bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Contraction Methods for Locating and Finding All the DC Operating Points of Diode-Transistor Circuits
Authors: Tadeusiewicz Michał , Hałgas Stanisław
Published: December 2010

Some Contraction Methods for Locating and Finding All the DC Operating Points of Diode-Transistor Circuits

The paper is focused on the analysis of diodetransistor circuits having multiple DC solutions (operating points) and brings two methods enabling us to find all the solutions. The first method contracts and eliminates some hyperrectangular regions where the solutions are sought. It is based on the idea of framing of the nonlinear functions appearing in the mathematical description of the circuit by linear ones and exploits the Woodbury formula in matrix theory. The other method finds quickly and easily preliminary bounds on the location of all the solutions. The method employs some monotonic functions and generates convergent sequences leading to a shrinked hyperrectangle that contains all the solutions. Both the proposed methods are rigorously proved. They constitute the core of an algorithm which efficiently finds all the DC operating points of diode-transistor circuits. It is illustrated via numerical examples.
Joint Source-Channel Coding in Dictionary Methods of Lossless Data Compression
Authors: Rodziewicz Marcin
Published: December 2010

Joint Source-Channel Coding in Dictionary Methods of Lossless Data Compression

Limitations on memory and resources of communications systems require powerful data compression methods. Decompression of compressed data stream is very sensitive to errors which arise during transmission over noisy channels, therefore error correction coding is also required. One of the solutions to this problem is the application of joint source and channel coding. This paper contains a description of methods of joint source-channel coding based on the popular data compression algorithms LZ'77 and LZSS. These methods are capable of introducing some error resiliency into compressed stream of data without degradation of the compression ratio. We analyze joint source and channel coding algorithms based on these compression methods and present their novel extensions. We also present some simulation results showing usefulness and achievable quality of the analyzed algorithms.
Fuzzy Processing Implementation in Dedicated Digital Hardware
Authors: Szecówka Przemysław , Musiał Adam
Published: December 2010

Fuzzy Processing Implementation in Dedicated Digital Hardware

The paper presents a concept of digital circuit dedicated for fuzzy processing with numerical inputs and outputs. Partially concurrent and pipelined data flow provides high performance, with relatively low dependence on particular algorithm complexity. Sample design with triangular fuzzy sets, rule strength calculation (minimumapproach) and defuzzyfication by weighted sum of fuzzy sets centers was implemented in VHDL, verified and synthesized for FPGA. Floating point arithmetic was applied, including dvision performed by dedicated synchronous machine. All modules were prepared for easy reuse/redesign.
Fatigue Detection Using Computer Vision
Authors: Patel Mitesh , Lal Sara , Kavanagh Diarmuid , Rossiter Peter
Published: December 2010

Fatigue Detection Using Computer Vision

Long duration driving is a significant cause of fatigue related accidents of cars, airplanes, trains and other means of transport. This paper presents a design of a detection system which can be used to detect fatigue in drivers. The system is based on computer vision with main focus on eye blink rate. We propose an algorithm for eye detection that is conducted through a process of extracting the face image from the video image followed by evaluating the eye region and then eventually detecting the iris of the eye using the binary image. The advantage of this system is that the algorithm works without any constraint of the background as the face is detected using a skin segmentation technique. The detection performance of this system was tested using video images which were recorded under laboratory conditions. The applicability of the system is discussed in light of fatigue detection for drivers.
EuCARD 2010 Accelerator Technology in Europe
Authors: Romaniuk Ryszard
Published: December 2010

EuCARD 2010 Accelerator Technology in Europe

Accelerators are basic tools of the experimental physics of elementary particles, nuclear physics, light sources of the fourth generation. They are also used in myriad other applications in research, industry and medicine. For example, there are intensely developed transmutation techniques for nuclear waste from nuclear power and atomic industries. The European Union invests in the development of accelerator infrastructures inside the framework programs to build the European Research Area. The aim is to build new infrastructure, develop the existing, and generally make the infrastructure available to competent users. The paper summarizes the first year of activities of the EU FP7 Project Capacities EuCARD - European Coordination of Accelerator R&D. Several teams from this country participate actively in this project. The contribution from Polish research teams concerns: photonic and electronic measurement - control systems, RF-gun co-design, thin-film superconducting technology, superconducting transport infrastructures, photon and particle beam measurements and control.
Prevalence of Behavioural and Emotional Problems in Children with High-Functioning Autism Spectrum Disorders
Authors: Ooi Yoon Phaik , Tan Ze Jia , Lim Cui Xi , Goh Tze Jui , Sung Min
Published: December 2010

Objective: The goal of the present study was to examine the prevalence of behavioural and emotional problems among children with high-functioning autism spectrum disorders (ASD).

Method: Archival data from a total of 71 children (Mage = 10.24, SD = 2.91) diagnosed by their clinicians to have high-functioning ASD were obtained. Information on demographics and behavioural and emotional problems from the Child Behavioural Checklist (CBCL) were entered.

Results: We found that between 72% and 86% of children with high-functioning ASD had at least one behavioural or emotional problem of clinical concerns as indicated by the CBCL syndromes and DSM-oriented scales. The most commonly reported problems were social problems (60.6%), thought problems (50.7%), attention problems (49.3%), and withdrawn/depressed (40.8%). Using the DSM-oriented scales, the most commonly reported problems were attention deficit/hyperactivity problems (35.2%), anxiety problems (33.8%) and affective problems (31%).

Conclusions: Findings from the present study provide further evidence to support the high prevalence of behavioural and emotional problems, which could result in multiple psychiatric diagnoses among children with high-functioning ASD.
Complex formation in liquid potassium-lead alloy
Authors: Singh BP , Adhikari D , Jha IS , Singh BK
Published: December 2010

Regular associated solution model has been used to study the mixing properties of KPb liquid alloy at 848 K. The values of different thermodynamic parameters obtained from this model are compared with corresponding experimental values. Most of the computed values are in good agreement with the observed values.Keywords: Compound forming alloy; Pairwise interaction energy; Equilibrium constantDOI: 10.3126/bibechana.v7i0.4035BIBECHANA 7 (2011) 1-5
Role of reductant for generation of solar energy in photogalvanic cell
Authors: Chandra Mahesh , Meena RC
Published: December 2010

The Photo voltages and photocurrents in photo galvanic cell containing a dye Rose Bengal and Oxalic Acid as reducing agent have been determined. The photo-outputs with Oxalic Acid are higher than Rose Bengal and Mannitol system. The efficiency of the Rose Bengal –Oxalic Acid photo galvanic cell has been estimated to be 0.981%. The photo potentials and photocurrent garneted, conversion efficiency, power of the cell and cell performance of the photo galvanic cells were determined. The effects of different parameters on electrical output of the cell were observed. A mechanism has also been proposed for the generation of the photocurrent in photo galvanic cell. Keywords: Photo galvanic cell; Photopotential; Rose Bengal; Oxalic acid,; Mannitol; Power point DOI: 10.3126/bibechana.v7i0.4036BIBECHANA 7 (2011) 6-13
Temperature regulation in animals
Authors: Koirala Ram Prasad
Published: December 2010

We have studied the rate of evaporation of sweat for the body of human of two different surface areas at different temperatures. We have also studied the rate of evaporation of sweat at different values of heat produced by chemical metabolism. It is found that a thin man perspires at lower temperature than a fat man when they both produce the same heat by chemical metabolism. Keywords: Chemical metabolism; Evaporation of sweat; Normal breathing DOI: 10.3126/bibechana.v7i0.4037BIBECHANA 7 (2011) 14-17
Free energy of mixing and activity of indium-tin alloy
Authors: Jha IS , Khan Arun K , Kumar BC
Published: December 2010

Flory's model has been used to calculate the free energy of mixing and activity of In in InSn liquid alloy at 700 K. The values of these thermodynamic parameters obtained from this model are compared with corresponding experimental values. The computed values are in reasonable agreement with the observed values. Keywords: Flory's model; Activity; Indium-tin alloy DOI: 10.3126/bibechana.v7i0.4040BIBECHANA 7 (2011) 26-29
Surfactants, its applications and effects on environment
Authors: Shah SK , Bhattarai A , Chatterjee SK
Published: December 2010

Surfactant is being considered as a very demandable molecule in the field of chemistry. This paper reviews most important factors especially the uses of surfactants and their effects on environment. Evaluation of surfactants are based on examining the ability of the surfactant to maintain lower interfacial tension between target contaminant and water, satisfying lower CMCs, and sustaining lower sorption and precipitation to target substrate. Surfactant mixtures of anionic and nonionic surfactant are shown to be excellent candidates for robust surfactant cleaners. Keywords: Surfactant; Interfacial tension; Critical micelle Concentration; Anionic surfactant; Nonionic surfactant DOI: 10.3126/bibechana.v7i0.4047BIBECHANA 7 (2011) 61-64
Derelicte and the Oppressed: Zoolander, Hollywood, and Representing Activism
Authors: Dobson Kit
Published: December 2010

Abstract:

This paper, reading from Gayatri Spivak's ongoing revisions of her critique of subalternity, examines how the rebel figure in the 2001 screwball comedy Zoolander is brought into being and draws out the represented power structures according to broader social patterns in Hollywood depictions of resistance. While Zoolander is caught up in a politics that might lead to displaced forms of representation, its visual spectacle, juxtaposing poverty and opulence, illustrates a continuing problem in popular visual depictions of resistance and political struggle, a problem that requires analysis on a transnational scale.
Between the Town and the Mountain: Abortion and the Politics of Life in Edith Wharton's Summer
Authors: Weingarten Karen
Published: December 2010

Abstract:

In the early twentieth century, American laws focused on women's reproductive capacities and were coalescing into the ethical and moral frameworks that subtend American reproductive politics today. Edith Wharton published her 1917 novel, Summer, at a time when anti-abortion sentiment was widespread in American culture. Through a reading of Summer, the article provides a theoretical and historical framework for understanding this new American obsession with the judicial regulation of women's reproductive options. In particular, I situate the novel's presentation of abortion within the tension between the carefully defined laws of North Dormer, the town in which the majority of the story takes place, and the lawlessness of the Mountain, a place that looms throughout the story as the protagonist's birthplace and a location of utmost abjection. The novel's profound insight is that power does not function unilaterally and individually but through and on the population. Furthermore, Wharton leaps ahead by recognizing that life is not simply that which lives but that which is recognized and embraced by the law. This realization, one that Wharton must have come to terms with through her painful work with World War I refugees, shapes Charity's character and her understanding not only of how reproduction is regulated but also of how living within this regulation and control generates the norm and offers the only possibility for a liveable and legible life.
Registration of Tx3361 Sorghum Germplasm
Authors: Kuhlman L. C. , Rooney W. L.
Published: December 2010

The sorghum [Sorghum bicolor (L.) Moench] germplasm Tx3361 (Reg. No. GP‐661, PI 659454) was developed and released by the Texas Agrilife Research sorghum breeding program in January 2010. This germplasm is unique because it lacks a key factor that represses alien‐pollen growth on the stigma. The inability to repress alien pollen‐tube growth increases the frequency of interspecific and intergeneric fertilization in sorghum. This increase is influenced by both the specific species and particular cultivars being tested. The line was developed using pedigree‐breeding approaches in breeding nurseries in College Station and Weslaco, TX. Selection was based on agronomic adaptability and the presence of alien‐pollen‐tube growth (detected via fluorescence microscopy). This line provides sorghum improvement programs with a unique opportunity to create interspecific and intergeneric sorghum hybrids for use as introgression parents.
Cost-Effective Management of Venous Ulcer
Authors: Alam SAN , Bashar AHM , Alam KM , Sabah MN , Hossain GMM , Hakim ME , Badiuzzaman M , Azad AK
Published: December 2010

Background: Venous disorders are very common. About 20% of the population suffer from varicose veins, 2% have skin changes which may precede venous ulceration. Venous ulcers represent a common and debilitating condition associated with significant financial loss for the patients as well as the society. Treatment options for these patients are costly and time consuming. In this study we tried to find out cost-effective measures for treating this group of patients.Method: To evaluate the effectiveness and safety of superficial and perforating leg venous surgery along with pharmacotherapy 66 patients with chronic venous leg ulcers are prospectively studied. After proper history taking and clinical examination all patients underwent venous duplex ultrasonography. Patients were divided into two groups. Group I (n=30) includes patients undergoing saphenofemoral ligation and stripping of the great saphenous vein (GSV). In group II (n=36) patients underwent saphenofemoral and incompetent leg perforator ligation along with stripping of the GSV. Conservative measures, local ulcer care and pharmacotherapy were common in both groups.Result: Postoperative complications, total hospital stay and ulcer healing were studied. Ulcer healing was earlier in group II. Remarkable complications were similar in both the groups.Conclusion: For effective and economic care of venous leg ulcers, combination of standard surgical procedures including incompetent perforator and saphenofemoral ligation with great saphenous vein stripping and standard physio-pharmacotherapeutic care is essential. This combined modality of treatment is highly effective in early and complete ulcer healing in patients suffering from venous ulcers.Keywords: Venous ulcer: Saphenofemoral ligation: Perforator ligation.  DOI: 10.3329/cardio.v2i2.6629Cardiovasc. j. 2010; 2(2) : 136-141
Cardiovascular Stability during Off-Pump Coronary Artery Bypass (OPCAB) Surgery- A Comparison between Combined High Thoracic Epidural Anaesthesia (HTEA) with TIVA and TIVA alone
Authors: Azad SI , Beg AK , Chowdhury AYFE , Khatun UHS
Published: December 2010

Background: In Bangladesh, although OPCAB surgery are done, the number of centers are limited and as a result, studies on this subject are also few. Consequently, there are no exclusive data regarding the best anaesthetic technique in the context of superior haemodynamic stability. This study has been undertaken with a view to find out whether a combined HTEA with GA (TIVA) is safe and more efficient in providing overall cardiovascular stability. The common challenges for the cardiac anaesthesiologist during off pump coronary artery surgery (OPCAB) to maintain optimal cardiovascular parameters such as heart rate, blood pressure, CVP and arrhythmias during the different stressful surgical events and multiple cardiac manipulations, providing adequate myocardial protection, are sometimes difficult. This study has been undertaken with a view to find out whether a combined HTEA with TIVA is safe and more efficient in providing overall cardiovascular stability. Method: Sixty patients aged between 40-70 years, without having any coagulopathy disorder , any emergency surgery or left main disease scheduled for CABG on beating heart were enrolled in prospective, randomized observational comparative study. Patients were divided in two groups. In group A patients received TIVA alone and in group B patients received high thoracic epidural anaesthesia with TIVA. The parameters including heart rate , SPO2 , CVP , arterial blood pressure , rate pressure product , arrhythmia in ECG, were recorded before induction, during induction , intubation and during different events of the surgery ( skin incision, sternotomy, pericardiotomy, coronary artery anastomosis with graft , sternum closure and wound closure) was recorded. Result: Significant per-operative mean heart rate changes were observed all the events except at wound closure and during anastomosis with D1/D2 and the mean difference of mean of mean arterial pressure at intubations, skin incision, sternotomy, pericardiotomy, during anastomosis of distal end of the graft with RCA, PDA, LCX and D1/D2 were observed statistically significant (p<0.05) . No incidence of different arrhythmia occurred in group B, premature ventricular complex (PVC) was statistically significant (p<0.05) between two groups. Conclusion: HTEA with TIVA appeared to be most comprehensive, allowing for revascularization of any coronary artery, providing good cardiovascular stability during OPCAB.Key Words: CABG; OPCAB; HTEA; TIVA DOI: 10.3329/cardio.v2i2.6633Cardiovasc. j. 2010; 2(2) : 163-167
Percutaneous Angioplasty and Stenting of Carotid Artery: Study of 18 Cases
Authors: Momenuzzaman NAM , Begam F , Khan KN , Dey A , Adhikary DK , Ilius ZM , Sohail KM , Haque F , Amin MU , Rahman R , Mallick Sk , Haque SMZ
Published: December 2010

Background: Carotid angioplasty & stenting is becoming an emerging therapeutic option for carotid revascularization. The use of cerebral protection system has expanded the area of application of the procedure worldwide. Purpose: To assess the feasibility, success rate, safety as well as in-hospital & early 30 days outcome in patients undergoing percutaneous carotid intervention. Methods: A retrospective, observational study where a total of 18 (Eighteen) consecutive patients who presented with symptomatic and > 70 % carotid artery stenosis & asymptomatic but > 90% stenosis underwent percutaneous carotid intervention. All of them had coronary artery disease; CABG was done in 3 patients & PCI in 9 patients. Three of them had previous stroke (Ischemic) & 7 had TIA. Results: Technical and angiographic success was achieved in all patients. Carotid artery obstruction diminishes from 85 ± 14 % to 10 ± 5 % (p< .001). Mean lesion length was 12 ± 3 mm and mean time of carotid occlusion during balloon inflation was 10 ± 2.5 sec. distal protection devices used in all patents. No major stroke or death occurred during procedure. One patient developed No-flow because of obstruction of distal protection device which was managed by thrombosuction. One patient developed TIA. All patients were discharged from hospital after an average of 3 days & all of them were prescribed dual antiplatalet therapy for 6 months. During follow-up one patient died secondary to acute myocardial infarction and one patient developed major stroke. Conclusion: Percutaneous angioplasty and stenting associated with distal protective devices appear feasible, effective and almost safe endovascular treatment modality for carotid artery stenosis. Key words: Carotid artery disease; Carotid angioplasty DOI: 10.3329/cardio.v2i2.6644Cardiovasc. j. 2010; 2(2) : 218-222
High Dose Statins: Is it Beneficial over Conventional Dose of Statin in Acute Coronary Syndrome?
Authors: Islam AEM M , Mazumder AAS
Published: December 2010

Increasing burden of cardiovascular disease risk factors has led to increase in the incidence in the coronary artery disease (CAD). Advancements in medical and surgical care of patients with heart disease have led to a large number of people surviving acute coronary events. Patients with acute coronary syndrome (ACS) are at high risk for recurrent coronary events, sudden death, and all cause mortality. Conventional revascularization therapies reduce the risk of further ischaemia but do not affect the underlying atherosclerotic disease. Statins have a proven record in the secondary prevention of coronary heart disease. Furthermore, statins have been shown to exert various pleotropic effects, which may stabilize vulnerable atherosclerotic plaques. Therefore, initiating, statin therapy in patients with established CAD is both beneficial and more cost effective. Trials conducted in recent times have addressed the issue of whether higher dose statin therapy provides further reductions in the risks of cardiovascular events following an acute coronary syndrome diagnosis, over and above that provided by a conventional dose statin regimen. However, recent trials of high dose statin therapy in patients with acute coronary syndromes have yielded conflicting results. The aim of this article is to provide a critical and up-to-date summary of the findings of clinical trials of intensive statin therapy, including a brief overview of safety and efficacy of such treatments. Keywords: Statin; Acute coronary syndrome. DOI: 10.3329/cardio.v2i2.6648Cardiovasc. j. 2010; 2(2) : 245-251
Forecasting the Stock Market with Linguistic Rules Generated from the Minimize Entropy Principle and the Cumulative Probability Distribution Approaches
Authors: Su Chung-Ho , Chen Tai-Liang , Cheng Ching-Hsue , Chen Ya-Ching
Published: December 2010

To forecast a complex and non-linear system, such as a stock market, advanced artificial intelligence algorithms, like neural networks (NNs) and genetic algorithms (GAs) have been proposed as new approaches. However, for the average stock investor, two major disadvantages are argued against these advanced algorithms: (1) the rules generated by NNs and GAs are difficult to apply in investment decisions; and (2) the time complexity of the algorithms to produce forecasting outcomes is very high. Therefore, to provide understandable rules for investors and to reduce the time complexity of forecasting algorithms, this paper proposes a novel model for the forecasting process, which combines two granulating methods (the minimize entropy principle approach and the cumulative probability distribution approach) and a rough set algorithm. The model verification demonstrates that the proposed model surpasses the three listed conventional fuzzy time-series models and a multiple regression model (MLR) in forecast accuracy.
Colorimetric Immunoassay for Detection of Tumor Markers
Authors: Yin Yongmei , Cao Ya , Xu Yuanyuan , Li Genxi
Published: December 2010

Tumor markers are substances, usually proteins, produced by the body in response to cancer growth, or by the cancer tissue itself. They can be detected in blood, urine, or tissue samples, and the discovery and detection of tumor markers may provide earlier diagnosis of cancer and improved therapeutic intervention. Colorimetric immunoassays for tumor marker detection have attracted considerable attention, due to their simplicity and high efficiency. The traditionally used colorimetric immunoassays for the detection of tumor markers are based on enzyme-linked immunosorbent assays, and the great achievement of nanotechnology has further opened opportunities for the development of such kind of immunoassays. This paper will summarize recent advances in the field of colorimetric immunoassays for detecting tumor markers, which is aimed to provide an overview in this field, as well as experimental guidance for the learner.
Synergistic Effect of Neural Stem Cells and Olfactory Ensheathing Cells on Repair of Adult Rat Spinal Cord Injury
Authors: Wang Gan , Ao Qiang , Gong Kai , Zuo Huancong , Gong Yandao , Zhang Xiufang
Published: December 2010

Spinal cord injury (SCI) is a common clinical disease that places a heavy burden on families and society. Cellular therapy provides a method of giving a supplement of cells lost in the injury and promoting functional recovery after SCI. Neural stem cells (NSCs) and olfactory ensheathing cells (OECs) are two most promising cell types. NSCs have the potential of differentiating into neurons and glial cells, and OECs could help the axons of neurons pass through the glial scar to promote functional recovery. NSCs were isolated from the cortices of fetal rats on days 12–14 of embryonic development and OECs were isolated from the olfactory bulbs of adult rats. In vitro coculture studies demonstrated OECs could promote NSCs to differentiate into neurons. Four groups of rats that had been 3/4 spinal cord transectioned at T9 were injected with DMEM/F12 solution, NSCs, OECs, and NSCs + OECs, respectively, 7 days post-SCI. Twelve weeks postoperation, the hindlimb locomotor function of rats in the cotransplantation group was significantly improved compared with that in the other three groups. Histological observation and immunohistochemical staining of NF-200 both showed new nerve fibers across the injured region. Cotransplantation of NSCs and OECs might have a synergistic effect on promoting neural regeneration and improving the recovery of locomotion function. Cotransplantation of NSCs and OECs was better than a single graft of either NSCs or OECs. These findings have provided a new way of thinking in the treatment of SCI.
Cell Therapy, a New Standard in Management of Chronic Critical Limb Ischemia and Foot Ulcer
Authors: Procházka V. , Gumulec J. , Jalůvka F. , Šalounová D. , Jonszta T. , Czerný D. , Krajča J. , Urbanec R. , Klement P. , Martinek J. , Klement G. L.
Published: December 2010

Fifty percent of diabetics (7% of general population) suffer from peripheral arterial occlusive disease, which may lead to amputation due to critical limb ischemia (CLI). The aim of our study was to prevent major limb amputation (MLA) in this group of patients using a local application of autologous bone marrow stem cells (ABMSC) concentrate. A total of 96 patients with CLI and foot ulcer (FU) were randomized into groups I and II. Patients in group I ( n = 42, 36 males, 6 females, 66.2 ± 10.6 years) underwent local treatment with ABMSC while those in group II ( n = 54, control, 42 males, 12 females, 64.1 ± 8.6 years) received standard medical care. The frequency of major limb amputation in groups I and II was 21% and 44% within the 120 days of follow up, respectively ( p < 0.05). Only in salvaged limbs of group I both toe pressure and toe brachial index increased (from 22.66 ± 5.32 to 25.63 ± 4.75 mmHg and from 0.14 ± 0.03 to 0.17 ± 0.03, respectively, mean ± SEM). The CD34+ cell counts in bone marrow concentrate (BMC) decreased (correlation, p = 0.024) with age, even though there was no correlation between age and healing. An unexpected finding was made of relative, bone marrow lymphopenia in the initial bone marrow concentrates in patients who failed ABMSC therapy (21% of MLA). This difference was statistically significant ( p < 0.040). We conclude ABMSC therapy results in 79% limb salvage in patients suffering from CLI and FU. In the remaining 21% lymphopenia and thrombocytopenia were identified as potential causative factors, suggesting that at least a partial correction with platelet supplementation may be beneficial.
Use of Perfluorodecalin for Pancreatic Islet Culture Prior to Transplantation: A Liquid-Liquid Interface Culture System—Preliminary Report
Authors: Juszczak M. T. , Elsadig A. , Kumar A. , Muzyamba M. , Pawelec K. , Powis S. H. , Press M.
Published: December 2010

Although the issue remains controversial, short-term culture is probably beneficial for islet graft quality. However, significant islet loss is invariably observed. This is related to reduced survival of large islets, which is compromised by hypoxia under standard culture conditions. We aimed to develop a method of culture, which would avoid exposure to relative hypoxia and hence maintain the quality of islets. Isolated rat islets cultured for 48 h in a liquid–liquid interface culture system (LICS) with a perfluorocarbon were compared to islets cultured under standard (C1) and suboptimal conditions (C2). Islets were tested for viability and response to a glucose challenge, and a marginal mass was transplanted into syngeneic diabetic recipients. The viability of islets after 24-h culture in LICS was higher than in C1 and C2 groups (89.0% vs. 77.5% and 64.6%, respectively) and decreased with time to reach 79.0%, 62.9%, and 53.4% after 72-h culture. The stimulation index in LICS-cultured islets was also significantly higher than in C1 and C2 groups (12.3 ± 0.4 vs. 5.8 ± 0.5 and 4.1 ± 0.2, respectively). Following transplantation of LICS-cultured islets 50% of recipients were rendered normoglycemic compared with 14.3% and 31.3% for C2 and fresh islets, respectively. Our liquid–liquid interface culture system using perfluorodecalin provides optimized culture conditions, which preserve both islet viability and their ability to engraft successfully after intraportal transplantation and could be used for islet transportation.
Transplantation of Human Wharton's Jelly-Derived Stem Cells Alleviates Chemically Induced Liver Fibrosis in Rats
Authors: Lin Shinn-Zong , Chang Yao-Jen , Liu Jen-Wea , Chang Li-Fu , Sun Li-Yi , Li Yuan-Sheng , Luo Geng-Hong , Liao Chia-Hui , Chen Pin-Hsin , Chen Tse-Min , Lee Ru-Ping , Yang Kuo-Liang , Harn Horng-Jyh , Chiou Tzyy-Wen
Published: December 2010

There is currently no effective treatment method available for liver fibrosis. We therefore evaluated the use of Wharton's jelly stem cells (WJSCs; the major umbilical cord stem cell population) to treat chemically induced liver fibrosis via intraperitoneal injection of thioacetamide. WJSCs were transplanted into liver-damaged rats via the portal vein and the treatment was evaluated by assessing serum biochemistry and histopathology. Transplanted WJSCs were distributed in the fibrotic area and around blood vessels, and hepatic recovery was accelerated. Serum prothrombin time significantly recovered, and serum albumin also improved at 21 days posttransplantation; collagen accumulation also decreased at 14 days. Thus, human WJSCs promoted recovery after chronic liver damage. Using immunohistochemical analyses, we determined that transplanted WJSCs produce albumin, hepatocyte growth factor (HGF), and metalloproteinase (MMP) after transplantation to chemically injured liver, indicating that WJSC may help to decrease liver collagen and thus may be useful for treating liver fibrosis.
An Efficient Approach to Isolation and Characterization of Pre- and Postnatal Umbilical Cord Lining Stem Cells for Clinical Applications
Authors: Gonzalez R. , Griparic L. , Umana M. , Burgee K. , Vargas V. , Nasrallah R. , Silva F. , Patel A.
Published: December 2010

There have been various forms of mesenchymal stem cell-like (MSC-like) cells isolated from umbilical cords (UCs). The isolation of umbilical cord lining stem cells (ULSCs) may be of great value for those interested in a possible treatment to several disease/disorders. Unlike umbilical cord blood cells, these cells are unique because they can be expanded to therapeutically relevant numbers and cryopreserved for several different uses. Here we efficiently isolate stem cells from a small segment of pre- and postnatal UCs, and obtain therapeutically relevant amounts of ULSCs within 3 weeks. We demonstrate their growth potential and characterize them using immunocytochemistry, flow cytometry, and RT-PCR. In addition, we differentiate ULSCs into multiple lineages. Pre- and postnatal ULSCs are morphologically similar to mesenchymal stem cells (MSCs) and easily expand to greater than 70 population doublings. They express pluripotent markers Oct4 and nanog at the protein and RNA level. Flow cytometry demonstrates that they express markers indicative of MSCs in addition to high SSEA-4 expression. ULSCs are easily differentiated into osteogenic, adipogenic, chondrogenic, cardiogenic, and neurogenic cells. Pre- and postnatal ULSCs are characteristically similar in respect to their growth, marker expression, and plasticity, demonstrating they are highly conserved throughout development. ULSCs have phenotypic and genotypic properties of MSCs. These studies demonstrate the therapeutic potential of an otherwise discarded tissue. They are a perfect HLA match for the donor and an excellent match for immediate family members; therefore, they may serve as a therapeutic cell source.
Late Passage Human Fibroblasts Induced to Pluripotency Are Capable of Directed Neuronal Differentiation
Authors: Liu Jun , Sumer Huseyin , Leung Jessie , Upton Kyle , Dottori Mirella , Pébay Alice , Verma Paul J.
Published: December 2010

It is possible to generate induced pluripotent stem (iPS) cells from mouse and human somatic cells by ectopic expression of defined sets of transcription factors. However, the recommendation that somatic cells should be utilized at early passages for induced reprogramming limits their therapeutic application. Here we report successful reprogramming of human fibroblasts after more than 20 passages in vitro, to a pluripotent state with four transcription factors: Oct4, Sox2, Klf4, and c-Myc. The late passage-derived human iPS cells resemble human embryonic stem cells in morphology, cell surface antigens, pluripotent gene expression profiles, and epigenetic states. Moreover, these iPS cells differentiate into cell types representative of the three germ layers in teratomas in vivo, and directed neuronal differentiation in vitro.
Pancreatic Islet Culture and Preservation Strategies: Advances, Challenges, and Future Outlook
Authors: Daoud Jamal , Rosenberg Lawrence , Tabrizian Maryam
Published: December 2010

Postisolation islet survival is a critical step for achieving successful and efficient islet transplantation. This involves the optimization of islet culture in order to prolong survival and functionality in vitro. Many studies have focused on different strategies to culture pancreatic islets in vitro through manipulation of culture media, surface modified substrates, and the use of various techniques such as encapsulation, embedding, scaffold, and bioreactor culture strategies. This review aims to present and discuss the different methodologies employed to optimize pancreatic islet culture in vitro as well as address their respective advantages and drawbacks.
Lack of Evidence for Recipient Precursor Cells Replenishing β-Cells in Transplanted Islets
Authors: Hamamoto Yoshiyuki , Akashi Tomoyuki , Inada Akari , Bonner-Weir Susan , Weir Gordon C.
Published: December 2010

Bone marrow and tissue precursor cells have been postulated to replenish grafts of transplanted islets. Several investigators have reported that bone marrow cells can promote the regeneration of injured islets. In this study, we investigated the potential of recipient-derived precursor cells to form new pancreatic endocrine cells in islet grafts transplanted under the kidney capsule. Mouse insulin promoter (MIP)-green fluorescence protein (GFP) mice, which express GFP only in β-cells, or β-actin GFP mice, which express GFP ubiquitously, were used to determine if the recipient-derived cells differentiate into β-cells or other types of endocrine cells. We transplanted MIP-GFP islets into wild-type mice, wild-type islets into MIP-GFP mice, β-actin GFP islets into wild-type mice, and wild-type islets into β-actin GFP mice. β-Actin GFP bone marrow cells were then injected into wild-type mice to evaluate the potential role of bone marrow stem cells to provide new islet cells to the graft. No β-cells with green fluorescence were seen in the graft when wild-type islets were transplanted into MIP-GFP mice. When wild-type islets were transplanted into β-actin GFP mice, no β-cells with GFP staining could be identified in the grafts. Similarly, no endocrine cells with GFP staining could be identified in the grafts after injection of β-actin GFP bone marrow cells into wild-type islet-transplanted wild-type mice. This study provides further support for the concept that recipient precursor cells do not produce new β-cells in grafts of transplanted islets.
Intravital Two-Photon Microscopy Assessment of Renal Protection Efficacy of siRNA for p53 in Experimental Rat Kidney Transplantation Models
Authors: Imamura Ryoichi , Isaka Yoshitaka , Sandoval Ruben M. , Ori Asaf , Adamsky Swetlana , Feinstein Elena , Molitoris Bruce A. , Takahara Shiro
Published: December 2010

Renal ischemia-reperfusion (I/R) injury, which is unavoidable in renal transplantation, frequently influences both short- and long-term allograft survival. Despite decades of laboratory and clinical investigations, and the advent of renal replacement therapy, the overall mortality rate due to acute tubular injury has changed little. I/R-induced DNA damage results in p53 activation in proximal tubule cells (PTC), leading to their apoptosis. Therefore, we examined the therapeutic effect of temporary p53 inhibition in two rat renal transplantation models on structural and functional aspects of injury using intravital two-photon microscopy. Nephrectomized Sprague-Dawley rats received syngeneic left kidney transplantation either after 40 min of intentional warm ischemia or after combined 5-h cold and 30-min warm ischemia of the graft. Intravenously administrated siRNA for p53 (siP53) has previously been shown to be filtered and reabsorbed by proximal tubular epithelial cells following the warm ischemia/reperfusion injury in a renal clamp model. Here, we showed that it was also taken up by PTC following 5 h of cold ischemia. Compared to saline-treated recipients, treatment with siP53 resulted in conservation of renal function and significantly suppressed the I/R-induced increase in serum creatinine in both kidney transplantation models. Intravital two-photon microscopy revealed that siP53 significantly ameliorated structural and functional damage to the kidney assessed by quantification of tubular cast formation and the number of apoptotic and necrotic tubular cells and by evaluation of blood flow rate. In conclusion, systemic administration of siRNA for p53 is a promising new approach to protect kidneys from I/R injury in renal transplantation.
Therapeutic Effects of Umbilical Cord Blood-Derived Mesenchymal Stem Cell Transplantation in Experimental Lupus Nephritis
Authors: Chang Jei-Wen , Hung Shun-Pei , Wu Hao-Hsiang , Wu Wen-Mien , Yang An-Hang , Tsai Hsin-Lin , Yang Ling-Yu , Lee Oscar K.
Published: December 2010

Mesenchymal stem cells (MSCs) have been shown to possess immunomodulatory properties. Systemic lupus erythematosus is an autoimmune disease that results in nephritis and subsequent destruction of renal microstructure. We investigated whether transplantation of human umbilical cord blood-derived MSCs (uMSCs) is useful in alleviating lupus nephritis in a murine model. It was found that uMSCs transplantation significantly delayed the development of proteinuria, decreased anti-dsDNA, alleviated renal injury, and prolonged the life span. There was a trend of decreasing T-helper (Th) 1 cytokines (IFN-γ, IL-2) and proinflammatory cytokines (TNF-α, IL-6, IL-12) and increasing Th2 cytokines (IL-4, IL-10). The in vitro coculture experiments showed that uMSCs only inhibited lymphocytes and splenocytes proliferation but not mesangial cells. Long-term engraftment of uMSCs in the kidney was not observed either. Together, these findings indicated that uMSCs were effective in decreasing renal inflammation and alleviating experimental lupus nephritis by inhibiting lymphocytes, inducing polarization of Th2 cytokines, and inhibition of proinflammatory cytokines production rather than direct engraftment and differentiating into renal tissue. Therapeutic effects demonstrated in this preclinical study support further exploration of the possibility to use uMSCs from mismatched donors in lupus nephritis treatment.
Optimal Time Point for Neuronal Generation of Transplanted Neural Progenitor Cells in Injured Spinal Cord following Root Avulsion
Authors: Su Huanxing , Wu Yin , Yuan Qiuju , Guo Jiasong , Zhang Wenming , Wu Wutian
Published: December 2010

Root avulsion of the brachial plexus results in a progressive and pronounced loss of motoneurons. Cell replacement strategies have therapeutic potential in the treatment of motoneuron degenerative neurological disorders. Here, we transplanted spinal cord-derived neural progenitor cells (NPCs) into the cervical ventral horn of adult rats immediately, 2 weeks, or 6 weeks after root avulsion to determine an optimal time scale for the survival and differentiation of grafted cells. We showed that grafted NPCs survived robustly at all three time points and there was no statistical difference in survival rate. Interestingly, however, transplantation at 2 weeks postavulsion significantly increased the neuronal differentiation of transplanted NPCs compared to transplantation immediately or at 6 weeks postavulsion. Moreover, only NPCs transplanted at 2 weeks postavulsion were able to differentiate into choline acetyltransferase (ChAT)-positive neurons. Specific ELISAs and quantitative reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated that expression levels of BDNF and GDNF were significantly upregulated in the ventral cord at 2 weeks postavulsion compared to immediately or at 6 weeks postavulsion. Our study suggests that the cervical ventral horn at 2 weeks postavulsion both supports neuronal differentiation and induces region-specific neuronal generation possibly because of its higher expression of BDNF and GDNF.
Beneficial Effect of Autologous Transplantation of Endothelial Progenitor Cells on Steroid-Induced Femoral Head Osteonecrosis in Rabbits
Authors: Sun Yuan , Feng Yong , Zhang Changqing , Cheng Xiangguo , Chen Shengbao , Ai Zisheng , Zeng Bingfang
Published: December 2010

Femoral head osteonecrosis (ON) is a serious complication of steroid administration. We examined whether implantation of autologous bone marrow-derived endothelial progenitor cells (EPCs) can augment neovascularization and bone regeneration in steroid-induced osteonecrosis of the femoral head. Forty 12-week-old male New-Zealand white rabbits were divided into group I (left untreated, n = 12), group II (core decompression, n = 12), and group III (core decompression + autologous EPCs implantation, n = 16) after receiving an established inductive protocol for inducing steroid-associated ON. Four weeks later, these rabbits were euthanized, bilateral femora were dissected for Micro-CT-based microangiography to assess vascularization, and then the osteonecrotic changes and repair processes were examined histopathologically. Quantitative analysis showed that new vessel formation in group III was significantly greater compared with other groups at 4 weeks after treatment. The histologic and histomorphometric analyses revealed that the new bone volume was significantly higher in group III than in groups I and II 4 weeks after treatment. A combination of EPCs and core decompression enhances the neovascularization and bone regeneration in rabbit steroid-induced femoral head ON. Local implantation of EPCs may provide a novel and effective therapeutic option for early corticosteroid-induced ON.
Bone Marrow Mononuclear Cells Increase Retinal Ganglion Cell Survival and Axon Regeneration in the Adult Rat
Authors: Zaverucha-Do-Valle Camila , Gubert Fernanda , Bargas-Rega Michelle , Coronel Juliana L. L. , Mesentier-Louro Louise A. , Mencalha Andre , Abdelhay Eliana , Santiago Marcelo F. , Mendez-Otero Rosalia
Published: December 2010

The central nervous system (CNS) of adult mammals generally does not regenerate, and many studies have attempted to identify factors that could increase neuroprotection and/or axonal outgrowth after CNS lesions. Using the optic nerve crush of rats as a model for CNS injury, we investigated the effect of intravitreal transplantation of syngeneic bone-marrow mononuclear cells (BMMCs) on the survival of retinal ganglion cells (RGC) and on the regeneration of optic axons. Control animals received intravitreal saline injections after lesion. Injections of BMMCs resulted in a 1.6-fold increase in the number of RGCs surviving 14 days after injury. The BMMC-treated animals also had increased numbers of axons, which grew up to 1.5 mm from the crush site, and also had reduced Müller glia activation. Analysis of mRNAs in all conditions revealed an increase in levels of fibroblast growth factor 2 (FGF-2) mRNA in treated animals 14 days after injury. To investigate whether the regenerated axons could reach the brain, we retrograde labeled the RGCs by injecting a lipophilic tracer into the superior colliculus. We also analyzed the expression of NGFI-A in the superficial layers of the superior colliculus as a possible marker of synaptic input from RGC axons. We found evidence that more RGCs were able to reach the brain after treatment and we showed that NGFI-A expression was higher in the treated animals 60 days after injury. These results demonstrate that transplant of BMMCs can increase neuroprotection and neuroregeneration after injury in a model of optic nerve crush, and these effects could be mediated by FGF-2.
Functional Endothelial Progenitor Cells from Cryopreserved Umbilical Cord Blood
Authors: Lin Ruei-Zeng , Dreyzin Alexandra , Aamodt Kristie , Dudley Andrew C. , Melero-Martin Juan M.
Published: December 2010

Umbilical cord blood (UCB) is recognized as an enriched source of endothelial progenitor cells (EPCs) with potential therapeutic value. Because cryopreservation is the only reliable method for long-term storage of UCB cells, the clinical application of EPCs depends on our ability to acquire them from cryopreserved samples; however, the feasibility of doing so remains unclear. In this study we demonstrate that EPCs can be isolated from cryopreserved UCB-derived mononuclear cells (MNCs). The number of outgrowth EPC colonies that emerged in culture from cryopreserved samples was similar to that obtained from fresh UCB. Furthermore, EPCs obtained from cryopreserved MNCs were phenotypically and functionally indistinguishable from freshly isolated ones, including the ability to form blood vessels in vivo. Our results eliminate the necessity of performing cell isolation procedures ahead of future clinical needs and suggest that EPCs derived from cryopreserved UCB may be suitable for EPC-related therapies.