Novel variants and uncommon cases among southern Chinese children with X-linked hypophosphatemia

PURPOSE

X-linked hypophosphatemia (XLH) is the most common inherited renal phosphate wasting disorder and is often misdiagnosed as vitamin D deficiency. This study aims to provide clinical and mutational characteristics of 65 XLH pediatric patients in southern China.

METHODS

In this work, a combination of DNA sequencing and qPCR analysis was used to study the PHEX gene in 80 pediatric patients diagnosed with hypophosphatemia. The clinical and laboratory data of confirmed 65 XLH patients were assessed and analyzed retrospectively.

RESULTS

In 65 XLH patients from 61 families, 51 different variants in the PHEX gene were identified, including 23 previously reported variants and 28 novel variants. In this cohort of XLH patients, the c.1601C>T(p.Pro534Leu) variant appears more frequently. Fourteen uncommon XLH cases were described, including four boys with de novo mosaic variants, eight patients with large deletions and a pair of monozygotic twins. The clinical manifestations in this cohort are very similar to those previously reported.

CONCLUSION

This study extends the mutational spectrum of the PHEX gene, which will contribute to accurate diagnosis. This study also suggests a supplementary qPCR or MLPA assay may be performed along with classical sequencing to confirm the gross insertion/deletion.

Particle-in-cell simulation method for macroscopic degenerate plasmas

Nowadays hydrodynamic equations coupled with external equation of states provided by quantum mechanical calculations is a widely used approach for simulations of macroscopic degenerate plasmas. Although such an approach is proven to be efficient and shows many good features, especially for large scale simulations, it encounters intrinsic challenges when involving kinetic effects. As a complement, here we have invented a fully kinetic numerical approach for macroscopic degenerate plasmas. This approach is based on first principle Boltzmann-Uhling-Uhlenbeck equations coupled with Maxwell's equation, and is eventually achieved via an existing particle-in-cell simulation code named LAPINS. In this approach, degenerate particles obey Fermi-Dirac statistics and nondegenerate particles follow the typical Maxwell-Boltzmann statistics. The equation of motion of both degenerate and nondegenerate particles are governed by long range collective electromagnetic fields and close particle-particle collisions. Especially, Boltzmann-Uhling-Uhlenbeck collisions ensure that evolution of degenerate particles is enforced by the Pauli exclusion principle. The code is applied to several benchmark simulations, including electronic conductivity for aluminium with varying temperatures from 2 eV to 50 eV, thermalization of alpha particles in a cold fuel shell in inertial confinement fusion, and rapid heating of solid sample by short and intense laser pulses.

[Evaluation of the analgesic effect of Acute Pain Service in thoracic surgery]

Objective: To observe the analgesic effect, complication and patient satisfaction of Acute Pain Service (APS) after thoracic surgery. Methods: The clinical data were collected from 264 patients who underwent different thoracic surgery from January 2017 until December 2019 retrospectively. They were divided into thoracotomy group (group O) and thoracoscopy surgery group (group T). There were 90 cases in group O and 174 cases in group T. According to the use of APS, the group O is divided into the no-APS group (group O1) and the APS group (group O2), the group T is divided into the no-APS group (group T1) and the APS group (group T2). The effect of postoperative analgesia, the incidence of nausea and vomiting and the satisfaction of patients were compared between group O1 and group O2, group T1 and group T2, respectively. Results: In the resting state, the Numeric Rating Scales (NRS) scores of the group O2 at 0 h (0.92±0.50 vs 1.59±0.62), 4 h (0.92±0.50 vs 2.06±1.03), 8 h (0.92±0.50 vs 2.18±1.13), 12 h (0.92±0.50 vs 2.47±1.42), 24 h (1.00±0.71 vs 2.53±1.42), and 48 h (1.00±0.71 vs 2.35±1.80) after leaving the Anesthesia Recovery Room (PACU) were significantly lower than those of the group O1 (all P<0.05), and in the active state, the NRS scores of the group O2 at 0 h (P=0.023), 4 h (P=0.001), 8 h (P=0.000), 12 h (P=0.001), 24 h (P=0.000), 48 h (P=0.000), and 72 h (P=0.019) after leaving the PACU were significantly lower than those of the group O1 (all P<0.05). In the resting state, the NRS scores of the group T2 at 4 h (P=0.029), 8 h (P=0.008), 12 h (P=0.006), and 24 h (P=0.013) after leaving the PACU were significantly lower than those of the group T1 (all P<0.05). In the active state, the NRS scores of the group T2 at 4 h (P=0.019), 8 h (P=0.000), 12 h (P=0.001), 24 h (P=0.002), and 48 h (P=0.002) after leaving the PACU were significantly lower than those of the group T1 (all P<0.05). Conclusion: APS can significantly reduce the NRS scores after thoracotomy and thoracoscopic surgery compared to ordinary analgesia model.

An open-source handheld extruder loaded with pore-forming bioink for in situ wound dressing

The increasing demand in rapid wound dressing and healing has promoted the development of intraoperative strategies, such as intraoperative bioprinting, which allows deposition of bioinks directly at the injury sites to conform to their specific shapes and structures. Although successes have been achieved to varying degrees, either the instrumentation remains complex and high-cost or the bioink is insufficient for desired cellular activities. Here, we report the development of a cost-effective, open-source handheld bioprinter featuring an ergonomic design, which was entirely portable powered by a battery pack. We further integrated an aqueous two-phase emulsion bioink based on gelatin methacryloyl with the handheld system, enabling convenient shape-controlled in situ bioprinting. The unique pore-forming property of the emulsion bioink facilitated liquid and oxygen transport as well as cellular proliferation and spreading, with an additional ability of good elasticity to withstand repeated mechanical compressions. These advantages of our pore-forming bioink-loaded handheld bioprinter are believed to pave a new avenue for effective wound dressing potentially in a personalized manner down the future.

Forsythia suspensa extract enhances performance via the improvement of nutrient digestibility, antioxidant status, anti-inflammatory function, and gut morphology in broilers

This experiment aims to determine the effects of Forsythia suspense extract (FSE) as an antibiotic substitute on performance, antioxidant status, anti-inflammatory function, intestinal morphology, and meat fatty acid deposition in broilers. 192 male Arbor Acre broilers (1-day-old, weighing 45.6 ± 1.3 g) were randomly allocated to 3 treatments, 8 replicate pens per treatment, 8 broilers per pen. The treatments contain a control diet (corn-soybean meal basal diet, CTL), an antibiotic diet (basal diet + 75 mg/kg chlortetracycline, CTC), and an FSE diet (basal diet + 100 mg/kg FSE; FSE). The experiment includes phase 1 (day 1 to 21) and 2 (day 22 to 42). Compared with CTL and CTC, broilers supplemented with FSE showed higher (P < 0.05) ADG and ADFI in phase 2 and overall (day 1 to 42). On day 21, serum catalase and total antioxidant capacity contents were enhanced (P < 0.05) in broilers fed FSE compared with CTL. On day 42, broilers fed FSE showed increased (P < 0.05) serum superoxide dismutase and glutathione peroxidase contents, and enhanced (P < 0.05) apparent total tract digestibility of dry matter, organic matter, gross energy, total carbohydrates, and phosphorus, as well as reduced (P < 0.05) nitrogen and phosphorus excretion in feces compared with CTL. These broilers also showed decreased (P < 0.05) n-6/n-3 polyunsaturated fatty acid ratio in thigh meat, and tumor necrotic factor-alpha, interleukin-1β and interleukin-6 contents in the liver on day 42 compared with CTL. The villus height was increased (P < 0.05) in the duodenum, jejunum, and ileum of broilers fed FSE compared with CTL. In conclusion, dietary F.suspense extract supplementation as a chlortetracycline substitute under non-challenge conditions enhanced performance via the improvement of nutrient digestibility, antioxidant status, anti-inflammatory function, and intestinal morphology in broilers. Moreover, F.suspense extract may also benefit environment by reducing nitrogen and phosphorus excretion and benefit human health via modulating meat fatty acid profiles in broilers.

AI detection of M. Tuberculosis pathogens using Generative Adversarial Network (GAN) analyses

Background

Rapid identification of pathogens is critical to outbreak detection and sentinel surveillance; however most diagnoses are made in laboratory settings. Advancements in artificial intelligence (AI) and computer vision offer unprecedented opportunities to facilitate detection and reduce response time in field settings. An initial step is the creation of analysis algorithms for offline mobile computing applications.

Methods

AI models to identify objects using computer vision are typically “trained” on previously labeled images. The scarcity of labeled image-libraries creates a bottleneck, requiring thousands of labor hours to annotate images by hand to create “training data.” We describe the applicability of Generative Adversarial Network (GAN) methods to amass sufficient training data with minimal manual input.

Results

Our AI models are built with a performance score of 0.84-0.93 for M. Tuberculosis, a measure of the AI model's accuracy using precision and recall. Our results demonstrate that our GAN pipeline boosts model robustness and learnability of sparse open source data.

Conclusions

The use of labeled training data to identify M. Tuberculosis developed using our GAN pipeline techniques demonstrates the potential for rapid identification of known pathogens in field settings. Our work paves the way for the development of offline mobile computing applications to identify pathogens outside of a laboratory setting. Advancements in artificial intelligence (AI) and computer vision offer unprecedented opportunities to decrease detection time in field settings by combining these technologies. Further development of these capabilities can improve time-to-detection and outbreak response significantly.

Key messages

Rapidly deploy AI detectors to aid in disease outbreak and surveillance. Our concept aligns with deploying responsive alerting capabilities to address dynamic threats in low resource, offline computing environs.

Effect of chestnut wood extract on performance, meat quality, antioxidant status, immune function, and cholesterol metabolism in broilers

Plant extracts have been proved as natural antioxidants resources as well as alternative feed additives in livestock and poultry species. Chestnut wood extract (CWE) as a source of hydrolysable tannic acid was used to evaluate the growth performance, nutrient retention, meat quality, antioxidant status, and immune function of broilers. A total of 168, day-old Arbor Acre male broilers (weight 46.59 ± 0.44 g) were randomly divided to 3 treatments, 7 replicate pens per treatment, 8 broilers per pen. The treatments contain a control diet, CON (corn-soybean meal basal diet); an antibiotic diet, CTC (basal diet + 75 mg/kg chlortetracycline); and chestnut wood extract diet, CWE (basal diet + 1,000 mg/kg chestnut tannins). At the finisher phase, final body weight was higher (P < 0.05) in CWE supplemented diet than in CON. Average daily body weight gain was higher (P < 0.05) and feed gain ratio was lower (P < 0.05) in broilers fed CWE than in those fed CON at the finisher phase. Crude protein digestibility was higher (P < 0.05) in broilers offered CWE than that in broilers fed CON and CTC diets. Breast muscle pH value at 24 h (pH24 h) was higher (P < 0.05) in broilers fed CWE than that in those fed CON and CTC diets. The bursa weight was higher (P < 0.05) in broilers offered CWE than that in those fed CON and CTC. Total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) values were higher (P < 0.05) in both breast muscle and thigh muscle of broilers offered CWE supplemented diet than those in broilers fed CON and CTC diets. Similarly, broilers offered with CWE diets showed higher (P < 0.05) T-AOC, GSH-PX, and SOD value in serum than those fed CON and CTC diets. Serum concentration of IgG was higher (P < 0.05) in broilers offered with CWE diets than that in those fed CON and CTC diets. Total cholesterol, low-density lipoprotein cholesterol, and urea-N concentration were lower (P < 0.05) in broilers offered CWE diet than those in broilers fed CON and CTC diets. It was recommended to supply CWE at the 1,000 mg/kg level for improving antioxidant status, cholesterol metabolism, and growth performance without affecting normal meat quality in broilers.

[Efficacy and safety of non-vitamin K antagonist versus vitamin K antagonist oral anticoagulants in the prevention and treatment of thrombotic disease in active cancer patients: a systematic review and meta-analysis of randomized controlled trials]

Object We aimed to compare the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOAC) and vitamin K antagonist (VKA) in the prevention and treatment of thrombotic diseases in patients with active cancer. Methods: To find randomized controlled trials (RCT) in which NOACs were compared VKAs in active cancer, we searched the electronic databases (PubMed, Web of Science and Clinical Trials) up to May 2019 and and languages restricted to Chinese and English. According to the screening strategy, two researchers independently screened and extracted literature, evaluated the quality of literature, the suitability of collected cross study data for analysis, and tested the heterogeneity. The relative risk (RR) and 95% confidence interval (95%CI) of major bleeding, clinically related non-major bleeding, VTE, stroke and all-cause mortality in active cancer patients with VTE, active cancer patients with non-valvular atrial fibrillation (NVAF) was calculated and the results were compared between NOAC with VKA. Results: A total of 9 RCTs were included, including 5 cancers with VTE (5/9) and 4 cancers with NVAF (4/9). A total of 5 867 patients were included. After excluding 1 818 (30.99%) patients with cancer history, 4 049 (68.86%) patients with active cancer were statistically analyzed. Among them, 2 278 (56.26%) received NOAC treatment, 1 771 patients (43.74%) received VKA treatment. The quality of the included documents was high (all scores were>5 points), and the data of each included document could be summarized and analyzed (P>0.05). The heterogeneity of main outcome events was very low (I2 = 0). In VTE patients with active cancer, NOACs were more effective in reducing recurrence of VTE （RR=0.55, 95%CI 0.36 -0.84; P = 0.005) and clinically related non-major bleeding (RR=0.77, 95%CI 0.60 -0.98; P = 0.03) than VKAs. In NVAF patients with active cancer, efficacy of NOACs and VKAs was similar in terms of reducing VTE, stroke, clinically related non-major bleeding, major bleeding and all-cause mortality events (P>0.05). Conclusions: For patients with active cancer accompanied by VTE, NOAC may has more advantages in efficacy and safety compared to VKA in the prevention and treatment of thrombotic diseases.

[Endoscopic features and clinical correlation analysis of 24 patients with Cronkhite-Canada syndrome]

Objective: To clarify the endoscopic changes prior to corticosteroid therapy in Cronkhite-Canada syndrome (CCS) patients and to explore the correlation between endoscopic features and clinical characteristics. Methods: A total of 24 CCS patients who were hospitalized in Peking Union Medical College Hospital from January 1999 to June 2019 and underwent gastroscopy and colonoscopy before corticosteroid therapy were retrospectively enrolled. The endoscopic images were re-interpreted. The demographic characteristics, clinical manifestations, laboratory tests and histopathological data were collected and analyzed. Results: Of all 24 patients, 15 (62.5%) were male and 9(37.5%) were female, with an average age of (59±10) years and disease course of 6 (1~36) months. Based on the endoscopic findings, the percentages of stomach, colon, duodenum, rectum and terminal ileum involvement were 100%, 100%, 95.7%, 66.7% and 50.0% respectively. Gastric involvement was more severe in the lower part of the body and the antrum of the stomach, while the cardia and the fundus were spared in 5 (20.8%) cases. Colonic involvement was more severe in the right colon. No patient showed remarkable esophageal involvement. The typical appearance under endoscopy were diffuse mucosal hyperemia and edema with polyps or nodular changes. The lesions may have mulberry-like or imbricate changes in severe cases. Lymphatic dilation in the duodenum was found in 47.8% patients. Most of the polyps were pedunculated or sub-pedunculated, with occasionally seen sessile polyps in the colon. The pit patterns of the 12 resected colon polyps in 11 patients could be classified as Kudo type Ⅲ(S), Ⅲ(L), Ⅳ and Ⅴ(I), among which 2 tubular adenomas had the Kudo type Ⅲ(L). Other resected polyps were hyperplastic polyps or CCS polyps. The disease duration prior to diagnosis was positively correlated with the maximum diameter of colon polyps (r=0.625, P=0.006). Serum albumin levels in patients with whole stomach involvement were significantly lower than those in patients with cardia spared [(29±8) g/L vs (37±5) g/L, P=0.034]. Conclusions: The typical initial endoscopic finding of CCS is multiple polyps or nodular changes on the background of diffuse hyperemia and edema lining the gastric, duodenal and colonic mucosa. Lymphatic dilatation in the duodenum could also be found. Some endoscopic features are correlated to clinical characteristics.

Uniform warm dense matter formed by direct laser heating in the presence of external magnetic fields

With the recent realization of kilotesla quasistatic magnetic fields, the interaction of a laser with magnetized solids enters an unexplored new regime. In particular, a circularly polarized (CP) laser pulse may propagate in a highly magnetized plasma of any high density without encountering cutoff reflection in the whistler mode. With this, we propose a scheme for producing uniform warm dense matter (WDM) by direct laser heating with a CP laser irradiating onto the target along the magnetic field. It is shown by particle-in-cell simulations, which include advanced ionization dynamics and collision dynamics, moderately intense right-hand CP laser light at 10^{15}W/cm^{2} can propagate in solid aluminum and heat it efficiently to the 100 eV level within picoseconds. By using two laser pulses irradiating from two sides of a thin solid target, uniform heating to WDM can be achieved. This provides a controllable way to create WDM at different temperatures.

OP0210 EFFICACY AND SAFETY OF SM03, A RECOMBINANT ANTI-HUMAN CD22 MONOCLONAL ANTIBODY IN CHINESE PATIENTS WITH RHEUMATOID ARTHRITIS: A PHASE II RANDOMIZED, DOUBLE-BLIND, MULTI-DOSE, PLACEBO-CONTROLLED STUDY

Background:

Rheumatoid arthritis (RA) is a common chronic inflammatory rheumatic disease in China. SM03 is a novel chimeric monoclonal antibody (mAb) specific to the B cell restricted antigen CD22 developed for the treatment of rheumatoid arthritis (RA) and other B cell related immunological diseases.

Objectives:

We aim to evaluate the efficacy and safety of SM03 in patients with moderately-to-severely active RA in China.

Methods:

In this 24-week Phase II randomized, double-blind, multi-dose, placebo-controlled study, 156 patients were randomized with ratio of 1:1:1 to receive 3600mg cumulative dose of SM03 (group A, 600mg * 6 infusions at 0, 2, 4, 12, 14, and 16 week), 2400mg cumulative dose of SM03 (group B, 600mg*4 infusions at 0, 2, 12, and 14 week) and placebo (group C). All patients remained on background treatment of MTX. Efficacy and safety were assessed at weeks 4, 8, 12,16 and 24.The primary efficacy end point was the American College of Rheumatology 20% improvement criteria (ACR20) response rate at week 24.Safety profile was also assessed.

Results:

ACR20 response rates at 24-week were significant for group A (65.3%, p=0.002) and B (56.9 %, p=0.024) versus group C (34.0%). There is no significant difference in ACR20 between group A and B(Table 1 & Fig 1). We did not observe significant difference in any adverse event (AE) among group A (35.3%), B (51.9%) and C (34.6%)(Table 2). In groups A and B, 13 (12.6%) patients reported treatment-related infection, and 5 (6.8%) patients were positive in anti-drug antibodies analysis. In group A (higher dose), 3.9% patient had AE of treatment-related infections. No patients reported treatment-related severe infection or any malignancies caused by treatment in groups A and B.

Table 1.

Summary of ACR/DAS EULAR Responses of Patients with RA to SM03 at Week 24

ResponseGroup CPlacebo+MTX(n=47)Group A SM03600mg*6+MTX(n=49)Group B SM03600mg*4 +MTX(n=51)ACR 2034.0%65.3% *56.9% *ACR 5017.0%44.9%**29.4%ACR 704.3%18.4%***9.8%EULAR response good & moderate40.4%75.5%^70.6%^EULAR response good12.8%30.6%^^15.7%Change of DAS28 from baseline-0.70-1.65^^^-1.38^^^DAS28≤3.214.9%30.6%19.6%DAS28<2.68.5%18.4%5.9%

Compared with group C(Placebo), results of group A and B were shown respectively

*P=0.002, P=0.024; **P= 0.003; ***P= 0.03;

^ P<0.001, P=0.003; ^^ P=0.034; ^^^P=0.008, P=0.047

Table 2.

Profile of Adverse Events

Adverse event, N (%)Group C(N=52)Group A(N=51)Group B(N=52)Any AE18(34.6)18(35.3)27(51.9)AE-drug related7(13.5)5(9.8)8(15.4)AE-mild16 (30.8)15(29.4)24(46.2)AE-moderate2(3.8)2(3.9)3(5.8)AE-severe-1(2.0)-AE-leading to discontinuation-2(3.9)-Serious adverse event, SAE1(1.9)1(2.0)-AE-1stcycle(week 0-12)151322AE-2ndcycle(week 12-24)9914Fig 1.

Percent of Patients Achieving ACR 20 Response by Visit

Conclusion:

In Chinese patients with active RA, both 2400mg and 3600mg cumulative doseof SM03,in combination with MTX were efficacious and well tolerated. throughout the 24 weeks of treatment.Moreover, SM03 has demonstrated a good safety profile, especially in terms of treatment-related infection, malignancy and immunogenicity.

References:

None

Disclosure of Interests:

None declared

AB1277 AUTOANTIBODIES IN NLRP3-ASSOCIATED AUTOINFLAMMATORY DISEASE: A CASE REPORT AND LITERATURE REVIEW

Background:

We present the first report of high-titer autoantibodies inNLRP3-associated autoinflammatory disease(NLRP3-AID).Because systemic autoinflammatory disease(SAID) is characterised by the lack of autoreactive T-cells or autoantibodies,we made a systemic review on the theme of autoantibody in SAID to clarify this phenomenon.

Objectives:

We present the first report of high-titer autoantibodiesNLRP3-AID, and discuss autoantibody in classical SAID.

Methods:

We collected the clinical data of the patient withNLRP3-AID who had high-titer autoantibodies,and made a systemic review about autoantibody in SAID.

Results:

A 38-year-old Chinese Han patient was definitely diagnosed asNLRP3-AID because of cold-triggered urticaria-like rash and fever,arthralgia,binaural sensorineural deafness,chronic meningitis,high inflammatory marker and de novoNLRP3T348M variant. Figure 1 shows pedigree of the patient.Meanwhile,she had positive antinuclear antibody(ANA) with a nucleolar pattern of 1:160, positive anti-β2GPI antibody 54-68 AU/ml (normal range < 20 AU/ml) and positive lupus anticoagulant 1.24-1.29 (normal range ≤ 1.2). Literature review found that 13 articles reported autoantibodies in Familial Mediterranean fever (FMF), and there was no autoantibody reported in hyperimmunoglobulinemia D syndrome (HIDS),TNF receptor–associated periodic syndrome(TRAPS) andNLRP3-AID. The prevalence of ANA,anti-dsDNA,RF and anti-CCP in patients with FMF was similar to healthy controls.

Fig. 1.

Pedigree of the patient. The black arrow indicates the proband. The asterisks indicate the individuals who had clinical manifestations and carry the NLRP3 T348M variant.

Conclusion:

Patients withNLRP3-AID can have high-titer ANA and APLs by accident. If patients with high-titer autoantibodies have characteristic manifestations of SAIDs instead of typical features of autoimmune diseases, we should make the final diagnosis through detailed investigation and genetic testing.

References:

[1]Ben-Chetrit E, Gattorno M, Gul A, et al. Consensus proposal for taxonomy and definition of the autoinflammatory diseases (AIDs): a Delphi study. Annals of the rheumatic diseases 2018; 77(11): 1558-65.

[2]Kuemmerle-Deschner JB, Ozen S, Tyrrell PN, et al. Diagnostic criteria for cryopyrin-associated periodic syndrome (CAPS). Annals of the rheumatic diseases 2017; 76(6): 942-7.

Disclosure of Interests:

None declared

[Early containment strategies and core measures for prevention and control of novel coronavirus pneumonia in China]

In December 2019, novel coronavirus pneumonia epidemic occurred in Wuhan, Hubei Province, and spread rapidly across the country. In the early stages of the epidemic, China adopted the containment strategy and implemented a series of core measures around this strategic point, including social mobilization, strengthening case isolation and close contacts tracking management, blocking epidemic areas and traffic control to reduce personnel movements and increase social distance, environmental measures and personal protection, with a view to controlling the epidemic as soon as possible in limited areas such as Wuhan. This article summarizes the background, key points and core measures in the country and provinces. It sent prospects for future prevention and control strategies.

[Guidelines for the use of post-traumatic tetanus vaccines and passive immune preparation]

Post-traumatic tetanus is the main type of non-neonatal tetanus. To reduce the incidence and mortality rateof tetanus and guide the primary medical institutions to prevent and control tetanus after trauma, the National Immunization Planning Technical Working Group of the Chinese Center for Disease Control and Prevention has compiled this document in the reference with Position Paper by World Health Organization, and the latest research progress both at home and abroad. The guidelines focus on the basic procedures for the prevention and treatment of post-traumatic tetanus, the application of tetanus vaccines and immune preparation, and pre-exposure immunization in high-risk populations of trauma.

Transport of intense particle beams in large-scale plasmas

Transport of particle beams in plasmas is widely employed in fundamental research, industry, and medicine. Due to the high inertia of ion beams, their transport in plasmas is usually assumed to be stable. Here we report the focusing and flapping of intense slab proton beams transporting through large-scale plasmas by using a recently developed kinetic particle-in-cell simulation code. The beam self-focusing effect in the simulation is prominent and agrees well with previous experiments and theories. Moreover, the beam can curve and flap like turbulence as the beam density increases. Simulation and analysis indicate that the self-generated magnetic fields, produced by movement of collisional plasmas, are the dominant driver of such behaviors. By analyzing the spatial growth rate of magnetic energy and energy deposition of injected proton beams, it is found that the focusing and flapping are significantly determined by the injected beam densities and energies. In addition, a remarkable nonlinear beam energy loss is observed. Our research might find application in inertial confinement fusion and also might be of interest to the laboratory astrophysics community.