Raluca Purtan - Academia.edu (original) (raw)
Papers by Raluca Purtan
Propensity Score-Matched Analysis of Minimal Invasive Surgery versus Open Surgery for Colorectal Cancer in Older Patients
PubMed, Sep 30, 2023
Introduction: Currently, surgeons deal with an older patient cohort, confronting new challenges b... more Introduction: Currently, surgeons deal with an older patient cohort, confronting new challenges brought by the raised life expectancy. This population is unrepresented in surgical trials; therefore, the optimal therapy is still a matter of debate. The efficacy of open versus minimal invasive management of colorectal cancer (CRC) in an elderly cohort is not clearly established. The current study assesses the minimal invasive approach in elderly patients undergoing colorectal surgery. Material and Methods: The General Surgery Department database was inquired between 2012 and 2015 using the following filters: age â?¥ 65 and rectal or colon adenocarcinoma. After applying the exclusion criteria, 975 cases were obtained: 842 underwent open surgery (OS) and 133 underwent minimal invasive surgery (MIS). A propensity score matching was performed to reduce patient selection bias. Results: After the propensity score matching, the MIS group had a shorter postoperative hospital stay than the OS group (p = 0.025). From the preoperative variables, the presence of chronic lung disease was significantly higher in the OS group (p = 0.039). The presence of chronic lung disease positively associates with the Clavien-Dindo classification (p 0.001) and with the number of days from surgery to discharge (p = 0.028). Conclusion: The chronological age alone should not be a limit to MIS granting that it showed no inferiority to the OS in terms of postoperative morbidity, correlating with lower postoperative stay in the elderly. Further prospective studies are needed to assess the outcome of MIS in elderly population.
Medicina
Background and Objectives: Although many of the neuroendocrine neoplasms (NEN) have a typically p... more Background and Objectives: Although many of the neuroendocrine neoplasms (NEN) have a typically prolonged natural history compared with other gastrointestinal tract cancers, at least 40% of patients develop liver metastases. This study aims to identify whether liver resection improves the overall survival of patients with liver metastases from NEN. Materials and Methods: We conducted a retrospective study at “Fundeni” Clinical Institute over a time period of 15 years; we thereby identified a series of 93 patients treated for NEN with liver metastases, which we further divided into 2 groups as follows: A (45 patients) had been subjected to liver resection complemented by systemic therapies, and B (48 patients) underwent systemic therapy alone. To reduce the patient selection bias we performed at first a propensity score matching. This was followed by a bootstrapping selection with Jackknife error correction, with the purpose of getting a statistically illustrative sample. Results: Th...
Acta Endocrinologica (Bucharest), 2018
Context. Pancreatic neuroendocrine tumours (PanNETs) are rare pancreatic neoplasms. PanNETs can b... more Context. Pancreatic neuroendocrine tumours (PanNETs) are rare pancreatic neoplasms. PanNETs can be treated by multimodal approach including surgery, locoregional and systemic therapy. Objective. The aim of the present study is to evaluate predictive factors of overall survival in patients with PanNETs surgically treated at a single center. Subjects and methods. The study group consisted of 120 patients with PanNETs who had undergone surgery at the
Cercetare și Politici Sociale. Volumul conferinței naţionale cu participare internațională organizată de Facultatea de Ştiinţe Socio-Umane, Universitatea din Oradea, în 28-29 Mai 2010 (Research and Social Policies. The Volume of the National Conference with International Participation Organized b...
Social Science Research Network, Mar 30, 2012
TNF-alpha levels drop after splenectomy, but increase after partial/subtotal or minimally invasive splenectomy
Acta Chirurgica Belgica, Apr 22, 2021
The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this stu... more The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. We prospectively collected blood before (D0) and at multiple time points after (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) splenectomy and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after S/PS (p = .0388). Open sur...
Chirurgia (Bucharest, Romania : 1990)
Surgery remains a mainstay of current approaches for the treatment of gastric cancer. Since the i... more Surgery remains a mainstay of current approaches for the treatment of gastric cancer. Since the introduction of the first mechanical stapling devices, a debate started about whether mechanical staplers or manual suture produce better results. 88 patients operated by a single team between January 2004 and November 2011 were included in this study: 14 patients underwent minimally invasive total gastrectomy and 74 patients had an open total gastrectomy. Manual suture anastomoses were performed on 59 patients and stapled anastomoses were done on 29 patients. There were no cases of anastomotic leakage or stenosis for the stapled group. There were 4 cases of anastomotic leakage in the manually suture group. There were no cases of anastomosis related mortality. the data support the use of stapled esophagojejunal anastomosis as a safe way to create a esophagojejunal anastomosis, with superior results in term of anastomotic leakage or stenosis to those with hand suturing.
Prognostic Factors After Surgery for Pancreatic Neuroendocrine Tumors: A Single Center Experience
Background/Aim: The aim of the present study is to analyze a single-institution experience for su... more Background/Aim: The aim of the present study is to analyze a single-institution experience for surgically treated pancreatic neuroendocrine tumors (PNET). Patients and Methods: From 2002 to 2012, 98 patients with PNETs underwent surgery at the Center of Digestive Diseases and Liver Transplantation of Fundeni Clinical Institute, Bucharest, Romania. Overall survival rates were calculated using the Kaplan-Meier method. Results: There were 59 (60%) patients with functional PTEN and 39 (40%) with non-functional tumors. Surgical resection of the primary PNET tumor was performed in 88 patients. Twenty five patients (24.5%) presented with synchronous liver metastases; they underwent liver directed therapy: resection (5), transarterial chemoembolization (1), radiofrequency ablation (1). Univariate analysis showed that synchronous liver metastases (p<0.001), lymph node metastases (p=0.047), Ki67 (p<0.001), ENET grading (p<0.001) were prognostic factors of survival. Conclusion: Locore...
Hepato-gastroenterology
Central pancreatectomy is a pancreas-sparing alternative to standard pancreatic resections in sel... more Central pancreatectomy is a pancreas-sparing alternative to standard pancreatic resections in selected cases. Although associated with high morbidity, the risk factors for surgical complications of this procedure are not yet defined. The clinicopathological and perioperative data of 24 patients who underwent central pancreatectomies (2002-2010) were correlated with surgical complications. The overall morbidity rate was 54% (pancreatic fistula, 40%). In a univariate analysis, age over 40 years, body mass index ≥30kg/m2, smoking and American Society of Anesthesiologists III scores were significantly correlated with increased morbidity. In a multivariate analysis, a significant correlation with the development of complications was found for body mass index ≥30kg/m2 and age over 40 years. Certain patient-related factors (older age, obesity and smoking) appear to have a negative impact on early postoperative outcome after central pancreatectomy. For patients with these factors, an altern...
World Journal of Surgery, 2014
A Modified Stochastic Simulation Algorithm for Time-Dependent Intensity Rates
2013 19th International Conference on Control Systems and Computer Science, 2013
ABSTRACT There are two main approaches in the mathematical modeling of coupled systems of (bio)ch... more ABSTRACT There are two main approaches in the mathematical modeling of coupled systems of (bio)chemical reactions: continuous, represented by differential equations whose variables are concentrations or discrete, represented by stochastic processes whose variables are numbers of molecules. The latter approach is used mostly for biochemical systems with a low to moderate number of molecules of certain species and this kind of systems are typically modeled as continuous time - discrete state Markov Process. There are exact stochastic algorithms to simulate state trajectories of discrete, stochastic systems and these algorithms are based on methods that are rigorously equivalent to the Master Equation approach. Two of the most widely used methods for simulating the stochastic dynamics of a chemical system are the exact stochastic simulation algorithm (SSA, known also as Gillespie algorithm) and its approximate variant, the tau-leaping algorithm. This paper describes a modified version of SSA - First reaction method - by letting the intensity rates of the reactions to be functions of time. The importance of this adaptation is obvious when considering some classes of biological models (for example, the one involving circadian rhythm). The underlying assumptions are that the system is well stirred such that at any moment, each reactions occur with equal probability at any position, that each reaction, once occurred, completes instantaneously (there are no reactions with delay involved) and that the system is non stiff (there are no different time scales of the reactions involved).
TNF-alpha levels drop after splenectomy, but increase after partial/subtotal or minimally invasive splenectomy
Acta chirurgica Belgica, 2021
BACKGROUND The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim ... more BACKGROUND The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. METHODS We prospectively collected blood before (D0) and at multiple time points after (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) splenectomy and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. RESULTS When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after...
Blockchain in Intelligent Transportation Systems
Electronics, 2020
Blockchain is an emerging technology that has shaken the financial sector, and which is already p... more Blockchain is an emerging technology that has shaken the financial sector, and which is already perceived as having an impact. A blockchain is a network of many interconnected nodes, both trustworthy and malicious, which can reach a consensus and generate valid data. The resulting information is packed into a block and permanently saved on the network in a tamper-proof way. In this paper, we propose an adaptation of blockchain for securely storing data in a vehicular-based network. Our approach can work for storing data such as traffic events and user reputation. The proposed solution has two interconnected components: the Intelligent Transportation System (ITS) blockchain and the reputation system. The paper presents synthetic tests which validate the use cases of the solution: users reporting speeds and alerts behind which we see a fair reputation system penalising the (wrong/false) users.
TNF-alpha releasing capacity of the whole blood drops after open total splenectomy, but increases after partial/subtotal or minimally invasive splenectomy
Acta Chirurgica Belgica, 2021
Background The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim ... more Background The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. Methods We prospectively collected blood before (D0) and at multiple time points after splenectomy (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. Results When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after...
The goal of the paper is to develop methods and algorithms based on the chaotic dynamical systems... more The goal of the paper is to develop methods and algorithms based on the chaotic dynamical systems theory (fractal dimension analysis) and specific nonparametric statistics methods (bootstrap and bias-corrected and accelerated percentile intervals) and to apply them to study CT images of sinus tumors. The statistical analysis shows that the use of the fractal dimension of the mass texture discriminate best between malignant and benignant sinus tumor, therefore leads to an improvement of the diagnosis.
Constant Internet connectivity has become a necessity in our lives. Hence, music festival organiz... more Constant Internet connectivity has become a necessity in our lives. Hence, music festival organizers allocate part of their budget for temporary Wi-Fi equipment in order to sustain the high network traffic generated in such a small geographical area, but this naturally leads to high costs that need to be decreased. Thus, in this paper, we propose a solution that can help offload some of that traffic to an opportunistic network created with the attendees’ smartphones, therefore minimizing the costs of the temporary network infrastructure. Using a music festival-based mobility model that we propose and analyze, we introduce two routing algorithms which can enable end-to-end message delivery between participants. The key factors for high performance are social metrics and limiting the number of message copies at any given time. We show that the proposed solutions are able to offer high delivery rates and low delivery delays for various scenarios at a music festival.
Sensors
With the rate at which smartphones are currently evolving, more and more of human life will be co... more With the rate at which smartphones are currently evolving, more and more of human life will be contained in these devices. At a time when data privacy is extremely important, it is crucial to protect one’s mobile device. In this paper, we propose a new non-intrusive gait recognition based mechanism that can enhance the security of smartphones by rapidly identifying users with a high degree of confidence and securing sensitive data in case of an attack, with a focus on a potential architecture for such an algorithm for the Android environment. The motion sensors on an Android device are used to create a statistical model of a user’s gait, which is later used for identification. Through experimental testing, we prove the capability of our proposed solution by correctly classifying individuals with an accuracy upwards of 90% when tested on data recorded during multiple activities. The experiments, conducted on a low sampling rate and at short time intervals, show the benefits of our so...
Long-Term Evaluation of the Outcomes of Subtotal Laparoscopic and Robotic Splenectomy in Hereditary Spherocytosis
World Journal of Surgery
BIOMATH
We develop a stochastic model for an intracellular active transport problem. Our aims are to calc... more We develop a stochastic model for an intracellular active transport problem. Our aims are to calculate the probability that a molecular motor reaches a hidden target, to study what influences this probability and to calculate the time required for the molecular motor to hit the target (Mean First Passage Time). We study different biologically relevant scenarios, which include the possibility of multiple hidden targets (which breed competition) and the presence of obstacles. The purpose of including obstacles is to illustrate actual disruptions of the intracellular transport (which can result, for example, in several neurological disorders. From a mathematical point of view, the intracellular active transport is modelled by two independent continuous-time, discrete space Markov chains: one for the dynamics of the molecular motor in the space intervals and one for the domain of target. The process is time homogeneous and independent of the position of the molecular motor.
Texts in Biomathematics
We develop a stochastic model for an intracellular active transport problem. Our aims are to calc... more We develop a stochastic model for an intracellular active transport problem. Our aims are to calculate the probability that a molecular motor reaches a hidden target, to study what influences this probability and to calculate the time required for the molecular motor to hit the target (mean first passage time). We study different biologically relevant scenarios, which include the possibility of multiple hidden targets (which breed competition) and the presence of obstacles. The purpose of including obstacles is to illustrate actual disruptions of the intracellular transport (which can result, for example, in several neurological disorders. From a mathematical point of view, the intracellular active transport is modelled by two independent continuous-time, discrete space Markov chains: one for the dynamics of the molecular motor in the space intervals and one for the domain of target. The process is time homogeneous and independent of the position of the molecular motor.
PloS one, 2017
Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and trea... more Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and treatment. A large panel of small non-coding microRNAs was reported to modulate the immune response in sepsis but have not been tested in clinical practice. Large-scale identification of microRNA networks in sepsis might reveal a new biological mechanism that can be also targeted by gene therapy. Therefore, the main objective of this study is to perform a comparison of the miRNA network between septic patients and healthy controls. We used the previously measured levels of expression of 16 different circulating human and viral microRNAs in plasma from 99 septic patients and 53 healthy controls. We used three different computational methods to find correlations between the expressions of microRNAs and to build microRNA networks for the two categories, septic patients and healthy controls. We found that the microRNA network of the septic patients is significantly less connected when compared t...
Propensity Score-Matched Analysis of Minimal Invasive Surgery versus Open Surgery for Colorectal Cancer in Older Patients
PubMed, Sep 30, 2023
Introduction: Currently, surgeons deal with an older patient cohort, confronting new challenges b... more Introduction: Currently, surgeons deal with an older patient cohort, confronting new challenges brought by the raised life expectancy. This population is unrepresented in surgical trials; therefore, the optimal therapy is still a matter of debate. The efficacy of open versus minimal invasive management of colorectal cancer (CRC) in an elderly cohort is not clearly established. The current study assesses the minimal invasive approach in elderly patients undergoing colorectal surgery. Material and Methods: The General Surgery Department database was inquired between 2012 and 2015 using the following filters: age â?¥ 65 and rectal or colon adenocarcinoma. After applying the exclusion criteria, 975 cases were obtained: 842 underwent open surgery (OS) and 133 underwent minimal invasive surgery (MIS). A propensity score matching was performed to reduce patient selection bias. Results: After the propensity score matching, the MIS group had a shorter postoperative hospital stay than the OS group (p = 0.025). From the preoperative variables, the presence of chronic lung disease was significantly higher in the OS group (p = 0.039). The presence of chronic lung disease positively associates with the Clavien-Dindo classification (p 0.001) and with the number of days from surgery to discharge (p = 0.028). Conclusion: The chronological age alone should not be a limit to MIS granting that it showed no inferiority to the OS in terms of postoperative morbidity, correlating with lower postoperative stay in the elderly. Further prospective studies are needed to assess the outcome of MIS in elderly population.
Medicina
Background and Objectives: Although many of the neuroendocrine neoplasms (NEN) have a typically p... more Background and Objectives: Although many of the neuroendocrine neoplasms (NEN) have a typically prolonged natural history compared with other gastrointestinal tract cancers, at least 40% of patients develop liver metastases. This study aims to identify whether liver resection improves the overall survival of patients with liver metastases from NEN. Materials and Methods: We conducted a retrospective study at “Fundeni” Clinical Institute over a time period of 15 years; we thereby identified a series of 93 patients treated for NEN with liver metastases, which we further divided into 2 groups as follows: A (45 patients) had been subjected to liver resection complemented by systemic therapies, and B (48 patients) underwent systemic therapy alone. To reduce the patient selection bias we performed at first a propensity score matching. This was followed by a bootstrapping selection with Jackknife error correction, with the purpose of getting a statistically illustrative sample. Results: Th...
Acta Endocrinologica (Bucharest), 2018
Context. Pancreatic neuroendocrine tumours (PanNETs) are rare pancreatic neoplasms. PanNETs can b... more Context. Pancreatic neuroendocrine tumours (PanNETs) are rare pancreatic neoplasms. PanNETs can be treated by multimodal approach including surgery, locoregional and systemic therapy. Objective. The aim of the present study is to evaluate predictive factors of overall survival in patients with PanNETs surgically treated at a single center. Subjects and methods. The study group consisted of 120 patients with PanNETs who had undergone surgery at the
Cercetare și Politici Sociale. Volumul conferinței naţionale cu participare internațională organizată de Facultatea de Ştiinţe Socio-Umane, Universitatea din Oradea, în 28-29 Mai 2010 (Research and Social Policies. The Volume of the National Conference with International Participation Organized b...
Social Science Research Network, Mar 30, 2012
TNF-alpha levels drop after splenectomy, but increase after partial/subtotal or minimally invasive splenectomy
Acta Chirurgica Belgica, Apr 22, 2021
The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this stu... more The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. We prospectively collected blood before (D0) and at multiple time points after (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) splenectomy and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after S/PS (p = .0388). Open sur...
Chirurgia (Bucharest, Romania : 1990)
Surgery remains a mainstay of current approaches for the treatment of gastric cancer. Since the i... more Surgery remains a mainstay of current approaches for the treatment of gastric cancer. Since the introduction of the first mechanical stapling devices, a debate started about whether mechanical staplers or manual suture produce better results. 88 patients operated by a single team between January 2004 and November 2011 were included in this study: 14 patients underwent minimally invasive total gastrectomy and 74 patients had an open total gastrectomy. Manual suture anastomoses were performed on 59 patients and stapled anastomoses were done on 29 patients. There were no cases of anastomotic leakage or stenosis for the stapled group. There were 4 cases of anastomotic leakage in the manually suture group. There were no cases of anastomosis related mortality. the data support the use of stapled esophagojejunal anastomosis as a safe way to create a esophagojejunal anastomosis, with superior results in term of anastomotic leakage or stenosis to those with hand suturing.
Prognostic Factors After Surgery for Pancreatic Neuroendocrine Tumors: A Single Center Experience
Background/Aim: The aim of the present study is to analyze a single-institution experience for su... more Background/Aim: The aim of the present study is to analyze a single-institution experience for surgically treated pancreatic neuroendocrine tumors (PNET). Patients and Methods: From 2002 to 2012, 98 patients with PNETs underwent surgery at the Center of Digestive Diseases and Liver Transplantation of Fundeni Clinical Institute, Bucharest, Romania. Overall survival rates were calculated using the Kaplan-Meier method. Results: There were 59 (60%) patients with functional PTEN and 39 (40%) with non-functional tumors. Surgical resection of the primary PNET tumor was performed in 88 patients. Twenty five patients (24.5%) presented with synchronous liver metastases; they underwent liver directed therapy: resection (5), transarterial chemoembolization (1), radiofrequency ablation (1). Univariate analysis showed that synchronous liver metastases (p<0.001), lymph node metastases (p=0.047), Ki67 (p<0.001), ENET grading (p<0.001) were prognostic factors of survival. Conclusion: Locore...
Hepato-gastroenterology
Central pancreatectomy is a pancreas-sparing alternative to standard pancreatic resections in sel... more Central pancreatectomy is a pancreas-sparing alternative to standard pancreatic resections in selected cases. Although associated with high morbidity, the risk factors for surgical complications of this procedure are not yet defined. The clinicopathological and perioperative data of 24 patients who underwent central pancreatectomies (2002-2010) were correlated with surgical complications. The overall morbidity rate was 54% (pancreatic fistula, 40%). In a univariate analysis, age over 40 years, body mass index ≥30kg/m2, smoking and American Society of Anesthesiologists III scores were significantly correlated with increased morbidity. In a multivariate analysis, a significant correlation with the development of complications was found for body mass index ≥30kg/m2 and age over 40 years. Certain patient-related factors (older age, obesity and smoking) appear to have a negative impact on early postoperative outcome after central pancreatectomy. For patients with these factors, an altern...
World Journal of Surgery, 2014
A Modified Stochastic Simulation Algorithm for Time-Dependent Intensity Rates
2013 19th International Conference on Control Systems and Computer Science, 2013
ABSTRACT There are two main approaches in the mathematical modeling of coupled systems of (bio)ch... more ABSTRACT There are two main approaches in the mathematical modeling of coupled systems of (bio)chemical reactions: continuous, represented by differential equations whose variables are concentrations or discrete, represented by stochastic processes whose variables are numbers of molecules. The latter approach is used mostly for biochemical systems with a low to moderate number of molecules of certain species and this kind of systems are typically modeled as continuous time - discrete state Markov Process. There are exact stochastic algorithms to simulate state trajectories of discrete, stochastic systems and these algorithms are based on methods that are rigorously equivalent to the Master Equation approach. Two of the most widely used methods for simulating the stochastic dynamics of a chemical system are the exact stochastic simulation algorithm (SSA, known also as Gillespie algorithm) and its approximate variant, the tau-leaping algorithm. This paper describes a modified version of SSA - First reaction method - by letting the intensity rates of the reactions to be functions of time. The importance of this adaptation is obvious when considering some classes of biological models (for example, the one involving circadian rhythm). The underlying assumptions are that the system is well stirred such that at any moment, each reactions occur with equal probability at any position, that each reaction, once occurred, completes instantaneously (there are no reactions with delay involved) and that the system is non stiff (there are no different time scales of the reactions involved).
TNF-alpha levels drop after splenectomy, but increase after partial/subtotal or minimally invasive splenectomy
Acta chirurgica Belgica, 2021
BACKGROUND The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim ... more BACKGROUND The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. METHODS We prospectively collected blood before (D0) and at multiple time points after (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) splenectomy and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. RESULTS When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after...
Blockchain in Intelligent Transportation Systems
Electronics, 2020
Blockchain is an emerging technology that has shaken the financial sector, and which is already p... more Blockchain is an emerging technology that has shaken the financial sector, and which is already perceived as having an impact. A blockchain is a network of many interconnected nodes, both trustworthy and malicious, which can reach a consensus and generate valid data. The resulting information is packed into a block and permanently saved on the network in a tamper-proof way. In this paper, we propose an adaptation of blockchain for securely storing data in a vehicular-based network. Our approach can work for storing data such as traffic events and user reputation. The proposed solution has two interconnected components: the Intelligent Transportation System (ITS) blockchain and the reputation system. The paper presents synthetic tests which validate the use cases of the solution: users reporting speeds and alerts behind which we see a fair reputation system penalising the (wrong/false) users.
TNF-alpha releasing capacity of the whole blood drops after open total splenectomy, but increases after partial/subtotal or minimally invasive splenectomy
Acta Chirurgica Belgica, 2021
Background The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim ... more Background The mechanisms that induce immunodeficiency after splenectomy remain unknown. The aim of this study was to measure the cytokine releasing capacity of the whole blood as an expression of the innate immunity after total (TS) and subtotal/partial splenectomy (S/PS) in order to assess the impact of splenectomy on the individual cytokine reactivity. Methods We prospectively collected blood before (D0) and at multiple time points after splenectomy (7 days - D7, 30 days - D30, 90 days - D90, 180 days - D180, and 360 days - D360) and measured the cytokines releasing capacity of IL-6, TNF-alpha and IL-10 from whole blood under LPS stimulation which we normalized to the monocytes number. Results When analyzing all splenectomies at D0, D7 and D30, normalized ΔTNF-alpha significantly dropped after splenectomy (p = .0038) and normalized ΔIL-6 and ΔIL-10 did not significantly change. More specifically, normalized ΔTNF-alpha dropped after TS (p = .0568) and significantly increased after...
The goal of the paper is to develop methods and algorithms based on the chaotic dynamical systems... more The goal of the paper is to develop methods and algorithms based on the chaotic dynamical systems theory (fractal dimension analysis) and specific nonparametric statistics methods (bootstrap and bias-corrected and accelerated percentile intervals) and to apply them to study CT images of sinus tumors. The statistical analysis shows that the use of the fractal dimension of the mass texture discriminate best between malignant and benignant sinus tumor, therefore leads to an improvement of the diagnosis.
Constant Internet connectivity has become a necessity in our lives. Hence, music festival organiz... more Constant Internet connectivity has become a necessity in our lives. Hence, music festival organizers allocate part of their budget for temporary Wi-Fi equipment in order to sustain the high network traffic generated in such a small geographical area, but this naturally leads to high costs that need to be decreased. Thus, in this paper, we propose a solution that can help offload some of that traffic to an opportunistic network created with the attendees’ smartphones, therefore minimizing the costs of the temporary network infrastructure. Using a music festival-based mobility model that we propose and analyze, we introduce two routing algorithms which can enable end-to-end message delivery between participants. The key factors for high performance are social metrics and limiting the number of message copies at any given time. We show that the proposed solutions are able to offer high delivery rates and low delivery delays for various scenarios at a music festival.
Sensors
With the rate at which smartphones are currently evolving, more and more of human life will be co... more With the rate at which smartphones are currently evolving, more and more of human life will be contained in these devices. At a time when data privacy is extremely important, it is crucial to protect one’s mobile device. In this paper, we propose a new non-intrusive gait recognition based mechanism that can enhance the security of smartphones by rapidly identifying users with a high degree of confidence and securing sensitive data in case of an attack, with a focus on a potential architecture for such an algorithm for the Android environment. The motion sensors on an Android device are used to create a statistical model of a user’s gait, which is later used for identification. Through experimental testing, we prove the capability of our proposed solution by correctly classifying individuals with an accuracy upwards of 90% when tested on data recorded during multiple activities. The experiments, conducted on a low sampling rate and at short time intervals, show the benefits of our so...
Long-Term Evaluation of the Outcomes of Subtotal Laparoscopic and Robotic Splenectomy in Hereditary Spherocytosis
World Journal of Surgery
BIOMATH
We develop a stochastic model for an intracellular active transport problem. Our aims are to calc... more We develop a stochastic model for an intracellular active transport problem. Our aims are to calculate the probability that a molecular motor reaches a hidden target, to study what influences this probability and to calculate the time required for the molecular motor to hit the target (Mean First Passage Time). We study different biologically relevant scenarios, which include the possibility of multiple hidden targets (which breed competition) and the presence of obstacles. The purpose of including obstacles is to illustrate actual disruptions of the intracellular transport (which can result, for example, in several neurological disorders. From a mathematical point of view, the intracellular active transport is modelled by two independent continuous-time, discrete space Markov chains: one for the dynamics of the molecular motor in the space intervals and one for the domain of target. The process is time homogeneous and independent of the position of the molecular motor.
Texts in Biomathematics
We develop a stochastic model for an intracellular active transport problem. Our aims are to calc... more We develop a stochastic model for an intracellular active transport problem. Our aims are to calculate the probability that a molecular motor reaches a hidden target, to study what influences this probability and to calculate the time required for the molecular motor to hit the target (mean first passage time). We study different biologically relevant scenarios, which include the possibility of multiple hidden targets (which breed competition) and the presence of obstacles. The purpose of including obstacles is to illustrate actual disruptions of the intracellular transport (which can result, for example, in several neurological disorders. From a mathematical point of view, the intracellular active transport is modelled by two independent continuous-time, discrete space Markov chains: one for the dynamics of the molecular motor in the space intervals and one for the domain of target. The process is time homogeneous and independent of the position of the molecular motor.
PloS one, 2017
Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and trea... more Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and treatment. A large panel of small non-coding microRNAs was reported to modulate the immune response in sepsis but have not been tested in clinical practice. Large-scale identification of microRNA networks in sepsis might reveal a new biological mechanism that can be also targeted by gene therapy. Therefore, the main objective of this study is to perform a comparison of the miRNA network between septic patients and healthy controls. We used the previously measured levels of expression of 16 different circulating human and viral microRNAs in plasma from 99 septic patients and 53 healthy controls. We used three different computational methods to find correlations between the expressions of microRNAs and to build microRNA networks for the two categories, septic patients and healthy controls. We found that the microRNA network of the septic patients is significantly less connected when compared t...