1
|
Carbillon L. Commentary: AI-based preeclampsia detection and prediction with electrocardiogram data. Front Cardiovasc Med 2024; 11:1437369. [PMID: 39139750 PMCID: PMC11319159 DOI: 10.3389/fcvm.2024.1437369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 06/25/2024] [Indexed: 08/15/2024] Open
Affiliation(s)
- Lionel Carbillon
- Department of Obstetrics and Gynecology, Hôpital Jean Verdier, Assistance Publique—Hôpitaux de Paris, Bondy, France
- Sorbonne North Paris University, Bobigny, France
| |
Collapse
|
2
|
Sedaghati F, Gleason RL. A mathematical model of vascular and hemodynamics changes in early and late forms of preeclampsia. Physiol Rep 2023; 11:e15661. [PMID: 37186372 PMCID: PMC10132946 DOI: 10.14814/phy2.15661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 05/17/2023] Open
Abstract
Preeclampsia-eclampsia syndrome is a leading cause of maternal mortality. The precise etiology of preeclampsia is still not well-defined and different forms exist, including early and late forms or preeclampsia, which may arise via distinctly different mechanisms. Low-dose aspirin administered at the end of the first trimester in women identified as high risk has been shown to reduce the incidence of early, but not late, preeclampsia; however, current risk factors show only fair predictive capability. There is a pressing need to develop accurate descriptions for the different forms of preeclampsia. This paper presents 1D fluid, solid, growth, and remodeling models for pregnancies complicated with early and late forms of preeclampsia. Simulations affirm a broad set of literature results that early forms of preeclampsia are characterized by elevated uterine artery pulsatility index (UA-PI) and total peripheral resistance (TPR) and lower cardiac output (CO), with modestly increased mean arterial blood pressure (MAP) in the first half of pregnancy, with elevation of TPR and MAP beginning at 20 weeks. Conversely, late forms of preeclampsia are characterized by only slightly elevated UA-PI and normal pre-term TPR, and slightly elevated MAP and CO throughout pregnancy, with increased TPR and MAP beginning after 34 weeks. Results suggest that preexisting arterial stiffness may be elevated in women that develop both early forms and late forms of preeclampsia; however, data that verify these results are lacking in the literature. Pulse wave velocity increases in early- and late-preeclampsia, coincident with increases in blood pressure; however, these increases are mainly due to the strain-stiffening response of larger arteries, rather than arterial remodeling-derived changes in material properties. These simulations affirm that early forms of preeclampsia may be associated with abnormal placentation, whereas late forms may be more closely associated with preexisting maternal cardiovascular factors; simulations also highlight several critical gaps in available data.
Collapse
Affiliation(s)
- Farbod Sedaghati
- The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Rudolph L. Gleason
- The George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- The Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| |
Collapse
|
3
|
Lavie A, Ram M, Lev S, Blecher Y, Amikam U, Shulman Y, Avnon T, Weiner E, Many A. Maternal cardiovascular hemodynamics in normotensive versus preeclamptic pregnancies: a prospective longitudinal study using a noninvasive cardiac system (NICaS™). BMC Pregnancy Childbirth 2018; 18:229. [PMID: 29898711 PMCID: PMC6001131 DOI: 10.1186/s12884-018-1861-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/25/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Preeclampsia is among the most common medical complications of pregnancy. The clinical utility of invasive hemodynamic monitoring in preeclampsia (e.g., Swan-Ganz catheter) is controversial. Thoracic impedance cardiography (TIC) and Doppler echocardiography are noninvasive techniques but they both have important limitations. NICaS™ (NI Medical, PetachTikva, Israel) is a noninvasive cardiac system for determining cardiac output (CO) that utilizes regional impedance cardiography (RIC) by noninvasively measuring the impedance signal in the periphery. It outperformed any other impedance cardiographic technology and was twice as accurate as TIC. METHODS We used the NICaS™ system to compare the hemodynamic parameters of women with severe preeclampsia (PET group, n = 17) to a cohort of healthy normotensive pregnant women with a singleton pregnancy at term (control group, n = 62) (1/2015-6/2015). Heart rate (HR), stroke volume (SV), CO, total peripheral resistance (TPR) and mean arterial pressure (MAP) were measured 15-30 min before CS initiation, immediately after administering spinal anesthesia, immediately after delivery of the fetus and placenta, at the abdominal fascia closure and within 24-36 and 48-72 h postpartum. RESULTS The COs before and during the CS were significantly higher in the control group compared to the PET group (P < .05), but reached equivalent values within 24-36 h postpartum. CO peaked at delivery of the newborn and the placenta and started to decline afterwards in both groups. The MAP and TPR values were significantly higher in the PET group at all points of assessment except at 48-72 h postpartum when it was still significantly higher for MAP while the TPR only exhibited a higher trend but not statistically significant. The NICaS™ device noninvasively demonstrated low CO and high TPR profiles in the PET group compared to controls. CONCLUSIONS The immediate postpartum period is accompanied by the most dramatic hemodynamic changes and fluid shifts, during which the parturient should be closely monitored. The NICaS™ device may help the clinician to customize the most optimal management for individual parturients. Our findings require validation by further studies on larger samples.
Collapse
Affiliation(s)
- Anat Lavie
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel. .,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Maya Ram
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shaul Lev
- General ICU, Hasharon Hospital, Rabin Medical Center, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yair Blecher
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Uri Amikam
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yael Shulman
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tomer Avnon
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eran Weiner
- Department of Obstetrics and Gynecology, Edith Wolfson Medical Center, Holon, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ariel Many
- Department of Obstetrics and Gynecology, Lis Hospital, Tel Aviv Sourasky Medical Center, 6 Weizman Street, 6423906, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
4
|
Osman MW, Nath M, Khalil A, Webb DR, Robinson TG, Mousa HA. Longitudinal study to assess changes in arterial stiffness and cardiac output parameters among low-risk pregnant women. Pregnancy Hypertens 2017; 10:256-261. [PMID: 29089251 DOI: 10.1016/j.preghy.2017.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/13/2017] [Accepted: 10/14/2017] [Indexed: 11/15/2022]
Abstract
AIM A single-centre, prospective longitudinal study to assess changes in maternal arterial stiffness and cardiac output parameters among low-risk healthy pregnant women. METHODOLOGY Thirty low-risk, healthy, pregnant women attending their routine antenatal dating ultrasound scan were recruited. Non-invasive assessment of arterial stiffness and cardiac output was undertaken at five gestational windows from 11 to 40 weeks of pregnancy. Data were analysed using a linear mixed model incorporating time and other relevant predictors as fixed effects, and patient as a random effect. RESULTS Gestational age had a significant effect on all arterial stiffness parameters, including brachial augmentation index (AIx) (p = .001), aortic AIx (p = .002) and aortic pulse wave velocity (p = .002). The aortic AIx (%) reduced during pregnancy: the lowest mean (standard error, SE) was 4.07 (1.01) at 28 weeks before it increased to 7.04 (SE 1.64) at 40 weeks. Similarly, non-invasive assessments of cardiac output (p < .001), stroke volume (p = .014), heart rate (p < .001) and total peripheral resistance (p < .001) demonstrated significant changes with gestational age. Mean cardiac output (l/m) increased during pregnancy reaching a peak at 28 weeks gestation 6.66 (SE 0.28), but dropped thereafter to reach 5.71 (SE 0.25) around term. CONCLUSION The current study provides pregnancy normograms for gestational changes in arterial stiffness and cardiac output parameters among low-risk, healthy pregnant women. Further work will be required to assess the risk of placental mediated diseases and pregnancy outcome among pregnant women with parameters outside the normal range.
Collapse
Affiliation(s)
- Mohamed Waseem Osman
- Clinical Research Fellow, University Hospitals of Leicester, United Kingdom; University Hospitals of Leicester, United Kingdom.
| | - Mintu Nath
- University of Leicester, United Kingdom.
| | - Asma Khalil
- St George's University of London, United Kingdom.
| | - David R Webb
- Diabetes Research Centre, University of Leicester, United Kingdom.
| | - Thompson G Robinson
- Department of Cardiovascular Sciences and NIHR Leicester Biomedical Research Centre, University of Leicester, United Kingdom.
| | - Hatem A Mousa
- University Hospitals of Leicester, United Kingdom; University of Leicester, United Kingdom.
| |
Collapse
|
5
|
Andreas M, Kuessel L, Kastl SP, Wirth S, Gruber K, Rhomberg F, Gomari-Grisar FA, Franz M, Zeisler H, Gottsauner-Wolf M. Bioimpedance cardiography in pregnancy: A longitudinal cohort study on hemodynamic pattern and outcome. BMC Pregnancy Childbirth 2016; 16:128. [PMID: 27251149 PMCID: PMC4888315 DOI: 10.1186/s12884-016-0918-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/25/2016] [Indexed: 12/22/2022] Open
Abstract
Background Pregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child. Bioimpedance cardiography may provide additional outcome-relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases. Methods We performed a prospective longitudinal cohort trial in an outpatient setting and included 242 pregnant women. Cardiac output and concomitant hemodynamic data were recorded from 11th–13th week of gestation every 5th week as well as at two occasions post partum employing bioimpedance cardiography. Results Cardiac output increased during pregnancy and peaked early in the third trimester. A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes. Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy. Furthermore, an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis. Conclusions Cardiovascular adaptation during pregnancy is characterized by distinct pattern described herein. These may be altered in women at risk for preeclampsia or reduced birthweigth. The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks.
Collapse
Affiliation(s)
- Martin Andreas
- Department of Surgery, Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
| | - Lorenz Kuessel
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Stefan P Kastl
- Department of Internal Medicine II, Division of Cardiology and Angiology all above, Medical University of Vienna, Austria, Vienna, Austria
| | - Stefan Wirth
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Kathrin Gruber
- Institute for Service Marketing and Tourism, University of Economics and Business, Vienna, Austria
| | - Franziska Rhomberg
- Department of Internal Medicine II, Division of Cardiology and Angiology all above, Medical University of Vienna, Austria, Vienna, Austria
| | - Fatemeh A Gomari-Grisar
- Department of Internal Medicine II, Division of Cardiology and Angiology all above, Medical University of Vienna, Austria, Vienna, Austria
| | - Maximilian Franz
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Harald Zeisler
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Michael Gottsauner-Wolf
- Department of Internal Medicine II, Division of Cardiology and Angiology all above, Medical University of Vienna, Austria, Vienna, Austria
| |
Collapse
|
6
|
Meah VL, Cockcroft JR, Backx K, Shave R, Stöhr EJ. Cardiac output and related haemodynamics during pregnancy: a series of meta-analyses. Heart 2016; 102:518-26. [PMID: 26794234 DOI: 10.1136/heartjnl-2015-308476] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/11/2015] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE Cardiac output, a fundamental parameter of cardiovascular function, has consistently been shown to increase across healthy pregnancy; however, the time course and magnitude of adaptation remains equivocal within published literature. The aim of the present meta-analyses was to comprehensively describe the pattern of change in cardiac output during healthy pregnancy. METHOD A series of meta-analyses of previously published cardiac output data during healthy, singleton pregnancies was completed. PubMed and Scopus databases were searched for studies published between 1996 and 2014. Included studies reported absolute values during a predetermined gestational age (non-pregnant, late first trimester, early and late second trimester, early and late third trimester, early and late postpartum). Cardiac output was measured through echocardiography, impedance cardiography or inert gas rebreathing. Observational data were meta-analysed at each gestational age using a random-effects model. If reported, related haemodynamic variables were evaluated. RESULTS In total, 39 studies were eligible for inclusion, with pooled sample sizes ranging from 259 to 748. Cardiac output increased during pregnancy reaching its peak in the early third trimester, 1.5 L/min (31%) above non-pregnant values. The observed results from this study indicated a non-linear rise to this point. In the early postpartum, cardiac output had returned to non-pregnant values. CONCLUSION The present results suggest that cardiac output peaks in the early third trimester, following a non-linear pattern of adaptation; however, this must be confirmed using longitudinal studies. The findings provide new insight into the normal progression of cardiac output during pregnancy.
Collapse
Affiliation(s)
- Victoria L Meah
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| | | | - Karianne Backx
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| | - Rob Shave
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| | - Eric J Stöhr
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| |
Collapse
|
7
|
Noninvasive cardiac monitoring in pregnancy: impedance cardiography versus echocardiography. J Perinatol 2013; 33:675-80. [PMID: 23680787 PMCID: PMC3751992 DOI: 10.1038/jp.2013.35] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 01/16/2013] [Accepted: 02/12/2013] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of this study was to report thoracic impedance cardiography (ICG) measurements and compare them with echocardiography (echo) measurements throughout pregnancy and in varied maternal positions. METHOD A prospective cohort study involving 28 healthy parturients was performed using ICG and echo at three time points and in two maternal positions. Pearson's correlations, Bland-Altman plots and paired t-tests were used for statistical analysis. RESULT Significant agreements between many but not all ICG and echo contractility, flow and resistance measurements were demonstrated. Differences in stroke volume (SV) due to maternal position were also detected by ICG in the antepartum (AP) period. Significant trends were observed by ICG for cardiac output and thoracic fluid content (TFC; P<0.025) with advancing pregnancy stages. CONCLUSION ICG and echo demonstrate significant correlations in some but not all measurements of cardiac function. ICG has the ability to detect small changes in SV associated with maternal position change. ICG measurements reflected maximal cardiac contractility in the a AP period yet reflected a decrease in contractility and an increase in TFC in the postpartum period.
Collapse
|
8
|
Lau SY, Barrett CJ, Guild SJ, Chamley LW. Necrotic trophoblast debris increases blood pressure during pregnancy. J Reprod Immunol 2013; 97:175-82. [DOI: 10.1016/j.jri.2012.12.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 11/16/2012] [Accepted: 12/13/2012] [Indexed: 11/30/2022]
|
9
|
Digby GC, Driver HS, Fitzpatrick M, Ropchan G, Parker CM. Use of Bioimpedance to Assess Changes in Hemodynamics During Acute Administration of CPAP. Cardiol Res 2011; 2:51-57. [PMID: 28348662 PMCID: PMC5358188 DOI: 10.4021/cr18w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2011] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Attempts to investigate the mechanisms by which continuous positive airway pressure (CPAP) therapy improves heart function in patients with obstructive sleep apnea (OSA) have been limited by the lack of non-invasive methods to assess cardiac performance. We used transthoracic electrical bioimpedance (TEB) to assess acute hemodynamic changes including heart rate (HR), stroke volume (SV), cardiac output (CO) and cardiac index (CI) during PAP titration in (1) post-operative cardiac surgery patients, (2) patients with severe OSA, and (3) normal healthy volunteers. METHODS Post-operative cardiac surgery patients were studied via TEB and pulmonary artery catheter (PAC) during acute titration of positive end-expiratory pressure (PEEP) while mechanically ventilated. Patients with severe OSA were studied non-invasively by TEB during acute CPAP titration in supine stage 2 sleep, and normal subjects while awake and recumbent. RESULTS In post-operative cardiac surgery patients (n = 3), increasing PEEP to 18 cmH2O significantly reduced SV and CI relative to baseline. There was no difference between TEB and PAC in terms of ability to assess variations in hemodynamic parameters. In patients with severe OSA (n = 3), CPAP titration to optimal pressure to alleviate obstructive apneas reduced HR, SV, CO and CI significantly compared to without CPAP. In three healthy subjects, maximal tolerated CPAP reduced SV and CO significantly compared to baseline. CONCLUSIONS Acute administration of CPAP causes a decrease in CO and CI, apparently a consequence of a reduction in SV. TEB appears to be an accurate and reproducible non-invasive method of detecting changes in hemodynamics.
Collapse
Affiliation(s)
| | - Helen S. Driver
- Department of Medicine, Queen’s University, Kingston, Ontario, Canada
- Sleep Disorders Laboratory, Kingston General Hospital, Kingston, Ontario, Canada
| | - Michael Fitzpatrick
- Department of Medicine, Queen’s University, Kingston, Ontario, Canada
- Sleep Disorders Laboratory, Kingston General Hospital, Kingston, Ontario, Canada
| | - Glorianne Ropchan
- Department of Surgery, Queen’s University, Kingston, Ontario, Canada
| | - Christopher M. Parker
- Department of Medicine, Queen’s University, Kingston, Ontario, Canada
- Department of Physiology, Queen’s University, Kingston, Ontario, Canada
| |
Collapse
|
10
|
Heiskanen N, Saarelainen H, Kärkkäinen H, Valtonen P, Lyyra-Laitinen T, Laitinen T, Vanninen E, Heinonen S. Cardiovascular autonomic responses to head-up tilt in gestational hypertension and normal pregnancy. Blood Press 2010; 20:84-91. [DOI: 10.3109/08037051.2010.532313] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Nonna Heiskanen
- Department of Obsteterics and Gynecology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland
| | - Heli Saarelainen
- Department of Obsteterics and Gynecology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland
| | - Henna Kärkkäinen
- Department of Obsteterics and Gynecology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland
| | - Pirjo Valtonen
- Department of Clinical Chemistry, Kuopio University Hospital, University of Kuopio, Finland
| | - Tiina Lyyra-Laitinen
- Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, University of Kuopio, Finland
| | - Tomi Laitinen
- Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, University of Kuopio, Finland
| | - Esko Vanninen
- Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, University of Kuopio, Finland
| | - Seppo Heinonen
- Department of Obsteterics and Gynecology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland
| |
Collapse
|
11
|
Ohashi Y, Ibrahim H, Furtado L, Kingdom J, Carvalho JCA. Non-Invasive Hemodynamic Assessment of Non-pregnant, Healthy Pregnant and Preeclamptic Women using Bio-Reactance. Braz J Anesthesiol 2010; 60:603-13, 335-40. [DOI: 10.1016/s0034-7094(10)70075-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 06/14/2010] [Indexed: 10/26/2022] Open
|