94 to 97) in the elderly group (p < 0.001). The very young had a higher rate of revision for complications related to metal-on-metal (MoM) bearing surfaces (p < 0.001). At last follow-up, the very young group had higher levels of physical function (p = 0.002), lower levels of mental health (p = 0.001), and similar levels of pain (p = 0.670) compared with their elderly counterparts. Conclusion: The overall revision rate was greater in very young THA patients. This was largely explained by the use of MoM bearings. Young patients with non-MoM bearings had high survivorship with similar complication profiles to patients aged ≥ 60 years. Cite this article: Bone Joint J 2018;100-B:867-74.

Bioassay of porcine relaxin components by in vitro inhibition of rat uterine contractions.

Isolation of porcine relaxin by the procedure of Sherwood and O'Byrne has resulted in three, slightly different relaxin molecules which differ in the length of their B chains. The purpose of this study was to determine if a difference in biological activity exists among the three relaxin forms as determined by the in vitro inhibition of spontaneous rat uterine contractions. Uterine segments from estrogen-primed, virgin rats were suspended in Locke's solution in a siliconized, water-jacketed organ bath at 37 C. After regular contractions were established, the minimum concentration of each relaxin component necessary to cause total inhibition was determined. Total inhibition for all three relaxin components was obtained at a chamber concentration of 0.2-0.36 U/ml. Thus, no difference in biological activity exists among the three relaxin forms as demonstrated by the rat uterine inhibition bioassay.

Ultrastructural localization of relaxin immunoreactivity in corpora lutea of pregnant rats.

Relaxin was localized in cells of corpora lutea of pregnant rats at the ultrastructural level using a highly specific antirat relaxin serum and the unlabeled peroxidase-antiperoxidase technique. Electron-dense, membrane-bound granules (maximum diameter, 270 nm), which are present in luteal cells during the last third of gestation, were the only inclusions that were immunochemically stained. The number of granules observed in the luteal cell cytoplasm varied from cell to cell within a particular section. Furthermore, in the granule-rich luteal cells, the granules appeared in clusters. This study establishes that these electron-dense granules represent the subcellular sites of relaxin localization within luteal cells of pregnant rats.

The source of relaxin in pregnant Syrian hamsters.

Serum immunoreactive relaxin (IR) was measured on days 8, 10, and 14 of gestation in intact and ovariectomized (day 8 of pregnancy) hamsters. In intact hamsters, IR increased from 3-4 ng/ml on day 8 to 20 ng/ml by day 14 of pregnancy. After ovariectomy on day 8, pregnancy failed, and IR decreased rapidly to 0.29 ng/ml on day 14. However, when pregnancy was maintained in ovariectomized hamsters by daily injections of 0.1 microgram 17 beta-estradiol and 4 mg progesterone, serum IR rose to levels similar to those in intact hamsters on days 10 and 14 of pregnancy (i.e. 15 and 20 ng/ml, respectively). Placentas were obtained from other groups of hamsters on days 11, 14, and 15 of pregnancy and homogenized for bioassay by the classical guinea pig pubic symphysis palpation bioassay. Homogenates of placentas obtained on days 14 and 15 contained, respectively, 4 and 10 micrograms eq porcine relaxin/serum relaxin/g fresh tissue. The placenta, rather than the ovary, appears to be the source of during pregnancy in the hamster.

Absence of relaxin immunostaining in the male reproductive tracts of the rat and mouse.

By use of the biotin-avidin immunohistochemical method and a homologous antiserum as the primary antiserum, relaxin immunostaining was absent in the testes, prostate, seminal vesicles, and epididymides of the rat. Relaxin immunostaining was also lacking when anti-porcine relaxin serum was employed as the primary antiserum. Furthermore, immunohistochemical studies for relaxin localization in the reproductive tract of the male mouse using both anti-rat and anti-porcine relaxin sera also revealed an absence of the hormone in the reproductive system of this species. Although this study suggests that immunoreactive relaxin is absent in the male reproductive tracts of both the rat and mouse, it raises some questions concerning the reports in the literature of the presence of relaxin-like substances in the male reproductive tracts of other species. These reports are discussed in relation to our current results.

Immunocytochemical studies of relaxin in ovaries of pregnant and cycling mice.

Immunocytochemical staining for relaxin in ovarian sections of pregnant mice from day 11 through day 18 of gestation revealed that only corpora lutea (CL) of pregnancy are stained. Evaluation of serial sections of ovaries from a day 16 pregnant mouse revealed that the only luteal structures present are CL of pregnancy. The number of CL present in each ovary equaled the number of implantation sites in each related horn (7 on the right side and 8 on the left side). These large CL varied in shape, being round in some profiles to very elongate in others. All CL were immunochemically stained for relaxin using the peroxidase-antiperoxidase method of L. Sternberger (Immunocytochemistry, 2nd ed. Wiley, New York, 1979). The intensity of the strain varied from cell to cell within each CL. Small luteal structures that were observed to be immunochemically stained for relaxin were demonstrated to represent the periphery of CL of pregnancy. No luteinized follicles were observed and interstitial cells and follicles were not immunochemically stained in any of the day 16 serial ovarian sections or in any of the ovarian sections from pregnant mice on the other days of gestation studied. CL of previous cycles were not observed to be present in the ovaries at days 15, 16, or 18 of gestation. However on day 14 and before, CL of previous cycles were observed and they did not exhibit any relaxin immunostaining. Immunocytochemical studies using the biotin-avidin system revealed that no relaxin immunostaining could be demonstrated in the ovaries of cycling mice at any stage of the estrous cycle. In conclusion, this study revealed that the only ovarian structures demonstrating relaxin immunocytochemical staining in the mouse were CL of pregnancy.

Chemoprevention of NMU-induced rat mammary carcinoma with the combination of melatonin and 9-cis-retinoic acid.

In experimental trials using the N-nitroso-N-methylurea (NMU)-induced rat mammary tumor model, a significant decrease in tumor incidence (to 5%) was observed in rats treated with melatonin and 9-cis-retinoic acid (9 cRA) compared to controls (55%). Although 9cRA alone decreased tumor incidence to 26%, this response did not reach statistical significance. Tumor incidence was significantly inhibited to 20% in the animals that received melatonin and 9cRA on alternating days. Latency to tumor onset was prolonged in animals receiving either of the combination treatments compared with controls, and tumor multiplicity was also significantly decreased.

Volume reduction surgery in the native lung after single lung transplantation for emphysema.

The natural history of emphysema suggests that progression of disease in the native lung may contribute to late deterioration in respiratory function after single lung transplantation. In this report, we describe our experience with unilateral volume reduction surgery in three single lung transplant recipients with emphysema. Each patient had had a late decline in lung function with a recurrence of symptoms. Chest radiographs demonstrated hyperinflation of the native lungs with encroachment on the grafts. Serial pulmonary function testing documented progressive reduction in expiratory flows with increases in residual volumes. Exercise testing confirmed severe intolerance to maximal exercise. Unilateral volume reduction surgery was undertaken at 36, 39, and 55 months after transplantation without incident. Radiographs obtained after the procedures demonstrated restoration of normal diaphragmatic contour, decreased aeration of the native lungs, and improved inflation of the allografts. Exercise testing at 3 months documented a mean improvement in maximal oxygen consumption of 35%. Expiratory flows improved by a mean of 60%. Quantitative ventilation and perfusion scans, however, were essentially unchanged. This experience suggests that unilateral volume reduction surgery may be considered as an alternative strategy in single lung transplant recipients with emphysema who exhibit clinically significant functional deterioration. Differentiation of the adverse effects of hyperinflation of the native lung from other potential causes of late deterioration might not be necessary but may be predictive of the degree of functional improvement after volume reduction. The relief of thoracic overdistention seems to play a primary role in the improvement pulmonary function.

Techniques for bronchial anastomosis.

BACKGROUND: Many techniques have been described to optimize the construction of the bronchial anastomosis in lung transplantation. Over the past 60 months we have performed 86 bronchial anastomoses in 70 patients receiving single lung or bilateral single lung transplants. METHODS: No anastomosis was wrapped and no attempt was made at revascularization of bronchial arteries. A continuous nonabsorbable suturing technique was used in all cases. Standard triple-drug immunotherapy with cyclosporine, azathioprine, and prednisone (starting at day 7) was used for each patient. RESULTS: There were no anastomotic leaks, and seven stenoses were identified in five patients (7%). All complications were managed conservatively with stenting, and there were no related deaths. Mean time to stent placement was 109 days. One patient had bilateral stents placed prophylactically during an episode of severe infection for questionable anastomotic viability but without evidence of airway necrosis or obstruction. This patient died of infection at 16 days. Another patient died with stents in place at 71 days. In the four remaining patients, all stents have been removed after a mean of 310 days. These patients were followed up with serial bronchoscopy and were without evidence of recurrent obstruction at 2, 34, 35, and 36 months. Six of seven stenoses occurred in patients with cystic fibrosis. In each patient where stenosis developed the anastomosis was telescoped. Since abandoning the telescoping technique in the remaining 50 anastomoses (14 in patients with cystic fibrosis), no dehiscence or stenosis was encountered. CONCLUSIONS: These data suggest that elaborate techniques aimed at construction of the bronchial anastomosis are not necessary. Moreover, attempts at telescoping may be detrimental. Patients with cystic fibrosis may be a population at higher risk for anastomotic complications. Airway complications can be managed conservatively with good results and little risk to the patient.

Primary pulmonary artery sarcoma: a report of six cases.

Pulmonary artery tumors are rare and a frequently overlooked cause of pulmonary artery occlusion. The presentation is one of progressive pulmonary dysfunction and right ventricular failure. The diagnosis seldom is made preoperatively. We report 6 cases of primary sarcoma of the pulmonary artery identified at operation, which were treated surgically. Resection with or without adjuvant therapy currently offers the only chance for survival. Emphasis must be placed on earlier identification of these tumors.

Introducing information technologies into medical education: activities of the AAMC.

Previous articles in this column have discussed how new information technologies are revolutionizing medical education. In this article, two staff members from the Association of American Medical College's Division of Medical Education discuss how the Association (the AAMC) is working both to support the introduction of new technologies into medical education and to facilitate dialogue on information technology and curriculum issues among AAMC constituents and staff. The authors describe six AAMC initiatives related to computing in medical education: the Medical School Objectives Project, the National Curriculum Database Project, the Information Technology and Medical Education Project, a professional development program for chief information officers, the AAMC ACCESS Data Collection and Dissemination System, and the internal Staff Interest Group on Medical Informatics and Medical Education.

Transformation of medical students' education: work in progress and continuing challenges.

In his book Time to Heal: American Medical Education from the Turn of the Century to the Era of Managed Care, Ludmerer expresses concern about the erosion of the environment in which medical students and residents learn the clinical skills, attitudes, and behaviors that they will need to practice high-quality medicine. Importantly, while he attributes the erosion of the clinical environment largely to the impact of managed care, he also places some responsibility within academic medicine itself, primarily the redirection of the clinical faculty's efforts away from traditional academic pursuits to the generation of clinical revenues. The Association of American Medical Colleges has information about the kinds of changes already occurring. In the preclinical curriculum, schools have introduced a wide range of new courses and topics, and there is more attention on professionalism and values. Schools are making fundamental changes in the design and conduct of the curriculum, primarily by adopting more integrated (non-departmental) approaches to course design and management. The clinical curriculum is changing primarily through the greatly expanded use of ambulatory care sites, and medical schools are developing new approaches to managing dispersed and varied instruction. Also, faculty are paying more attention to the role of residents as teachers and role models. These changes speak well for medical education. Nonetheless, substantial and sustained work remains to be done despite the present uncertainty about the future of academic medical centers. This work is essential--a challenge that the leaders of academic medicine must not fail.

Computer databases of medical school curricula.

As the pace of curriculum reform in medical education has accelerated during the past decade, so too have demands on curriculum managers to supply increasingly detailed information about the curriculum. In response, a number of schools have joined together to begin work on designs for computer databases of the curriculum. The authors describe three of the most mature curriculum database prototypes, developed by groups at the medical schools of the University of North Carolina at Chapel Hill (UNC), The University of Maryland, and the University of Miami. All three groups have employed relational database management systems to organize information about each "instructional unit" in the preclinical curriculum, including a set of keywords defining the major concepts presented. The keywords are indexed to a controlled vocabulary, either the Medical Subject Headings (MeSH) or a MeSH derivative. The UNC database also employs a textfile management system to provide users with an overview of the entire curriculum. Future work will focus on identifying a suitable controlled vocabulary; capturing content in greater contextual detail; incorporating alternative learning formats, such as problem-based learning; creating links between content items and examination questions; and capturing information generated by student-patient interactions in clinical settings. As a result of recent collaboration with the Association of American Medical Colleges, work to define a prototype national database has begun and a consortium of interested schools is addressing further development activities.

The value of preliminary traction in the treatment of congenital dislocation of the hip.

In forty-one children who had forty-seven congenitally dislocated hips, the results of attempted closed reduction with general anesthesia, but without preliminary traction, were studied. Twenty (43 per cent) of the hips could not be reduced closed, and an open reduction was needed. After the reduction, all of the involved hips were immobilized in the so-called human position (marked flexion and slight abduction). At a minimum follow-up of two years, osteonecrosis of the femoral head had developed in only two hips (4 per cent). Patients who were more than one year old when the hip was reduced had a higher incidence of osteonecrosis of the femoral head and were more likely to need reconstructive procedures later. Patients who were more than eighteen months old at the time of the attempted closed reduction were more likely to need an open reduction of the hip. Treatment of congenital dislocation of the hip in young children remains an extremely complex problem. It has not been clearly established that the use of preliminary traction decreases the incidence of osteonecrosis of the femoral head or improves the outcome of treatment. In our experience, uncomplicated (non-teratological, postnatal) congenital dislocation of the hip has been safely treated with either open or closed reduction without preliminary traction in patients who were younger than two years old, provided that the reduction could be obtained without excessive force.

Effects of acute and chronic exposure to cobalt on male reproduction in mice.

Chronic exposure of male mice to cobaltous chloride dramatically affected their reproductive potential, while acute administration had minimal effects. Acute exposure, followed by evaluation weekly over a 7-week period, revealed no significant changes in epididymal sperm concentration or testicular weight. However, small but significant decreases in fertility at weeks 2 and 3 of the study were observed. Sperm motility was depressed only during the first week of the study. In chronic studies, cobalt affected fertility in a time- and dose-dependent manner. There was a decrease in testicular weight, epididymal sperm concentration, and fertility. Sperm motility was also depressed. Serum testosterone levels were dramatically increased in cobalt treated animals, while FSH and LH serum levels were normal. It appears that cobalt is directly or indirectly interfering with spermatogenesis and with local regulatory mechanisms in testosterone synthesis.