ObjectiveTranscranial magneto-acoustic stimulation (TMAS) is an emerging non-invasive neuromodulation technique that may provide a novel non-pharmacological intervention strategy for Parkinson's disease (PD). PD is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc), leading to motor impairments such as bradykinesia, tremor, and rigidity. Increasing evidence indicates that mitochondrial dysfunction and impaired mitochondrial quality control are central mechanisms underlying dopaminergic neuronal loss. In particular, abnormalities in mitophagy and mitochondrial fission-fusion balance contribute substantially to oxidative stress, energy metabolic failure, and neuronal injury. At present, most clinical treatments for PD mainly alleviate symptoms but do not effectively halt disease progression. Therefore, exploring new interventions targeting the core pathological mechanisms is of considerable significance. This study aims to investigate whether TMAS can improve neural damage and motor dysfunction in PD mice by regulating mitophagy and the fission/fusion dynamic balance, thereby providing theoretical and experimental support for its application in PD treatment. MethodsMale C57BL/6 mice were used in this study. A PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days. After model induction, mice in the intervention group received TMAS once daily for 14 consecutive days, whereas the corresponding control group received sham stimulation. The stimulation target was positioned over the primary motor cortex (M1). Motor performance was evaluated using the pole test and the open-field test. To verify the activation effect of TMAS on the target cortical region, c-Fos immunohistochemistry was performed in the M1. To assess nigral dopaminergic neuronal injury, tyrosine hydroxylase (TH) immunohistochemistry was used to quantify TH-positive neurons in the SNc. Mitochondrial function was evaluated by measuring reactive oxygen species (ROS) levels and adenosine triphosphate (ATP) content in the SNc. Western blot was further performed to determine the expression of mitophagy-related proteins, including PINK1, Parkin, LC3-II, and p62, as well as mitochondrial dynamics-related proteins, including Drp1 and Opa1. ResultsTMAS significantly increased the number of c-Fos-positive cells in M1 (P<0.000 1), indicating effective activation of neurons in the targeted cortical region. Compared with the control group, MPTP-treated mice exhibited marked motor dysfunction, including a significant reduction in total distance traveled in the open-field test (P<0.000 1) and mean speed (P=0.000 1), as well as significant prolongation of turn time and total climbing time in the pole test (P<0.000 1). These behavioral impairments were accompanied by a substantial loss of TH-positive dopaminergic neurons in the SNc, whereas TMAS significantly increased TH-positive neuron survival (P<0.000 1). In parallel, MPTP induced a pronounced increase in ROS levels and a significant reduction in ATP content, indicating severe mitochondrial dysfunction and energy metabolism impairment (P<0.01). TMAS treatment significantly improved motor performance, as reflected by the reversal of MPTP-induced impairment in the open-field and pole tests, and significantly reduced ROS accumulation (P<0.01) while restoring ATP production (P<0.001). At the molecular level, MPTP markedly downregulated PINK1 and Parkin, decreased p62 expression, increased LC3-II accumulation, elevated Drp1 expression, and reduced Opa1 expression, whereas TMAS significantly reversed these abnormalities, suggesting restoration of mitophagy-related mitochondrial quality control and re-establishment of mitochondrial fission-fusion balance. Collectively, these findings indicate that TMAS ameliorates MPTP-induced neurotoxicity and restores mitochondrial homeostasis and energy metabolism. ConclusionTMAS effectively attenuates neural damage and improves motor dysfunction in MPTP-induced PD mice. Its neuroprotective effects are closely associated with multidimensional regulation of the mitochondrial quality control system, including restoration of PINK1/Parkin-mediated mitophagy and rebalancing of Drp1/Opa1-related mitochondrial dynamics. Rather than acting only as a symptomatic neuromodulatory intervention, TMAS may influence a key pathological axis of PD by improving mitochondrial homeostasis in SNc and protecting nigral dopaminergic neurons. These findings provide experimental evidence supporting TMAS as a promising non-invasive physical intervention for PD.

ObjectiveTranscranial magneto-acoustic stimulation (TMAS) is an emerging non-invasive neuromodulation technique that may provide a novel non-pharmacological intervention strategy for Parkinson's disease (PD). PD is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc), leading to motor impairments such as bradykinesia, tremor, and rigidity. Increasing evidence indicates that mitochondrial dysfunction and impaired mitochondrial quality control are central mechanisms underlying dopaminergic neuronal loss. In particular, abnormalities in mitophagy and mitochondrial fission-fusion balance contribute substantially to oxidative stress, energy metabolic failure, and neuronal injury. At present, most clinical treatments for PD mainly alleviate symptoms but do not effectively halt disease progression. Therefore, exploring new interventions targeting the core pathological mechanisms is of considerable significance. This study aims to investigate whether TMAS can improve neural damage and motor dysfunction in PD mice by regulating mitophagy and the fission/fusion dynamic balance, thereby providing theoretical and experimental support for its application in PD treatment. MethodsMale C57BL/6 mice were used in this study. A PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days. After model induction, mice in the intervention group received TMAS once daily for 14 consecutive days, whereas the corresponding control group received sham stimulation. The stimulation target was positioned over the primary motor cortex (M1). Motor performance was evaluated using the pole test and the open-field test. To verify the activation effect of TMAS on the target cortical region, c-Fos immunohistochemistry was performed in the M1. To assess nigral dopaminergic neuronal injury, tyrosine hydroxylase (TH) immunohistochemistry was used to quantify TH-positive neurons in the SNc. Mitochondrial function was evaluated by measuring reactive oxygen species (ROS) levels and adenosine triphosphate (ATP) content in the SNc. Western blot was further performed to determine the expression of mitophagy-related proteins, including PINK1, Parkin, LC3-II, and p62, as well as mitochondrial dynamics-related proteins, including Drp1 and Opa1. ResultsTMAS significantly increased the number of c-Fos-positive cells in M1 (P<0.000 1), indicating effective activation of neurons in the targeted cortical region. Compared with the control group, MPTP-treated mice exhibited marked motor dysfunction, including a significant reduction in total distance traveled in the open-field test (P<0.000 1) and mean speed (P=0.000 1), as well as significant prolongation of turn time and total climbing time in the pole test (P<0.000 1). These behavioral impairments were accompanied by a substantial loss of TH-positive dopaminergic neurons in the SNc, whereas TMAS significantly increased TH-positive neuron survival (P<0.000 1). In parallel, MPTP induced a pronounced increase in ROS levels and a significant reduction in ATP content, indicating severe mitochondrial dysfunction and energy metabolism impairment (P<0.01). TMAS treatment significantly improved motor performance, as reflected by the reversal of MPTP-induced impairment in the open-field and pole tests, and significantly reduced ROS accumulation (P<0.01) while restoring ATP production (P<0.001). At the molecular level, MPTP markedly downregulated PINK1 and Parkin, decreased p62 expression, increased LC3-II accumulation, elevated Drp1 expression, and reduced Opa1 expression, whereas TMAS significantly reversed these abnormalities, suggesting restoration of mitophagy-related mitochondrial quality control and re-establishment of mitochondrial fission-fusion balance. Collectively, these findings indicate that TMAS ameliorates MPTP-induced neurotoxicity and restores mitochondrial homeostasis and energy metabolism. ConclusionTMAS effectively attenuates neural damage and improves motor dysfunction in MPTP-induced PD mice. Its neuroprotective effects are closely associated with multidimensional regulation of the mitochondrial quality control system, including restoration of PINK1/Parkin-mediated mitophagy and rebalancing of Drp1/Opa1-related mitochondrial dynamics. Rather than acting only as a symptomatic neuromodulatory intervention, TMAS may influence a key pathological axis of PD by improving mitochondrial homeostasis in SNc and protecting nigral dopaminergic neurons. These findings provide experimental evidence supporting TMAS as a promising non-invasive physical intervention for PD.

p21 (encoded by the CDKN1A gene) is a critical cell cycle regulatory protein endowed with versatile biological functions. In various sex hormone-related cancers, p21 exhibits a paradoxical dual role, capable of both inhibiting tumorigenesis and promoting cancer progression, exerting dual, often opposing, effects on cellular fate that are dictated by the specific context. The clinical targeting of p21 remains elusive, largely due to its functionally pleiotropic and context-dependent nature within intricate regulatory networks. During the initial, hormone-dependent phase of cancers like breast and prostate cancer, p21 expression and activity are largely governed by the transcriptional programs of estrogen or androgen receptor signaling. This hormonal regulation contributes to the control of tumor cell proliferation and underpins the initial efficacy of endocrine therapies. In contrast, as these diseases advance to late stages or evolve into non-hormone-dependent subtypes—exemplified by castration-resistant prostate cancer (CRPC) and specific forms of triple-negative breast cancer (TNBC)—these conventional hormonal control mechanisms often become dysfunctional or are entirely bypassed. This fundamental transition creates a critical therapeutic void, highlighting the urgent need to identify and exploit alternative molecular pathways to effectively target p21’s function. Promising strategies may include the precise modulation of its upstream transcriptional regulators, downstream effector proteins, or the intersecting parallel signaling networks that critically influence its activity. This review provides a systematic synthesis of the intricate and interconnected mechanisms that underpin the dual effects of p21 in sex hormone-related tumors. These mechanisms are categorized into three core, interrelated functional domains. (1) cell cycle regulation: p21 executes its canonical tumor-suppressive role by binding to and inhibiting cyclin-dependent kinases (CDKs) and by directly interacting with proliferating cell nuclear antigen (PCNA), thereby inducing cell cycle arrest, predominantly at the G1/S checkpoint; (2) apoptosis modulation: p21 exerts a highly context-dependent influence on programmed cell death, functioning either as a pro-apoptotic agent under severe genotoxic stress or as a pro-survival factor by inhibiting apoptosis through interactions with proteins like Bcl-2; (3) hormonal and signaling crosstalk: p21 is an integral node within broader cellular networks, engaging in direct physical interactions with hormone receptors(e.g., AR, ER) and participating in complex feedback loops with key oncogenic pathways, including PI3K/AKT, MAPK/ERK, and p53. Critically, the role of p21 is not static but highly dynamic. It can undergo a functional switch from tumor-suppressive to tumor-promoting in response to therapeutic pressures, metabolic alterations, or evolving tumor microenvironment cues. These adaptive shifts are frequently implicated in the development of therapy resistance and disease recurrence, particularly in advanced, hormone-resistant cancers. By synthesizing these insights, this review aims to establish a coherent theoretical framework to guide the future development of novel therapeutic strategies that target the p21 pathway. It underscores the necessity of moving beyond a simplistic, binary view of p21 and emphasizes the forthcoming challenges, such as the discovery of reliable biomarkers to predict its functional state and the rational design of context-specific pharmacological modulators to selectively harness its therapeutic potential.

ObjectiveHepatocellular carcinoma (HCC) represents 90% of all primary liver cancers. The main risk factors associated with HCC include viral hepatitis (B and/or C), alcohol abuse, and metabolic dysfunction-associated steatotic liver disease (MASLD), which progressively advance to liver fibrosis, cirrhosis, and ultimately evolve into HCC. Surgical resection represents the most effective treatment for HCC, while recent advances in immunotherapy, including immune checkpoint inhibitors and adoptive cell therapies, have provided improved treatment prospects for patients with unresectable HCC. However, the complex metabolic heterogeneity of HCC limits the therapeutic efficacy. Metabolic intermediates acyl-CoA not only provide energy and substrates for numerous biochemical reactions but also serve as donors for protein lysine acylation, a major class of post-translational modification (PTM). Therefore, a deeper understanding of the molecular mechanisms underlying protein lysine acylation and hepatocarcinogenesis is urgently needed. MethodsThe levels of protein lysine acylation and silence information regulator 5 (SIRT5) expression levels in clinical HCC samples were analyzed by Western blot. Quantitative malonylome and succinylome of HCC samples were analyzed by antibody-based affinity enrichment coupled with tandem mass spectrometry. The proliferation of HCC cells was analyzed with Cell Counting Kit-8 (CCK-8) assays, the apoptosis was quantified by Annexin V-FITC/propidium iodide (PI) staining coupled with flow cytometry, and the ability of cells to migrate was assayed by Transwell assays. The enzymatic activity of glutathione S-transferase Mu 1 (GSTM1) was quantified. Transgenic mice with hepatic overexpression of SIRT5 were constructed using CRISPR-Cas9, and primary hepatocarcinogenesis was induced by administration of diethylnitrosamine. ResultsWestern blot analysis indicated that the expression level of SIRT5 was elevated in clinical samples from HCC patients, and the levels of lysine malonylation, glutarylation, and succinylation were significantly reduced in HCC tissues. Knockout of SIRT5 in MHCC-97H and MHCC-97L hepatoma cells suppressed cell proliferation, and increased the percentage of apoptotic cells significantly. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the differentially malonylome and succinylome of HCC samples revealed significant enrichment in two major classes of biological processes: core energy metabolism (e.g., glycolysis/gluconeogenesis, tricarboxylic acid metabolic process, fatty acid beta oxidation) and detoxification and oxidative stress response (e.g., response to toxic substance, chemical carcinogenesis, reactive oxygen species (ROS)). SIRT5 removes malonylation from lysine residues in GSTM1 and restores its detoxification activity, which is crucial for the survival of hepatocytes under stressed conditions. More importantly, in vivo experiment indicated that hepatic-specific overexpression of SIRT5 in mice accelerated diethylnitrosamine-induced liver fibrosis and hepatocarcinogenesis, indicating the critical role of SIRT5 in HCC progression. ConclusionThis study highlights the previously unrecognized SIRT5-GSTM1 axis as a key regulator in hepatocarcinogenesis, and suggests a potential target for the treatment of patients with HCC.

ObjectiveTo observe the clinical efficacy and safety of Yishen Jiangtang decoction combined with conventional Western medicine treatment in managing stage G3A3 diabetic kidney disease （DKD） in the patients with the pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis， and to explore its mechanism of inhibiting the endoplasmic reticulum stress （ERS）-apoptosis axis and delaying renal fibrosis （RF）. MethodsA single-center， randomized， parallel-controlled clinical trial was conducted. A total of 78 patients diagnosed with stage G3A3 DKD and traditional Chinese medicine （TCM） pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis and treated in the Department of Nephrology and the Department of Endocrinology of the People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine from March 2025 to February 2026 were enrolled. They were randomly assigned at a 1∶1 ratio into a control group （conventional Western medicine treatment） and an experimental group （Yishen Jiangtang decoction combined with conventional Western medicine treatment）， with 39 patients in each group. The treatment lasted for 12 weeks. Basic demographic data and medical history were collected before and after treatment. The two groups before and after treatment were compared in terms of the following parameters： Blood urea nitrogen （BUN）， serum creatinine （SCr）， estimated glomerular filtration rate （eGFR）， urinary albumin-to-creatinine ratio （UACR）， fasting blood glucose （FBG）， triglycerides （TG）， total cholesterol （TC）， and low-density lipoprotein cholesterol （LDL-C）. Enzyme-linked immunosorbent assay （ELISA） kits were used to measure serum glucose-regulated protein 78 （GRP78）， serum cysteinyl aspartate-specific protease-3 （Caspase-3）， and serum and urinary transforming growth factor-β₁ （TGF-β₁） levels before and after treatment. TCM symptom scores， TCM syndrome efficacy， and overall clinical efficacy were evaluated before and after treatment. Spearman correlation analysis was performed to explore the correlations of serum levels of GRP78 and Caspase-3， as well as serum and urinary levels of TGF-β1， with renal function， proteinuria， and glucose and lipid metabolism indicators in patients with DKD. In addition， safety indicators were also monitored. ResultsA total of 75 patients completed the study （38 in the control group and 37 in the experimental group）. ① Baseline data： The two groups were comparable in terms of sex and age， with no statistically significant difference. ② Efficacy outcomes： Compared with baseline levels， both groups showed reductions in BUN， SCr， UACR， FBG， TG， TC， LDL-C， and TCM symptom scores （P<0.01） and increases in eGFR level （P<0.01）. Moreover， the experimental group outperformed the control group in altering the indicators above （P<0.05）. Regarding TCM syndrome efficacy， the total response rate in the experimental group was 83.78%， which was higher than that （57.89%） in the control group （P<0.05）. Regarding overall clinical efficacy， the total response rate in the experimental group was 78.38%， which was higher than that （50.00%） in the control group （P<0.05）. ③ Mechanism outcomes： Compared with baseline levels， both groups showed declined serum levels of GRP78， Caspase-3， and TGF-β₁ and urinary level of TGF-β₁ after treatment （P<0.01）. Moreover， the experimental group showed greater declines than the control group （P<0.05）. The serum levels of GRP78， Caspase-3，and TGF-β₁ and the urinary level of TGF-β₁ in DKD patients showed positive correlations with BUN， SCr， UACR， and FBG and negative correlations with eGFR （P<0.05）. ④ Safety outcomes： Neither group showed drug-related adverse reactions， and laboratory safety parameters remained within normal ranges. ConclusionYishen Jiangtang decoction combined with conventional Western medicine treatment may safely and effectively alleviate clinical symptoms， correct glucose and lipid metabolism disorders， and protect the renal function in patients with stage G3A3 DKD and the pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis. The mechanism may be associated with inhibition of the ERS-apoptosis axis and delay of the RF process.

ObjectiveTo observe the clinical efficacy and safety of Yishen Jiangtang decoction combined with conventional Western medicine treatment in managing stage G3A3 diabetic kidney disease （DKD） in the patients with the pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis， and to explore its mechanism of inhibiting the endoplasmic reticulum stress （ERS）-apoptosis axis and delaying renal fibrosis （RF）. MethodsA single-center， randomized， parallel-controlled clinical trial was conducted. A total of 78 patients diagnosed with stage G3A3 DKD and traditional Chinese medicine （TCM） pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis and treated in the Department of Nephrology and the Department of Endocrinology of the People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine from March 2025 to February 2026 were enrolled. They were randomly assigned at a 1∶1 ratio into a control group （conventional Western medicine treatment） and an experimental group （Yishen Jiangtang decoction combined with conventional Western medicine treatment）， with 39 patients in each group. The treatment lasted for 12 weeks. Basic demographic data and medical history were collected before and after treatment. The two groups before and after treatment were compared in terms of the following parameters： Blood urea nitrogen （BUN）， serum creatinine （SCr）， estimated glomerular filtration rate （eGFR）， urinary albumin-to-creatinine ratio （UACR）， fasting blood glucose （FBG）， triglycerides （TG）， total cholesterol （TC）， and low-density lipoprotein cholesterol （LDL-C）. Enzyme-linked immunosorbent assay （ELISA） kits were used to measure serum glucose-regulated protein 78 （GRP78）， serum cysteinyl aspartate-specific protease-3 （Caspase-3）， and serum and urinary transforming growth factor-β₁ （TGF-β₁） levels before and after treatment. TCM symptom scores， TCM syndrome efficacy， and overall clinical efficacy were evaluated before and after treatment. Spearman correlation analysis was performed to explore the correlations of serum levels of GRP78 and Caspase-3， as well as serum and urinary levels of TGF-β1， with renal function， proteinuria， and glucose and lipid metabolism indicators in patients with DKD. In addition， safety indicators were also monitored. ResultsA total of 75 patients completed the study （38 in the control group and 37 in the experimental group）. ① Baseline data： The two groups were comparable in terms of sex and age， with no statistically significant difference. ② Efficacy outcomes： Compared with baseline levels， both groups showed reductions in BUN， SCr， UACR， FBG， TG， TC， LDL-C， and TCM symptom scores （P<0.01） and increases in eGFR level （P<0.01）. Moreover， the experimental group outperformed the control group in altering the indicators above （P<0.05）. Regarding TCM syndrome efficacy， the total response rate in the experimental group was 83.78%， which was higher than that （57.89%） in the control group （P<0.05）. Regarding overall clinical efficacy， the total response rate in the experimental group was 78.38%， which was higher than that （50.00%） in the control group （P<0.05）. ③ Mechanism outcomes： Compared with baseline levels， both groups showed declined serum levels of GRP78， Caspase-3， and TGF-β₁ and urinary level of TGF-β₁ after treatment （P<0.01）. Moreover， the experimental group showed greater declines than the control group （P<0.05）. The serum levels of GRP78， Caspase-3，and TGF-β₁ and the urinary level of TGF-β₁ in DKD patients showed positive correlations with BUN， SCr， UACR， and FBG and negative correlations with eGFR （P<0.05）. ④ Safety outcomes： Neither group showed drug-related adverse reactions， and laboratory safety parameters remained within normal ranges. ConclusionYishen Jiangtang decoction combined with conventional Western medicine treatment may safely and effectively alleviate clinical symptoms， correct glucose and lipid metabolism disorders， and protect the renal function in patients with stage G3A3 DKD and the pattern of Qi-Yin deficiency combined with dampness-heat and blood stasis. The mechanism may be associated with inhibition of the ERS-apoptosis axis and delay of the RF process.

Objective:To observe the effect of moxibustion on angiogenesis-related indicators in knee joint synovial tissue of adjuvant arthritis model rats,and to explore the mechanism of moxibustion in inhibiting vascular endothelial growth factor(VEGF)expression in synovial tissue and further limiting the activation of Rho family proteins Rac1 and Cdc42,thereby inhibiting angiogenesis during rheumatoid arthritis(RA)treatment.Methods:Forty-eight male Sprague-Dawley rats were equally divided into a normal group,a model group,a moxibustion group,and a moxibustion+VEGF agonist group according to the random principle.The complete Freund's adjuvant method was used for modeling.On the 12th day after modeling,the moxibustion group and the moxibustion+VEGF agonist group were subjected to suspended moxibustion at bilateral Zusanli(ST36),Guanyuan(CV4),and Ashi points for 20 min each time,once a day,for a total of 15 times.The moxibustion+VEGF agonist group received VEGF agonist(tirofiban hydrochloride hydrate)injection in the knee joint cavity at the same time.Hematoxylin-eosin staining was used to evaluate the pathological changes of rat synovial tissue in each group.Immunohistochemistry was used to observe the CD31 expression level in rat synovial tissue.Western blotting was used to detect the levels of VEGF,Rac1,and Cdc42 protein in rat synovial tissue,and polymerase chain reaction(PCR)was used to detect the VEGF mRNA expression.Results:Compared to the normal group,the expression levels of CD31 protein and VEGF mRNA and protein in rat synovial tissue in the model group increased significantly(P<0.01),and the expression levels of phospho-Rac1 and phospho-Cdc42 proteins also increased significantly(P<0.01).After moxibustion intervention,the expression levels of CD31 protein and VEGF mRNA and protein in the moxibustion group were significantly lower than those in the model group(P<0.01),while the differences in each indicator between the moxibustion+VEGF agonist group and the model group were not statistically significant(P>0.05).Compared to the moxibustion group,the expression levels of CD31 protein,VEGF mRNA and protein,phospho-Cdc42,and phospho-Rac1 in the moxibustion+VEGF agonist group increased significantly(P<0.01).Conclusion:Moxibustion improved synovial inflammation in RA by inhibiting angiogenesis.The mechanism may be to regulate angiogenesis-related VEGF,restrict the activation of Rac1 and Cdc42,and inhibit pseudopodia formation in vascular endothelial cells,thereby reducing angiogenesis.

As a new generation of time-of-flight mass spectrometry,multiple-reflection time-of-flight mass spectrometry(MR-TOF-MS)has been increasingly applied in the fields such as nuclear physics,chemistry,and biology due to its ultra-high resolution and rapid analysis capabilities.However,the analytical performance of MR-TOF-MS largely depends on the ion bunch state entering the mass analyzer.In this study,a rectangular ion trap(RIT)was developed,designed and processed using printed circuit board technology,as an ion accumulating and focusing device for MR-TOF mass analyzer.Compared to traditional ion traps composed of two sets of planar electrodes,this RIT had higher voltage utilization efficiency,resulting in more efficient ion collection and focusing.The ions were cooled to a sufficiently small bunch for precise mass measurement with MR-TOF-MS mass spectrometry in only 1 ms of cooling time in the RIT,then orthogonally ejected to the MR-TOF mass spectrometer for mass analysis.Experimental results indicated that the working cycle,ion flux,and ion focusing state of the RIT fully met the requirements of the MR-TOF mass analyzer.When coupled with the MR-TOF mass analyzer,the RIT enabled MR-TOF-MS to achieve a mass resolution of 1.5×105.

In analytical techniques such as ion mobility spectrometry(IMS)and mass spectrometry(MS),the ionization efficiency of target analytes is primarily constrained by the type of ionization source and factors such as the species and number density of the reactant ions.Systematic investigation into the reactivity differences of various reactant ions under varying conditions can not only significantly enhance the detection sensitivity of target compound product ions but also provide a theoretical foundation for establishing efficient detection methods based on ion-molecule reaction mechanisms.In this study,the pressure of a pressure-tunable photoionization tandem ion mobility spectrometry(PI-tandem-IMS)was reduced from ambient pressure(100 kPa)to low pressure(20 kPa)to systematically examine the reactivity differences between two negative reactant ions,CO3-and CO4-,and methyl salicylate(MeSA)under varying pressures.When the pressure decreased,the increased relative signal intensity of CO4-significantly influenced the detection sensitivity of the characteristic product ion[MeSA·O2]-.Based on differences in ion mobility(k0),the delay time for the opening of TPG2 was adjusted to selectively inject CO-3 and CO-4 in the drift region 2.Independent characterization of the reactivity of these reactant ions with MeSA in the reaction region confirmed that CO4-exhibited superior reactivity toward MeSA.The theoretical model revealed an Arrhenius plot for the ion-molecule reaction between CO4-and MeSA,showing a positive correlation between the reaction rate coefficient(k)and temperature,the activation energy Ea was 62.45 kJ/mol.Furthermore,controlling parameters such as pressure or temperature significantly influenced the progression of this ion-molecule reaction,demonstrating the technical advantages of PI-tandem-IMS in mechanistic studies and regulation of ion-molecule reactions.

The resolving power and sensitivity are critical for on-site detection of hazardous chemicals using stand-alone ion mobility spectrometry(IMS).However,improving the sensitivity and resolving power of IMS has long been a prominent research hot spot.In the commonly used IMS based on the Bradbury-Nielsen gate(BNG),the gating voltage difference(GVD)applied between the two sets of grid wires affects the electric field distribution in the ionization region and the drift region.This,in turn,influences the spatial distribution and temporal width of the injected ion swarm,and has an impact on the ion mobility discrimination,sensitivity,and resolving power of the instrument.This study showed that increasing the GVD could induce an ion converging effect,boosting the ion number density in front of the BNG by nearly 300％.To simultaneously utilize temporal compression and ion converging effects,a novel BNG controlling mode was proposed by adding a chopping state to the conventional controlling mode.This chopping state reduced the mobility discrimination effects between ions with mobility differences up to about 0.90 cm2/(V·s)to 1/22 of their original value.When analyzing hazardous chemical mixtures using the novel BNG controlling mode,compared with conventional mode,the signal intensity of low-mobility methyl salicylate ions(MS·O2)-increased by 18-fold while the resolving power maintained around 100,and the detection limit for MS was improved from 3.75 μg/L to 97 ng/L.This novel BNG controlling mode only added a potential wave to the low voltage wires,with no requirement of changing the structure of the drift tube,and was easy to apply to existing commercial instruments.