bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Capital and Productivity in a Team Environment: Evidence from the Healthcare Sector
Authors: Bartel Ann P. , Beaulieu Nancy D. , Phibbs Ciaran S. , Stone Patricia W.
Published: April 2014

Using panel data from a large hospital system, this paper presents estimates of the productivity effects of human capital in a team production environment. Proxying nurses' general human capital by education and their unit-specific human capital by experience on the nursing unit, we find that greater amounts of both types of human capital significantly improve patient outcomes. Disruptions to team functioning attributable to the departure of experienced nurses, the absorption of new hires, and the inclusion of temporary contract nurses are associated with significant decreases in productivity beyond those attributable to changes in nurses' skill and experience. (JEL I11, J22, J24, M12, M54)
The Global Economics of Water: Is Water a Source of Comparative Advantage?
Authors: Debaere Peter
Published: April 2014

With newly available data, I investigate to what extent countries' international trade exploits the very uneven water resources on a global scale. I find that water is a source of comparative advantage and that relatively water abundant countries export more water-intensive products. Additionally, water contributes significantly less to the pattern of exports than the traditional production factors labor and physical capital. This suggests relatively moderate disruptions to overall trade on a global scale due to changing precipitation in the wake of climate change. (JEL F14, O13, O19, Q15, Q25, Q54)
Book Reviews
Authors: Rand Graham K.
Published: April 2014

In Book Reviews, we review an extensive and diverse range of books. They cover theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems. In addition, we include books in other fields that emphasize technical applications. The editor will be pleased to receive an e-mail from those willing to review a book, with an indication of specific areas of interest. If you are aware of a specific book that you would like to review, or that you think should be reviewed, please contact the editor.

The following books are reviewed in this issue of Interfaces, 44(2), March–April 2014: Efficiency and Logistics, Uwe Clausen, Michael Ten Hompel, and Matthias Klumpp; Managing Safety of Heterogeneous Systems: Decisions Under Uncertainties and Risks, Yuri Emoliev, Marek Makowski, and Kurt Marti; Principles of Business Forecasting, Keith Ord and Robert Fildes; Supply Chain Planning: Practical Frameworks for Superior Performance, Matthew J. Liberatore and Tan Miller; Multicriteria Portfolio Management, Panos Xidonas, George Mavrotas, Theodore Krintas, John Psarras, and Constantin Zopounidis; Handbook of Networks in Power Systems I (Energy), Handbook of Networks in Power Systems II (Energy), Alexey Sorokin, Steffen Rebennack, Panos M. Pardalos, Niko A. Iliadis, and Mario V. F. Pereira, eds.; and Antifragile: Things that Gain from Disorder, Nassim Nicholas Talib.
A Review of Primary Mine Ventilation System Optimization
Authors: Acuña Enrique I. , Lowndes Ian S.
Published: April 2014

Within the mining industry, a safe and economical mine ventilation system is an essential component of all underground mines. In recent years, research scientists and engineers have explored operations research methods to assist in the design and safe operation of primary mine ventilation systems. The main objective of these studies is to develop algorithms to identify the primary mine ventilation systems that minimize the fan power costs, including their working performance. The principal task is to identify the number, location, and duty of fans and regulators for installation within a defined ventilation network to distribute the required fresh airflow at minimum cost. The successful implementation of these methods may produce a computational design tool to aid mine planning and ventilation engineers. This paper presents a review of the results of a series of recent research studies that have explored the use of mathematical methods to determine the optimum design of primary mine ventilation systems relative to fan power costs.
Dynamic Targeted Pricing in B2B Relationships
Authors: Zhang Jonathan Z. , Netzer Oded , Ansari Asim
Published: April 2014

We model the multifaceted impact of pricing decisions in business-to-business (B2B) relationships that are governed by trust. We show how a seller can develop optimal intertemporal targeted pricing strategies to maximize profits over time while taking into consideration the impact of pricing decisions on short-term profit margin, reference price formation, and long-term relationships. Our modeling framework uses a hierarchical Bayesian approach to weave together a multivariate nonhomogeneous hidden Markov model, buyer heterogeneity, and control functions to facilitate targeting, capture the evolution of trust, and control for price endogeneity. We estimate our model on longitudinal transactions data from a retailer in the industrial consumables domain. We find that buyers in our data set can be best represented by two latent states of trust toward the seller—a “vigilant” state that is characterized by heightened price sensitivity and a cautious approach to ordering and a “relaxed” state with purchase behaviors that are consistent with high relational trust. The seller's pricing decisions can transition buyers between these two states. An optimal dynamic and targeted pricing strategy based on our model suggests a 52% improvement in profitability compared with the status quo. Furthermore, a counterfactual analysis examines the seller's optimal pricing policy under fluctuating commodity prices.
Analysis of Kinematic Waves Arising in Diverging Traffic Flow Models
Authors: Jin Wen-Long
Published: April 2014

Diverging junctions are important network bottlenecks, and a better understanding of diverging traffic dynamics has both theoretical and practical implications. In this paper, we present a new framework for constructing kinematic wave solutions to the Riemann problem of kinematic wave models of diverging traffic with jump initial conditions. Within this framework, the function space of weak solutions is enlarged to include interior states that occur with stationary discontinuities, and various discrete flux functions in cell transmission models of diverging traffic are used as entropy conditions to pick out unique physical solutions. Then in demand-supply space, we prove that the Riemann problem can be uniquely solved for existing discrete flux functions, in the sense that stationary states and, therefore, shock or rarefaction waves on all links, can be uniquely determined under given initial conditions. We show that the two diverge models by Lebacque and Daganzo are asymptotically equivalent. We also prove that the supply proportional and priority-based diverge models are locally optimal evacuation strategies. With numerical examples, we demonstrate the validity of the analytical solutions of interior states, stationary states, and corresponding kinematic waves. This study presents a unified framework for analyzing traffic dynamics arising at diverging junctions and could be helpful for developing emergency evacuation strategies.
Outcome, revision rate and indication for revision following resurfacing hemiarthroplasty for osteoarthritis of the shoulder
Authors: Rasmussen J. V. , Polk A. , Sorensen A. K. , Olsen B. S. , Brorson S.
Published: April 2014

In this study, we evaluated patient-reported outcomes, the rate of revision and the indications for revision following resurfacing hemiarthroplasty of the shoulder in patients with osteoarthritis.

All patients with osteoarthritis who underwent primary resurfacing hemiarthroplasty and reported to the Danish Shoulder Arthroplasty Registry (DSR), between January 2006 and December 2010 were included. There were 772 patients (837 arthroplasties) in the study. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index was used to evaluate patient-reported outcome 12 months (10 to 14) post-operatively. The rates of revision were calculated from the revisions reported to the DSR up to December 2011 and by checking deaths with the Danish National Register of Persons.

A complete questionnaire was returned by 688 patients (82.2%). The mean WOOS was 67 (0 to 100). A total of 63 hemiarthroplasties (7.5%) required revision; the cumulative five-year rate of revision was 9.9%. Patients aged < 55 years had a statistically significant inferior WOOS score, which exceeded the minimal clinically important difference, compared with older patients (mean difference 14.2 (8.8; 95% CI 19.6; p < 0.001), but with no increased risk of revision. There was no significant difference in the mean WOOS or the risk of revision between designs of resurfacing hemiarthroplasty.

Cite this article: Bone Joint J 2014;96-B:519–25.
A prospective, randomised trial comparing the use of absorbable and metallic screws in the fixation of distal tibiofibular syndesmosis injuries
Authors: Sun H. , Luo C. F. , Zhong B. , Shi H. P. , Zhang C. Q. , Zeng B. F.
Published: April 2014

Our aim was to compare polylevolactic acid screws with titanium screws when used for fixation of the distal tibiofibular syndesmosis at mid-term follow-up. A total of 168 patients, with a mean age of 38.5 years (18 to 72) who were randomly allocated to receive either polylevolactic acid (n = 86) or metallic (n = 82) screws were included. The Baird scoring system was used to assess the overall satisfaction and functional recovery post-operatively. The demographic details and characteristics of the injury were similar in the two groups. The mean follow-up was 55.8 months (48 to 66). The Baird scores were similar in the two groups at the final follow-up. Patients in the polylevolactic acid group had a greater mean dorsiflexion (p = 0.011) and plantar-flexion of the injured ankles (p < 0.001). In the same group, 18 patients had a mild and eight patients had a moderate foreign body reaction. In the metallic groups eight had mild and none had a moderate foreign body reaction (p <  0.001). In total, three patients in the polylevolactic acid group and none in the metallic group had heterotopic ossification (p = 0.246).

We conclude that both screws provide adequate fixation and functional recovery, but polylevolactic acid screws are associated with a higher incidence of foreign body reactions.

Cite this article: Bone Joint J 2014;96-B:548–54.
The use of a syndesmosis procedure for the treatment of hallux valgus
Authors: Wong D. W. C. , Wu D. Y. , Man H. S. , Leung A. K. L.
Published: April 2014

Metatarsus primus varus deformity correction is one of the main objectives in hallux valgus surgery. A ‘syndesmosis’ procedure may be used to correct hallux valgus. An osteotomy is not involved. The aim is to realign the first metatarsal using soft tissues and a cerclage wire around the necks of the first and second metatarsals.

We have retrospectively assessed 27 patients (54 feet) using the American Orthopaedic Foot and Ankle Society (AOFAS) score, radiographs and measurements of the plantar pressures after bilateral syndesmosis procedures. There were 26 women. The mean age of the patients was 46 years (18 to 70) and the mean follow-up was 26.4 months (24 to 33.4). Matched-pair comparisons of the AOFAS scores, the radiological parameters and the plantar pressure measurements were conducted pre- and post-operatively, with the mean of the left and right feet. The mean AOFAS score improved from 62.8 to 94.4 points (p < 0.001). Significant differences were found on all radiological parameters (p < 0.001). The mean hallux valgus and first intermetatarsal angles were reduced from 33.2° (24.3° to 49.8°) to 19.1° (10.1° to 45.3°) (p < 0.001) and from 15.0° (10.2° to 18.6°) to 7.2° (4.2° to 11.4°) (p < 0.001) respectively. The mean medial sesamoid position changed from 6.3(4.5 to 7) to 3.6 (2 to 7) (p < 0.001) according to the Hardy’s scale (0 to 7). The mean maximum force and the force–time integral under the hallux region were significantly increased by 71.1% (p = 0.001), (20.57 (0.08 to 58.3) to 35.20 (6.63 to 67.48)) and 73.4% (p = 0.014), (4.44 (0.00 to 22.74) to 7.70 (1.28 to 19.23)) respectively. The occurrence of the maximum force under the hallux region was delayed by 11% (p = 0.02), (87.3% stance (36.3% to 100%) to 96.8% stance (93.0% to 100%)). The force data reflected the restoration of the function of the hallux. Three patients suffered a stress fracture of the neck of the second metatarsal. The short-term results of this surgical procedure for the treatment of hallux valgus are satisfactory.

Cite this article: Bone Joint J 2014;96-B:502–7.
The alpha angle in cam-type femoroacetabular impingement
Authors: Laborie L. B. , Lehmann T. G. , Engesæter I. Ø. , Sera F. , Engesæter L. B. , Rosendahl K.
Published: April 2014

We report on gender-specific reference intervals of the alpha angle and its association with other qualitative cam-type findings in femoroacetabular impingement at the hip, according to a population-based cohort of 2038 19-year-olds, 1186 of which were women (58%). The alpha angle was measured on standardised frog-leg lateral and anteroposterior (AP) views using digital measurement software, and qualitative cam-type findings were assessed subjectively on both views by independent observers. In all, 2005 participants (837 men, 1168 women, mean age 18.6 years (17.2 to 20.1) were included in the analysis. For the frog-leg view, the mean alpha angle (right hip) was 47° (26 to 79) in men and 42° (29 to 76) in women, with 97.5 percentiles of 68° and 56°, respectively. For the AP view, the mean values were 62° (40 to 105) and 52° (36 to 103) for men and women, respectively, with 97.5 percentiles of 93° and 94°. Associations between higher alpha angles and all qualitative cam-type findings were seen for both genders on both views. The reference intervals presented for the alpha angle in this cross-sectional study are wide, especially for the AP view, with higher mean values for men than women on both views.

Cite this article: Bone Joint J 2014;96-B:449–54.
Performance of the CLS Spotorno uncemented stem in the third decade after implantation
Authors: Evola F. R. , Evola G. , Graceffa A. , Sessa A. , Pavone V. , Costarella L. , Sessa G. , Avondo S.
Published: April 2014

In 2012 we reviewed a consecutive series of 92 uncemented THRs performed between 1986 and 1991 at our institution using the CLS Spotorno stem, in order to assess clinical outcome and radiographic data at a minimum of 21 years. The series comprised 92 patients with a mean age at surgery of 59.6 years (39 to 77) (M:F 43;49).

At the time of this review, seven (7.6%) patients had died and two (2.2%) were lost to follow-up. The 23-year Kaplan–Meier survival rates were 91.5% (95% confidence intervals (CI) 85.4% to 97.6%; 55 hips at risk) and 80.3% (95% CI, 71.8% to 88.7%; 48 hips at risk) respectively, with revision of the femoral stem or of any component as endpoints. At the time of this review, 76 patients without stem revision were assessed clinically and radiologically (mean follow-up 24.0 years (21.5 to 26.5)). For the 76 unrevised hips the mean Harris hip score was 87.1 (65 to 97). Femoral osteolysis was detected in five hips (6.6%) only in Gruen zone 7. Undersized stems were at higher risk of revision owing to aseptic loosening (p = 0.0003). Patients implanted with the stem in a varus position were at higher risk of femoral cortical hypertrophy and thigh pain (p = 0.0006 and p = 0.0007, respectively).

In our study, survival, clinical outcome and radiographic data remained excellent in the third decade after implantation. Nonetheless, undersized stems were at higher risk of revision owing to aseptic loosening.

Cite this article: Bone Joint J 2014;96-B:455–61.
The long-term outcome following the use of frozen autograft treated with liquid nitrogen in the management of bone and soft-tissue sarcomas
Authors: Igarashi K. , Yamamoto N. , Shirai T. , Hayashi K. , Nishida H. , Kimura H. , Takeuchi A. , Tsuchiya H.
Published: April 2014

In 1999, we developed a technique for biological reconstruction after excision of a bone tumour, which involved using autografts of the bone containing the tumour treated with liquid nitrogen. We have previously reported the use of this technique in 28 patients at a mean follow up of 27 months (10 to 54).

In this study, we included 72 patients who underwent reconstruction using this technique. A total of 33 patients died and three were lost to follow-up, at a mean of 23 months (2 to 56) post-operatively, leaving 36 patients available for a assessment at a mean of 101 months 16 to 163) post-operatively. The methods of reconstruction included an osteo-articular graft in 16, an intercalary in 13 and, a composite graft with prosthesis in seven.

Post-operative function was excellent in 26 patients (72.2%), good in seven (19.4%), and fair in three (8.3%) according to the functional evaluation system of Enneking. No recurrent tumour occurred within the grafts. The autografts survived in 29 patients (80.6%), and the rates of survival at five and ten years were 86.1% and 80.6 %, respectively. Seven of 16 osteo-articular grafts (44%) failed because of fracture or infection, but all the composite and intercalary grafts survived.

The long-term outcomes of frozen autografting, particularly using composite and intercalary grafts, are satisfactory and thus represent a good method of treatment for patients with a sarcoma of bone or soft tissue.

Cite this article: Bone Joint J 2014;96-B:555–61.
The fixation of a collagen type I/III membrane in the distal radioulnar joint of a human cadaver model
Authors: van Amerongen E. A. , Creemers L. B. , Kaoui N. , Bekkers J. E. J. , Kon M. , Schuurman A. H.
Published: April 2014

Damage to the cartilage of the distal radioulnar joint frequently leads to pain and limitation of movement, therefore repair of this joint cartilage would be highly desirable. The purpose of this study was to investigate the fixation of scaffold in cartilage defects of this joint as part of matrix-assisted regenerative autologous cartilage techniques. Two techniques of fixation of collagen scaffolds, one involving fibrin glue alone and one with fibrin glue and sutures, were compared in artificially created cartilage defects of the distal radioulnar joint in a human cadaver. After being subjected to continuous passive rotation, the methods of fixation were evaluated for cover of the defect and pull out force.

No statistically significant differences were found between the two techniques for either cover of the defect or integrity of the scaffold. However, a significantly increased mean pull out force was found for the combined procedure, 0.665 N (0.150 to 1.160) versus 0.242 N (0.060 to 0.730) for glue fixation (p = 0.001).

This suggests that although successful fixation of a collagen type I/III scaffold in a distal radioulnar joint cartilage defect is feasible with both forms of fixation, fixation with glue and sutures is preferable.

Cite this article: Bone Joint J 2014;96-B:508–12.
Is the length of the femoral component important in primary total hip replacement?
Authors: Feyen H. , Shimmin A. J.
Published: April 2014

Many different lengths of stem are available for use in primary total hip replacement, and the morphology of the proximal femur varies greatly. The more recently developed shortened stems provide a distribution of stress which closely mimics that of the native femur. Shortening the femoral component potentially comes at the cost of decreased initial stability. Clinical studies on the performance of shortened cemented and cementless stems are promising, although long-term follow-up studies are lacking. We provide an overview of the current literature on the anatomical features of the proximal femur and the biomechanical aspects and clinical outcomes associated with the length of the femoral component in primary hip replacement, and suggest a classification system for the length of femoral stems.

Cite this article: Bone Joint J 2014;96-B:442-8.
The risk of venous thromboembolism, myocardial infarction, stroke, major bleeding and death in patients undergoing total hip and knee replacement
Authors: Pedersen A. B. , Mehnert F. , Sorensen H. T. , Emmeluth C. , Overgaard S. , Johnsen S. P.
Published: April 2014

We examined the risk of thrombotic and major bleeding events in patients undergoing total hip and knee replacement (THR and TKR) treated with thromboprophylaxis, using nationwide population-based databases. We identified 83 756 primary procedures performed between 1997 and 2011. The outcomes were symptomatic venous thromboembolism (VTE), myocardial infarction (MI), stroke, death and major bleeding requiring hospitalisation within 90 days of surgery.

A total of 1114 (1.3%) and 483 (0.6%) patients experienced VTE and bleeding, respectively. The annual risk of VTE varied between 0.9% and 1.6%, and of bleeding between 0.4% and 0.8%. The risk of VTE and bleeding was unchanged over a 15-year period. A total of 0.7% of patients died within 90 days, with a decrease from 1% in 1997 to 0.6% in 2011 (p < 0.001). A high level of comorbidity and general anaesthesia were strong risk factors for both VTE and bleeding, with no difference between THR and TKR patients. The risk of both MI and stroke was 0.5%, which remained unchanged during the study period.

In this cohort study of patients undergoing THR and TKR patients in routine clinical practice, approximately 3% experienced VTE, MI, stroke or bleeding. These risks did not decline during the 15-year study period, but the risk of dying fell substantially.

Cite this article: Bone Joint J 2014;96-B:479–85.
Short segment pedicle screw instrumentation with an index level screw and cantilevered hyperlordotic reduction in the treatment of type-A fractures of the thoracolumbar spine
Authors: Kose K. C. , Inanmaz M. E. , Isik C. , Basar H. , Caliskan I. , Bal E.
Published: April 2014

The purpose of this study was to evaluate and compare the effect of short segment pedicle screw instrumentation and an intermediate screw (SSPI+IS) on the radiological outcome of type A thoracolumbar fractures, as judged by the load-sharing classification, percentage canal area reduction and remodelling.

We retrospectively evaluated 39 patients who had undergone hyperlordotic SSPI+IS for an AO-Magerl Type-A thoracolumbar fracture. Their mean age was 35.1 (16 to 60) and the mean follow-up was 22.9 months (12 to 36). There were 26 men and 13 women in the study group. In total, 18 patients had a load-sharing classification score of seven and 21 a score of six. All radiographs and CT scans were evaluated for sagittal index, anterior body height compression (%ABC), spinal canal area and encroachment. There were no significant differences between the low and high score groups with respect to age, duration of follow-up, pre-operative sagittal index or pre-operative anterior body height compression (p = 0.217, 0.104, 0.104, and 0.109 respectively). The mean pre-operative sagittal index was 19.6° (12° to 28°) which was corrected to -1.8° (-5° to 3°) post-operatively and 2.4° (0° to 8°) at final follow-up (p = 0.835 for sagittal deformity). No patient needed revision for loss of correction or failure of instrumentation.

Hyperlordotic reduction and short segment pedicle screw instrumentation and an intermediate screw is a safe and effective method of treating burst fractures of the thoracolumbar spine. It gives excellent radiological results with a very low rate of failure regardless of whether the fractures have a high or low load-sharing classification score.

Cite this article: Bone Joint J 2014;96-B:541–7.
Exam Corner – April 2014
Authors: Khanduja V.
Published: April 2014

The FRCS (Tr & Orth) examination has three components: MCQs, Vivas and Clinical Examination. The Vivas are further divided into four sections comprising Basic Science, Adult Pathology, Hands and Children’s Orthopaedics and Trauma. The Clinical Examination section is divided into Upper and Lower limb cases. The aim of this section in the Journal is to focus specifically on the trainees preparing for the exam and to cater to all the sections of the exam. The vision is to complete the cycle of all relevant exam topics (as per the syllabus) in four years.
Chemical composition and antibacterial activity of Thymus zygis subsp. gracilis (Boiss.) R. Morales essential oils from Morocco
Authors: Yakoubi Souad , Cherrat Ali , Diouri Mohamed , EL Hilali Fatima , Zair Touriya
Published: April 2014

Thymus zygis subsp. gracilis samples were collected from different Moroccan Middle Atlas sites at three phenological stages. Chemical composition of essential oils obtained from these samples was studied and their antimicrobial activity was evaluated. GC-MS analysis of essential oils shows quantitative and qualitative changes in the chemical profile. Twenty-three components were detected. These compounds fall under at least four chemical families whose relative importance varies with the sites and the phenological stages. Monoterpens were the most abundant and their percentage in essential oils varied from 61.38 to 94.91. Carvacrol (16.07 to 74.33%), thymol (1.47 to 32.46%), p-cymene (6.97 to 40.26%) and Î³-terpinene (2.68 to 22%) were the main constituents. Bactericidal property of Thymus zygis essential oils was also evaluated in vitro against six strains of phytopathogenic bacteria. All bacterial strains tested were susceptible to essential oils. Maximum activity was observed against the Gram-negative bacterium Erwinia amylovora and Gram-positive actinomycete Streptomyces scabiei. The most bactericidal effect was observed against Streptomyces scabei. Its minimum bactericidal concentration (MBC) was 50 Î¼g.mL-1 . At post-flowering stage, carvacrol chemical profile was the most efficient.
ST-Elevation Myocardial Infarction and Myelodysplastic Syndrome with Acute Myeloid Leukemia Transformation
Authors: Jao Geoffrey T. , Knovich Mary Ann , Savage Rodney W. , Sane David C.
Published: April 2014

Acute myocardial infarction and acute myeloid leukemia are rarely reported as concomitant conditions. The management of ST-elevation myocardial infarction (STEMI) in patients who have acute myeloid leukemia is challenging: the leukemia-related thrombocytopenia, platelet dysfunction, and systemic coagulopathy increase the risk of bleeding, and the administration of thrombolytic agents can be fatal. We report the case of a 76-year-old man who presented emergently with STEMI, myelodysplastic syndrome, and newly recognized acute myeloid leukemia transformation. Standard antiplatelet and anticoagulation therapy were contraindicated by the patient's thrombocytopenia and by his reported ecchymosis and gingival bleeding upon admission. He declined cardiac catheterization, was provided palliative care, and died 2 hours after hospital admission.

We searched the English-language medical literature, found 8 relevant reports, and determined that the prognosis for patients with concomitant STEMI and acute myeloid leukemia is clearly worse than that for either individual condition. No guidelines exist to direct the management of STEMI and concomitant acute myeloid leukemia. In 2 reports, dual antiplatelet therapy, anticoagulation, and drug-eluting stent implantation were used without an increased risk of bleeding in the short term, even in the presence of thrombocytopenia. However, we think that a more conservative approach—balloon angioplasty with the provisional use of bare-metal stents—might be safer. Simultaneous chemotherapy for the acute myeloid leukemia is crucial. Older age seems to be a major risk factor: patients too frail for emergent treatment can die within hours or days.
Use of a Sandwich Technique to Repair a Left Ventricular Rupture after Mitral Valve Replacement
Authors: Lee Myles E. , Tamboli Mallika , Lee Anthony W.
Published: April 2014

One difficulty with external repair of left ventricular rupture after mitral valve replacement is collateral bleeding in friable myocardium adjacent to the rupture. The bleeding is caused by tension on the closing sutures, whether or not pledgets have been used.

We report the case of a 69-year-old woman who underwent an uneventful mitral valve replacement. After cardiopulmonary bypass was terminated, brisk bleeding started from high in the posterior left ventricular wall, typical of a type III defect. We undertook external repair, placing a plug of Teflon felt into the cavity of the rupture and sandwiching it into place with pledgeted mattress and figure-of-8 sutures. The space occupied by the plug decreased the distance needed to obliterate the defect and thereby reduced the tension on the sutures necessary to achieve hemostasis. This simple technique enabled closure of the defect and avoided collateral tears that would have compromised an otherwise successful repair. Two years postoperatively, the patient had normal mitral valve function and no left ventricular aneurysm. In addition to reporting the patient's case, we review the types of left ventricular rupture that can occur during mitral valve replacement and discuss the various repair options.
Right Ventricular Sarcoidosis: Is It Time for Updated Diagnostic Criteria?
Authors: Vakil Kairav , Minami Elina , Fishbein Daniel P.
Published: April 2014

A 55-year-old woman with a history of complete heart block, atrial flutter, and progressive right ventricular failure was referred to our tertiary care center to be evaluated for cardiac transplantation. The patient's clinical course included worsening right ventricular dysfunction for 3 years before the current evaluation. Our clinical findings raised concerns about arrhythmogenic right ventricular cardiomyopathy. Noninvasive imaging, including a positron emission tomographic scan, did not reveal obvious myocardial pathologic conditions. Given the end-stage nature of the patient's right ventricular failure and her dependence on inotropic agents, she underwent urgent listing and subsequent heart transplantation. Pathologic examination of the explanted heart revealed isolated right ventricular sarcoidosis with replacement fibrosis. Biopsy samples of the cardiac allograft 6 months after transplantation showed no recurrence of sarcoidosis. This atypical presentation of isolated cardiac sarcoidosis posed a considerable diagnostic challenge. In addition to discussing the patient's case, we review the relevant medical literature and discuss the need for updated differential diagnostic criteria for end-stage right ventricular failure that mimics arrhythmogenic right ventricular cardiomyopathy.
Two Cases of Apical Ballooning Syndrome Masking Apical Hypertrophic Cardiomyopathy
Authors: Roy Ranjini Raina , Hakim Fayaz A. , Hurst R. Todd , Simper David , Appleton Christopher P.
Published: April 2014

Apical akinesis and dilation in the absence of obstructive coronary artery disease is a typical feature of stress-induced (takotsubo) cardiomyopathy, whereas apical hypertrophy is seen in apical-variant hypertrophic cardiomyopathy. We report the cases of 2 patients who presented with takotsubo cardiomyopathy and were subsequently found to have apical-variant hypertrophic cardiomyopathy, after the apical ballooning from the takotsubo cardiomyopathy had resolved. The first patient, a 43-year-old woman with a history of alcohol abuse, presented with shortness of breath, electrocardiographic and echocardiographic features consistent with takotsubo cardiomyopathy, and no significant coronary artery disease. An echocardiogram 2 weeks later revealed a normal left ventricular ejection fraction and newly apparent apical hypertrophy. The 2nd patient, a 70-year-old woman with pancreatitis, presented with chest pain, apical akinesis, and a left ventricular ejection fraction of 0.39, consistent with takotsubo cardiomyopathy. One month later, her left ventricular ejection fraction was normal; however, hypertrophy of the left ventricular apex was newly noted. To our knowledge, these are the first reported cases in which apical-variant hypertrophic cardiomyopathy was masked by apical ballooning from stress-induced cardiomyopathy.
A Case of Survival after Cardiac Arrest and 3½ Hours of Resuscitation
Authors: Nusbaum Derek M. , Bassett Scott T. , Gregoric Igor D. , Kar Biswajit
Published: April 2014

Although survival rates after cardiac arrest remain low, new techniques are improving patients' outcomes. We present the case of a 40-year-old man who survived a cardiac arrest that lasted approximately 3½ hours. Resuscitation was performed with strict adherence to American Heart Association/American College of Cardiology Advanced Cardiac Life Support guidelines until bedside extracorporeal membrane oxygenation could be placed. A hypothermia protocol was initiated immediately afterwards. The patient had a full neurologic recovery and was bridged from dual ventricular assist devices to a total artificial heart. On hospital day 160, he underwent orthotopic heart and cadaveric kidney transplantation. On day 179, he was discharged from the hospital in ambulatory condition.

To our knowledge, this is the only reported case in which a patient survived with good neurologic outcomes after a resuscitation that lasted as long as 3½ hours. Documented cases of resuscitation with good recovery after prolonged arrest give hope for improved overall outcomes in the future.
Perioperative Outcomes after On- and Off-Pump Coronary Artery Bypass Grafting
Authors: Bakaeen Faisal G. , Chu Danny , Kelly Rosemary F. , Holman William L. , Jessen Michael E. , Ward Herbert B.
Published: April 2014

Although numerous reports describe the results of off-pump coronary artery bypass grafting (CABG) at specialized centers and in select patient populations, it remains unclear how off-pump CABG affects real-world patient outcomes. We conducted a large, multicenter observational cohort study of perioperative death and morbidity in on-pump (ON) versus off-pump (OFF) CABG.

We reviewed Veterans Affairs Surgical Quality Improvement Program data for all patients (N=65,097) who underwent isolated CABG from October 1997 through April 2011 (intention-to-treat data were available from 2005 onward). The primary outcome was perioperative (30-day or in-hospital) death; the secondary outcomes were perioperative stroke, dialysis dependence, reoperation for bleeding, mechanical circulatory support, myocardial infarction, ventilator support ≥48 hr, and mediastinitis. Propensity scores calculated from age, 17 preoperative risk factors, and year of surgery were used to match 8,911 OFF with 26,733 ON patients.

In the complete cohort, compared with the ON patients (n=53,468), the OFF patients (n=11,629) had less perioperative death (2.02% vs 2.53%, P=0.0012) and lower incidences of all morbidities except perioperative myocardial infarction. In the matched cohort, perioperative death did not differ significantly between OFF and ON patients (1.94% vs 2.28%, P=0.06), but the OFF group had lower incidences of all morbidities except for perioperative myocardial infarction and mediastinitis. A subgroup intention-to-treat analysis yielded similar but smaller outcome differences between the ON and OFF groups.

Off-pump CABG might be associated with decreased operative morbidity but did not affect operative death, compared with on-pump CABG. Future studies should examine the effect of off-pump CABG on long-term outcomes.
Peripheral structures of relatively hyperbolic groups
Authors: Yang Wen-yuan
Published: April 2014

In this paper, we introduce and characterize a class of
parabolically extended structures for relatively hyperbolic groups. A characterization of relative quasiconvexity with respect to
parabolically extended structures is obtained. The connection
between the existence of a minimal relatively hyperbolic structure
on a given group and the action on its Floyd boundary is examined. It is shown that Dunwoody's inaccessible group that has no minimal
relatively hyperbolic structure turns out to be acting
non-geometrically finitely on its Floyd boundary.
Weakly-exceptional singularities in higher dimensions
Authors: Cheltsov Ivan , Shramov Constantin
Published: April 2014

We show that infinitely many Gorenstein weakly-exceptional quotient
singularities exist in all dimensions, we prove
a weak-exceptionality criterion for five-dimensional quotient
singularities, and we find a sufficient condition for being
weakly-exceptional for six-dimensional quotient singularities. The
proof is naturally linked to various classical geometrical
constructions related to subvarieties of small degree in
projective spaces, in particular Bordiga surfaces and Bordiga
threefolds.
Synthesis of new 2- and 3-hydroxyquinoline-4-carboxylic acid derivatives as potential antioxidants
Authors: Massoud Mohammed A. , El Bialy Serry A. , Bayoumi Waleed A. , El Husseiny Walaa M.
Published: April 2014

A new series of 3-aryl-2-hydroxyquinoline-4-carboxylic acids 17a,b, 2-aryl-3-hydroxyquinoline-4-carboxylic acids 12a–d and their derivatives 13–16 and 18–21 were designed, synthesized and evaluated for their antioxidant activity using the ABTS assay method. Compounds 14 and 21a,b showed good antioxidant activity, whereas the remaining compounds displayed mild to moderate activity. All compounds were characterized by physical and spectral data.
Synthesis and molecular docking of indole and carbazole derivatives with potential pharmacological activity
Authors: Kaczor Agnieszka A. , Pihlaja Kalevi , Sinkkonen Jari , Wiinamäki Kirsti , Kronbach Christiane , Unverferth Klaus , Wróbel Tomasz , Stachal Tomasz , Matosiuk Dariusz
Published: April 2014

Indole and carbazole derivatives were designed as non-competitive antagonists of the GluK2 receptor. The synthesized compounds were found to interact with the transduction domain of the receptor. The binding pocket is situated within one receptor subunit.
Exponentially Stagnation Point Flow of Non-Newtonian Nanofluid over an Exponentially Stretching Surface
Authors: Nadeem S. , Sadiq M. A. , Choi Jung-il , Lee Changhoon
Published: April 2014

The steady stagnation point flow of Jeffrey nanofluid over an exponential stretching surface under the boundary layer assumptions is discussed analytically. The transport equations include the effects of Brownian motion and thermophoresis. The boundary layer coupled partial differential equations of Jeffrey nanofluid are simplified with the help of suitable semi-similar transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions have been discussed by plotting h-curve. The expressions for velocity, temperature and nano particle volume fraction are computed for some values of the parameters namely, Jeffrey relaxation and retardation parameters B and λ
1, stretching/ shrinking parameter A, suction injection parameter vw
, Lewis number Le, the Brownian motion Nb, thermophoresis parameter Nt and Prandtl number Pr.
Open problems in Petri net modeling and simulation of biological
systems
Authors: Chen Ming , Hofestädt Ralf
Published: April 2014

Petri net methodology has been widely used for modeling and
simulation of biological systems due to its intuitive graphical
representation and mathematical power for concurrent systems. In this
article, some of the major problems arising in this field are addressed,
ongoing progresses are discussed, and possible solutions are suggested.
Convergence of posteriors for structurally non-identified problems using results from the theory of inverse problems
Authors: Radde Nicole E. , Offtermatt Jonas
Published: April 2014

We consider convergence of the posterior distribution in a Bayesian parameter estimation framework in the large sample size limit for structurally non-identified problems. These belong to the class of ill-posed problems, and the large sample theory is not applicable here. In particular, the influence of the prior distribution does not vanish in the large sample size limit. We review recent results in this area and present ideas inspired from the theory of ill-posed inverse problems that can be used towards a more general concept of posterior convergence for non-identified problems.
Geometric measures of finite carbon nanotube molecules: a proposal for length index and filling indexes
Authors: Matsuno Taisuke , Naito Hisashi , Hitosugi Shunpei , Sato Sota , Kotani Motoko , Isobe Hiroyuki
Published: April 2014

The structural chemistry of carbon nanotube molecules has been of increasing interest, as molecular entities with fundamental structures of finite nanotube molecules have emerged. For the new field to be developed further, appropriate structural descriptors are necessary as the basis for discussion. In this paper, we propose new geometric descriptors for finite nanotube molecules. Based on popular existing descriptors, these new descriptors provide geometric measures for length and bond- and atom-filling in tubular molecular structures.
Simulation und Auswahl von psychometrischen Verfahren zur Ermittlung von Kennwerten menschlicher Wahrnehmung
Authors: Hatzfeld Christian , Werthschützky Roland
Published: April 2014

Zur Bestimmung von Wahrnehmungskennwerten des Menschen werden psychometrische Verfahren verwendet. Diese werden wiederum in einer Vielzahl von Anwendungen zur Optimierung und Anpassung von Systemen zur Mensch-Technik-Interaktion benötigt. Zur Auswahl eines geeigneten Verfahrens werden in diesem Beitrag unterschiedliche psychometrische Verfahren, ein Rahmenwerk für die Simulation solcher Messverfahren und mögliche objektive Bewertungskriterien vorgestellt. Die Leistungsfähigkeit der Simulation wird an Beispielen zum Methodenvergleich und dem Einfluss einzelner Konfigurationsparameter gezeigt.
Modellbasierte deflektometrische Messung von transparenten Objekten
Authors: Fischer Marc , Petz Marcus , Tutsch Rainer
Published: April 2014

Für die Messung der Geometrie transparenter Objekte stehen eine Reihe
etablierter optischer Messverfahren zur Verfügung. Bei diesen Verfahren
werden im Allgemeinen die Vorder- und die Rückfläche eines
Prüflings getrennt in Reflexion gemessen. Dieses Vorgehen birgt einige
Nachteile, insbesondere geht der geometrische Zusammenhang zwischen den
Flächen zunächst verloren und muss durch aufwendige Kalibrierung der
Systemgeometrie oder durch zusätzliche Messungen, z. B. mit einem
Koordinatenmessgerät, wieder hergestellt werden. Als Alternative dazu
wird im Rahmen der vorliegenden Arbeit eine deflektometrische Messung der
Lichtstrahlverläufe durch den Prüfling in Transmission mit einer
anschließenden modellbasierten Rekonstruktion der Prüflingsgeometrie
vorgeschlagen. Es werden unterschiedliche Rekonstruktionsansätze
vorgestellt und diskutiert und die Leistungsfähigkeit des Verfahrens
wird anhand einer Beispielmessung eines asphärischen Brillenglasrohlings
demonstriert.
Bile Salts Aggregation Behavior at Various Temperatures under the Influence of Amphiphilic Drug Imipramine Hydrochloride in Aqueous Medium
Authors: Rub Malik Abdul , Sheikh Mohmad Shafi , Khan Farah , Khan Sher Bahadar , Asiri Abdullah M.
Published: April 2014

The aim of this investigation is the characterization of interaction
of different bile salts – sodium cholate (NaC), sodium deoxycholate
(NaDC) and sodium taurocholate (NaTC) with amphiphilic drug imipramine
hydrochloride (IMP) because the bioavailability of lipophilic drugs
following oral administration strongly depends on the presence of food
components. These bile salts improve the bioavailability of poorly
absorbable drugs by lowering the surface tension of the
gastrointestinal fluid or by solubilization. The interactions in the
binary systems (drug and bile salts) were studied by determining
various physicochemical parameters like critical micelle concentration
(cmc), ideal cmc (cmcid
),
counterion dissociation (g), standard Gibbs free energy (ΔG
m
0), enthalpy (ΔH
m
0), and
entropy of micellization (ΔS
m
0), micellar
mole fractions of bile salt (X
1
Rub, X
1
M,
X
1
Rod), micellar mole fraction of bile salt in ideal
state (X
1
id), interaction parameter (β),
activity coefficients (f
1, f
2), and excess free energy of
mixing (ΔG
ex) of the mixed micelles using
Clint's, Rubingh's, Motomura's and Rodenas's theories for mixed
micellar systems. All the results point out synergism and attractive
interactions in the mixed systems of drug and bile salts. NaDC is more
effective in reducing the cmc of drug IMP as compared to NaC
and NaTC because it binds strongly to the positively charged drug ions
and reduces the head group area more in comparison to other. This
study will give insight into the selection of drugs in different
applications as their properties get modified by interaction with bile
salts, thus influencing their solution behavior which, in turn,
modifying the phase-forming behavior, microemulsion, clouding
phenomenon, besides solubilization. The modification of solubilization
ability in a medium can be exploited for the purpose of selective
encapsulation and release.
Adverse prenatal environment and kidney development: implications for programing of adult disease
Authors: Dorey Emily S , Pantaleon Marie , Weir Kristy A , Moritz Karen M
Published: April 2014

The ‘developmental origins of health and disease’ hypothesis suggests that many adult-onset diseases can be attributed to altered growth and development during early life. Perturbations during gestation can be detrimental and lead to an increased risk of developing renal, cardiovascular, metabolic, and neurocognitive dysfunction in adulthood. The kidney has emerged as being especially vulnerable to insult at almost any stage of development resulting in a reduction in nephron endowment. In both humans and animal models, a reduction in nephron endowment is strongly associated with an increased risk of hypertension. The focus of this review is twofold: i) to determine the importance of specific periods during development on long-term programing and ii) to examine the effects of maternal perturbations on the developing kidney and how this may program adult-onset disease. Recent evidence has suggested that insults occurring around the time of conception also have the capacity to influence long-term health. Although epigenetic mechanisms are implicated in mediating these outcomes, it is unclear as to how these may impact on kidney development. This presents exciting new challenges and areas for research.
Effects of IL8 and immune cells on the regulation of luteal progesterone secretion
Authors: Talbott Heather , Delaney Abigail , Zhang Pan , Yu Yangsheng , Cushman Robert A , Cupp Andrea S , Hou Xiaoying , Davis John S
Published: April 2014

Recent studies have suggested that chemokines may mediate the luteolytic action of prostaglandin F2α (PGF). Our objective was to identify chemokines induced by PGFin vivoand to determine the effects of interleukin 8 (IL8) on specific luteal cell typesin vitro. Mid-cycle cows were injected with saline or PGF, ovaries were removed after 0.5–4 h, and expression of chemokine was analyzed by qPCR.In vitroexpression of IL8 was analyzed after PGF administration and with cell signaling inhibitors to determine the mechanism of PGF-induced chemokine expression. Purified neutrophils were analyzed for migration and activation in response to IL8 and PGF. Purified luteal cell types (steroidogenic, endothelial, and fibroblast cells) were used to identify which cells respond to chemokines. Neutrophils and peripheral blood mononuclear cells (PBMCs) were cocultured with steroidogenic cells to determine their effect on progesterone production.IL8,CXCL2,CCL2, andCCL8transcripts were rapidly increased following PGF treatmentin vivo. The stimulatory action of PGF onIL8mRNA expressionin vitrowas prevented by inhibition of p38 and JNK signaling. IL8, but not PGF, TNF, or TGFB1, stimulated neutrophil migration. IL8 had no apparent action in purified luteal steroidogenic, endothelial, or fibroblast cells, but stimulated ERK phosphorylation in neutrophils. In coculture experiments neither IL8 nor activated neutrophils altered basal or LH-stimulated luteal cell progesterone synthesis. In contrast, activated PBMCs inhibited LH-stimulated progesterone synthesis from cultured luteal cells. These data implicate a complex cascade of events during luteolysis, involving chemokine signaling, neutrophil recruitment, and immune cell action within the corpus luteum.