bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling air leakage in buildings caused by the cyclic variation of the atmospheric pressure
Authors: Patrascu Monica , Baracu Tudor , Badescu Viorel , Birsan Marius-Victor , Teodosiu Catalin , Degeratu Mircea , Avram Elena Rita , Udrea Mihnea , Calancea Lidia , Mesteru Calin
Published: January 2018

This article considers a new type of air infiltration through building envelopes caused by the barometric pressure variation. This process is independent from wind action or stack effect. A new building–atmosphere differential equation of air exchange is established. Based on the solution of the differential equation of air exchange, we propose the notion of pressure equilibration time [Formula: see text] that characterizes the dynamic response of the building. Furthermore, experimental climatic data were processed using Fourier analysis methods in order to build an identification model based on the regular harmonics of external pressure oscillation. The barometric pressure reconstructed in its parameterized form was introduced in the differential equation of air exchange as a term that models the dynamics of the external action.

The analytic solution of the differential equation of air exchange demonstrates that the indoor–outdoor pressure difference is insignificant at less than 10−3 Pa for any harmonic of the external pressure variation. At the same time, it is concluded that the airtightness of the envelope has little influence on the process, as the indoor–outdoor pressure equilibration is almost instantaneous in a continuous regime of variation.

The described mechanism of air infiltration explains the alternation of infiltration and exfiltration of air in buildings. For this, a mass balance of air exchange for the specific ranges of time is performed. We prove that the barometric pressure variation has an effect that accounts for 3.19% of the total quantity of air exchanged.

The advances provided by this paper constitute a useful instrument for further studies concerning the stack effect in thermal dynamic conditions.

Practical application: The paper proposes a novel methodology of determining the air exchange building–environment by considering a new component of infiltration and its cyclic variation: the barometric pressure. A new mechanism of natural air infiltration is determined and modeled and it should be added to the existing ones: wind action and stack effect. A complete methodology of analysis and extraction of the cyclic processes hidden in an envelope of stochastic variations is defined and applied with the support of signal processing techniques and spectral analysis. The refinement of the mathematical instrument was able to distinguish through a deterministic approach an influence of 3.19% of the new barometric component. Furthermore, with few adaptations, the methodology constructed in this study can be applied for investigation of the stack effect by considering the cyclic variation of the atmospheric temperature. Currently, the stack effect is analyzed only for average conditions of temperature, a simplistic approach that suggests a large potential for further improvement.
Petrological characteristics and the impact of mineral content on reservoir quality in coal-bearing strata of Linxing area, eastern margin of Ordos Basin, China
Authors: Liu Chuang , Zhong Jianhua , Wang Xi , Cao Mengchun , Wu Jianguang , Zhang Shouren , Wu Xiang , Sun Ningliang , Du Yan , Liu Yin
Published: January 2018

Tight sandstone gas is on the first position of unconventional natural gas sources, which can be developed under today’s technical conditions. In recent years, tight sandstone gas reservoirs have been found in several wells in the Linxing area, eastern margin of Ordos Basin, China. In this article, a variety of methods, including cast thin sections, X-ray diffraction analysis, scanning electron microscope, and drill core data were used to study the petrological characteristics and their influences on tight sandstone reservoir in coal-bearing strata of the Linxing area. Based on the analysis of thin section, it can be concluded that the sandstone reservoir is essentially constituted of lithic sandstone as well as lithic arkose and feldspathic litharenite. Cement types are complicated, including carbonate minerals, clay minerals, and quartz overgrowth. Illite, kaolinite, chlorite, illite–smectite mixed layer, and chlorite–smectite mixed layer are found in clay minerals. Compared with other clay minerals, illite is in the dominant position. Pores can be divided into residual intergranular pore, intragranular dissolution pore, intergranular dissolution pore, cement dissolution pore, intercrystalline pore, and microcrack in sandstone reservoir of the Linxing area. Quartz has an average content of 68% with the feature of low compositional maturity and plays a major role in increasing porosity due to dissolution and protecting of quartz. Feldspar dissolution plays a role in decreasing porosity because the by-product materials of feldspar dissolution remain in original place, instead of being transported to other areas. Dissolution pores are 2–20 µm and may be filled with kaolinite, illite, or halite. It is worth mentioning that grain-coating chlorite may be of sufficient thickness to protect reservoirs along with the increasing content of chlorite, which is testified by the crossplot between the chlorite and porosity when the absolute content of chlorite is less than 1.5%.
Porosity evolution of high-quality reservoirs in deep Palaeogene lacustrine carbonate rocks in the central Bohai Sea
Authors: Qing Yuanhua , Lü Zhengxiang , Wang Xiandong , Song Xiuzhang , Zhang Shunli , Meng Hailong
Published: January 2018

The oil and gas in the Palaeogene lacustrine carbonate rock reservoirs in the Bohai Sea accumulated during several periods. The reservoir porosity formed during each period affected the degree of accumulation that occurred. In this paper, the percentages of particles, authigenic minerals and pores in the reservoir bed were calculated with the statistical method of microstructure analysis. The formation time was determined with an isotopic analysis of the authigenic carbonate minerals and the homogenization temperature of the gas–liquid inclusions. The percentages of the primary intergranular pores that formed during the different stages were recovered based on the compaction features both before and after the formation of the major authigenic minerals. The evolution of porosity was thus described quantitatively and chronologically, employing the percentages of the residual primary intergranular pores, visceral cavity pores and dissolved pores at the different burial depths. The results indicate that in the initial sediments of the reservoir rock, the primary intergranular porosity was 32.4%. During the early burial stage, the total reservoir porosity increased by up to 46.9%, due to the addition of another type of primary pore, namely visceral cavity pores, which were generated from the decomposition of bioclasts. During the late, deep burial stage, the compaction reduced only 8.2% of the porosity, due to the support of the pore-lining dolomite precipitating during the early stage. Authigenic minerals occupied 12.6% of the porosity, and the dissolution created the secondary porosity by 3.8%. Good preservation of the visceral cavity pores and the growth of the pore-lining dolomites during the early stages are the major factors leading to the high reservoir porosity. The quantitative and chronological characteristics of the reservoir porosity evolution could be described accurately. The prediction of reservoir beds can be better guided than in previously reported methods by applying high resolution microscopic quantitative analysis technology and authigenic mineral timing analysis technology.
A Novel NGO Approach to Facilitate the Adoption of Sustainable Innovations in Low-Income Countries: Lessons from Small-scale Farms in Nicaragua
Authors: Dyck Bruno , Silvestre Bruno S.
Published: January 2018

There are about 500 million small-scale farms in low-income countries on the planet. Farmers have been slow to adopt a threefold set of sustainable agronomic practices known as “conservation agriculture” (CA) that have been shown to double productivity. Our study of a novel CA project in Nicaragua, organized based on principles that counter convention, may point to improved ways of understanding and managing sustainable innovations in low-income countries. In particular, by connecting core ideas from the innovation literature to the literature that explores the role of intermediaries such as NGOs, our case study suggests that the efficacy of NGOs to facilitate the adoption of sustainable innovations by small-scale farmers in these settings may be enhanced if NGOs employ non-centrist approaches in order to address the critical uncertainties associated with such innovations. We discuss how our findings contradict some of long-standing arguments in the literature, and their implications for theory and practice.
In-situ left-sided bilateral internal thoracic artery: elevated hemidiaphragm
Authors: Lev-Ran Oren , Abrahamov Dan , Baram Nina , Matsa Menachem , Ishai Yaron , Gabai Ohad , Refaely Yael , Abu Salah Mahmud , Sahar Gideon
Published: January 2018

Background

Procurement of the internal thoracic artery risks ipsilateral phrenic nerve injury and elevated hemidiaphragm. Anatomical variations increase the risk on the right side. Patients receiving left-sided in-situ right internal thoracic artery configurations appear to be at greatest risk.

Methods

From 2014 to 2016, 432 patients undergoing left-sided in-situ bilateral internal thoracic artery grafting were grouped according to right internal thoracic artery configuration: retroaortic via transverse sinus (77%) or ante-aortic (23%); targets were the circumflex and left anterior descending artery territories, respectively. Elevated hemidiaphragm was assessed by serial chest radiographs and categorized by side, complete (≥2 intercostal spaces) versus partial, and permanent versus transient.

Results

Right elevated hemidiaphragm occurred in 4.2% of patients. The incidence of radiological complete right elevated hemidiaphragm was 2.8% (12/432); 8 cases were transient with recovery in 3.5 ± 0.3 weeks. Permanent right elevated hemidiaphragm occurred in 0.9% (retroaortic group only). Permanent left elevated hemidiaphragm occurred in 0.9% and was significantly higher in the ante-aortic group (3/99 vs. 1/333, p = 0.039). No bilateral hemidiaphragm elevation was documented. Partial right elevated hemidiaphragm occurred in 1.4% and was not associated with adverse early or late respiratory outcomes.

Conclusions

Despite susceptible right phrenic nerve-internal thoracic artery anatomy, the incidence of permanent right elevated hemidiaphragm is low and no higher than left-sided in prone bilateral internal thoracic artery subsets. This reflects skeletonized internal thoracic artery procurement. Although statistical significance was not achieved, a retroaortic right internal thoracic artery configuration may constitute a higher risk of right phrenic nerve injury.
Outcomes of lung transplant recipients with preoperative atrial fibrillation
Authors: Yerasi Charan , Roy Sreeja Biswas , Olson Michael , Elnahas Shaimaa , Kang Paul , Hashimi A Samad , Huang Jasmine , Abdelrazek Hesham , Patel Vipul , Omar Ashraf , Bremner Ross M , Smith Michael , Walia Rajat , Bhattacharya Sanjoy , Kalya Anantharam
Published: January 2018

Background

Preoperative atrial fibrillation is associated with poor outcomes after cardiac surgery, but its effect on lung transplantation outcomes remains unknown.

Methods

We retrospectively reviewed the charts of 235 patients who underwent lung transplantation in our institution from 2013 to 2015, analyzing demographics, length of stay, survival, readmissions, and cardiac events. Mean recipient age was 59 ± 11 years, and 142 (60.4%) were men. Patients were grouped according to pre-transplantation atrial fibrillation status (atrial fibrillation/no atrial fibrillation).

Results

The atrial fibrillation group ( n = 38; 16.2%) was significantly older with a longer ischemic time, more postoperative atrial arrhythmias (73.7% vs. 20.8%, p = 0.01), and a longer median postoperative length of stay (16 vs. 13 days, p = 0.02). The median total hospital stay in the first postoperative year was also higher in the atrial fibrillation group (27 vs. 21 days, p = 0.25). Short-term survival and survival during follow-up did not differ significantly between groups.

Conclusions

Lung transplant recipients with preoperative atrial fibrillation are at increased risk of adverse cardiovascular outcomes and longer hospital stay. Preoperative atrial fibrillation may portend adverse events after lung transplantation.
Morphological analysis using geometric parameters for splenic aneurysms
Authors: Kimura Masaru , Hoshina Katsuyuki , Kobayashi Masaharu , Yamamoto Sota , Ohshima Marie , Watanabe Toshiaki
Published: January 2018

Background

Considering the unique characteristics of splenic artery aneurysms, we hypothesized that hemodynamic forces could play an important role in splenic artery aneurysm formation and that splenic artery geometry should be correlated with aneurysm development.

Methods

Tortuosity of the splenic artery was evaluated three-dimensionally by calculating the curvature using software and the original modeling system. We selected 54 splenic artery aneurysm patients who had undergone thin-slice computed tomography imaging with contrast. We compared the splenic artery aneurysm group to non-vascular patients via propensity-score matching (35 patients in each group). The splenic artery length index, average curvature, and maximum curvature were analyzed.

Results

Splenic artery aneurysm patients tended to have a longer splenic artery and the curvature was more severe compared to the non-vascular control patients. The average curvature of splenic artery aneurysm patients was associated with the dilatation rate in female patients.

Conclusion

Females with a tortuous splenic artery may have an increased risk of aneurysm formation.
Effect of preparation methods on morphology of active manganese dioxide and 2,4-dinitrophenol adsorption performance
Authors: Chen Hua-jun , Tian Wenjie , Ding Wuxiu
Published: January 2018

Herein active manganese dioxide was prepared by different methods using KMnO4 and MnSO4·H2O as inorganic precursors. The impact of preparation methods on morphology and adsorption performance of the synthesized products was investigated. The experimental results show that the reaction temperature and pressure had a great effect on the morphology and adsorption performance of active manganese dioxide. The shape of active manganese dioxide prepared at room temperature and pressure was short rod-like while active manganese dioxide synthesized by hydrothermal method was mesoporous fibers and had better adsorption performance. The adsorption behavior of 2,4-dinitrophenol on mesoporous manganese dioxide was well described by Langmuir and Freundlich isotherm equation ( R2>0.99) and pseudo-second-order kinetic equation ( R2>0.99), so the adsorption process maybe a chemical and monolayer adsorption. The pH of solution had significant effect on the adsorption performance of 2,4-dinitrophenol on mesoporous manganese dioxide. The adsorption capacity was 2.539 mg/g in the condition of pH = 7.
Exploring antecedents of service innovation performance in manufacturing SMEs
Authors: Mennens Kars , Van Gils Anita , Odekerken-Schröder Gaby , Letterie Wilko
Published: January 2018

Various factors enable manufacturing firms to attain a competitive advantage based on service innovation – that is, to achieve service innovation performance. Starting from a dynamic capabilities perspective, this article predicts that absorptive capacity is one such critical factor, which in turn may be driven by employee collaboration and the firm’s search breadth. The findings of a survey study of small to medium-sized Dutch manufacturing firms confirm that employee collaboration and search breadth have positive effects on an organization’s potential absorptive capacity, whereas employee collaboration also reinforces its realized absorptive capacity. Thus realized absorptive capacity ultimately enhances service innovation performance. The results have implications for dynamic capabilities theory, and they provide practitioners with potential means to outperform their competitors in service innovation efforts.
Does acute kidney injury affect survival in adults with acute respiratory distress syndrome requiring extracorporeal membrane oxygenation?
Authors: Devasagayaraj Richard , Cavarocchi Nicholas C. , Hirose Hitoshi
Published: January 2018

Introduction:

Patients who develop severe acute respiratory distress syndrome (ARDS) despite full medical management may require veno-venous extracorporeal membrane oxygenation (VV ECMO) to support respiratory function. Survival outcomes remain unclear in those who develop acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) during VV ECMO for isolated severe respiratory failure in adult populations.

Methods:

A retrospective chart review (2010-2016) of patients who underwent VV ECMO for ARDS was conducted with university institutional review board (IRB) approval. Patients supported by veno-arterial ECMO were excluded. AKI was defined by acute renal failure receiving CRRT and the outcomes of patients on VV ECMO were compared between the AKI and non-AKI groups.

Results:

We identified 54 ARDS patients supported by VV ECMO (mean ECMO days 12 ± 6.7) with 16 (30%) in the AKI group and 38 (70%) in the non-AKI group. No patient had previous renal failure and the serum creatinine was not significantly different between the two groups at the time of ECMO initiation. The AKI group showed a greater incidence of complications during ECMO, including liver failure (38% vs. 5%, p=0.002) and hemorrhage (94% vs. 45%, p=0.0008). ECMO survival of the AKI group (56% [9/16]) was inferior to the non-AKI group (87% [33/38], p=0.014).

Conclusions:

Our study demonstrated that VV ECMO successfully manages patients with severe isolated lung injury. However, once patients develop AKI during VV ECMO, they are likely to further develop multi-organ dysfunction, including hepatic and hematological complications, leading to inferior survival.
Rehabilitation of patients with venous diseases of the lower limbs: State of the art
Authors: Caggiati Alberto , De Maeseneer Marianne , Cavezzi Attilio , Mosti Giovanni , Morrison Nick
Published: January 2018

Background

To date, no document comprehensively focused on the complex issue of the rehabilitation of chronic venous diseases of the lower limbs.

Method

This article overviews and summarizes current strategies concerning venous rehabilitation of lower limbs.

Results

Venous rehabilitation is based on four main strategies: (1) lifestyle adaptations and occupational therapies; (2) physical therapies; (3) adapted physical activities; (4) psychological and social support. Rehabilitative protocols must be tailored to the specific needs of each patient, depending on the severity of chronic venous disease and on the location and pattern of venous lesion(s), but also on age, motor deficits, co-morbidities and psychosocial conditions.

Conclusions

Venous rehabilitation consists of non-pharmacologic and non-surgical interventions aiming at prevention of venous disease progression and complications, reduction of symptoms and improvement of quality of life. Well-designed clinical trials are required to evaluate the efficacy of the described rehabilitative protocols in influencing the evolution of venous disorders.
Regulator of G protein signaling-12 modulates the dopamine transporter in ventral striatum and locomotor responses to psychostimulants
Authors: Gross Joshua D , Kaski Shane W , Schroer Adam B , Wix Kimberley A , Siderovski David P , Setola Vincent
Published: January 2018

Regulators of G protein signaling are proteins that accelerate the termination of effector stimulation after G protein-coupled receptor activation. Many regulators of G protein signaling proteins are highly expressed in the brain and therefore considered potential drug discovery targets for central nervous system pathologies; for example, here we show that RGS12 is highly expressed in microdissected mouse ventral striatum. Given a role for the ventral striatum in psychostimulant-induced locomotor activity, we tested whether Rgs12 genetic ablation affected behavioral responses to amphetamine and cocaine. RGS12 loss significantly decreased hyperlocomotion to lower doses of both amphetamine and cocaine; however, other outcomes of administration (sensitization and conditioned place preference) were unaffected, suggesting that RGS12 does not function in support of the rewarding properties of these psychostimulants. To test whether observed response changes upon RGS12 loss were caused by changes to dopamine transporter expression and/or function, we prepared crude membranes from the brains of wild-type and RGS12-null mice and measured dopamine transporter-selective [3H]WIN 35428 binding, revealing an increase in dopamine transporter levels in the ventral–but not dorsal–striatum of RGS12-null mice. To address dopamine transporter function, we prepared striatal synaptosomes and measured [3H]dopamine uptake. Consistent with increased [3H]WIN 35428 binding, dopamine transporter-specific [3H]dopamine uptake in RGS12-null ventral striatal synaptosomes was found to be increased. Decreased amphetamine-induced locomotor activity and increased [3H]WIN 35428 binding were recapitulated with an independent RGS12-null mouse strain. Thus, we propose that RGS12 regulates dopamine transporter expression and function in the ventral striatum, affecting amphetamine- and cocaine-induced increases in dopamine levels that specifically elicit acute hyperlocomotor responses.
Administration of the metabotropic glutamate receptor subtype 5 allosteric modulator GET 73 with alcohol: A translational study in rats and humans
Authors: Haass-Koffler Carolina L , Goodyear Kimberly , Loche Antonella , Long Victoria M , Lobina Carla , Tran Harrison H , Cacciaglia Roberto , Swift Robert M , Colombo Giancarlo , Leggio Lorenzo
Published: January 2018

Preclinical work suggests that GET 73 (N-[4-(trifluoromethyl)benzyl]-4-methoxybutyramide), a novel metabotropic glutamate receptor subtype 5 negative allosteric modulator, may represent a novel pharmacological treatment for alcohol use disorder. Two independent experiments evaluated the effect of acutely administered GET 73 (0, 30, and 100 mg/kg, intragastrically) on alcohol-induced hypolocomotion ( n=72) and sedation/hypnosis ( n=36) in rats. In healthy male volunteers ( n=14), an open-label, randomised, crossover study was conducted to compare adverse events and pharmacokinetic parameters, in two experiments in which 300 mg GET 73 was administered, with and without alcohol, once and thrice. In rats, when administered with alcohol-vehicle, 100 mg/kg, but not 30 mg/kg, GET 73 reduced spontaneous locomotor activity. When administered with alcohol, no dose of GET 73 altered either alcohol-induced hypolocomotion or sedation/hypnosis. In humans, both single and thrice 300 mg GET 73 administration were well tolerated, in the presence and absence of alcohol, with no differences in adverse events. There were no significant differences in relative bioavailability between administering 300 mg GET 73 in the presence or absence of alcohol.
Image quality in coronary computed tomography angiography: influence of adaptive statistical iterative reconstruction at various radiation dose levels
Authors: Precht Helle , Gerke Oke , Thygesen Jesper , Egstrup Kenneth , Auscher Søren , Waaler Dag , Lambrechtsen Jess
Published: January 2018

Background

Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose.

Purpose

To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality.

Material and Methods

A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR).

Results

The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32–0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02–1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01–1.12; P = 0.034) compared to FBP.

Conclusion

ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.
Downregulation of SIRT6 is associated with poor prognosis in patients with non-small cell lung cancer
Authors: Zhu Bojin , Yan Yongjin , Shao Boyun , Tian Luwen , Zhou Weihua
Published: January 2018

Objective

To explore the prognostic significance of nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase sirtuin-6 (SIRT6), encoded by the sirtuin 6 ( SIRT6) gene, in a population of Chinese Han patients with non-small cell lung cancer (NSCLC).

Methods

Cancer tissues and normal lung tissues (>5 cm adjacent to cancer tissue) were collected from Chinese Han patients with NSCLC. Expression levels of SIRT6 and histone H3-acetyl K56 ( H3K56), in cancer and normal lung tissues from patients with NSCLC, were detected by reverse-transcription polymerase chain reaction, Western blot and immunohistochemistry. Correlations between SIRT6 expression and various clinicopathologic features were investigated.

Results

Out of 86 patients included in the study, mRNA and protein SIRT6 levels were down-regulated in NSCLC tissue versus normal lung tissue, and SIRT6 levels were inversely correlated with H3K56 levels. Positive rates of SIRT6 were significantly correlated with degree of cell differentiation, TNM stage, lymph node metastasis, overall survival and metastasis-free survival.

Conclusion

Downregulation of SIRT6 expression may promote NSCLC malignancy in the Chinese Han population. SIRT6 may be a potential therapeutic target in Chinese Han patients with NSCLC.
High-temperature tensile property measurements using digital image correlation over a non-uniform temperature field
Authors: van Rooyen Melody , Becker Thorsten Hermann
Published: January 2018

Standard test methods for measuring temperature-specific mechanical properties are typically specimen and time intensive when the influence of varying parameters is taken into consideration. Often, multiple specimens and test runs are required to build a complete database of constitutive parameters. This article presents a numerical–experimental methodology that employs digital image correlation to measure temperature-specific tensile properties of a 12% Cr steel. The methodology presents the unique ability to obtain temperature-specific properties from a single sample: the sample is subjected to a longitudinal thermal gradient through resistive heating in a thermomechanical loading system, while the full-field capabilities of digital image correlation and thermal imaging are used to measure strain and temperature surface maps, respectively. A study on the robustness of the methodology with regard to image saturation control and stress state found the setup capable of deformation measurement up to 900 °C. Elastic moduli and Poisson’s ratios were extracted in the 480 °C–600 °C range from a single specimen. The presented metrology sets the framework for investigations that are aimed at extracting temperature-specific mechanical properties for 12% Cr steels.
Sister library cooperation
Authors: Onifade Fehintola Nike , Bridges Laurie
Published: January 2018

The study examined the perceptions of team members of a sister library initiative between Nimbe Adedipe Library, Federal University of Agriculture, Abeokuta, Nigeria and the Valley Library, Oregon State University, Corvallis, USA. An online survey and focus group discussion were used as data collecting instruments. All of the 26 members of the team were sent an email to respond to an online questionnaire; only 16 members responded representing a 61.5% response rate, while 20 members participated in the focus group discussions. The finding revealed that members had positive perceptions towards the relationship. They were enthusiastic in learning about each other’s culture; thereby inspiring cross-cultural capabilities in knowledge and information handling. Although members on both sides of the relationship had great concerns about the technology gap between the libraries, the study revealed that they were willing and looking forward to assisting one another.
Lesion Size Does Not Predict Outcomes in Fresh Osteochondral Allograft Transplantation
Authors: Tírico Luis E.P. , McCauley Julie C. , Pulido Pamela A. , Bugbee William D.
Published: January 2018

Background:

Cartilage repair algorithms use lesion size to choose surgical techniques when selecting a cartilage repair procedure. The association of fresh osteochondral allograft (OCA) size with graft survivorship and subjective patient outcomes is still unknown.

Purpose:

To determine if lesion size (absolute or relative) affects outcomes after OCA transplantation.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The study included 156 knees in 143 patients who underwent OCA transplantation from 1998 to 2014 for isolated femoral condyle lesions. The mean age was 29.6 ± 11.4 years, and 62.9% were male. The majority of patients (62.2%) presented for cartilage repair because of osteochondritis dissecans. The mean graft area, used as a surrogate for absolute size of the lesion, was 6.4 cm2 (range, 2.3-11.5 cm2). The relative size of the lesion was calculated as the tibial width ratio (TWR; ratio of graft area to tibial width) and affected femoral condyle ratio (AFCR; ratio of graft area to affected femoral condyle width) using preoperative radiographs. All patients had a minimum follow-up of 2 years. Further surgical procedures were documented, and graft failure was defined as revision OCA transplantation or conversion to arthroplasty. International Knee Documentation Committee (IKDC) pain, function, and total scores were obtained. Satisfaction with OCA transplantation was assessed.

Results:

The mean follow-up among patients with grafts remaining in situ was 6.0 years (range, 1.9-16.5 years). The OCA failure rate was 5.8%. Overall survivorship of the graft was 97.2% at 5 years and 93.5% at 10 years. No difference in postoperative outcomes between groups was found in absolute or relative size. Change in IKDC scores (from preoperative to latest follow-up) was greater for knees with large lesions compared to knees with small lesions, among all measurement methods. Overall satisfaction with the results of OCA transplantation was 89.8%.

Conclusion:

The size of the lesion, either absolute or relative, does not influence outcomes after OCA transplantation for isolated femoral condyle lesions of the knee.
Dimensions of Central Venous Structures in Humans Measured in vivo using Magnetic Resonance Imaging: Implications for Central-Vein Catheter Dimensions
Authors: Twardowski Z.J. , Seger R.M.
Published: January 2018

The tip of a central vein catheter for hemodialysis should be located in the upper right atrium for the best performance. Hemodialysis catheters do have internal diameters unadjusted to the catheter length; however, the longer the catheter the slower the flow at the same pressure difference. On the other hand, the catheter diameter cannot be so large as to fill the vein too tightly as it predisposes to damage of the vein wall, thrombosis and stenosis. Therefore, the catheter length and diameter should be appropriate for the patient. For this purpose, the exact dimensions of the venous system in vivo should be known. In this study we correlated the anthropometric measurements and the dimensions of the large upper body veins in 31 adult volunteers.

After deep inspiration, magnetic resonance imaging of the chest was performed in three planes; the positions of specific points in the three-dimensional coordinate system were measured, and the distance to adjacent points was calculated according to the analytic geometry formula. The total length from the catheter entry point to the right atrium was the sum of distances between the adjacent points. The lengths of the veins were correlated with the body anthropometric measurements (height, weight, body surface area, bi-acromion span, and height plus bi-acromion span).

The best overall correlations of the lengths and diameters of the large upper body veins are with the body surface area. A table is included to guide the selection of the total catheter length and diameter in relation to the body surface area and insertion site.
A simplified Cardiopulmonary Bypass Technique for Animal Experiments on Implantable Ventricular Assist Devices
Authors: Kim W.G. , Lee W.Y. , Lee B.H. , Cho H.S.
Published: January 2018

We have developed and report on a simplified cardiopulmonary bypass technique for experiments on implantable ventricular assist devices in calves. We used an electromechanical implantable ventricular assist device with a double cylindrical cam in three calves. Cannulas for the ventricular assist system were designed to be inserted between the left atrium and the descending aorta. We used the outflow cannula of the ventricular assist device, anastomosed to the descending aorta, as a temporary arterial return route for the cardiopulmonary bypass. A cannula for venous drainage was iserted into the right ventricle through the pulmonary artery. There were no problems related to the procedure and the cardiopulmonary bypass was succesful. In conclusion, this simplified cardiopulmonary bypass technique without neck incision in calves, as used in developmental work involving implantable ventricular assist devices, can be reliably performed.
Combined Effect of Oxygen and Ammonia on the Kinetics of Ammonia Elimination and Oxygen Consumption of Adherent Rat Liver Cells
Authors: Catapano G. , De Bartolo L.
Published: January 2018

Oxygen is essential for the survival of isolated liver cells and its concentration is known to affect their viability and function. Recent reports have also shown that ammonia is eliminated at a rate depending on its concentration and that high ammonia concentrations may be cytotoxic to rat liver cells. Nonetheless, little quantitative information on the effect of either metabolite on liver cell reaction kinetics is available although important to the design of bioreactors for bioartificial livers (BALs).

In this investigation, we characterized the dependence of the rate of oxygen consumption (OCR), ammonia elimination (AER) and urea synthesis (USR) on ammonia concentration at physiological (i.e., 43 and 72 mmHg) and supra-physiological (i.e., 134 mmHg) dissolved oxygen tensions. To this purpose, isolated rat liver cells were cultured in adhesion on collagen in a continuous-flow bioreactor optimised for the kinetic characterisation of liver cell metabolic reactions. Rates of the investigated reactions generally increased with increasing ammonia concentrations. OCR and USR significantly increased with increasing dissolved oxygen tensions, particularly at high ammonia concentrations. The actual dissolved oxygen tension significantly influenced also OCR and USR dependence on ammonia concentration. The best-fit rate equations were used to show that, at the beginning of the treatment with a bioreactor packed with primary liver cells, high ammonia concentration in the blood may cause large hypoxic zones in the bioreactor as a result of its effect on OCR. This suggests that plasma (or blood) detoxification prior to entering the bioreactor might enhance BAL efficacy by preserving a large fraction of the available cell activity for longer times.
Artificial Skin: Past, Present and Future
Authors: Beele H.
Published: January 2018

The integrity of the skin should be restored as soon as possible whenever the skin gets wounded. Recent research has revealed some of the complex pathways in wound healing. Based on this knowledge, researchers have been looking for better skin substitutes to treat difficultly healing or large wounds. Some of these highly sophisticated wound dressings, also known as bio-dressings, contain material of human or animal origin, e.g. cultured skin cells. Although the ideal skin substitute has not been established yet, the currently available bio-dressings help clinicians close difficultly healing skin wounds.
Recent Developments on Human Cell Lines for the Bioartificial Liver
Authors: Hoekstra R. , Chamuleau R.A.F.M.
Published: January 2018

Most bioartificial liver (BAL) devices contain porcine primary hepatocytes as their biological component. However, alternatives are needed due to xenotransplantation associated risks. Human liver cell lines have excellent growth characteristics and are therefore candidates for application in BAL devices. Tumour-derived cell lines HepG2 and C3A express a variety of liver functions, but some specific liver functions, like ammonia detoxification and ureagenesis are insufficient. Immortalised human hepatocytes might offer better prospects. The balance between immortalisation and transformation with dedifferentiation of cells seems controllable by conditional immortalisation and/or the use of telomerase as immortalising agent. Another promising approach will be the use of embryonic or adult human stem cells. Rodent stem cells have been directed to hepatic differentiation in vitro, which might be applicable to human stem cells. However, both functionality and safety of immortalised human liver cell lines and differentiated stem cells should be improved before successful use in BAL devices becomes reality.
Early Experiences with a Porcine Hepatocyte-based Bioartificial Liver in Acute Hepatic Failure Patients
Authors: Morsiani E. , Pazzi P. , Puviani A.C. , Brogli M. , Valieri L. , Gorini P. , Scoletta P. , Marangoni E. , Ragazzi R. , Azzena G. , Frazzoli E. , Di Luca D. , Cassai E. , Lombardi G. , Cavallari A. , Faenza S. , Pasetto A. , Girardis M. , Jovine E. , Pinna A.D.
Published: January 2018

Orthotopic liver transplantation (OLT) is the only effective therapeutic modality in severe acute hepatic failure (AHF). The scarcity of organs for transplantation leads to an urgent necessity for temporary liver support treatments in AHF patients. A hepatocyte-based bioartificial liver (BAL) is under investigation with the main purpose to serve as bridging treatment until a liver becomes available for OLT, or to promote spontaneous liver regeneration. We developed a novel radial-flow bioreactor (RFB) for three-dimensional, high-density hepatocyte culture and an integrated pumping apparatus in which, after plasmapheresis, the patient's plasma is recirculated through the hepatocyte-filled RFB. Two hundred thirty grams of freshly isolated porcine hepatocytes were loaded into the RFB for clinical liver support treatment. The BAL system was used 8 times in supporting 7 AHF patients in grade III-IV coma, all waiting for an urgent OLT. Three patients with no history of previous liver diseases were affected by fulminant hepatic failure (FHF) due to hepatitis B virus, 3 by primary non-function (PNF) of the transplanted liver, and one by AHF due to previous abdominal trauma and liver surgery. Six out of 7 patients underwent OLT following BAL treatment(s), which lasted 6–24 hours. All patients tolerated the procedures well, as shown by an improvement in the level of encephalopathy, a decrease in serum ammonia, transaminases and an amelioration of the prothrombin time, with full neurological recovery after OLT. Our initial clinical experience confirms the safety of this BAL configuration and suggests its clinical efficacy as a temporary liver support system in AHF patients.
Albumin Loss in On-Line Hemodiafiltration
Authors: Combarnous F. , Tetta C. , Cellier C. Chapuis , Wratten M.L. , Custaud M.A. , De Catheu T. , Fouque D. , David S. , Carraro G. , Laville M.
Published: January 2018

Background

Based on the increased hydraulic permeability of the new high permeability polyethersulfone membrane, DIAPES®HF-800, we investigated the kinetics and handling of albumin in high volume on-line hemodiafiltration (HDF).

Methods

Seven patients on predilutional HDF were studied in two consecutive sessions. Blood flow rate and transmembrane pressure were continuously monitored. Spent dialysate was spilled at 20 ml/h every hour. Albumin was measured in blood and dialysate by immunonephelometry. Albumin and proteins adsorbed onto the dialyzer membrane were eluted after treatment with Triton X. Ultrafiltrates collected at 1 and 2 hours of treatment were pooled from different patients and incubated for 24 hours at 37°C with bovine serum albumin (BSA). Total sulphydryl groups were evaluated using Ellmann's reagent [5, 5'-dithio-bis(2-nitrobenzoic acid)].

Results

In all 7 patients, the total loss of albumin was 3.99±1.81 g, ranging between 1.09 and 6.82 g/session. Most albumin loss occurred in the first 60 min of pre-dilutional hemodiafiltration (1.92+0.83 g). There was no correlation between transmembrane pressure, urea clearance and the loss of albumin. Plasma water urea clearance values were stable over the treatment (234±14.3 mI/min). Plasma albumin concentration did not decrease during HDF sessions. Albumin adsorbed onto the dialyzers was 0.7±1.6 mg but the total amount of adsorbed proteins was much higher (130+90 mg). In addition, the ultrafiltrate collected during HDF sessions was able to induce oxidation of bovine serum albumin as measured by total protein sulfhydryl groups: bovine serum albumin incubated in the presence of ultrafiltrate collected at 1 hour had a sulfhydryl loss of 56.3±5.7% (p<0.0001 vs control), and bovine serum albumin incubated with ultrafiltrate collected at 2 hours had a loss of 67.5±3.8% (p<0.003 vs control).

Conclusion

The present study shows the high inter- and intra-patient variability of transmembrane passage of albumin in chronically uremic patients undergoing pre-dilutional HDF. Factors involved do not seem to be correlated to transmembrane pressure but rather to an interaction with the polymer surface. Albumin adsorption was minimal and was significantly lower than that of other plasma proteins. Albumin loss during HDF seemed to have no acute impact on plasma albumin. In addition, we demonstrated the presence of prooxidative compounds able to oxidize albumin, of which extracorporeal removal by HDF procedure could be beneficial for HD patients.
In Vitro Evaluation of the Hydraulic Permeability of Polysulfone Dialysers
Authors: Eloot S. , De Wachter D. , Vienken J. , Pohlmeier R. , Verdonck P.
Published: January 2018

An in vitro set-up has been designed to study the hydraulic permeability of hollow fiber dialysers. Forward and reverse dialysate ultrafiltration were determined using both sterile dialysers and samples with a protein layer settled on the membrane (Fresenius F6, F8, F60 and F80). The ultrafiltration coefficient KUF (ml/h.mmHg) was calculated as the ratio of volumetrical flow (QUF) and transmembrane pressure (TMP) measurements. The protein layer on the membrane was induced either by recirculating human plasma through the dialysers (in vitro) or by a standard hemodialysis session (in vivo).

KUF is largely independent of TMP up to 600mmHg (low flux) and 60mmHg (high flux) for forward and reverse flow. In sterile dialysers, backfiltration yields a significantly different KUF except for the F80. An in vitro induced protein layer on the membrane decreases KUF15–30% (forward) and 4–12% (backward) in low flux and 45–70% (forward) and 65–73% (backward) in high flux dialysers.
Reversibility of Artifacts of Fluid Volume Measurements by Bioimpedance Caused by Position Changes during Dialysis
Authors: Fenech M. , Jaffrin M.Y. , Malmen U.
Published: January 2018

The effect of temporary position changes, sitting up from supine, on extracellular (ECW) and intracellular (ICW) resistances and fluid volumes calculated from whole body bioimpedance using a Xitron 4200 impedancemeter was investigated on 8 patients during dialysis for a total of 11 tests. It was found that ECW resistance decreased instantaneously by an average of 2.3% when the patient sits up, due to plasma and interstitial fluid shift into the legs which decreases leg resistance, the major contributor to total resistance. This drop in resistance is incorrectly interpreted by the device as an increase in ECW volume which averages 235 ml. But this effect is completely reversible and both ECW resistance and fluid volume rapidly resume their normal course when the patient returns to his initial position. No significant variation in ICW resistance was observed in any of the patients at the position change. We conclude that segmental impedance, which has been proposed to minimize this artifact, is not advisable in dialysis monitoring and that it is simpler to ignore or switch off measurements during the position change so that later data are not affected by it.
Poly2-methoxyethylacrylate (PMEA) Coated Oxygenator: An ex Vivo Study
Authors: Mueller X.M. , Jegger D. , Augstburger M. , Horisberger J. , von Segesser L.K.
Published: January 2018

PMEA is a hydrophilic polymer coating with a unique design that minimizes the adsorption and denaturation of proteins and blood cells. This study compares thrombus resistance, blood path resistance, thrombocyte profile, and blood trauma of the PMEA coated Capiox membrane oxygenator (Terumo, Japan) vs. an uncoated version.

Methods

Six calves (mean bodyweight: 75.3±4.5kg) were placed on cardiopulmonary bypass for 6 hours and randomly assigned to the coated or uncoated oxygenator, with a low heparinisation protocol (ACT>180s).

Results

Macroscopically, red staining was observed in all uncoated oxygenators, and in none of the coated ones. Inlet pressure was significantly higher in the uncoated group (at 1h: 279±25 vs. 175±11mmHg, p<0.01 and at 6h: 217±10 vs. 171(8mmHg, p<0.01). Thrombocyte count values (corrected for hematocrit and normalized by prebypass values) were significantly higher in the coated group (at 1h: 76±6 vs. 53±13%, p<0.01 and at 6h: 70±6 vs. 44±26%, p<0.01). Plasma hemoglobin was below 100mg/L in both groups throughout the experiments.

Conclusions

When compared with uncoated oxygenator, PMEA coated oxygenator exhibited increased thrombus resistance with lower inlet pressure and lower thrombocyte consumption. In both groups, trauma to red cells was minimal, emphasizing the efficient design of this type of oxygenator.