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Replacing heavy fuel oil with liquefied natural gas in marine engines can potentially provide significant CO2 savings due to the higher hydrogen to carbon ratio of natural gas. For many existing engines, the change can be done only minor modifications. One challenge remains to realize the potential green house gas savings: Methane slip. This longstanding issue with large engines revolves around the stability of the CH4 molecule, resulting in significant amounts of unburned methane being emitted to the atmosphere. The high global warming potential (GWP) of methane means that the CO2 savings are nullified by just a few percent of methane slip. To solve this challenge in the already highly optimized engines, a catalyst can be used to convert the last CH4 to CO2. Methane oxidation catalysts have been in development for several decades and are essentially still faced with the same set of challenges as 40 years ago, namely three different types of deactivation. The first part of this dissertation aims to thoroughly present the progress in the field of methane oxidation and attempts to prevent catalyst deactivation. Arguably the most interesting leap forward has been the adoption of zeolite-supported catalysts which promises to solve both hydrothermal sintering and direct water-induced deactivation by offering nanoparticle encapsulation in a hydrophobic microporous structure. This topic is so novel and interesting that it was decided to cover it in a review article, presented here as Paper 1. The first experimental project was an attempt to build on top of the promising work by others on zeolite-supported methane oxidation catalysts. A series of Pd/MOx@S-1 catalysts (M = Ce, Ba) was synthesized and tested in a purpose-built catalytic test setup. None of the synthesized materials exhibited a catalytic performance or durability superior to the state-of-the-art P

Tuberculosis (TB) presents a serious health problem with approximately a quarter of the world’s population infected with Mycobacterium tuberculosis (M. tuberculosis) in an asymptomatic latent state of which 5–10% develops active TB at some point in their lives. The antimicrobial protein cathelicidin has broad antimicrobial activity towards viruses and bacteria including M. tuberculosis. Vitamin D increases the expression of cathelicidin in many cell types including macrophages, and it has been suggested that the vitamin D-mediated antimicrobial activity against M. tuberculosis is dependent on the induction of cathelicidin. However, unraveling the immunoregulatory effects of vitamin D in humans is hampered by the lack of suitable experimental models. We have previously described a family in which members suffer from hereditary vitamin D-resistant rickets (HVDRR). The family carry a mutation in the DNA-binding domain of the vitamin D receptor (VDR). This mutation leads to a non-functional VDR, meaning that vitamin D cannot exert its effect in family members homozygous for the mutation. Studies of HVDRR patients open unique possibilities to gain insight in the immunoregulatory roles of vitamin D in humans. Here we describe the impaired ability of macrophages to produce cathelicidin in a HVDRR patient, who in her adolescence suffered from extrapulmonary TB. The present case is a rare experiment of nature, which illustrates the importance of vitamin D in the pathophysiology of combating M. tuberculosis.

The high fuel efficiency of natural gas makes it an attractive alternative to coal and oil during the transition towards renewable energy resources. Natural gas engines are needed to ensure a stable power grid that can accommodate fluctuations in renewable energy production. Unfortunately, these engines emit as much as 3-4% of the methane (CH4) in the natural gas under learn-burn conditions. This methane slip has a high environmental cost since CH4 is a potent greenhouse gas. Complete catalytic oxidation of CH4 can potentially control the emission. Unfortunately, the best performing Pd/Al2O3 catalysts suffer from severe deactivation under operating conditions. After decades of little progress, zeolite-supported catalysts have recently attracted increased attention. Here, we review the current status, challenges, and prospects for controlling methane emissions from large engines using zeolite-based catalysts. The determining factors for catalytic activity and stability are the zeolite topology, alumina content, counter-ion, and active metal nanoparticles incorporation. In addition, we highlight the importance of testing under realistic operation conditions. Thus, the review provides a framework for developing a catalyst technology critically needed to fulfill the Paris Climate Agreement.

New vaccines are urgently needed against Mycobacterium tuberculosis (Mtb), which kills more than 1.4 million people each year. CD4 T cell differentiation is a key determinant of protective immunity against Mtb, but it is not fully understood how host-pathogen interactions shape individual antigen-specific T cell populations and their protective capacity. Here, we investigated the immunodominant Mtb anti-gen, MPT70, which is upregulated in response to gamma interferon (IFN-γ) or nutrient/ oxygen deprivation of in vitro-infected macrophages. Using a murine aerosol infection model, we compared the in vivo expression kinetics of MPT70 to a constitutively expressed antigen, ESAT-6, and analyzed their corresponding CD4 T cell phenotype and vaccine protection. For wild-type Mtb, we found that in vivo expression of MPT70 was delayed compared to ESAT-6. This delayed expression was associated with induction of less differentiated MPT70-specific CD4 T cells but, compared to ESAT-6, also reduced protection after vaccination. In contrast, infection with an MPT70-overexpress-ing Mtb strain promoted highly differentiated KLRG1+CX3CR1+ CD4 T cells with lim-ited lung-homing capacity. Importantly, this differentiated phenotype could be pre-vented by vaccination, and against the overexpressing strain, vaccination with MPT70 conferred protection similar to vaccination with ESAT-6. Together, our data indicate that high in vivo antigen expression drives T cells toward terminal differentiation and that targeted vaccination with adjuvanted protein can counteract this phenomenon by maintaining T cells in a protective less differentiated state. These observations shed new light on host-pathogen interactions and provide guidance on how future Mtb vaccines can be designed to tip the immune balance in favor of the host. IMPORTANCE Tuberculosis, caused by Mtb, constitutes a global health crisis of mas-sive proportions and the impact of the current coronavirus disease 201

Natural isolates of the soil‐dwelling bacterium Bacillus subtilis form robust biofilms under laboratory conditions and colonize plant roots. B. subtilis biofilm gene expression displays phenotypic heterogeneity that is influenced by a family of Rap‐Phr regulatory systems. Most Rap‐Phr systems in B. subtilis have been studied independently, in different genetic backgrounds and under distinct conditions, hampering true comparison of the Rap‐Phr systems’ impact on bacterial cell differentiation. Here, we investigated each of the 12 Rap‐Phr systems of B. subtilis NCIB 3610 for their effect on biofilm formation. By studying single ∆rap‐phr mutants, we show that despite redundancy between the cell–cell communication systems, deletion of each of the 12 Rap‐Phr systems influences matrix gene expression. These Rap‐Phr systems therefore enable fine‐tuning of the timing and level of matrix production in response to specific conditions. Furthermore, some of the ∆rap‐phr mutants demonstrated altered biofilm formation in vitro and colonization of Arabidopsis thaliana roots, but not necessarily similarly in both processes, indicating that the pathways regulating matrix gene expression and other factors important for biofilm formation may be differently regulated under these distinct conditions.

Heterogeneous immobilized molecular catalysis has gained significant attention as a platform for creating more efficient and selective catalysts. A promising type of immobilized molecular catalysts are made from porous organic polymers (POPs) due to their high stability, porosity, and ability to mimic the catalytic activity and selectivity of homogeneous organometallic catalysts. These properties of the POP‐based systems make them very attractive as heterogeneous catalysts for hydrogenation of CO 2 to formate, where predominately homogeneous systems have been applied. In this study, five POPs were synthesized and assessed in the hydrogenation of CO 2 where the active catalysts were made in‐situ by mixing IrCl 3 and the POPs. One of the Ir/POP catalysts provided a turn‐over number (TON) >20,000, which is among the highest for POP‐based systems. Thorough characterization (CO 2 ‐ and N 2 ‐physisorption, TGA, CHN‐analysis, XRD, XPS, SEM, STEM and TEM) was performed. Notably, the developed Ir/POP system also showed catalytic activity for the decomposition of formic acid into H 2 enabling the use of formic acid as a renewable energy carrier.