Publications by authors named "Michał Piątek"

9 Publications

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Surface-Related Kinetic Models for Anaerobic Digestion of Mi-crocrystalline Cellulose: The Role of Particle Size.

Materials (Basel) 2021 Jan 20;14(3). Epub 2021 Jan 20.

Department of Biosystems Engineering, Institute of Mechanical Engineering, Warsaw University of Life Sciences, Nowoursynowska 166, 02-787 Warsaw, Poland.

In this work, for modelling the anaerobic digestion of microcrystalline cellulose, two surface-related models based on cylindrical and spherical particles were developed and compared with the first-order kinetics model. A unique dataset consisting of particles with different sizes, the same crystallinity and polymerisation degree was used to validate the models. Both newly developed models outperformed the first-order kinetics model. Analysis of the kinetic constant data revealed that particle size is a key factor determining the anaerobic digestion kinetics of crystalline cellulose. Hence, crystalline cellulose particle size should be considered in the development and optimization of lignocellulose pre-treatment methods. Further research is necessary for the assessment of impact of the crystalline cellulose particle size and surface properties on the microbial cellulose hydrolysis rate.
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http://dx.doi.org/10.3390/ma14030487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864345PMC
January 2021

The effects of solid lignin on the anaerobic digestion of microcrystalline cellulose and application of smoothing splines for extended data analysis of its inhibitory effects.

Bioresour Technol 2021 Jan 16;320(Pt A):124262. Epub 2020 Oct 16.

Department of Biosystems Engineering, Institute of Mechanical Engineering, Warsaw University of Life Sciences, Nowoursynowska 166, 02-787 Warsaw, Poland.

Lignocellulose is an abundant substrate for biogas production; however, for efficient utilization, proper pre-treatment is required to enhance the biomethane yield and hydrolysis rate significantly. Phenolic compounds from dissolved lignin, produced during alkali pre-treatment, have inhibitory effects on the anaerobic digestion; however, the possible inhibitory effects of solid lignin have not gathered enough interest. Especially, the effect of solid lignin on methanogenesis remains a knowledge gap. In this study, kraft lignin was used as a model solid lignin substrate for its co-digestion with microcrystalline cellulose. A new approach of modelling biomethane production curves using smoothing splines was developed to describe the long-term inhibitory effects of solid lignin on hydrolysis and methanogenesis. The method gives possibility to describe long-term inhibitory effects by using batch instead of continuous test data. Results revealed that kraft lignin showed mild inhibitory effects on methanogens. However lignin impact combined with volatile fatty accumulation can prolong hydrolysis and reactor recovery start-up by 47.3% and 75.3%, respectively. For small dosages of solid lignin adaptation of methanogens is possible.
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http://dx.doi.org/10.1016/j.biortech.2020.124262DOI Listing
January 2021

Influence of Fraction Particle Size of Pure Straw and Blends of Straw with Calcium Carbonate or Cassava Starch on Pelletising Process and Pellet.

Materials (Basel) 2020 Oct 16;13(20). Epub 2020 Oct 16.

Department of Applied Mathematics, Institute of Information Technology, Warsaw University of Life Sciences, Nowoursynowska 166, 02-787 Warsaw, Poland.

The aim of this study was to investigate the pressure agglomeration process of wheat straw (WS) and the blends of WS with calcium carbonate (CC) or cassava straw (CS) with a ratio of 6% wt./wt. from seven separate fractions with sizes in the range of 0.21-2.81 mm. The agglomeration was performed at a moisture of 30% wb and a material temperature of 78 °C, with a dose of 0.1 g, in a die of diameter 8 mm and height 80 mm. The effects of the process were evaluated based on the compaction parameters and the pellets' density, tensile strength, and water absorption. The incorporation of additives into the WS improved the pellet process and quality. Refined results were achieved after adding CC, as compared to those achieved after adding CS, and the preferred particle size was in the range of 1.00-1.94 mm. This was because, under the given conditions, the back pressure in the die chamber significantly increased, allowing the achievement of a single pellet density of 800 kg·m. The pellets were resistant to compressive loads and cracked only at tensile strength of 6 MPa and a specific compression work of 6.5 mJ·mm. The addition of CC to the WS improved the strength of the adhesive and the cohesive bonds between the particles. The water absorption for the uncrushed pellets was considerably less than that for crushed pellets, which results in the safer storage of uncrushed pellets and excellent moisture absorption of crushed pellets. The addition of CC to the WS offers benefits in the form of pellet strength with a high water absorption capability. Notably, a study of crushed pellet litter under broiler rearing conditions and an analysis of the operational costs of using WS additives are required for implementing this study.
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http://dx.doi.org/10.3390/ma13204623DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7602947PMC
October 2020

Primarily resectable pancreatic adenocarcinoma - to operate or to refer the patient to an oncologist?

Crit Rev Oncol Hematol 2019 Mar 25;135:95-102. Epub 2019 Jan 25.

Department of Radiotherapy, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.

The aim of this work is to investigate the optimal therapeutic sequence of resectable pancreatic cancer - primary surgery with adjuvant therapy or neoadjuvant followed by resection. Application of the neoadjuvant approach in routine treatment of pancreatic cancer is rapidly growing every year, despite the lack of final results from randomized trials. Recent advancements in the adjuvant therapy, due to the more effective chemotherapy regimens, favor the upfront surgery strategy. On the other hand, theoretical background and metaanalyses favor the neoadjuvant strategy. Currently, primary resection with adjuvant chemotherapy remains the standard approach in resectable pancreatic cancer, but the first recommendations considering the neoadjuvant approach as an option seem to arise among the scientific societies with a global impact. Preliminary results of Prodige 24 study and PREOPANC-1 trial demonstrates that both options are worth further evaluation in clinical trials. Their results should soon provide more answers to this important clinical questions.
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http://dx.doi.org/10.1016/j.critrevonc.2019.01.010DOI Listing
March 2019

Application of titration methods for measuring the contents of ammonium nitrogen and volatile fatty acids in agricultural biogas plants.

J Biotechnol 2017 Dec 14;264:38-42. Epub 2017 Oct 14.

Department of Anaesthesiology, Medical Centre for Postgraduate Education Clinical Hospital Adam Gruca, CMKP,Konarskiego Street 13, 05-400 Otwock, Poland.

The aim of our research was to assess a relatively new method of estimating ammonium nitrogen concentration in anaerobic digestion of plant substrates. We analysed our own data, received from the anaerobic digestion of maize silage (PM), as well as data published by Purser et al. (2014) who measured energy crops and slurry (ECS), and food waste (FW). In our study, the process was monitored for VFA content that was determined by gas chromatography, and for the content of ammonium nitrogen determined using the HACH LANGE LCK 303 cuvette test. We created polynomial regression models that bind the content of ammonium nitrogen with the volume of HSO used to titrate the sample from initial pH to pH 5. To estimate parameters of model, the PM dataset was used. The obtained models were positively validated using ECS and FW datasets. Our results confirmed the effectiveness of the Purser et al. method with an average absolute error of less than 223mgl of the VFA concentration, which was approximately 20-times less than the level that caused inhibition. In conclusion, we can affirm the suitability of using titration methods to assess the ammonium nitrogen content of bioreactors with a stable composition.
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http://dx.doi.org/10.1016/j.jbiotec.2017.10.008DOI Listing
December 2017

Keratin 7 expression in lymph node metastases but not in the primary tumour correlates with distant metastases and poor prognosis in colon carcinoma.

Pol J Pathol 2016;67(3):228-234

Department of Pathomorphology, Medical University of Gdańsk, Gdańsk, Poland.

Colorectal carcinoma (CRC) is one of the leading causes of cancer-related deaths worldwide. Alterations in keratin expression, including keratin 7 (K7), are frequent findings in multiple cancers, and they constitute a prognostic factor. The aim of our study was to evaluate the prognostic significance of K7 in the primary tumour and lymph node metastases in two separate cohorts of patients: the first one with lymph node involvement (LN+, 129 cases) and the second one free of LN metastases (LN-, 85 cases). Keratin 7 expression in CRC was analysed on tissue microarrays with immunohistochemistry and evaluated using the h-score. In the LN+ group K7 positivity was identified in 7/129 (5.4%) of primary tumours (PT) and lymph node metastases (LNM); concordance between them was 94% ( 0.396). Keratin 7 was expressed in 8/85 cases (9.4%) in the LN- group. K7 expression in LNM of the LN+ cohort correlated with shorter overall survival (OS) (p = 0.047) and presence of distant metastases at diagnosis (p = 0.005). Expression of K7 in the primary tumour in both cohorts did not correlate with survival. We conclude that the status of K7 expression in metastatic lymph nodes from CRC is a poor prognostic factor.
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http://dx.doi.org/10.5114/pjp.2016.63774DOI Listing
June 2017

The dynamics of an anaerobic digestion of crop substrates with an unfavourable carbon to nitrogen ratio.

Bioresour Technol 2016 Sep 31;216:607-12. Epub 2016 May 31.

Department of Anaesthesiology, Medical Centre for Postgraduate Education, Clinical Hospital Adam Gruca, CMKP, Konarskiego Street 13, 05-400 Otwock, Poland.

The purpose of this study was to investigate the effects of the characteristics of basic crop substrates, such as the carbon, nitrogen, ash and volatile fatty acids contents, on the dynamics of the anaerobic digestion process. For this purpose, the stepwise anaerobic digestion of silage from six different plant species was carried out. Scaled probability distributions (log-normal, log-logistic, logistic, Weibull and Gompertz) were used to approximate the cumulative methane production curves obtained. The results indicated that the Gompertz distribution best fit the process. The hazard function of the Gompertz distribution was used to describe the process change dynamics. Ridge regression models were made and tested to clarify the impact of the crop properties on the distribution parameters. The analysis results indicated that the initial rate of the process depended on the reactor acidity and that the nitrogen content of the substrate was a key factor that affected the process dynamics.
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http://dx.doi.org/10.1016/j.biortech.2016.05.122DOI Listing
September 2016

Assessment of the safety and efficiency of sunitinib malate in metastatic neuroendocrine tumours of the pancreas (NEN G1/G2) depending on the number and type of earlier therapeutic lines - initial report.

Endokrynol Pol 2014 ;65(6):472-8

Division of Radiotherapy and Oncology, Department of Clinical Oncology, Silesian Medical University, Katowice, Poland.

Introduction: The objective of this paper was to assess the safety and efficacy of sunitinib malate in patients with well-differentiated metastatic pancreatic neuroendocrine neoplasms (PNENs) who relapsed on standard therapy.

Material And Methods: Overall, eight patients with well-differentiated pancreatic neuroendocrine tumours/neoplasm (NET/NEN G1/G2, Ki-67 < 20%), who had relapsed on a standard therapy approach, were treated. All had non-resectable, progressive disease. All received therapy using a standard dose of sunitinib malate. Adverse events were evaluated using NCI-CTC AE v. 3.0.

Results: Of the eight patients, seven had non-secretor and single secretor tumour (gastrinoma). Partial remission (PR) was noted in three patients (one after a single therapeutic line, two after two lines), five patients had stabilisation (SD) - including three individuals after three lines, one patient after two lines and another after a single line. Haematological adverse events: leukopenia (25%) - occurred in one patient after three lines and in one patient after two lines; anaemia (25%) - in one patient after three lines and in one patient after one therapeutic line. Mucocutaneous lesions were noted in 37.5% of patients after 2-3 lines of treatment. All of them experienced fatigue syndrome irrespective of the number of therapies. The majority of the patients simultaneously received somatostatin analogues, which did not exacerbate the toxicity profile. The median progression-free survival time (PFS) was 11 months.

Conclusions: Sunitinib may be considered as a fairly well-tolerated and effective therapeutic option in progressive non-resectable PNEN patients in the second and subsequent lines of treatment, irrespective of the types of treatment previously applied.
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http://dx.doi.org/10.5603/EP.2014.0066DOI Listing
December 2016

A comparative quality appraisal of finely comminuted batters produced using three types of knives.

Meat Sci 2014 Jan 15;96(1):429-35. Epub 2013 Aug 15.

Institute of Meat Technology, Poznań University of Life Sciences, Wojska Polskiego 31, 60-624 Poznań, Poland.

The aim of this study was to compare the work efficiency of three types of knives mounted successively on a knife roll of a cutter by evaluating the quality and structure of produced finely comminuted batters as well as power consumption and electric energy consumption during chopping. Experimental material comprised finely comminuted meat batters produced under commercial scale production conditions using smooth knives, knives with riffles and knives with holes. Parameters measured in batter included temperature, water, fat, free water, apparent viscosity, thermal drip and batter structure using computer image analysis. Computer image analysis showed that the best comminution and dispersion of fat globules in the protein matrix together with very good comminution of collagen fibres were observed at the application of knives with holes. Among the three types of knives used in the production of finely comminuted meat batters the best batter in terms of its quality and structure was produced using knives with holes.
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http://dx.doi.org/10.1016/j.meatsci.2013.08.011DOI Listing
January 2014