Adequate mixing is essential during reactions, especially in heterogeneous systems such as Solid Phase Synthesis (SPS), where the reagents transit from the fluid phase into the solid support. Despite the importance of mixing, a quantitative analysis within a theoretical framework is missing for SPS reactors. We analyze mechanical stirring (100–1300 rpm) and argon bubbling (1–30 cm 3 /min; 0.02–0.70 cm/s) as mixing methods in a milligram-scale batch reactor. Digital Image Analysis (DIA) was used to characterize the liquid mixing and particle dispersion. Typical solvents for SPS of biomoleculesacetonitrile (ACN), dichloromethane (DCM), and dimethylformamide (DMF)were studied. The dispersion model represented the mixing process. Both mixing methods homogenize the liquid in times as short as 1s. Particle dispersion is accomplished in DCM and DMF but is limited in ACN, where the Archimedes number (Ar) was larger. The synthesis of various glycan probes through Automated Glycan Assembly (AGA) suggests that adequate mixing and thermal conditions are indispensable for process optimization.

Introduction: In Germany, as in other countries, a shortage of veterinarians is threatening the health and welfare of pets and livestock. Against this background, the aim of this study was to find out what plans veterinary graduates have after their studies, what field they want to work in and whether their career aspirations change during their studies. In addition, it was investigated whether the factors of gender, origin (urban/rural), and animal ownership before studying were associated with future planning/decision-making.

Materials and methods: With the help of an online survey, German graduates of veterinary medicine from the class of 2023 were interviewed. Responses from 157 people were analyzed, which corresponds to a response rate of around 17%.

Results: The results of this study show that almost half of the participants (n = 76; 48%) would like to work in a practice directly after graduation and 63% of respondents (n = 98) saw themselves working in a practice in 5 years’ time. The field of small animal medicine was the most strongly represented, followed by equine medicine. Only 42% of participants (n = 66) saw themselves in the same veterinary field in the future as they had aspired to before their studies. Neither gender nor origin were associated with future planning. However, the husbandry of certain animal species before studying was significantly associated with the field in which the respondents wanted to work later.

Discussion: These results provide an initial basis for estimating how many veterinarians enter the respective fields and should be taken into account when discussing changing the admission requirements of universities of veterinary medicine to attract more young people to a certain animal field or a certain region of Germany.

Introduction: Streptococcus suis represents a growing zoonotic pathogen, exacerbated by increasing antimicrobial resistance due to a widespread and often inappropriate antimicrobial use. This escalating challenge underscores the pressing need for innovative treatment strategies against streptococcal infections in pigs. In our study, we identified Ply691, a prophage-encoded lytic enzyme.

Methods: The corresponding gene was identified during whole genome analysis of S. suis SC267. Structural domain analysis revealed that Ply691 consists of an N-terminal Amidase-5 catalytic domain, a C-terminal Glucosaminidase catalytic domain, and two centrally located CW-7-binding structural domains. In order to investigate the bactericidal potential of Ply691, an in vitro bactericidal assay was conducted using Ply691, and its bactericidal effect was evaluated by colony counting method after applying it to different strains of bacteria and at different temperatures and pH conditions. Subsequently, a mouse bacteremia model was established, and the in vivo bactericidal efficacy of Ply691 was evaluated by measuring the bacterial residues in the blood and different organs of mice treated with Ply691.

Results: In-vitro antimicrobial susceptibility testing demonstrated that Ply691 exhibits potent lytic activity against 11 serotypes of S. suis, including serotypes 2, 3, 5, 9, 10, 12, 17, 18, 19, 29, and 30. Furthermore, Ply691 reduced the number of S. suis colonies by approximately 1 log within 20 min. Ply691 also displayed a broad temperature adaptability range (4°C-37°C) and remarkable alkaline tolerance (pH 7-10). In an in vivo murine bacteremia model, Ply691 demonstrated significant therapeutic effects. Administration of Ply691 at a dose of 2 mg per mouse by intraperitoneal injection an hour post-infection resulted in a 100% survival rate and substantially reduced the bacterial load in the blood and various organs (heart, liver, spleen, lung, kidney, and brain). Histological analysis confirmed that these organs closely resembled those of the control group.

Discussion: Ply691 exhibits broad-spectrum lytic activity against S. suis with unique structural advantages. It demonstrates robust efficacy in vivo without inducing resistance, showing significant therapeutic potential for streptococcal infections.

The Martian isochrons are the basis in analyzing the impact flux and surface dating, and currently, they are usually derived from those of the Moon because no samples have been collected from Mars. However, the isochrons obtained by this method have substantial uncertainty, and they urgently need to be optimized based on the samples that are about to be obtained. To support the upcoming Mars sample return missions, we utilized a high-resolution Context Camera mosaic and selected 17 regions from diverse geological units and ages across Mars's surface to establish an observed Martian crater production function (PF). Craters were manually mapped across these regions. The crater size-frequency distributions (CSFDs) from these regions have a strong correlation at the same diameter range on a logarithmic scale, indicating that they share a similar distribution shape regardless of geological units and ages. We obtained 155 effective CSFD bins suitable for fitting the crater PF. After testing on different fitting functions, we finally obtained the crater PF for the Martian surface over the diameter range of 0.15 to 13.5 km. There were significant differences between the directly mapped Mars crater PF and those derived from lunar models. In addition, the CSFDs obtained by previous researchers when doing dating works on the Martian surface are more consistent with the newly established crater PF than with the earlier proposed PFs. With the radiometric ages of the samples returned by future Mars sample return missions, this research could become the basis for establishing a new chronology system for Mars.

Despite high confidence in the intensification of the hydrological cycle due to global warming, the future spatiotemporal patterns of extreme precipitation remain uncertain. Here we explore how climate change influences the seasonal timing of extreme precipitation events, using daily output from the Coupled Model Intercomparison Project Phase 6. We show that at latitudes between about 45°N and 75°N in Eurasia and North America, where extreme precipitation typically peaks in summer, climate models project a substantial shift in the seasonal timing of extreme precipitation from summer into the colder seasons, spring and autumn, or even into winter, by the late 21st century. We show that this shift is associated with reduced moisture supply during strong updraft events in summer. These results point towards a need for improved representations of processes determining the change in the moisture availability and simulated vertical winds of the atmosphere as well as for adaptation to higher flood risk in colder seasons.

Essential mechanistic principles of proteins, such as the lock-and-key principle in substrate binding, were identified over the last few decades. The CRC 1078 had set itself the goal of introducing a new principle in the understanding of protein mechanisms of action: The control and coordination of complex protein function by protonation dynamics. Spatio-temporal fluctuations of these functionally relevant hydrogen-bonded networks result from proton movements on different time and length scales - from femtoseconds to seconds and from less than 0.1 nm to more than 10 nm. The experimental studies of the CRC 1078 were combined with theory and simulations to achieve a deeper understanding of the proton-dependent mechanisms in the selected protein families. Different facets of protonation dynamics were investigated in two proteins central to biological energy conversion: Oxygen reduction coupled to proton pumping by cytochrome c oxidase and water oxidation catalyzed by photosystem II, respectively. While electron transfer in these proteins can be slowed down or even prevented by major structural changes, light-induced conformational changes play a crucial role in the mechanism of both phytochromes and channelrhodopsins as well as in pH-controlled proton channels. The functionality of the latter was compared with that of the pH-gated viroporins. These structural changes are often associated with or driven by proton movements. The development and adaptation of various experimental and theoretical methods to the requirements of specific protein systems was an essential aspect of research in the CRC 1078. These included the incorporation of non-canonical amino acids into proteins, time-resolved serial femtosecond X-ray crystallography, nuclear magnetic resonance spectroscopy at high magnetic fields, time-resolved electronic and vibrational spectroscopy over a large dynamic range as well as multiscale modeling approaches from quantum mechanics, molecular dynamics simulation and their hybrids. The application of such advanced techniques was challenging, as most of the proteins are integral membrane proteins. Finally, the CRC 1078 achieved its original goal of gaining a comprehensive understanding of protonation dynamics as an important element of the functional mechanisms of five selected protein families and, thus, understanding this process as a generic principle of protein function.

Paleosols in different climatic zones and geomorphological settings serve as important paleoenvironmental archives. Crete (Greece) with its central location in the eastern Mediterranean area constitutes an important (paleo)climatic transition zone between northern Africa and the Eurasia. While paleosols have been commonly described and used as chronostratigraphic markers within a large number of geological and archaeological studies in Crete, they have not been subject of a comparative study so far. In the present study, we analyse seven pedocomplexes in central and western Crete within different climatic, geological and geomorphological settings. Our analysis is based on geochemistry, grain size distribution, bulk and clay mineralogy, micromorphology and absolute datings (luminescence, radiocarbon). In all cases, the paleosol horizons, mainly Bt- und Bk-horizons, display strong indications for pedogenesis, such as increased clay contents or carbon accumulation, similar reddish-brown colours and abundant characteristic clay minerals, especially vermiculite, smectite and kaolinite, compared to the over- and underlying sediments. However, clay composition also reveals desequilibrium conditions indicating an allochthonous origin of at least part of the material. Furthermore, micromorphological results do not clearly confirm in-situ pedogenesis. Therefore, open questions related to the redeposition of Terra Rossa as pedosediments as well as the importance of dust inputs from long-range sources remain. Chronostratigraphically, the timing of the deposition of soil parent materials as well as the formation of petrocalcic horizons indicate that soil formation was related to climatic transition phases during the late Pleistocene in most studied cases. However, due to the limited number of profiles, datings and comparable geo-archives in Crete, these results need to be substantiated in future studies incorporating further paleosols in Crete and the surroundings areas in the Eastern Mediterranean.

Large language models (LLMs) are now widely accessible, reaching learners across all educational levels. This development has raised concerns that their use may circumvent essential learning processes and compromise the integrity of established assessment formats. In physics education, where problem solving plays a central role in both instruction and assessment, it is therefore essential to understand the physicsspecific problem-solving capabilities of LLMs. Such understanding is key to informing responsible and pedagogically sound approaches to integrating LLMs into instruction and assessment. This study therefore compares the problem-solving performance of a general-purpose LLM (GPT-4o, using varying prompting techniques) and a reasoning-optimized model (o1-preview) with that of participants in the German Physics Olympiad, based on a set of well-defined Olympiad problems. In addition to evaluating the correctness of the generated solutions, the study analyzes the characteristic strengths and limitations of LLM-generated solutions. The results of this study indicate that both tested LLMs (GPT-4o and o1-preview) demonstrate advanced problem-solving capabilities on Olympiad-type physics problems, on average outperforming the human participants. Prompting techniques had little effect on GPT-4o's performance, and o1-preview almost consistently outperformed both GPT-4o and the human benchmark. The main implications of these findings are twofold: LLMs pose a challenge for summative assessment in unsupervised settings, as they can solve advanced physics problems at a level that exceeds top-performing students, making it difficult to ensure the authenticity of student work. At the same time, their problem-solving capabilities offer potential for formative assessment, where LLMs can support students in evaluating their own solutions to problems.

Einstein-aether theory provides a model to test the validity of local Lorentz invariance in gravitational interactions. The speed of gravitational waves as measured from the binary neutron star event GW170817 sets stringent limits on Einstein-aether theory, but only on a combination of the theory’s free parameters. For this reason, a significant part of the theory’s parameter space remains unconstrained by observations. Motivated by this, we explore the propagation of gravitational waves in Einstein-aether theory over an inhomogeneous background (i.e., gravitational wave lensing) as a potential mechanism to break the degeneracies between the theory’s free parameters, and hence enable new constraints on the theory to be obtained. We reduce our analysis to gravitational waves that pass far from the lens’ center and short wavelength signals, both compared to the lens’ gravitational radius (eikonal limit). By applying these approximations and bringing the field equations into the form of the so-called kinetic matrix and applying a formalism known as the propagation eigenstate framework, we find that the speed of gravitational waves is modified by inhomogeneities in the aether field. However, the modification is common to both gravitational polarizations and vanishes in the limit in which gravitational waves propagate with luminal speed. This lens-dependent gravitational wave speed contrasts with the lens-induced birefringence observed in other theories beyond general relativity, like Horndeski’s theory. While the potential to improve tests based on gravitational-wave speed is limited, our formalism sets the basis to fully describe signal propagation over inhomogeneous spacetimes in Einstein-aether theory and other extensions of general relativity.

The imposition of crystalline symmetries is known to lead to a rich variety of insulating and superconducting topological phases. These include higher-order topological phases and obstructed atomic limits with and without filling anomalies. We here comprehensively classify such topological crystalline phases (TCPs) with mirror, twofold rotation, and inversion symmetries in the presence of disorder that preserves the crystalline symmetry on average. We find that the inclusion of disorder leads to a simplification of the classification in comparison to the clean case. We also find that, while clean TCPs evade a general bulk-boundary principle, disordered TCPs admit a complete bulk-boundary correspondence, according to which (bulk) topological phases are topologically equivalent if and only if they have the same anomalous boundary states and filling anomaly. We corroborate the stability of disordered TCPs by way of field-theoretic, numerical, and symmetry-based analyses in various case studies. While the boundary signatures of most disordered TCPs are similar to their clean counterparts, the addition of disorder to certain mirror-symmetric TCPs results in novel higher-order statistical topological phases, in which zero-energy hinge states have critical wave-function statistics, while remaining protected from Anderson localization.

Niche-based models are essential for predicting invasion risks. Although most invasive species tend to conserve their ecological niches after introduction, some challenge this assumption by expanding or contracting their niches, yet such patterns remain underexplored in microorganisms. Since larger niche shifts can reduce the predictive performance of these models, this study examines whether the climatic niches of the invasive dinoflagellates Ceratium hirundinella (Müller, 1841) and C. furcoides (Langhans, 1925) have shifted following their invasion from native European to non-native American ranges, where they have caused significant impacts on biodiversity and water quality. Though both species are native to temperate European lakes, their colonization patterns in the Americas differ, and the drivers of their spread remain unclear. In this study, niche conservatism was analyzed using five niche dynamic metrics for both species. The current distribution of C. hirundinella primarily in subtropical and temperate non-native areas aligns with its native climate (i.e., higher niche stability), suggesting preadaptation. Meanwhile, for C. furcoides, a niche shift—indicated by maximum expansion and unfilling—suggests a much higher potential for rapid spread across both tropical and subtropical climates. These findings show distinct climatic responses of congeneric species in non-native ranges, emphasizing the need to move beyond native environmental predictors when assessing invasion risk. Future research should explore niche shifts over time and whether invasions begin in ecologically matched habitats (as expected for C. hirundinella) or are driven by propagule pressure and human activity despite niche mismatches (as in C. furcoides).

The RNA helicase Moloney leukemia virus 10 (MOV10) is involved in several RNA processing pathways, including RNA silencing, defense against viral RNA and nonsense-mediated mRNA decay (NMD). MOV10 is a member of the Up-frameshift 1 (UPF1)-family of superfamily 1 (SF1) helicases and like its prototype member, unwinds RNA duplexes bearing a 5′-single-stranded overhang. Sequence comparisons of MOV10 and UPF1 revealed significant identity between their RecA domains and considerable divergence between the N-terminal domains preceding the helicase core. Using in vitro biochemical approaches, we show that the N-terminal domain of MOV10 is functionally distinct from the CH domain of UPF1, both in terms of its impact on catalytic activity and the protein-protein interactions it mediates. MOV10 engages the NMD factor UPF2 via its N-terminal regulatory domain but binds a different region than the UPF1-CH domain. We propose that the interactions mediated by the MOV10-N-terminal domain dictate its localization to cytoplasmic RNA condensates such as P-bodies and stress granules. This is distinct from UPF1, whose localization appears to be driven by its interaction with RNA. Taken together, our work presents a mechanistic model for the recruitment and involvement of MOV10 in NMD, where it was proposed to act as an RNA clearance factor for UPF1.

La economía de plataformas digitales está transformando la naturaleza del trabajo. En paralelo a las grandes compañías dinamizadoras de este cambio hay grupos subalternos precarios que refuerzan la reestructuración. Un caso ejemplar es el de las mujeres latinoamericanas del programa Migrant Woman Entrepreneur: Collaborative Growth Community (MWECGC) de Chile. Por lo mismo, el objetivo general de la investigación es analizar la modalidad de inserción de las mujeres de este programa en la economía digital de Chile y dilucidar el perfil laboral del grupo antes y después de su llegada al país. Partiendo de la hipótesis de que el cruce de sus biografías con el contexto socioeconómico chileno es fundamental para desarrollar sus emprendimientos digitales, se practicó una netnography a las 49 mujeres que participaron en el proyecto. Los resultados muestran que la confluencia de factores individuales y contextuales produjo cuatro tipos de emprendedoras. Las conclusiones sugieren que la digitalización del emprendimiento no garantiza la visibilidad y alcance de este, lo que relativiza el supuesto potencial democratizador de las plataformas.

The first waves of the COVID-19 pandemic were accompanied by an unprecedented decrease of influenza activity which persisted throughout the 2020/21 and 2021/22 winter seasons. Here, we report on the unusual influenza circulation patterns that followed in the year 2022, which was dominated throughout by A(H3N2) influenza viruses. After a delayed spring wave in 2022, A(H3N2) influenza viruses circulated at low levels throughout the summer and rose to a prominent, prematurely-timed fall/winter wave peaking in December, with highest positivity rates observed in 10–12-years old children. This winter wave ended abruptly with the national school holidays, when positivity rates decreased sharply not only in children but also in other age groups. Genetic analysis of influenza virus hemagglutinin (HA) showed cocirculation of 10 A(H3N2) clades, of which three (2a.1b, 2a.3a.1, and 2b) became dominant in late 2022. All A(H3N2) viruses, including those assigned to the new clades, displayed high titers in HA inhibition tests with postinfection ferret antiserum raised against the A(H3N2) vaccine strains A/Cambodia/e0826360/2020 and A/Darwin/9/2021. All viruses were susceptible to neuraminidase inhibitors and the polymerase inhibitor baloxavir marboxil, but carried the M2-S31N substitution conferring adamantane resistance. Our findings shed light on disturbed seasonality of A(H3N2) circulation in the post-COVID-19 era.

Evidence indicates that transposable elements (TEs) can contribute to the evolution of new traits, with some TEs acting as deleterious elements while others are repurposed for beneficial roles in evolution. In mammals, some KRAB-ZNF proteins can serve as a key defense mechanism to repress TEs, offering genomic protection. Notably, the family of KRAB-ZNF genes evolves rapidly and exhibits diverse expression patterns in primate brains, where some TEs, including autonomous LINE-1 and non-autonomous Alu and SVA elements, remain mobile. This prompts questions about their interactions in primate brains and potential roles in human brain evolution and disease. For a systematic comparative analysis of TE interactions with other genes, we developed the tool TEKRABber and focused on strong and experimentally validated cases. Our bipartite network analysis revealed significantly more interactions between KRAB-ZNF genes and TEs in humans than in other primates, especially with recently evolved, i.e., Simiiformes-specific, TEs. Notably, ZNF528, under positive selection in humans, shows numerous human-specific TE interactions. Most negative interactions in our network, indicative of repression by KRAB-ZNF proteins, entail Alu TEs, while links to other TEs are generally positive. In Alzheimer’s patients, a subnetwork involving 21 interactions with an Alu module appears diminished or lost. Our findings suggest that KRAB-ZNF and TE interactions vary across TE families, have increased throughout human evolution, and may influence susceptibility to Alzheimer’s disease.

Pesticides are a major anthropogenic input to the environment and a factor in global change that puts pressure on soil microbial communities. However, the effects of different rates of pesticide application on soils remain poorly understood. This study investigates how abrupt versus gradual pesticide applications influence soil bacterial and fungal communities. Employing high-throughput sequencing, we examined the microbial diversity and community composition in response to ten commonly used pesticides. Bacterial communities exhibited minimal changes across treatments, whereas fungal communities responded strongly to pesticide exposure. Gradual applications reduced the relative abundance of dominant fungal taxa, resulting in an overall increase in community evenness. This effect was particularly pronounced for two herbicides and a triazole fungicide, which induced substantial shifts in fungal composition. Conversely, abrupt pesticide applications resulted in transient disruptions but did not promote the long-term proliferation of rare fungal variants. These findings suggest that prolonged exposure to pesticides exerts strong selective pressures on fungi, potentially altering fundamental soil functions such as nutrient cycling and decomposition. Future research should focus on the long-term responses of soil microbial communities to pesticide application and the cumulative effects of chronic low-dose exposure to provide a more comprehensive understanding of how they shape microbial communities.

The transition to flowering is governed by different pathways integrating endogenous and exogenous signals. Here, we evaluated the role of the phytohormone cytokinin (CK) in regulating Arabidopsis thaliana flowering time. By analyzing key mutants in CK metabolism, transport, and signaling, we found that the hormone promotes flowering under both long-day (LD) and short-day (SD) conditions, with a stronger impact on flowering under SDs. Genetic analyses indicated that both trans- and cis-zeatin regulate the floral transition, while isopentenyladenine plays a minor role. Blocking CK export from roots and reciprocal grafting experiments revealed that root-derived CK is an important flowering signal. Perception and transmission of the CK flowering signal depended on distinct CK receptors, phosphotransmitter proteins and several B-type response regulators. Further, CK functioned through floral integrators such as SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) and components of the age pathway. The CK status of plants affected the levels of the age pathway microRNAs miR156 and miR172. Cytokinin-promoted flowering required the miR156-target SQUAMOSA PROMOTER BINDING PROTEIN-LIKE15 (SPL15) and miR172, and the late-flowering phenotype of LD-grown CK-deficient plants depended on miR172-targeted APETALA2 (AP2)-like genes encoding floral repressors. Collectively, this study shows that CK regulates flowering time through the two-component signaling system and components of the age pathway, providing a genetic framework for future investigations.

Flexible manipulation of chiral terahertz electromagnetic waves holds substantial potential for a wide range of applications, such as terahertz circular dichroism spectroscopy in biomaterials analysis, ultrafast electron bunch manipulation, high-speed wireless communication, and imaging. However, the development of tunable terahertz polarization modulation has been impeded by the lack of terahertz flexible manipulation measures at room temperature. We demonstrate an innovative element based on patterned spintronic terahertz sources, which can achieve efficient and great flexibility in polarization adjustment. The contributory effect of built-in electric fields on chiral terahertz waves is experimentally revealed by arranging different periodical microscale stripes, and swift polarization switching among linear, elliptical, and circular states is achieved by rotating ferromagnetic heterostructures. Notably, the ellipticity of the circle polarization state remains above 0.85 over a broadband terahertz bandwidth (from 0.74 to 1.66 THz). Furthermore, various polarization states dependent on geometry and azimuth angles provide insight into the physical mechanism of terahertz modulation by the built-in electric field. These findings contribute to the development of novel multifunctional terahertz devices, which pave the way to implement on-chip tunable terahertz polarization spectroscopy applications in biomedical detection and high-speed communication.

Psychosoziale Belastungen in der Zeit nach der Geburt wirken sich negativ auf das elterliche Wohlbefinden und die Eltern-Kind-Beziehung aus. Häufig erreichen präventive Interventionen diese belasteten Familien nicht (Präventionsdilemma). Blended-Care-Ansätze, also digitale Interventionen mit Unterstützung von Gesundheitsfachkräften, bieten eine niedrigschwellige Möglichkeit, diese schwer zu erreichende Gruppe zu unterstützen. Dieser Artikel untersucht den Forschungsprozess, einschließlich der Entwicklung, Rekrutierung und Durchführung des I-PREGNO-Projekts – einer Blended-Care-Intervention zur Förderung der psychischen Gesundheit und des Gewichtsmanagements in psychosozial belasteten Familien postpartum. Diese wurde gemeinsam mit Fachkräften und Familien entwickelt und Stärken und Herausforderungen des Projekts wurden mittels Befragungen und Gesprächen mit Gesundheitsfachkräften identifiziert. Trotz (anfangs) großem Interesse der Fachkräfte erwies sich die Rekrutierung von psychosozial belasteten Familien als schwierig, was das Präventionsdilemma verdeutlicht. Die Abbrecherquote der erfolgreich rekrutierten Familien blieb jedoch während der gesamten Studie niedrig. Die nutzerzentrierte Entwicklung der App führte zu einer hohen Zufriedenheit, zeigte jedoch den Bedarf an Adhärenzstrategien (z. B. personalisierte Inhalte) und mehrsprachigen Materialien. Die Einbeziehung von Fachkräften war für den Zugang zu dieser vulnerablen Gruppe von entscheidender Bedeutung, erfordert jedoch eine großzügigere Ressourcenplanung für ihre Schulung und Unterstützung. I-PREGNO liefert wichtige Erkenntnisse für künftige Interventionen, um psychosozial belastete Familien besser zu erreichen und den Druck auf das Gesundheitssystem zu verringern.

The celebrated Lindblad equation governs the nonunitary time evolution of density operators used in the description of open quantum systems. It is usually derived from the von Neumann equation for a large system, at given physical conditions, when a small subsystem is explicitly singled out and the rest of the system acts as an environment whose degrees of freedom are traced out. In the specific case of a subsystem with variable particle number, the equilibrium density operator is given by the well-known grand canonical Gibbs state. Consequently, solving the Lindblad equation in this case should automatically yield, without any additional assumptions, the corresponding density operator in the limiting case of statistical equilibrium. Current studies of the Lindblad equation with varying particle number assume, however, the grand canonical Gibbs state a priori: the chemical potential is externally imposed rather than derived from first principles, and hence the corresponding density operator is not obtained as a natural solution of the equation. In this work, we investigate the compatibility of grand canonical statistical mechanics with the derivation of the Lindblad equation. We propose an alternative and complementary approach to the current literature that consists in using a generalized system Hamiltonian which includes a term 𝜇⁢𝑁 . In a previous paper, this empirically well-known term has been formally derived from the von Neumann equation for the specific case of equilibrium. Including 𝜇⁢𝑁 in the system Hamiltonian leads to a modified Lindblad equation which yields the grand canonical state as a natural solution, meaning that all the quantities involved are obtained from the physics of the system without any external assumptions.