[Current status and quality analysis of interventional therapy for patients with atrial fibrillation in China]

Objective: To define the current status and analyze the medical quality of interventional therapy for patients with atrial fibrillation (AF) in China. Methods: This survey was performed in all seven large regions of China, one to three regional major medical centers were selected from each region. Medical records of patients underwent interventional therapy for AF in the year 2017 were randomly inspected. CHA2DS2-VASc score, prescribed anticoagulant after ablation, indication of left atrial appendage occlusion (LAAO), and complications in the medical records were analyzed. Results: A total of 10 800 AF catheter ablations and 447 LAAOs were performed in 17 regional medical centers in 2017. There were 10/17 centers performing AF catheter ablation<500 cases and 7/17 centers performing LAAO<20 cases. A total of 1 347 cases of catheter ablation and 160 cases of LAAO were selected for further analysis. Among all selected cases, 15.8% (238/1 505) non-valvar AF cases recorded CHA2DS2-VASc scores. The anticoagulation rate after AF catheter ablation was 98.6% (1 328/1 347), anticoagulation rate was higher than 90% in 16 out of 17 centers. The complication and severe complication rates of AF catheter ablation were 0.9% (12/1 347) and 0.4% (5/1 347), respectively. The differences of complication and severe complication rates in AF catheter ablation were similar between centers performing<500 cases and centers performing ≥500 cases (0.5% (2/413) vs. 1.1% (10/934), P>0.05; 0.5% (2/413) vs. 0.3% (3/934), P>0.05). The coincidence rate of LAAO indication was 81.3% (130/160), and the rate was higher in center performing ≥20 cases than in centers performing<20 cases (84.8% (106/125) vs. 68.6% (24/35), P<0.05). The complication and severe complication rates of LAAO were 3.1% (5/160) and 1.9% (3/160). The rate of complications in LAAO was higher in center performing<20 cases than in centers performing ≥20 cases (8.6% (3/35) vs. 1.6% (2/125), P<0.05), and there was no significant difference in severe complication rate (5.7% (2/35) vs. 0.8% (1/125), P>0.05). Conclusions: Interventional therapy for AF in China is generally standardized and safe. The overall incidence of complications post AF interventional ablation is low, the anticoagulation rate after AF catheter ablation is high, and the adherence rate of LAAO indication is fair. The indicators mentioned above vary widely among centers.

Body Fat Indices as Effective Predictors of Insulin Resistance in Obstructive Sleep Apnea: Evidence from a Cross-Sectional and Longitudinal Study : BFI as Predictors of IR in OSA

PURPOSE

Body fat indices serve as predictive markers of insulin resistance (IR) in metabolic diseases. IR is common in obstructive sleep apnea (OSA). However, whether body fat indices have utility as predictors of IR in OSA remain unknown.

MATERIALS AND METHODS

A longitudinal study was conducted in 46 patients undergoing bariatric surgery to explore the relationship between IR and body fat indices. Then, a cross-sectional study was performed to evaluate the relationships between body fat indices and IR, and receiver operating characteristic (ROC) curves were generated. Body indices, homeostasis model assessment index of insulin resistance (HOMA-IR), biological indicators, and polysomnographic variables were collected.

RESULTS

In the longitudinal study, significant relationships were found between remission of IR and changes in visceral adiposity index (VAI) (r = 0.452, P < 0.05) and triglyceride-glucose index (TyG) (r = 0.650, P < 0.01). In the cross-sectional study, lipid accumulation product (LAP) (best cutoff value: 30.16, area under the curve (AUC) = 0.728, P < 0.001) and TyG (best cutoff value: 8.54, AUC = 0.740, P < 0.001) were indicators of IR in normal weight group. In overweight/obese group, body mass index (BMI) (best cutoff value: 27.69 AUC = 0.707, P < 0.001) and waist circumference (WC) (best cutoff value: 97.25, AUC = 0.708, P < 0.001) were markers of IR. TyG showed better ability to predict IR in normal weight females (best cutoff value: 8.39 AUC = 0.813, P < 0.001).

CONCLUSIONS

Body fat indices are predictive markers of IR in patients with OSA.

Coamorphous System of Florfenicol-Oxymatrine for Improving the Solubility and Dissolution Rate of Florfenicol: Preparation, Characterization and Molecular Dynamics Simulation

Coamorphous system has proved to be an effective approach to improve the solubility of BCSⅡ drugs. Florfenicol (FF) is a widely used veterinary antibiotic but has poor aqueous solubility. Therefore, the coamorphous system of florfenicol and oxymatrine (OMT) formulated at 1:1 and 1:2 M ratios were prepared by using solvent evaporation, followed by a series of characterization in terms of PXRD, DSC, FTIR and Raman spectroscopy. It was found that FF and OMT are miscible according to Hansen solubility parameters. The molecular electrostatic potential (MEP) and radial distribution function (RDF) analysis demonstrated the possible hydrogen bond interaction in coamorphous system, which was confirmed by FTIR and Raman spectra. The coamorphous FF-OMT (1:1) maintained stability for 60 days at 25 °C/0% RH and 30 days at 40 °C/75% RH, which may be attributed to better molecular miscibility of FF and OMT and the strong hydrogen bond of O-H (FF)⋯O-N (OMT) and N-H (FF)⋯O-N (OMT). In addition, the apparent solubility and permeability, dissolution and intrinsic dissolution rate (IDR) of the acquired coamorphous solids were obviously increased compared with crystalline FF. In conclusion, a drug-drug coamorphous formulation can be applied to improve the solubility and dissolution of crystalline FF.

[Investigation and analysis of questionnaire on clinical thinking in the diagnosis of severe infection in Guangxi]

OBJECTIVE

To understand the clinical thinking of clinical staff in the diagnosis of severe infection and evaluate their ability to recognize severe infection in the early stage.

METHODS

A questionnaire survey was conducted to investigate the clinical thinking of clinical staff attending the academic annual meeting of critical care physicians of Guangxi Medical Doctors Association from September 26 to September 28, 2019. The objects of investigation included doctors, nurses, clinical pharmacists and medical graduate students, except for non-clinical personnel. The basis factors of clinical diagnosis of infection included clinical symptoms, specific biochemical examination, microorganism examination and Next-generation sequencing technology (NGS). The credibility level of each indicator was summarized as high (credibility of 51%-100%) and low (credibility of 0%-50%).

RESULTS

Among the more than 600 participants, 540 people participated in the questionnaire survey (participation rate of about 90.0%), and 466 qualified questionnaires (effective rate of 86.3%) were collected, including 280 from doctors, 155 from clinical nurses, 10 from clinical pharmacists and 21 from clinical graduate students. The working years of doctors, nurses, clinical pharmacists and medical graduate students were (8.2±6.0), (6.4±6.3), (4.5±4.0) and (3.8±2.6) years, respectively. The intermediate title (43.2%) dominated in the doctors group, while junior title dominated in the nurses group, clinical pharmacists group and medical postgraduate group (53.5%, 80.0% and 81.0% respectively). Doctors and nurses were mainly from the general intensive care unit (ICU; 73.2% and 51.0% respectively). According to the results of investigation of clinical thinking on the diagnosis of severe infection, there was similar degree of recognition and credibility for infection-related symptoms in the four groups of doctors, nurses, clinical pharmacists and medical graduate students (the credibility of fever was 80.0%-91.1%, low blood pressure 76.2%-90.0%, disturbance of consciousness 80.0%-85.0%, breathing 81.0%-100.0%, reduced of urine 81.9%-90.0%). The interpretation for pathogen culture and NGS results was insufficient because 29.3%-42.6% of the medical staff did not understand NGS. There were differences in the interpretation of the results of pathogen culture (positive specimen culture could diagnose infection; medical vs. nursing vs. pharmacists vs. student: 93.6% vs. 85.2% vs. 90.0% vs. 85.7%, P = 0.021). There were significant differences among the four groups in some traditional infection-related laboratory indexes which included increased white blood cell count (WBC; χ² = 8.542, P = 0.026), increased C-reactive protein (CRP; χ² = 8.826, P = 0.024), increased interleukin-6 (IL-6; χ² = 13.944, P = 0.002), positive 1, 3-β-D glucan detection test (G test; χ² = 10.988, P = 0.009) and positive galactomannan antigen detection test (GM test; χ² = 12.306, P = 0.004).

CONCLUSIONS

There is difference in clinical thinking of diagnosis of severe infection among clinical medical staff in different positions, and the comprehensive diagnostic ability needs to be improved.

Influence of the pK a Value of Cinnamic Acid and P-Hydroxycinnamic Acid on the Solubility of a Lurasidone Hydrochloride-Based Coamorphous System

Coamorphization of a poorly water-soluble active pharmaceutical ingredient (API) has been proven to be effective in improving its solubility. Generally, API can form multiple coamorphous systems with different coformers. However, it remains unclear how the pK _a value of different coformers influences the solubility of the API. In this study, structurally related cinnamic acid (CA, pK _a = 4.37) and p-hydroxycinnamic acid (pHCA, pK _a = 4.65) were chosen as coformers for the coamorphization of lurasidone hydrochloride (LH). To investigate the influence of the pK _a value of the coformers on the solubility of LH, LH-CA/pHCA coamorphous systems were prepared by the vacuum rotary evaporation method and characterized by powder X-ray diffraction and differential scanning calorimetry. Fourier-transform infrared spectroscopy, Raman spectroscopy, and molecular dynamics (MD) simulations were employed to investigate the intermolecular interaction of the coamorphous systems. It was found that the solubility of LH in the coamorphous LH-pHAC with a higher-pK _a coformer was higher than that of the coamorphous LH-CA. In addition, according to the solubility product principle-based formula derivation, we established the functional relationship between the solubility of LH and the pK _a of the coformers at different-pH buffering solution. It was found that the coformer with a larger pK _a value would be more beneficial to improve the solubility profile of LH. Collectively, the current study offers an effective strategy to improve the poor solubility of drugs by increasing the pK _a value of the coformer in coamorphous systems.

Malnutrition Prolongs the Hospitalization of Patients with COVID-19 Infection: A Clinical Epidemiological Analysis

OBJECTIVES

During the 2019 coronavirus disease (COVID-19) outbreak, malnutrition may contribute to COVID-19 adverse outcomes. We conducted a clinical epidemiological analysis to investigate the association of malnutrition with hospitalized duration in patients with COVID-19.

DESIGN

Retrospective survey study.

SETTING

Taikang Tongji (Wuhan) hospital in Wuhan, China.

PARTICIPANTS

139 patients with COVID-19.

METHODS

In total, 139 patients with COVID-19 from patients in the Infection Department of Taikang Tongji (Wuhan) hospital from February 2020 to April 2020 were analyzed retrospectively. We used the "Global leadership Initiative on Malnutrition(GLIM)" assessment standard published in 2019 to assess nutritional status. Prolonged hospitalization was lasting more than the median value of the hospitalized days (17 days) in this population.

RESULTS

According to the assessment results of GLIM nutrition assessment, the patients were divided into malnutrition group and normal nutrition group. Compared with the patients in the normal nutrition group, the hospitalization time was longer(15.67±6.26 days versus 27.48±5.04 days, P = 0.001). Kaplan-Meier analysis showed patients with malnutrition were more likely to be hospitalized longer compared with those normal nutrition (mean with 95% confidence interval [CI]: 28.91[27.52-30.30] versus 22.78[21.76-23.79], P = 0.001). COX regression analysis showed that malnutrition (hazard ratio [HR] = 3.773, P for trend = 0.001) was proportional associated with being discharged from hospital delayed.

CONCLUSION AND IMPLICATIONS

Present findings suggested that malnutrition contributed to predicting a probability of prolonged hospitalization in patients with COVID-19 infection, to whom extra attentions and precautions should be paid during clinical treatments. Based on the existing results, it is recommended that inpatients with nutritional risk or malnutrition start nutritional support treatment as soon as possible.

Recent advances in graphene-family nanomaterials for effective drug delivery and phototherapy

INTRODUCTION

Owing to the unique properties of graphene, including large specific surface area, excellent thermal conductivity, and optical absorption, graphene-family nanomaterials (GFNs) have attracted extensive attention in biomedical applications, particularly in drug delivery and phototherapy.

AREAS COVERED

In this review, we point out several challenges involved in the clinical application of GFNs. Then, we provide an overview of the most recent publications about GFNs in biomedical applications, including diverse strategies for improving the biocompatibility, specific targeting and stimuli-responsiveness of GFNs for drug delivery, codelivery of drug and gene, photothermal therapy, photodynamic therapy, and multimodal combination therapy.

EXPERT OPINION

Although the application of GFNs is still in the preclinical stage, rational modification of GFNs with functional elements or making full use of GFNs-based multimodal combination therapy might show great potential in biomedicine for clinical application.

Optimization of the supercritical fluidized bed process for sirolimus coating and drug release

Directly coating an active pharmaceutical ingredient (API) onto excipient granules has been a common approach to prepare solid dosage forms. The combination of supercritical anti-solvent (SAS) and fluidized bed (FB) coating technology (SAS-FB) has the advantages of preventing nanoparticles aggregation, oxidation and light exposure. However individual operating parameters and factors which contribute to the overall coating efficiency remain to be defined. Sirolimus is an immunosuppressive agent for preventing the rejection of organ transplants and this drug is sensitive to light exposure and high temperature. Our study used sirolimus as the model API to evaluate parameters including temperature, pressure, drug concentration, mass, material and diameter of carrier, CO₂ flow rate and solvent in the SAS-FB process. By optimizing these parameters, we achieved a 3.5-fold enhancement of the coating efficiency over the standard condition. A series of characterizations of the sirolimus coated particles were performed from which scanning electron microscopy and Raman mapping confirmed that the sirolimus particles were uniformly coated on carriers as cuboid particles; X-ray powder diffraction showed that processed sirolimus is crystalline but has lower crystallinity than the API, and fourier transform infrared spectroscopy and differential scanning calorimeter confirmed that there is no chemical interaction between sirolimus and carriers after SAS-FB processing. Finally compared to sirolimus alone, sirolimus coated particles displayed a faster dissolution and higher bioavailability. Collectively, our optimized operation parameters for SAS-FB coating technique provide a useful guidance for achieving higher efficiency of drug coating and faster release rate of sirolimus pellets, which has the potential to apply to other APIs.

Endocytic recycling as cellular trafficking fate of simvastatin-loaded discoidal reconstituted high-density lipoprotein to coordinate cholesterol efflux and drug influx

Reconstituted high-density lipoproteins (rHDLs) hold promise as nanocarriers for atherosclerosis-targeted delivery, with biofunctions typified by mediating cholesterol efflux. The paradox is how rHDL offloads the delivered drugs into atherosclerotic foam cells, while simultaneously transferring cholesterol out of cells. Herein, simvastatin-loaded discoidal rHDL (ST-d-rHDL), constructed based on established paradigms, was employed to investigate its basic trafficking mechanism in foam cells. As proved, ST-d-rHDL was resecreted via lysosomal and Golgi apparatus-recycling endosome-mediated pathways following clathrin-mediated endocytosis. And the resecretion ratio reached 60% within 6-h chase with excessive ST-d-rHDLs. During the rHDL resecretion, 39% of cellular cholesterol efflux was detected, accompanied by 85% of the encapsulated cargo released intracellularly. Furthermore, the recycling rate was demonstrated to be promoted by smaller rHDL size and higher cellular lipid contents. Collectively, endocytic recycling confers the synergism in ST-d-rHDL to coordinate cholesterol efflux and intracellular drug release, providing new insights into design of biofunctional rHDL.

Assessment of surgical outcomes and oncological safety for submental artery perforator flap reconstruction after ablation of oral cancer

The submental artery perforator flap (SAPF) has been a new option for the intraoral reconstruction of oral squamous cell carcinoma (OSCC) patients in recent years, but its surgical outcomes have not been well assessed. We compared the surgical outcomes and oncological safety of SAPF reconstruction for medium-sized soft-tissue defects after the ablation of primary oral cancer with traditional submental island flaps (SIF) and anterolateral thigh perforator flaps (ALTPF). Fifty-one SAPFs, 30 SIF, and 74 ALTPF were reviewed for the intraoral medium-sized reconstructions after the ablation of oral cancer from our institutional clinical oncological databases. We performed comparative assessments on the variables of surgical outcome and oncological safety among the 3 cohorts. A Kaplan-Meier estimate of survival for each flap was calculated. Operating time was significantly reduced in the SIF and SAPF groups than ALTPF (p = 0.021 and 0.014, respectively). Flap thickness of SAPF was the significantly thinnest (mean 0.5 cm) among three groups. The common complications of donor site for both SAPF and SIF group were incision dehiscence and orocutaneous fistula. There was no significant difference in disease-free survival (DFS) among the 3 groups. However, several OSCC patients with the SIF reconstruction were found to have recurrences with a metastatic lymph node under the flap after the first operation. SAPF could be a versatile choice of the intraoral reconstruction for the medium-sized soft-tissue defects after the ablation of oral cancer.

[Impact of history of hypertension and blood pressure levels on the risk of thromboembolism in nonvalvular atrial fibrillation patients]

Objective: To investigate the impact of history of hypertension and blood pressure levels on the thromboembolism risk in the setting of nonvalvular atrial fibrillation (NVAF). Methods: China Atrial Fibrillation Registry Study prospectively enrolled 25 512 atrial fibrillation (AF) patients between August 2011 and December 2018. After exclusion of patients with valvular AF, hypertrophic cardiomyopathy, receiving anticoagulation or ablation therapy at the enrollment, 7 757 patients were included in analysis. The primary endpoint was the time to the first occurrence of ischemic stroke or systemic embolism. Cox proportional hazards models were performed to evaluate whether a history of hypertension or blood pressure levels were independently associated with thromboembolism. Results: During a mean follow up of (35±25) months, 455 （5.9%）thromboembolic events occurred. The crude incidence rate of thromboembolism in patients with a history of hypertension was higher than that in patients without hypertension (2.38 vs. 1.35 per 100 patient-years, χ²=16.8，Log-rank P<0.001). Patients were further divided into 4 groups according to systolic blood pressure (SBP) levels at baseline, the crude incidence rate of thromboembolism significantly increased in proportion to the elevation of SBP levels (χ²=17.9，Log-rank P<0.001). However, there was no significant difference in thromboembolism risk among 4 groups stratified by diastolic blood pressure (DBP) levels (χ²=0.6，Log-rank P=0.907). Multivariable regression analysis showed that history of hypertension was independently associated with a 27% higher risk of thromboembolism (HR=1.27, 95%CI 1.01-1.61, P=0.045). Patients with SBP≥140 mmHg (1 mmHg=0.133 kPa) was associated with 36% higher risk of thromboembolism than patients with SBP<120 mmHg (HR=1.36, 95%CI 1.02-1.82, P=0.036). However, patients with SBP 120-129 mmHg or 130-139 mmHg were not at a higher risk of thromboembolism as compared to the patients with SBP<120 mmHg (SBP 120-129 mmHg: HR=1.23, 95%CI 0.90-1.67, P=0.193; SBP 130-139 mmHg: HR=1.30, 95%CI 0.95-1.77, P=0.098). In addition, DBP levels were not independently associated with the increased thromboembolism risk. Conclusion: A history of hypertension and SBP≥140 mmHg are independent predictors of thromboembolism risk in patients with NVAF. These results indicate that intensive efforts to lower SBP below 140 mmHg might be an important strategy to reduce the risk of stroke in patients with NVAF.

[Research progress of curcumin in the prevention and treatment of periodontitis]

Curcumin is a plant-derived polyphenol extracted from the rhizome of turmeric. As curcumin has such favorable properties as anti-inflammation, anti-oxidation, anti-angiogenesis, immune regulation, anti-bacterial and pro-apoptosis and showed few side effects, the application of curcumin in prevention and treatment of periodontal diseases is promising. This article reviewed the research progress of curcumin in the prevention and treatment of periodontitis.

Applications of microbial co-cultures in polyketides production

Polyketides are a large group of natural biomolecules that are normally produced by bacteria, fungi and plants. These molecules have clinical importance due to their anti-cancer, anti-microbial, anti-oxidant and anti-inflammatory properties. Polyketides are biosynthesized from units of acyl-CoA by different polyketide synthases (PKSs), which display wide diversity of functional domains and mechanisms of action between fungi and bacteria. Co-culture of different micro-organisms can produce novel products distinctive from those produced during single cultures. This study compared the new polyketides produced in such co-culture systems and discusses aspects of the cultivation systems, product structures and identification techniques. Current results indicate that the formation of new polyketides may be the result of activation of previously silent PKSs genes induced during co-culture. This review indicated a potential way to produce pure therapeutic polyketides by microbial fermentation and a potential way to develop functional foods and agricultural products using co-co-culture of different micro-organisms. It also pointed out a new perspective for studies on the process of functional foods, especially those involving multiple micro-organisms.

Treatment outcomes of percutaneous radiofrequency ablation versus adrenalectomy for adrenal metastases: a retrospective comparative study

PURPOSE

To retrospectively evaluate the clinical outcomes of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) in treatment of adrenal metastasis (AM), and to compare with adrenalectomy (Adx).

METHODS

From June 2008 to August 2018, a total of 60 patients with AM treated at our hospital were retrospectively reviewed, of whom 29 treated by RFA (RFA group) and 31 by Adx (Adx group). The technical success, local tumor progression (LTP) and overall survival (OS) after the treatment were evaluated and compared.

RESULTS

In RFA group, the first technical success was 72.4% and the second technical success was 86.2%. In Adx group, all the AMs were successfully resected. After 24.5 ± 19.1 months follow-up period, a total of 8 patients (6 in RFA group and 2 in Adx group) were detected LTP. The 1-, 2- and 3- LTP rates after treatment were 17.1%, 30.9% and 44.7% in RFA group, and 6.5%, 6.5% and 6.5% in Adx group, respectively (P = 0.028). However, for AM ≤ 5 cm, the LTP between the two groups were comparable (P = 0.068). The 1-, 2- and 3- OS rates after treatment for AM were 85.0%, 42.4% and 27.8% in RFA group, and 93.0%, 66.1% and 52.3% in Adx group, respectively (P = 0.057). RFA offered shorter treatment time (23.6 ± 16.9 vs. 155.6 ± 58.8 min, P < 0.001), shorter hospital stay (7.8 ± 3.9 vs. 15.0 ± 4.9 days, P < 0.001), and lower hospital cost ($3405.7 ± 1067.8 vs. $5248.0 ± 2261.3, P = 0.003) than Adx.

CONCLUSION

In comparison with Adx, percutaneous US-guided RFA, as an alternative treatment, is feasible and effective in controlling AM, especially in AM ≤ 5 cm in diameter.

Electrochemical impedance spectroscopy of human cochleas for modeling cochlear implant electrical stimulus spread

Cochlear implants (CIs) have tremendously helped people with severe to profound hearing loss to gain access to sound and oral-verbal communication. However, the electrical stimulus in the cochlea spreads easily and widely, since the perilymph and endolymph (i.e., intracochlear fluids) are essentially electrolytes, leading to an inability to focus stimulation to discrete portions of the auditory nerve, which blurs the neural signal. Here, we characterize the complex transimpedances of human cadaveric cochleas to investigate how electrical stimulus spread is distributed from 10 Hz to 100 kHz. By using electrochemical impedance spectroscopy (EIS), both the resistive and capacitive elements of human cochleas are measured and modeled with an electrical circuit model, identifying spread-induced and spread-independent impedance components. Based on this electrical circuit model, we implement a Laplace transform to simulate the theoretical shapes of the spread signals. The model is validated by experimentally applying the simulated stimulus as a real stimulus to the cochlea and measuring the shapes of the spread signals, with relative errors of <0.6% from the model. Based on this model, we show the relationship between stimulus pulse duration and electrical stimulus spread. This EIS technique to characterize the transimpedances of human cochleas provides a new way to predict the spread signal under an arbitrary electrical stimulus, thus providing preliminary guidance to the design of CI stimuli for different CI users and coding strategies.

The Ca2+ -regulated protein kinase CIPK1 integrates plant responses to phosphate deficiency in Arabidopsis thaliana

Phosphate (Pi) deficiency severely restricts plant growth and development, as Pi is an essential macronutrient. Calcium (Ca²⁺ ) is a ubiquitous second messenger in plants; calcineurin B-like proteins (CBL) and CBL-interacting protein kinases (CIPK) are signalling pathways that act as an important Ca²⁺ signalling network which integrates plants to fine tune the response to stress; however, whether CIPK are involved in Pi deficiency stress remains largely unknown. In this study, we carried out a reverse genetic strategy to screen T-DNA insertion mutants of CIPK isoforms under Pi deficiency in Arabidopsis thaliana. Then Pi content, transcription of phosphate starvation-induced (PSI) genes, acid phosphatase activity and hydrogen peroxide were determined in the wild-type (WT) and cipk1 mutant, respectively. The phenotype of CIPK1 complementation lines was analysed. The cipk1 mutant had a more sensitive phenotype, with lower root elongation and root length, and decreased Pi content compared with the WT under Pi deficiency. Moreover, CIPK1 mutation caused phosphate starvation-induced (PSI) genes to be significantly induced under Pi deficiency. Histological staining demonstrated that the cipk1 mutant had increased acid phosphatase activity and hydrogen peroxide concentration under Pi deficiency. By using the yeast two-hybrid system, we further demonstrated the interaction between CIPK1 and the WRKY transcription factors, WRKY6 and WRKY42. Overall, we demonstrate that CIPK1 is involved in the Pi deficiency signalling pathway in A. thaliana, revealing the important role of Ca²⁺ in the Pi nutrition signalling pathway, and potentially providing a theoretical foundation for molecular breeding of crops with better Pi utilization efficiency.

Hollow Plasma Acceleration Driven by a Relativistic Reflected Hollow Laser

In order to address the present difficulty in experimentally generating the relativistic Laguerre-Gaussian laser, primarily due to damage caused to optical modulators, a high-reflectivity phase mirror is applied in the femtosecond petawatt laser system to generate a relativistic hollow laser at the highest intensity of 6.3×10^{19}  W/cm^{2} for the first time. A simple optical model is used to verify that the vortex laser may be generated in this new scheme; using such a relativistic vortex laser, the hollow plasma drill and acceleration are achieved experimentally and proven by particle-in-cell simulations. With the development of the petawatt laser, this scheme opens up possibilities for the convenient production of the relativistic hollow laser at high repetition and possible hollow plasma acceleration, which is important for a wide range of applications such as the generation of radiation sources with orbital angular momentum, fast ignition for inertial confinement fusion, and jet research in the astrophysical environment.