In order to show that in certain circumstances the presence of a structural trap is not required for CO2 storage, a set of conceptual models for CO2 injection in a deep saline aquifer represented by a horizontal, laterally infinite layer, i.e., without structural or stratigraphic trap, was developed. This is theoretically supported by the assumed gravitational migration of a CO2 plume towards cap-rock. The hypothesis was tested by varying injection depths and rock permeability to analyse the influence of these parameters on time and radius of CO2 plume lateral spreading. After running 30 simulation cases, an analytical term has been proposed and it was found that a logarithmic function is satisfactory for describing the relationship between time and maximum spreading radius from the injection well. Subsequently, a generalized analytical multi-parameter correlation was found to describe CO2 plume movement with time within the spread radius. After establishing such a fitted correlation, it is possible to predict the extent of the CO2 saturation zone, justifying less frequent 4D seismic measurements.

The urgent need for a significant reduction in global greenhouse gas emissions indicates that the change in the world’s energy mix is inevitable. In the power production sector, this would be achieved through decarbonization with renewables, and within the transport sector, this would be achieved by switching to alternative fuels and electric vehicles. However, this transition is neither fast nor cheap, and it will be gradual. The main goal of this article is to propose a feasible change in the present energy mix and to compare natural gas with other fuels used in power production and transport. The strengths, weaknesses, opportunities, and threats of the current system (traditional fossil fuels) and the potential future system (higher share of natural gas) in energy generation and transport were identified, and the influence of recent global trends was analyzed. Natural gas seems to be a viable solution that can help in the transition to a zero-carbon-emissions society.

Cilj: Važnost i uloga antitijela usmjerenih protiv humanih leukocitnih antigena (HLA) u reakcijama odbacivanja posredovanih antitijelima nakon transplantacije solidnih organa danas je jasno dokazana. Smatra se da su i antitijela usmjerena na antigene koji nisu dio sustava HLA, tzv. antitijela non-HLA, također povezana s humoralnim odbacivanjem te da mogu utjecati na preživljenje presatka. Prisutnost antitijela non-HLA dodatno ukazuje na bolesnike s povećanim imunološkim rizikom prije i nakon transplantacije organa. Cilj rada bio je odrediti prisutnost antitijela non-HLA u skupinama bolesnika prije i nakon transplantacije bubrega, odrediti njihovu učestalost pojavljivanja validiranim testovima probira te verificirati analizu rezultata. Ispitanici i metode: Analiza prisutnosti antitijela non-HLA provedena je u 17 visoko HLA-senzibiliziranih bolesnika na listi čekanja za transplantaciju bubrega (skupina pre-tx) i u 10 bolesnika s transplantiranim bubregom (skupina post-tx) čiji nalazi biopsija ukazuju na humoralno odbacivanje, a bez dokazanih prisutnih donor-specifičnih antitijela HLA (DSA). Za određivanje antitijela non-HLA korišten je test temeljen na tehnologiji Luminex koji omogućuje izravnu simultanu detekciju antitijela IgG protiv 60 različitih antigena non-HLA. Rezultati: Prisutnost antitijela non-HLA najmanje jedne specifičnosti dokazana je u 16/17 (94,1%) primatelja pre-tx skupine te u 7/10 (77,0%) primatelja post-tx skupine. Vrijednosti intenziteta fluorescencije pozitivnih reakcija bile su statistički značajno više u pre-tx skupini u usporedbi s post-tx skupinom. Broj specifičnosti antitijela non-HLA određenih po pojedinom primatelju bio je veći u pre-tx skupini. Zaključak: Test omogućuje vrlo osjetljivo dokazivanje prisutnosti i specifičnosti antitijela non-HLA. Prisutnost antitijela non-HLA visoka je u obje ispitivane skupine, a broj specifičnosti i intenzitet pozitivnih reakcija značajno je veći u visoko HLA-senzibiliziranih primatelja. Biopsijom dokazano humoralno odbacivanje bez prisutnih HLA DSA može biti povezano s antitijelima non-HLA u post-tx skupini.

The introduction of Next-Generation Sequencing (NGS) methodology in the histocompatibility testing for both allo-HSCT and solid organ transplantation enables the sequencing of all HLA genes, which in turn leads to the discovery of many new HLA alleles. Over the last 3 years, we have identified 28 novel alleles (HLA-A*02:1079, A*03:01:01:112, A*11:01:01:83, A*11:01:01:87, A*24:595, A*68:01:01:15, B*07:02:01:107, B*08:01:01:67, B*08:01:01:69, B*13:02:01:25, B*15:01:82, B*15:18:08, B*18:01:01:76, B*27:02:06, B*27:05:02:34, B*40:06:01:17, B*40:517, C*04:01:01:173, C*04:477, C*05:276, C*07:01:01:130, C*12:03:80, C*12:03:01:62, DQA1*05:01:01:10, DPB1*13:01:07, DPB1*1146:01, DPB1*1456:01 and DPB1*1514:01) using the NGS method. The presented data emphasises the benefits gained by the utilisation of the NGS-based techniques in HLA genotyping but also provides new insight on the HLA polymorphism in the Croatian population.

During the three-year EU-funded STRATEGY CCUS project [1] [3] (2019-2022), Carbon Capture, Use and Storage (CCUS) scenarios formulated for eight regions in Southern and Eastern Europe were developed and economically evaluated up to 2050. These regional CCUS scenarios are based on both the performances of local industries in operation and for which CCUS is a relevant mitigation alternative, as well as the regional storage capacities known to date. The eight CCUS regional scenarios are in: 1) Paris basin and 2) Rhône Valley in France, 3) Ebro basin in Spain, 4) Lusitanian basin in Portugal, 5) Northern Croatia, 6) Upper Silesia in Poland, 7) West Macedonian area in Greece and 8) Galati area in Romania. They cover an extensive and original portfolio of possible CCUS business models. While some scenarios assume that the captured CO2 is used for synthetic methane or chemical production, in most cases the captured CO2 is sent to CO2 storage facilities. The biogenic CO2 captured is monitored and its storage time in new uses watched. The economic evaluation considers the negative CO2 emissions resulting from the long-term storage or use of captured biogenic CO2.This paper compares the economic Key Performance Indicators (KPIs) of these eight CCUS business cases with the carbon penalties that would have been charged to the same industries to remain in compliance with the European Union - Emissions Trading System (EU ETS). The calculated KPIs mainly reflect the costs and revenues expressed in euros per ton of CO2 avoided or removed for the whole regional scenario until 2050

Background:Ulcerative colitis (UC) is a relapsing and remitting inflammatory disorder of the colonic mucosa.In 5% of UC cases, patients also develop primary sclerosing cholangitis (PSC).Both of the diseases are essentially autoimmune disorders and it is not uncommon to find other autoimmune diseases in affected patients. Case presentation:A 35-year-old female patient presented to the Department of Gastroenterology and Hepatology in 2014 with bloody diarrhea, weight loss, and fatigue.A colonoscopy was performed and the diagnosis of extensive, moderately severe ulcerative colitis was established.Her medical history was remarkable for type I diabetes mellitus diagnosed in 2001 and psoriasis diagnosed in 2010.The patient started treatment with mesalazine and corticosteroids, which resulted in clinical and endoscopic remission.During a follow-up, the elevation of cholestatic liver enzymes required further work-up, including MR cholangiopancreatography, which revealed changes consistent with PSC.The patient started treatment with ursodeoxycholic acid.In 2018, she discontinued corticosteroids, which resulted in a relapse of UC with exacerbation of psoriatic skin plaques and multiple-joint pain.A rheumatologist found no signs of spondyloarthritis at that moment.Treatment with an anti-TNF agent, adalimumab, was started in 2018, but had to be discontinued due to an episode of fever and hilar lymphadenopathy of unknown cause, which was resolved with steroid therapy.The trial of other biological agents, including vedolizumab and ustekinumab, showed no effect on UC symptoms.Finally, in 2021 the patient started treatment with tofacitinib, which showed great progress in reducing gastrointestinal symptoms, joint pain, and skin lesions. Conclusion:Treating patients with multiple autoimmune disorders is often complex and requires a multidisciplinary and individual approach.Frequent and thorough follow-up visits should be made to adjust medications and identify new symptoms that are possible indicators of underlying autoimmune diseases or complications related to the disease or treatment.

The EU considers carbon capture and storage (CCS) technology as an option for achieving climate goals, but its cost remains appreciable. Therefore, the purpose of this research was to investigate the implementation of a ton-based incentive system for CCS in the EU using Croatia as an example based on an analysis of the existing legislative framework in the EU and relevant tax credit provisions in the USA. A novel methodology for the design of the incentive system is presented in the form of partial allocation of the state’s auction revenues from the EU emissions trading system (ETS) into the CCS fund for five years. The CCS fund assets then incentivize the capture site for 10 years. The incentives are determined for each emitter in cement, electricity, paper and pulp, glass, oil refining, and petrochemical sectors based on varying European Union allowance (EUA) prices, CCS fund sizes, and CO2 emission scenarios. In addition to designing the methodology, a novel method for forecasting CO2 emissions is applied using geometric Brownian motion. The calculated incentives are categorized as underperforming, optimal, or overperforming, with upper and lower limits set to 80 and 10 EUR/t. The results are optimistic, since all sectors can be efficiently incentivized within the defined boundaries, meaning that the incentive system can be applied to all member states. The contracting of the incentives is proposed through carbon contracts for difference to avoid irregularities. Also, regulatory amendments are proposed so that emitters with emissions higher than 100 kt would have to consider CCS. Finally, the contributions are presented by proving the feasibility of the incentive system together with demonstrating its applicability to all member states.

Carbon Capture and Storage is a concept that is not yet fully implemented largely because of the high costs. Clustering of industrial stakeholders is imposed as a measure for cost reduction. All relevant emitters, possible transport routes, including existing gas pipeline corridors, and their geographic location in relation to potential storage locations are assessed in this paper. Site availability and CO2 storage capacity are examined, summarizing all study results gathered under the Strategy CCUS project. The CO2 enhanced oil recovery is being studied for CO2 storage rather than extra oil recovery. As logical choices, three clusters were recognized. Only less expensive, onshore injection was taken in consideration for assessment of early (economic) feasibility in the Adriatic, Central, and Eastern clusters. Because of the shorter distance between CO2 emitters and injection sites, the Eastern and Central clusters are being investigated in more detail, despite the fact that the largest point source emitter is in the Adriatic region. Because of small number of point source CO2 emitters and huge theoretical storage capacity, further research is needed to better assess the storage capacities as well as possibilities for development of cross-border projects. Based on previous research (particularly regarding the emitters), the number of facilities (fewer facilities, with more concentrated emissions), and the availability of storage objects, the Eastern cluster is recommended to be further studied as the next stage of Carbon Capture, Utilization and Storage cluster research and development in Croatia and nearby cross-border regions.

The gas sector in the EU is very developed and advanced, but there are still some steps and measures to improve this sector. One of the measures for the improvement, but also for the collection of data on energy consumption for an easy transition to a low carbon economy, are the projects of installing smart meters. This paper analyzes a pilot project of installing modules for remote reading of natural gas consumption on existing membrane gas meters. In the pilot project observed, modules for remote reading were installed on more than 10,000 existing meters, and their use, activation, and as well as the benefits that are achieved by using them are described in detail. These modules use the increasingly popular Sigfox network, which has proven to be an excellent tool for data transmission with low energy consumption, which can greatly simplify the digitization of many energy sectors. The installation of modules for remote reading on existing meters represents a novelty improvement of classic membrane meters towards modern and increasingly sought-after smart meters, which has proven to be time effective because, unlike some smart meter installation projects, this approach requires a very short installation time. The results of the financial and sensitivity analysis have shown that with the currently valid legal regulation the financial savings achieved by energy supplier due to exemption from paying penalties are more than sufficient to cover the investment and operating costs of the entire investment. In case the legislation changes or is different, this paper proposes the concept of transferring partial financial value of energy savings from end consumers to energy supplier in order to cover the investment and operating costs of implementation. (C) 2022 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Kidney donor-recipient mismatches (MM) in human leukocyte antigen (HLA) system can have the impact on graft survival as de novo formation of donor-specific HLA antibodies (DSA) post-transplant can increase the risk of acute and chronic rejections. Eplets, the smallest functional units of epitopes, are in recent years also being considered in recipient-donor matching. We have retrospectively analysed the relationship between MM at HLA-A, -B, -DRB1 and -DQB1 loci and the development of DSA in 47 kidney transplant recipients that were negative for the presence of HLA antibodies pre-transplant. A total of 19 patients (40%) developed DSA (DSA+) post-transplant, revealing sensitization to HLA class II MM antigens as the most prevalent (84% of DSA+ patients). MM at all HLA loci contributed to the development of HLA locus-specific antibodies, with the prevalence of HLA-DQ sensitization, as 41% of recipients with HLA-DQ MM developed DSA. HLAMatchmaker analysis for HLA-DR/DQ total eplet MM showed statistically significant difference between DSA- (N=33) and DSA+ recipients (N=14) for a total number of eplet MM (300 in DSA- vs 248 in DSA+; P=0.0004). These results emphasize the importance of HLA Class II matching in kidney transplantation.

Benefits of CO2 injection into a gas-condensate reservoir were examined based on a real-field data. The observed natural gas reservoir has high content of CO2, therefore it is desirable to inject the produced CO2 back to the reservoir in order to reduce the emissions at the natural gas processing plant and possibly increase hydrocarbon production. Simulation was made as to compare hydrocarbons production with and without CO2 injection. Since the CO2 source is the reservoir itself, CO2 injection is limited by the produced gas quantities. Investments in low-risk projects on already producing natural gas fields can be feasible compared to investments in completely new and high-risk/high-gain projects, as the highest storability, and additional recovery of hydrocarbon part of the gas is achieved near the end of production. As in late production periods the process can be carbon-negative, i.e., more CO2 is injected than produced, such an enhanced gas recovery scheme can be considered as an advantageous preliminary step before converting the reservoir to CO2 storage facility.

An accurate prediction of energy indicators is critical for orientation in the energy market, and it could give direction for policymakers and market participants. The aim of this research was to examine the accuracy of projections of natural gas market indicators. This paper presents a comparative analysis of historic predictions and actual global natural gas movements in several segments, namely production, consumption, and regional import dependence, as well as forecasted and actual price movements. The goal of this paper is to compare projected and actual natural gas market indicators. Predictions of market movements 20 years into the future are very useful, but they do have certain limitations. Those limitations especially apply to goods whose prices are regional and linked to price movements of another good, as is the case with natural gas. External influences have a direct impact on production and consumption, and it is rather clear that changes in one of the fundamental factors entails and magnifies the error of further predictions. Despite that, predictions of global production and consumption have proven to be very accurate. Based on the research results, it could be emphasized that for strategical planning and policy-making purposes, the predictions of natural gas production, consumption, or even import independence could be considered with great certainty, while price assumptions in the case of natural gas have shown significant mismatching, therefore, should be very carefully perceived.

In 2019, natural gas accounted for 25.4% of gross inland consumption in the European Union (EU), making it one of the most important energy sources in the EU. The importance of natural gas, together with the ongoing liberalization of the gas market, has made the natural gas sector significantly commercially sensitive. To reduce the risk of financial losses, balance group managers often need to have an accurate forecast of natural gas consumption. An accurate forecast will ensure small deviations between actual gas consumption and reserved gas volumes and transmission system capacity resulting in less balancing energy required, which is sold at a higher price in the final balancing process. This paper researches the optimal number of smart meters and best fitted consumption data distribution in order to achieve satisfactory results in terms of the accuracy by using simple forecasting methods. Beside mentioned, this paper provides accuracy overview of various already available forecasting methods, as well as the selection of input parameters for forecasting short term natural gas consumption. Using the calculated linear temperature dependence together with the lognormal distribution, the consumption of natural gas was simulated for 12 different cases. The simulation showed that, if more than 10 000 smart meters were installed, deviation between average estimated natural gas consumption and the real data would be less than ±2.96 %. In case of 100 000 smart meters installed, deviation would be less than ±1.20 %, but the "large" partly temperature independent consumers must be disregarded.

Hydrocarbon exploration and production activities are basic to the functioning of the oil and gas industry, while concession contracts and fees are central concepts in the aforementioned activities. The authors consider several questions regarding these concepts, such as: what is the legislative, institutional, and fiscal framework in certain European countries regarding hydrocarbon exploration and production? What are the major differences between them? Finally, is there room for improvement of the framework in the Republic of Croatia? To answer these questions, the authors contacted some of the relevant institutions and accessed official government gazettes, institution websites, legal aggregators, journal articles, books, and different legal publications regarding the oil and gas industry for several European countries, namely the Kingdom of Norway, the Russian Federation, the Republic of Austria, and the Republic of Croatia. As a result, this paper presents an overview of legislation, institutions, concession contracts, taxes, and fees for each of the aforementioned countries. The authors conclude that the Republic of Croatia could benefit from applying some foreign solutions in its own legislative and fiscal framework, i.e., using a sliding scale for royalty calculation and simplifying some administrative procedures.

A gas condensate reservoir in Northern Croatia was used as an example of a CO2 injection site during natural gas production to test whether the entire process is carbon-negative. To confirm this hypothesis, all three elements of the CO2 life cycle were included: (1) CO2 emitted by combustion of the produced gas from the start of production from the respective field, (2) CO2 that is separated at natural gas processing plant, i.e., the CO2 that was present in the original reservoir gas composition, and (3) the injected CO2 volumes. The selected reservoir is typical of gas-condensate reservoirs in Northern Croatia (and more generally in Drava Basin), as it contains about 50% CO2 (mole). Reservoir simulations of history-matched model showed base case (production without injection) and several cases of CO2 enhanced gas recovery, but with a focus on CO2 storage rather than maximizing hydrocarbon gas production achieved by converting a production well to a CO2 injection well. General findings are that even in gas reservoirs with such extreme initial CO2 content, gas production with CO2 injection can be carbon-negative. In almost all simulated CO2 injection scenarios, the process is carbon-negative from the time of CO2 injection, and in scenarios where CO2 injection begins earlier, it is carbon-negative from the start of gas production, which opens up the possibility of cost-effective storage of CO2 while producing natural gas with net negative CO2 emissions.

In this study, oil production and retention were observed and compared in 72 reservoir simulation cases, after which an economic analysis for various CO2 and oil prices was performed. Reservoir simulation cases comprise different combinations of water alternating gas (WAG) ratios, permeabilities, and well distances. These models were set at three different depths; thus different pressure and temperature conditions, to see the impact of miscibility on oil production and CO2 sequestration. Those reservoir conditions affect oil production and CO2 retention differently. The retention trend dependence on depth was not monotonic-optimal retention relative to the amount of injected CO2 could be achieved at middle depths and mediocre permeability as well. Results reflecting different reservoir conditions and injection strategies are shown, and analysis including the utilization factor and the net present value was conducted to examine the feasibility of different scenarios. The analysis presented in this paper can serve as a guideline for multiparameter analysis and optimization of CO2-enhanced oil recovery (EOR) with a WAG injection strategy.

European Trading Scheme should encourage the idea of CO2 utilization and/or underground storage. Despite the large estimates of CO2 storage capacities, cost-effective storage has not been performed in the EU. As EU ETS went through several phases and is tested to the level that it can be called mature, the trends of CO2 allowance market prices can be analyzed. CO2 reduction can be achieved by simultaneous injection for CO2 Enhanced Oil Recovery (EOR) commercially, which is proved outside the EU. The technology is well developed as a part of the oil and gas business, and the mover for implementing such technologies might be CO2 allowance price. As investments in those technologies are long-term and extremely capital intensive, this chapter discussed CO2 utilization and storage in the context of EU ETS. Additionally, the chapter presented statistical analysis that helps long-term CO2 price understanding; the connection of CO2 price with oil, gas, and electricity price; and guidelines for risk mitigation in assessing the feasibility of applying CO2 utilization and storage (CUS) technologies.