Characterization of a Novel Pathogenic PLCG2 Variant Leading to APLAID Syndrome Responsive to a TNF inhibitor.

OBJECTIVE: Autoinflammation and PLCγ2-associated antibody deficiency and immune dysregulation (APLAID) syndrome is an autoinflammatory disease caused by gain-of-function variants in PLCG2. This study investigates the pathogenic mechanism of a novel variant of PLCG2 in a patient with APLAID syndrome. METHODS: Whole exome sequencing and Sanger sequencing were used to identify the pathogenic variant in the patient. Single-cell RNA sequencing, immunoblotting, luciferase assay, IP-one ELISA, calcium flux assay, quantitative PCR, and immunoprecipitation were used to define inflammatory signatures and evaluate the effects of the PLCG2 variant on protein functionality and immune signaling. RESULTS: We identified a novel de novo variant, PLCG2 p.D993Y, in a patient with colitis, pansinusitis, skin rash, edema, recurrent respiratory infections, B cell deficiencies, and hypogammaglobulinemia. The single-cell transcriptome revealed exacerbated inflammatory responses in the patient's PBMCs. Expression of the D993Y variant in HEK293T, COS-7, and PLCG2 knock-out THP-1 cell lines showed heightened PLCγ2 phosphorylation, elevated IP3 production and intracellular Ca2+ release, and activation of the MAPK, NFκB, and NFAT signaling pathways compared to control-transfected cells. In vitro experiments indicated that the D993Y variant altered amino acid properties, disrupting the interaction between the catalytic and auto-inhibitory domains of PLCγ2, resulting in PLCγ2 auto-activation. CONCLUSIONS: Our findings demonstrated that the PLCG2 D993Y variant is a gain-of-function mutation via impairing its auto-inhibition, activating multiple inflammatory signaling pathways, thus leading to APLAID syndrome. This study further broadens the molecular underpinnings and phenotypic spectrum of PLCγ2-related disorders.

Capillary-driven microchip integrated with nickel phosphide hybrid-modified electrode for the electrochemical detection of glucose.

BACKGROUND: Transition metal phosphides with properties similar to platinum metal have received increasing attention for the non-enzymatic detection of glucose. However, the requirement of highly corrosive reagent during sample pretreatment would impose a potential risk to the human body, limiting their practical applications. RESULTS: In this study, we report a self-powered microfluidic device for the non-enzymatic detection of glucose using nickel phosphide (Ni2P) hybrid as the catalyst. The Ni2P hybrid is synthesized by pyrolysis of metal-organic framework (MOF)-based precursor and in-situ phosphating process, showing two linear detection ranges (1 µM-1 mM, 1 mM-6 mM) toward glucose with the detection limit of 0.32 µM. The good performance of Ni2P hybrid for glucose is attributed to the synergistic effect of Ni2P active sites and N-doped porous carbon matrix. The microchip is integrated with a NaOH-loaded paper pad and a capillary-based micropump, enabling the automatic NaOH redissolution and delivery of sample solution into the detection chamber. Under the optimized condition, the Ni2P hybrid-based microchip realized the detection of glucose in a user-friendly way. Besides, the feasibility of using this microchip for glucose detection in real serum samples has also been validated. SIGNIFICANCE: This article presents a facile fabrication method utilizing a MOF template to synthesize a Ni2P hybrid catalyst. By leveraging the synergy between the Ni2P active sites and the N-doped carbon matrix, an exceptional electrochemical detection performance for glucose has been achieved. Additionally, a self-powered chip device has been developed for convenient glucose detection based on the pre-established high pH environment on the chip.

Prevalence and Characteristics of Low-renin Hypertension in a Primary Care Population.

Introduction: Low-renin hypertension is an underrecognized subtype of hypertension with specific treatment options. This study aims to identify the prevalence in primary care and to compare patient characteristics to those with normal-renin hypertension and primary aldosteronism (PA). Methods: In a cohort study, patients with treatment-naïve hypertension were screened for PA with plasma aldosterone and direct renin concentrations. Patients with an elevated aldosterone-to-renin ratio [≥70 pmol/mU (≥2.5 ng/dL:mU/L)] underwent confirmatory testing. All screened patients were then classified as having (1) normal-renin hypertension, (2) low-renin hypertension (direct renin concentration <10mU/L (plasma renin activity ∼<1 ng/mL/hour) and not meeting the criteria for PA), or (3) confirmed PA. Results: Of the 261 patients, 69 (26.4%) had low-renin hypertension, 136 (51.9%) had normal renin hypertension, and 47 (18.0%) had PA. Patients with low-renin hypertension were older and more likely to be female compared to normal-renin hypertension (57.1 ± 12.8 years vs 51.8 ± 14.0 years, P < .05 and 68.1% vs 49.3%, P < .05, respectively) but similar to PA (53.5 ± 11.5 years and 55.3%). However, in an adjusted binomial logistic regression, there was no association between increasing age or sex and low-renin hypertension. The median aldosterone concentration was lower compared to patients with normal-renin hypertension and PA: 279 pmol/L (216-355) vs 320 pmol/L (231-472), P < .05 and 419 pmol/L (360-530), P < .001. Conclusion: At least a quarter of treatment-naïve hypertensive patients in primary care had a low direct renin concentration but did not meet the criteria for PA. Patient characteristics were similar, aside from a lower aldosterone concentration compared to patients with normal-renin hypertension and PA. Further research is needed to understand the underlying pathophysiology of low-renin hypertension and the optimal first-line treatment.

Pseudomeningocele Following Posterior Cranial Fossa Surgery Significantly Increases the Risk of Intracranial Infection: A 10-Year Retrospective Analysis.

Background: Posterior fossa craniotomy is commonly performed for various pathologies. However, intra-cranial infection following craniotomy causes morbidity. Pseudomeningocele is one of the main complications following posterior fossa operation. This study aimed to test the hypothesis that the risk of intra-cranial infection is increased in patients who undergo posterior fossa craniotomy with pseudomeningocele compared with those without pseudomeningocele. Methods: We retrospectively analyzed the data of patients undergoing posterior fossa craniotomy for the management of neurological pathologies at our institute from 2011 to 2020. A total of 308 craniotomies were included, and the primary outcome of interest was the occurrence of intra-cranial infection. Standard statistical methods were used to explore associations between several parameters, including pseudomeningocele, intra-cranial infection, and wound leak. Results: Of the 308 craniotomies, 41 (13.3%) developed intra-cranial infection and 59 (19.2%) involved pseudomeningocele. Of cases involving pseudomeningocele, 27 (45.8%) developed an intra-cranial infection compared with only 14 of 249 without pseudomeningocele (5.6%; p < 0.001). In the multi-variable analysis, pseudomeningocele was associated with intra-cranial infection (odds ratio [OR] 8.56; 95% confidence interval [CI] 3.145-23.299; p < 0.001) and wound leak (OR 91.339; 95% CI 10.437-799.364; p < 0.001). Conclusion: The findings indicate that patients undergoing posterior fossa craniotomy are at a greater risk of intra-cranial infection if there is pseudomeningocele after the operation.

Azacitidine combined with interferon-α for pre-emptive treatment of AML/MDS after allogeneic peripheral blood stem cell transplantation: A prospective phase II study.

This prospective clinical study aimed to evaluate the efficacy and safety of the pre-emptive treatment modality of azacitidine in combination with interferon-α (IFN-α) in AML/MDS patients post-transplantation. Forty-seven patients aged 17-62 were enrolled with 14 patients having completed the planned 12 cycles. Following initiation, 72.3% responded positively after the first cycle, peaking at 77.2% by the fifth cycle. Notably, 24 patients maintained sustained responses throughout a median follow-up of 1050 days (range, 866-1234). Overall survival, leukaemia-free survival and event-free survival probabilities at 3 years were 69.5%, 60.4% and 35.7% respectively. Cumulative incidences of relapse and non-relapse mortality were 36.5% and 4.3% respectively. Multivariate analysis identified that receiving pre-emptive treatment for fewer than six cycles and the absence of chronic graft-versus-host disease after intervention was significantly associated with poorer clinical outcomes. The combination of azacitidine with IFN-α was well-tolerated with no observed severe myelotoxicity, and the majority of adverse events were reversible and manageable. In conclusion, the use of azacitidine in conjunction with IFN-α as pre-emptive therapy is a safe and effective treatment to prevent disease progression in AML/MDS patients with MRD positivity post-allo-HSCT.

A patient with AL amyloidosis presenting with refractory tuberculosis, chest tightness and hypotension: case report.

INTRODUCTION: Immunoglobulin light chain (AL) amyloidosis presents a clinical spectrum characterized by diverse manifestations and involvement of multiple organs, posing a significant diagnostic challenge for physicians. METHODS AND RESULTS: We present a case of a patient admitted to our hospital due to recurrent cough and sputum, which was initially diagnosed as refractory tuberculosis. Throughout his hospitalization, the patient experienced distressing symptoms, including uncontrollable chest tightness, hypotension, and fever. Noteworthy observations included a persistent elevation in cardiac biomarkers, indicative of cardiac damage. Bronchoalveolar lavage revealed the presence of various pathogenic microorganisms, while bone marrow flow cytometry demonstrated the existence of clonal plasma cells. Additionally, the urine free light chain assay detected the presence of M protein, and the positive congo red staining of the abdominal wall fat biopsy confirmed amyloid deposition in the tissues. Taking into account the patient's clinical presentation and the examination findings, we reached a conclusive diagnosis of immunoglobulin light chain (AL) amyloidosis. CONCLUSION: This case serves as a reminder for physicians to consider rare diseases like AL amyloidosis when patients present with symptoms involving multiple organ systems such as heart, lung and kidney that are unresponsive to conventional treatment options.

Airborne pollen exposure and risk of hospital admission for allergic rhinitis in Beijing: A time-stratified case-crossover study.

BACKGROUND: Airborne pollen is a crucial risk factor in allergic rhinitis (AR). The severity of AR symptoms can vary based on pollen type and concentration. This study aimed to estimate the association between exposure to different pollen types and AR risk. METHODS: We obtained data from patients admitted to the Beijing Tongren Hospital for AR, and data on pollen concentration, meteorological factors, and fine particulate matter (PM2.5) from 13 districts in Beijing from 2016 to 2019. We used a time-stratified case-crossover study design and calculated odds ratios (ORs) related to the risk of AR associated with a 10 grain/1000 mm2 increase in total pollen concentrations for specific pollen types. A stratified analysis was conducted to assess whether the associations were varied by age and sex. RESULTS: The OR of AR associated with a 10 grain/1000 mm2 increase in the 7-day average pollen concentration was 1.014 (95% CI: 1.014, 1.015), 1.076 (95% CI: 1.070, 1.082), 1.024 (95% CI: 1.023, 1.025), 1.042 (95% CI: 1.039, 1.045), 1.142 (95% CI: 1.137, 1.147), 1.092 (95% CI: 1.088, 1.097), 1.046 (95% CI: 1.035, 1.058), and 1.026 (95% CI: 1.024, 1.028) for total pollen, Ulmus, Cupressaceae, Populus, Fraxinus, Pinus, Betula, and Artemisia, respectively. Both tree pollen (Ulmus, Cupressaceae, Populus, Fraxinus, Betula, and Pinus) and weed pollen (Artemisia, Chenopodium, and Humulus) were correlated with an increased risk of AR. These associations remained consistent across distinct subgroups defined by both age and sex. CONCLUSION: Exposure to pollen from trees and weeds might be associated with an increased risk of AR. This research provides valuable scientific support for both clinical practitioners and patients with AR regarding the hazards of pollen exposure.

Urban health advantage and penalty in aging populations: a comparative study across major megacities in China.

Background: Urban living is linked to better health outcomes due to a combination of enhanced access to healthcare, transportation, and human development opportunities. However, spatial inequalities lead to disparities, resulting in urban health advantages and penalties. Understanding the relationship between health and urban development is needed to generate empirical evidence in promoting healthy aging populations. This study provides a comparative analysis using epidemiological evidence across diverse major Chinese cities, examining how their unique urban development trajectories over time have impacted the health of their aging residents. Methods: We tracked changes in air pollution (NO2, PM2.5, O3), green space (measured by NDVI), road infrastructure (ring road areas), and nighttime lighting over 20 years in six major cities in China. We followed a longitudinal cohort of 4992 elderly participants (average age 87.8 years) over 16,824 person-years. We employed Cox proportional hazard regression to assess longevity, assessing 14 variables, including age, sex, ethnicity, marital status, residence, household income, occupation, education, smoking, alcohol consumption, exercise, and points of interest (POI) count of medicine-related facilities, sports, and leisure service-related places, and scenic spots within a 5 km-radius buffer. Findings: Geographic proximity to points of interest significantly improves survival. Elderly living in proximity of the POI-rich areas had a 34.6%-35.6% lower mortality risk compared to those in POI-poor areas, for the highest compared to the lowest quartile. However, POI-rich areas had higher air pollution levels, including PM2.5 and NO2, which was associated with a 21% and 10% increase in mortality risk for increase of 10 µg/m3, respectively. The benefits of urban living had higher effect estimates in monocentric cities, with clearly defined central areas, compared to polycentric layouts, with multiple satellite city centers. Interpretation: Spatial inequalities create urban health advantages for some and penalties for others. Proximity to public facilities and economic activities is associated with health benefits, and may counterbalance the negative health impacts of lower green space and higher air pollution. Our empirical evidence show optimal health gains for age-friendly urban environments come from a balance of infrastructure, points of interest, green spaces, and low air pollution. Funding: Natural Science Foundation of Beijing (IS23105), National Natural Science Foundation of China (82250610230, 72061137004), World Health Organization (2024/1463606-0), Research Fund Vanke School of Public Health Tsinghua University (2024JC002), Beijing TaiKang YiCai Public Welfare Foundation, National Key R&D Program of China (2018YFC2000400).

Half-curcumin-based chemiluminescence probes and their applications in detecting quasi-stable oxidized protein.

Numerous methods have been reported for detecting ROS/RNS in vitro and in vivo; however, detecting methods for the secondary products of the ROS/RNS reactions, particularly quasi-stable oxidized products, have been much less explored. In this report, we observed that half-curcumins could generate chemiluminescence. In contrast to other chemiluminescence scaffolds, the distinguishing feature of a half-curcumin is the formation of a carbanion intermediate of its acetylacetone moiety, opening unique avenues for applications. In this study, we designed a series of half-curcumins CRANAD-Xs and found that CRANAD-164 could be used to detect quasi-stable oxidized proteins (QSOP) in vivo and in patient serum samples. We illustrated that CRANAD-164 could be used to monitor the responses of taurine, an amino acid with newly reported anti-aging capacity, in an inflammatory mouse model. Remarkably, we further demonstrated that the QSOP levels were much higher in the disease serum samples, including Alzheimer's disease, compared to the samples from healthy controls. Moreover, our results revealed that the sera chemiluminescence intensities were higher in aged healthy controls compared to young healthy subjects, suggesting that CRANAD-164 can be used to monitor the increase of QSOP during aging.

Selective correlations between aliphatic 13C nuclei in protein solid-state NMR.

Solid-state nuclear magnetic resonance (NMR) is a potent tool for studying the structures and dynamics of insoluble proteins. It starts with signal assignment through multi-dimensional correlation experiments, where the aliphatic 13Cα-13Cß correlation is indispensable for identifying specific residues. However, developing efficient methods for achieving this correlation is a challenge in solid-state NMR. We present a simple band-selective zero-quantum (ZQ) recoupling method, named POST-C4161 (PC4), which enhances 13Cα-13Cß correlations under moderate magic-angle spinning (MAS) conditions. PC4 requires minimal 13C radio-frequency (RF) field and proton decoupling, exhibits high stability against RF variations, and achieves superior efficiency. Comparative tests on various samples, including the formyl-Met-Leu-Phe (fMLF) tripeptide, microcrystalline ß1 immunoglobulin binding domain of protein G (GB1), and membrane protein of mechanosensitive channel of large conductance from Methanosarcina acetivorans (MaMscL), demonstrate that PC4 selectively enhances 13Cα-13Cß correlations by up to 50 % while suppressing unwanted correlations, as compared to the popular dipolar-assisted rotational resonance (DARR). It has addressed the long-standing need for selective 13C-13C correlation methods. We anticipate that this simple but efficient PC4 method will have immediate applications in structural biology by solid-state NMR.

A connectome-based model of delusion in schizophrenia using functional connectivity under working memory task.

Delusion is an important feature of schizophrenia, which may stem from cognitive biases. Working memory (WM) is the core foundation of cognition, closely related to delusion. However, the knowledge of neural mechanisms underlying the relationship between WM and delusion in schizophrenia is poorly investigated. Two hundred and thirty patients with schizophrenia (dataset 1: n = 130; dataset 2: n = 100) were enrolled and scanned for an N-back WM task. We constructed the WM-related whole-brain functional connectome and conducted Connectome-based Predictive Modelling (CPM) to detect the delusion-related networks and built the correlation model in dataset 1. The correlation between identified networks and delusion severity was tested in a separate, heterogeneous sample of dataset 2 that mainly includes early-onset schizophrenia. The identified delusion-related network has a strong correlation with delusion severity measured by the NO.20 item of SAPS in dataset 1 (r = 0.433, p = 2.7 × 10-7, permutation-p = 0.035), and can be validated in the same dataset by using another delusion measurement, that is, the P1 item of PANSS (r = 0.362, p = 0.0005). It can be validated in another independent dataset 2 (NO.20 item of SAPS for r = 0.31, p = 0.0024, P1 item of PANSS for r = 0.27, p = 0.0074). The delusion-related network comprises the connections between the default mode network (DMN), cingulo-opercular network (CON), salience network (SN), subcortical, sensory-somatomotor network (SMN), and visual networks. We successfully established correlation models of individualized delusion based on the WM-related functional connectome and showed a strong correlation between delusion severity and connections within the DMN, CON, SMN, and subcortical network.

Low-dose anti-thymocyte globulin plus low-dose posttransplant cyclophosphamide-based regimen for prevention of graft-versus-host disease in haploidentical peripheral blood stem cell transplantation for pediatric patients with hematologic malignancies.

The low-dose anti-thymocyte globulin (ATG) plus low-dose post transplantation cyclophosphamide (PTCy) -based (low-dose ATG/PTCy-based) regimen had a promising activity in preventing of graft-versus-host disease (GVHD) in adult patients. However, its efficacy in pediatric patients remain to be defined. Here, we presented the findings from 35 pediatric patients undergoing haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with the new regimen for GVHD prophylaxis. The cumulative incidences (CIs) of grades II-III and III-IV acute GVHD (aGVHD) were 34% (95% CI, 17-48%) and 11% (95% CI, 0-21%) within 180 days post-transplantation, respectively. The CIs of chronic GVHD (cGVHD) and moderate-to-severe cGVHD within 2 years were 26% (95% CI, 7-41%) and 12% (95% CI, 0-25%), respectively. The 2-year probabilities of overall survival, relapse-free survival, and graft-versus-host disease and relapse-free survival were 89% (95% CI, 78-100%), 82% (95% CI, 68-98%) and 59% (95% CI, 43-80%), respectively. The CIs of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation by day 180 were 37% (95% CI, 19-51%) and 20% (95% CI, 6-32%) respectively. These results strongly advocate for the efficacy of the low-dose ATG/PTCy-based regimen as a robust strategy for GVHD prevention in haplo-PBSCT for pediatric patients.

Carbon pricing policies and renewable energy development: Analysis based on cross-country panel data.

While studies have theoretically discussed the impact of carbon pricing on renewable energy, the practical implementation and effectiveness of these policies remain uncertain. This study empirically examines the role of carbon emissions trading and carbon tax in global renewable energy development using panel data from 196 countries and regions and employing the staggered difference-in-differences (DID) model and Bacon decomposition method. The results suggest that: (1) From the perspective of policy shocks, carbon trading has increased non-hydro renewable electricity generation by 73.32%, while carbon tax has increased it by 31.79%. This indicates that the overall impact of carbon trading on renewable energy is greater than that of carbon tax. However, the elasticity coefficients of renewable energy to carbon trading prices and carbon tax rates are 0.1801 and 0.1845, respectively, suggesting a slightly greater marginal effect of carbon tax on renewable energy compared to carbon trading. (2) Both carbon tax and carbon trading have mitigated the growth of fossil electricity and encouraged public investment in renewable energy, thereby fostering its development. (3) The influence of carbon pricing on renewable energy varies by income level; notably, the implementation of these policies in high-income countries has diminished their promotional effect on renewable energy. (4) The contribution of technological innovation to renewable energy development is smaller than that of policies including carbon trading and carbon tax, indicating that renewable energy development during the sample period was predominantly driven by policy measures. The findings indicate that the application of carbon pricing policies should be further promoted to accelerate the energy mix transition.

Investigation on the environmental causes of tomato fruit cracking and its propagation prediction in greenhouse.

In this study, Provence tomato variety was chosen for investigating the environmental causes of tomato fruit cracking, cracks characteristics, and their propagation prediction in a greenhouse. Fruit bagging approach was used to alter the temperature and humidity and to create a microclimate around the fruit to induce fruit cracking for testing. Results showed that the fruit cracking rate increased when the environment temperature exceeded 30°C, and the difference between the highest and lowest temperature values in a day was greater than 20°C. The cracking rate was aggravated when the difference between the highest and lowest humidity values in a day was less than 20%. The proportions of top cracking, longitudinal cracking, ring cracking, radial cracking, and combined cracking were 5.4%, 16.1%, 28.3%, 26.8%, and 32.1%, respectively. The fruit shoulder was the most susceptible region to crack, followed by fruit belly and top regions, whereas longer cracks were observed in the fruit belly region indicating a higher propensity to crack propagation in that region. Finally, the measured data were used to validate an extended finite element method developed to effectively predict cracking susceptibility and propagation in tomato fruit with a relative error of 4.68%.

Minisci-Type Dehydrogenative Coupling of C(sp3)-H and N-Heteroaromatics Enabled by Photoelectrochemical Hydrogen Atom Transfer.

Minisci-type dehydrogenative coupling of C(sp3)-H and N-heteroaromatics was performed with N-hydroxysuccinimide as a hydrogen atom transfer catalyst in a photoelectrochemical cell composed of a mesoporous BiVO4 photoanode and a Pt electrode. In the absence of metal catalysts and chemical oxidants, a range of N-heteroarenes (e.g., quinolines, isoquinolines, and quinoxaline) can undergo coupling with various C(sp3)-H partners to form the corresponding products in excellent yields.

The alarmin IL-33 exacerbates pulmonary inflammation and immune dysfunction in SARS-CoV-2 infection.

Dysregulated host immune responses contribute to disease severity and worsened prognosis in COVID-19 infection and the underlying mechanisms are not fully understood. In this study, we observed that IL-33, a damage-associated molecular pattern molecule, is significantly increased in COVID-19 patients and in SARS-CoV-2-infected mice. Using IL-33-/- mice, we demonstrated that IL-33 deficiency resulted in significant decreases in bodyweight loss, tissue viral burdens, and lung pathology. These improved outcomes in IL-33-/- mice also correlated with a reduction in innate immune cell infiltrates, i.e., neutrophils, macrophages, natural killer cells, and activated T cells in inflamed lungs. Lung RNA-seq results revealed that IL-33 signaling enhances activation of inflammatory pathways, including interferon signaling, pathogen phagocytosis, macrophage activation, and cytokine/chemokine signals. Overall, these findings demonstrate that the alarmin IL-33 plays a pathogenic role in SARS-CoV-2 infection and provides new insights that will inform the development of effective therapeutic strategies for COVID-19.

Chlorido-[5,10,15,20-tetra-kis-(quinoline-7-carboxamido)-porphinato]iron(III).

The title compound, [Fe(C84H52N12O4)Cl], crystallizes in space group C2/c. The central FeIII cation (site symmetry 2) is coordinated in a fivefold manner, with four pyrrole N atoms of the porphyrin core in the basal sites and one Cl atom (site symmetry 2) in the apical position, which completes a slightly distorted square-pyramidal environment. The porphyrin macrocycle shows a characteristic ruffled-shape distortion and the iron atom is displaced out of the porphyrin plane by 0.42 Šwith the average Fe-N distance being 2.054 (4) Å; the Fe-Cl bond length is 2.2042 (7) Å. Inter-molecular C-H⋯N and C-H⋯O hydrogen bonds occur in the crystal structure.

(2,5-Di-methyl-imidazole){N,N',N'',N'''-[porphyrin-5,10,15,20-tetra-yltetra-(2,1-phenyl-ene)]tetra-kis(pyridine-3-carboxamide)}manganese(II) chloro-benzene disolvate.

In the title compound, [Mn(C68H44N12O4)(C5H8N2)]·2C6H5Cl, the central MnII ion is coordinated by four pyrrole N atoms of the porphyrin core in the basal sites and one N atom of the 2,5-di-methyl-imidazole ligand in the apical site. Two chloro-benzene solvent mol-ecules are also present in the asymmetric unit. Due to the apical imidazole ligand, the Mn atom is displaced out of the 24-atom porphyrin mean plane by 0.66 Å. The average Mn-Np (p = porphyrin) bond length is 2.143 (8) Å, and the axial Mn-NIm (Im = 2,5-di-methyl-imidazole) bond length is 2.171 (8) Å. The structure displays inter-molecular and intra-molecular N-H⋯O, N-H⋯N, C-H⋯O and C-H⋯N hydrogen bonding. The crystal studied was refined as a two-component inversion twin.

Research on the Mechanism and Propagation Characteristics of Combustion and Explosion of Natural Gas/Ammonia/Hydrogen Mixed Gas Fuel.

The addition of ammonia and hydrogen into natural gas fuel is an effective method to reduce carbon emissions. This study aims to investigate the effect of adding ammonia and hydrogen on the mechanism of natural gas combustion and emission characteristics. Based on a self-developed mixed gas deflagrate experimental platform, the deflagrate characteristics, emission characteristics, and chemical reaction kinetics mechanism of mixed gas fuels under different composition ratios (natural gas 0-100%, hydrogen 10-85%, and ammonia 0-100%) were studied. The results indicate that the propagation of the deflagration shock wave can be categorized into an initial stage (L < 3 m) and a development stage (L > 3 m) based on the observed trend of shock wave intensity variation with distance. The intensity of the deflagration shock wave for the mixed gases increases monotonically as the hydrogen content ratio rises. In contrast, the impact of the ammonia content ratio on the shock wave intensity exhibits a distinct pattern that varies with changes in the equivalence ratio and hydrogen content ratio. In terms of carbon emissions per unit of heat value produced by the fuel, adding hydrogen to natural gas proves to be more effective at reducing carbon emissions than adding ammonia. When the ammonia content ratio is 50% and the hydrogen content ratio is 40%, the combustion performance of the mixed gas fuel is similar to that of natural gas, but its carbon emissions are lower than 30% of natural gas, making it a new type of mixed fuel with potential application value; the interaction between reflected pressure waves and flames is the main reason for the fluctuation of deflagrate shock wave pressure; ammonia lowers the temperature of the reaction system by reducing the concentration of OH radicals.