[Application of branch-first technique in total thoracic aorta replacement: short and medium term effect of 11 cases]

Objective: To examine the short and medium term effect of branch-first technique in total thoracic aorta replacement. Methods: The clinical data of eleven patients with ascending aortic aneurysms or type A aortic dissection+Crawford Ⅰ or Ⅱ total thoracoabdominal aortic aneurysm who were treated at Department of Cardiovascular Surgery in Henan Province Chest Hospital from January 2018 to July 2021 were retrospectively analyzed. There were 7 males and 4 females, aging (38±5) years (range: 28 to 45 years), 7 cases of whom were diagnosed with Marfan syndrome, 1 case was diagnosed with coarctation of aorta. Operations were performed under mild hypothermic and branch-first technique. Firstly, the middle and small incision in the chest was combined with the 6th intercostal incision in the left posterior lateral side. Secondly, four branches artificial blood vessels were anastomosed with the brachiocephalic artery to ensure the blood supply to the brain. After the circulation was blocked, intracardiac and aortic proximal operations were performed. Intercostal artery reconstruction and thoracic descending aorta replacement were completed after opening circulation. Results: The operative time of this group was (645.9±91.7) minutes (range: 505 to 840 minutes). One case had cerebral infarction and 1 case had chylothorax. The patients were followed up 4 to 47 months, 1 patient underwent thoracic and abdominal aorta+iliac artery resection and replacement due to the progression of abdominal aortic aneurysm 3 months after operation. Intercostal artery obstruction occurred in 2 cases, and the rest lived well. Conclusions: One-stage whole thoracic aorta replacement with branch-first technique has satisfactory results in the short and medium term, with no risk of residual aortic aneurysm rupture. It is an effective treatment for young and organs function well patients with complex aortic lesions.

Toripalimab (anti-PD-1) versus High-Dose Interferon-α2b as Adjuvant Therapy in Resected Mucosal Melanoma: A Phase II Randomized Trial

BACKGROUND

No standard of care for mucosal melanoma (MM) in the adjuvant setting has been established. Meanwhile, relapse-free survival (RFS) is only about five months after surgery alone. This phase II trial aimed to compare toripalimab vs. high-dose interferon-α2b (HDI) as an adjuvant therapy for resected MM.

PATIENTS AND METHODS

From July 2017 to May 2019, 145 patients with resected MM were randomized (1:1) to receive HDI (N = 72) or toripalimab (N = 73) for one year until disease relapse/distant metastasis, unacceptable toxicity, or withdrawal of consent. The primary endpoint was RFS. The secondary endpoints included distant metastasis-free survival (DMFS), overall survival (OS), and safety.

RESULTS

After a median follow-up of 26.3 months, the numbers of RFS, OS, and DMFS events were 51 vs. 46, 33 vs. 29, and 49 vs. 44 in the toripalimab arm and the HDI arm, respectively. The median RFS were 13.6 (95%CI: 8.31-19.02) months and 13.9 (95%CI: 8.28-19.61) months in the toripalimab arm and HDI arm, respectively. The DMFS was not significantly different between the two arms (HR: 1.00, 95%CI: 0.65-1.54). The median OS was 35.1 months (95%CI: 27.93-NR) in the toripalimab arm, with no significant difference in all-cause death (HR: 1.11, 95% CI: 0.66-1.84) for the two arms. The median sums of the patients' actual infusion doses were 3672 mg and 1054.5 MIU in the toripalimab arm and HDI arm, respectively. The incidence of treatment-emergent adverse events with a grade ≥ 3 was much higher in the HDI arm than in the toripalimab arm (87.5% vs. 27.4%).

CONCLUSION

Toripalimab showed a similar RFS and a more favorable safety profile than HDI, both better than historical data, suggesting that toripalimab might be the better treatment option. However, additional translational studies and better treatment regimens are still warranted to improve the clinical outcome of MM.

High efficiency and collimated terahertz pulse from ultra-short intense laser and cone target

We propose a new, to the best of our knowledge, method to radiate a high-efficiency and collimated terahertz (THz) pulse from a relativistic femtosecond laser and cone target. Particle-in-cell simulations demonstrate that a THz source of 40 mJ, pointing at an angle of ∼20 ^∘, can be generated from a laser pulse of 1.9 J by using a cone target whose open angle is 10 ^∘. The peak power of the THz pulse is 10¹¹ W. This method, which manipulates the divergence angle and the energy conversion efficiency of the THz source, should promote THz science into the extra strong region with a compact laser system.

[Preliminary effects of toripalimab combined with axitinib in the treatment of advanced renal cell carcinoma]

Objective: To analyze the efficacy and safety of toripalimab combined with axitinib in the treatment of advanced renal cell carcinoma. Methods: Clinical data of 50 patients with advanced renal cell carcinoma who received axitinib combined with toripalimab were retrospectively collected from the database of Peking University Cancer Hospital. ORR, DCR, PFS, and OS were analyzed. Results: Among the 50 patients, 37 were males; median age was 56 (22-73) years; 38 were pathologically diagnosed as clear cell renal cell carcinoma and 12 were non-clear cell carcinoma. Common metastatic sites included lung, bone, lymph node, liver, and so on. 90% of the patients had received at least one-line of systemic therapy. With a median follow-up time of 11.9 months (0.8-24), 27 of the 50 patients are still on treatment, ORR was 34%, DCR was 86%, median PFS was 13.1 months (95%CI 5.8-20.4), and median OS has not yet reached. One-year OS rate was 84.6%. Common adverse reactions were proteinuria, diarrhea, hypertension, abnormal thyroid function, elevated transaminase, and hand-foot syndrome. Most adverse events were grade 1-2. Conclusion: Toripalimab combined with axitinib was efficient in the treatment of advanced renal cell carcinoma, and had manageable adverse reactions.

[Clinical diagnosis and treatment characteristics of pancreatic cystic neoplasms in pediatric patients: a report of 13 cases]

Objective: To investigate the clinical characteristics of pancreatic cystic neoplasms in pediatric patients. Methods: The clinical data of 13 patients with pancreatic cystic neoplasm at Wuhan Children's Hospital from July 2007 to November 2019 were collected.There were 5 males and 8 females, with a mean age of 133 months(range: 9 to 170 months). Eleven patients presented with abdominal pain, vomiting, and a palpable mass. Tumors were located in the pancreatic head(n=7), body(n=2) and tail(n=4), respectively. Results: The preoperative diagnosis was confirmed by imaging examination in 11 patients, CT and MRI was significantly superior to ultrasound in the exact diagnosis of the tumor types. In this group, surgical methods mainly included pancreaticoduodenectomy(n=3), pylorus-preserving pancreatoduodenectomy(n=1), duodenum-preserving pancreas head resection(n=3), spleen-preserving distal pancreatectomy (n=3), distal pancreatectomy plus splenectomy(n=2), and tumor enucleation(n=1). Postoperative complications including biochemical leakage(n=1), delayed gastric emptying(grade A) (n=1), adhesive intestinal obstruction(n=1), transient elevation of platelet count(n=2), all were cured by conservative treatment. In one patient biliary leakage occurred and later developed into biliary stricture, this patient underwent the second operation 6 weeks later and recovered smoothly. All patients were diagnosed by postoperative pathology, including solid pseudopapillary neoplasm(n=10), serous cystadenoma(n=1), mucinous cystadenoma(n=1) and cystic lymphangiom(n=1). Three cases were lost in this group, the rest of patients were all accepted outpatient or telephones follow-up. There was no evidence of recurrence or metastasis during 3 to 92 months follow-up. Conclusions: The incidence of pancreatic cystic neoplasm is low in the pediatric patients. Symptomatic patients should receive surgical treatment timely. It's safe and effective to choose the organs and functions-preserving surgical method.

Direct laser acceleration of electrons assisted by strong laser-driven azimuthal plasma magnetic fields

A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasistatic azimuthal magnetic field. The laser field efficiently accelerates electrons in such a field that confines the transverse motion and deflects the electrons in the forward direction. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents. We study the electron dynamics via a test-electron model, specifically deriving the corresponding critical current density. We confirm the model's predictions by numerical simulations, indicating energy gains two orders of magnitude higher than achievable without the magnetic field.

Deflection of a reflected intense circularly polarized light beam induced by asymmetric radiation pressure

A deflection effect of an intense laser beam with spin angular momentum is revealed theoretically by an analytical modeling using radiation pressure and momentum balance of laser plasma interaction in the relativistic regime as a deviation from the law of reflection. The reflected beam deflects out of the plane of incidence with a deflection angle up to several milliradians, when a nonlinear polarized laser, with the intensity I_{0}∼10^{19}W/cm^{2} and duration around tens of femtoseconds, is obliquely incident and reflected by an overdense plasma target. This effect originates from the asymmetric radiation pressure caused by spin angular momentum of the laser photons. The dependence of the deflection angle of a Gaussian-type laser on the parameters of laser pulse and plasma foil is theoretically derived, which is also confirmed by three-dimensional particle-in-cell simulations of circularly polarized laser beams with the different intensity and pulse duration.

Radiation reaction as an energy enhancement mechanism for laser-irradiated electrons in a strong plasma magnetic field

Conventionally, friction is understood as a mechanism depleting a physical system of energy and as an unavoidable feature of any realistic device involving moving parts. In this work, we demonstrate that this intuitive picture loses validity in nonlinear quantum electrodynamics, exemplified in a scenario where spatially random friction counter-intuitively results in a highly directional energy flow. This peculiar behavior is caused by radiation friction, i.e., the energy loss of an accelerated charge due to the emission of radiation. We demonstrate analytically and numerically how radiation friction can dramatically enhance the energy gain by electrons from a laser pulse in a strong magnetic field that naturally arises in dense laser-irradiated plasma. We find the directional energy boost to be due to the transverse electron momentum being reduced through friction whence the driving laser can accelerate the electron more efficiently. In the considered example, the energy of the laser-accelerated electrons is enhanced by orders of magnitude, which then leads to highly directional emission of gamma-rays induced by the plasma magnetic field.

[Research progress in the methods for evaluating depth of invasion of tongue squamous cell carcinoma]

Depth of invasion is a newly added index for TNM staging of oral cancer in the eighth edition. Preoperative evaluation of depth of invasion not only provides a reference for surgical margin, but also serves as an independent prognostic factor for predicting lymph node metastases. At present, the main methods for assessing the depth of invasion of tongue squamous cell carcinoma include ultrasound examination, MRI, CT, positron emission tomography (PET) and histopathological examination. This paper summarizes the evaluation method and clinical effect of depth of invasion of tongue cancer, and analyzes its advantages and boundedness. In addition, this study is expected to provide a reference for the surgical treatment of tongue squamous cell carcinoma.

BRAF inhibitors: efficacious and tolerable in BRAF-mutant acral and mucosal melanoma

BRAF inhibitors substantially have impressive clinical efficacy in cutaneous melanoma. However, their role in acral and mucosal melanoma remains unclear. Records were reviewed of patients with metastatic or unresectable BRAF-mutant acral and mucosal melanoma hospitalized and administrated BRAF inhibitors during January 2011 and March 2016. Clinical data were collected to determine PFS, ORR, DCR, OS, and safety. Among 28 acral and 12 mucosal melanoma patients treated with BRAF inhibitors, median PFS were 3.6 (95%CI 3.0-6.4) and 4.4 (95%CI 0.8-12.7) months, median OS were 6.2 (95%CI 6.1-12.1) and 8.2 (95%CI 6.6-19.9) months; ORRs were 38.1% and 20.0%, DCRs were 81.0% and 70.0% in acral and mucosal melanoma, respectively. BRAF inhibitors were well tolerated. The most common adverse effects (AEs) were cutaneous and hematological. Grade 3/4 AEs were relatively rare. In conclusion, BRAF inhibitors have acceptable efficacy and good tolerance in BRAF mutant acral and mucosal melanoma.

Detection and analysis of laser driven proton beams by calibrated Gafchromic HD-V2 and MD-V3 radiochromic films

The radiochromic film (RCF) is a high-dose, high-dynamic range dosimetry detection medium. A stack of RCFs can be used to detect both spatial and energetic distribution of laser driven ion beams with a large divergence angle and continuous energy spectrum. Two types of RCFs (HD-V2 and MD-V3, from Radiation Products Design, Inc.) have been calibrated using MeV energy protons and carbon ions produced by using a 2 × 6 MV tandem electrostatic accelerator. The proportional relationship is obtained between the optical density and the irradiation dose. For protons, the responses are consistent at all energies with a variation of about 15%. For carbon ions, the responses are energy related, which should be noted for heavy ion detection. Based on the calibration, the broad energy spectrum and charge distribution of laser accelerated proton beam with energy from 3 to 8 MeV and pC charge were detected and reconstructed at the Compact LAser Plasma Accelerator at Peking University.

Creation of Electron-Positron Pairs in Photon-Photon Collisions Driven by 10-PW Laser Pulses

A novel approach is proposed to demonstrate the two-photon Breit-Wheeler process by using collimated and wide-bandwidth γ-ray pulses driven by 10-PW lasers. Theoretical calculations suggest that more than 3.2×10^{8} electron-positron pairs with a divergence angle of 7° can be created per shot, and the signal-to-noise ratio is higher than 10^{3}. The positron signal, which is roughly 100 times higher than the detection limit, can be measured by using the existing spectrometers. This approach, which could demonstrate the e^{-}e^{+} pair creation process from two photons, would provide important tests for two-photon physics and other fundamental physical theories.

Laser Acceleration of Highly Energetic Carbon Ions Using a Double-Layer Target Composed of Slightly Underdense Plasma and Ultrathin Foil

We report the experimental generation of highly energetic carbon ions up to 48 MeV per nucleon by shooting double-layer targets composed of well-controlled slightly underdense plasma and ultrathin foils with ultraintense femtosecond laser pulses. Particle-in-cell simulations reveal that carbon ions are ejected from the ultrathin foils due to radiation pressure and then accelerated in an enhanced sheath field established by the superponderomotive electron flow. Such a cascaded acceleration is especially suited for heavy ion acceleration with femtosecond laser pulses. The breakthrough of heavy ion energy up to many tens of MeV/u at a high repetition rate would be able to trigger significant advances in nuclear physics, high energy density physics, and medical physics.

[Impact of first-line chemotherapy on renal function in patients with advanced upper tract urothelial carcinoma]

Objective: To observe the impact of first-line chemotherapy on renal function in patients with unresectable/metastatic upper tract urothelial carcinoma(UTUC). Methods: A total of 222 (130 males and 92 females) unresectable/metastatic upper tract urothelial carcinoma patients were included in the study between January 2005 and May 2017, with age of 29 to 87 (62.4±10.1) years old. The serum creatinine level and estimated glomerular filtration rate (eGFR) were compared before and after first-line chemotherapy. And predictive factors for decreased renal function were analyzed in logistic regression model. Results: After the first-line chemotherapy, the average serum creatinine level increased, with a median changing value of 1.5 μmol/L. Howerver, the eGFR improved, with a median changing value of 0.5 ml·min^-1· (1.73 m²)^-1, but the differences were not statistically significant (all P>0.05). In 149 patients who were treated with cisplatin-based chemotherapy, the average serum creatinine level increased by 1.31 μmol/L and eGFR improved by 0.14 ml·min^-1·(1.73 m²)^-1, but the differences were not statistically significant (P>0.05). In multivariate logistic regression model, age more than and equal to 60 years old (OR=0.88, P=0.745) and cisplatin-based chemotherapy (OR=0.95, P=0.893) did not increase the risk of renal dysfunction after first-line chemotherapy. If the time interval between surgery and first-line chemotherapy was more than 1 year, the risk of renal dysfunction due to chemotherapy decreased (OR=0.54, P=0.196). Eastern Cooperative Oncology Group Performance Status (ECOG PS) Scale≥1 (OR=1.81, P=0.131), anemia before treatment (OR=1.14, P=0.764), the cycles of first-line chemotherapy (OR=1.41, P=0.398) may lead to increase the risk of renal dysfunction, but the differences were not statistically significant. However in the patients who accepted nephrectomy, the risk of renal dysfunction after chemotherapy increased, but the difference was still not statistically significant (OR=3.06, P=0.089). Conclusions: First-line chemotherapy, especially the cisplatin-based regimen, had no significant impact on renal function in the patients with UTUC. Nephrectomy maybe a predictive risk factor for decreased renal function after chemotherapy. Adequate assessment of renal function before treatment, hydration and close monitoring during chemotherapy can effectively protect renal function of the patients.

Brilliant petawatt gamma-ray pulse generation in quantum electrodynamic laser-plasma interaction

We show a new resonance acceleration scheme for generating ultradense relativistic electron bunches in helical motions and hence emitting brilliant vortical γ-ray pulses in the quantum electrodynamic (QED) regime of circularly-polarized (CP) laser-plasma interactions. Here the combined effects of the radiation reaction recoil force and the self-generated magnetic fields result in not only trapping of a great amount of electrons in laser-produced plasma channel, but also significant broadening of the resonance bandwidth between laser frequency and that of electron betatron oscillation in the channel, which eventually leads to formation of the ultradense electron bunch under resonant helical motion in CP laser fields. Three-dimensional PIC simulations show that a brilliant γ-ray pulse with unprecedented power of 6.7 PW and peak brightness of 10²⁵ photons/s/mm²/mrad²/0.1% BW (at 15 MeV) is emitted at laser intensity of 1.9 × 10²³ W/cm².

High-efficiency γ-ray flash generation via multiple-laser scattering in ponderomotive potential well

γ-ray flash generation in near-critical-density target irradiated by four symmetrical colliding laser pulses is numerically investigated. With peak intensities about 10^{23} W/cm^{2}, the laser pulses boost electron energy through direct laser acceleration, while pushing them inward with the ponderomotive force. After backscattering with counterpropagating laser, the accelerated electron is trapped in the electromagnetic standing waves or the ponderomotive potential well created by the coherent overlapping of the laser pulses, and emits γ-ray photons in a multiple-laser-scattering regime, where electrons act as a medium transferring energy from the laser to γ rays in the ponderomotive potential valley.

Characterization of magnetic reconnection in the high-energy-density regime

The dynamics of magnetic reconnection (MR) in the high-energy-density (HED) regime, where the plasma inflow is strongly driven and the thermal pressure is larger than the magnetic pressure (β>1), is reexamined theoretically and by particle-in-cell simulations. Interactions of two colliding laser-produced plasma bubbles with self-generated poloidal magnetic fields of, respectively, antiparallel and parallel field lines are considered. Through comparison, it is found that the quadrupole magnetic field, bipolar poloidal electric field, plasma heating, and even the out-of-plane electric field can appear in both cases due to the mere plasma bubble collision, which may not be individually recognized as evidences of MR in the HED regime separately. The Lorentz-invariant scalar quantity D(e) ≃ γ(e)j · (E + v(e) × B) (γ(e) = [1-(v(e)/c)(2)](-1/2)) in the electron dissipation region is proposed as the key sign of MR occurrence in this regime.

Generation of overdense and high-energy electron-positron-pair plasmas by irradiation of a thin foil with two ultraintense lasers

A scheme for enhanced quantum electrodynamics (QED) production of electron-positron-pair plasmas is proposed that uses two ultraintense lasers irradiating a thin solid foil from opposite sides. In the scheme, under a proper matching condition, in addition to the skin-depth emission of γ-ray photons and Breit-Wheeler creation of pairs on each side of the foil, a large number of high-energy electrons and photons from one side can propagate through it and interact with the laser on the other side, leading to much enhanced γ-ray emission and pair production. More importantly, the created pairs can be collected later and confined to the center by opposite laser radiation pressures when the foil becomes transparent, resulting in the formation of unprecedentedly overdense and high-energy pair plasmas. Two-dimensional QED particle-in-cell simulations show that electron-positron-pair plasmas with overcritical density 10(22) cm(-3) and a high energy of 100s of MeV are obtained with 10 PW lasers at intensities 10(23) W/cm(2), which are of key significance for laboratory astrophysics studies.

Ion Acceleration Using Relativistic Pulse Shaping in Near-Critical-Density Plasmas

Ultraintense laser pulses with a few-cycle rising edge are ideally suited to accelerating ions from ultrathin foils, and achieving such pulses in practice represents a formidable challenge. We show that such pulses can be obtained using sufficiently strong and well-controlled relativistic nonlinearities in spatially well-defined near-critical-density plasmas. The resulting ultraintense pulses with an extremely steep rising edge give rise to significantly enhanced carbon ion energies consistent with a transition to radiation pressure acceleration.

Bright subcycle extreme ultraviolet bursts from a single dense relativistic electron sheet

Double-foil targets separated by a low density plasma and irradiated by a petawatt-class laser are shown to be a copious source of coherent broadband radiation. Simulations show that a dense sheet of relativistic electrons is formed during the interaction of the laser with the tenuous plasma between the two foils. The coherent motion of the electron sheet as it transits the second foil results in strong broadband emission in the extreme ultraviolet, consistent with our experimental observations.

Suppression of transverse ablative Rayleigh-Taylor-like instability in the hole-boring radiation pressure acceleration by using elliptically polarized laser pulses

It is shown that the transverse Rayleigh-Taylor-like (RT) instability in the hole-boring radiation pressure acceleration can be suppressed by using an elliptically polarized (EP) laser. A moderate J×B heating of the EP laser will thermalize the local electrons, which leads to the transverse diffusion of ions, suppressing the short wavelength perturbations of RT instability. A proper condition of polarization ratio is obtained analytically for the given laser intensity and plasma density. The idea is confirmed by two-dimensional particle-in-cell simulations, showing that the ion beam driven by the EP laser is more concentrated and intense compared with that of the circularly polarized laser.

Three-dimensional fast magnetic reconnection driven by relativistic ultraintense femtosecond lasers

Three-dimensional fast magnetic reconnection driven by two ultraintense femtosecond laser pulses is investigated by relativistic particle-in-cell simulation, where the two paralleled incident laser beams are shot into a near-critical plasma layer to form a magnetic reconnection configuration in self-generated magnetic fields. A reconnection X point and out-of-plane quadrupole field structures associated with magnetic reconnection are formed. The reconnection rate is found to be faster than that found in previous two-dimensional Hall magnetohydrodynamic simulations and electrostatic turbulence contribution to the reconnection electric field plays an essential role. Both in-plane and out-of-plane electron and ion accelerations up to a few MeV due to the magnetic reconnection process are also obtained.

Laser-driven three-stage heavy-ion acceleration from relativistic laser-plasma interaction

A three-stage heavy ion acceleration scheme for generation of high-energy quasimonoenergetic heavy ion beams is investigated using two-dimensional particle-in-cell simulation and analytical modeling. The scheme is based on the interaction of an intense linearly polarized laser pulse with a compound two-layer target (a front heavy ion layer + a second light ion layer). We identify that, under appropriate conditions, the heavy ions preaccelerated by a two-stage acceleration process in the front layer can be injected into the light ion shock wave in the second layer for a further third-stage acceleration. These injected heavy ions are not influenced by the screening effect from the light ions, and an isolated high-energy heavy ion beam with relatively low-energy spread is thus formed. Two-dimensional particle-in-cell simulations show that ∼100MeV/u quasimonoenergetic Fe24+ beams can be obtained by linearly polarized laser pulses at intensities of 1.1×1021W/cm2.

Generating overcritical dense relativistic electron beams via self-matching resonance acceleration

We show a novel self-matching resonance acceleration regime for generating dense relativistic electron beams by using ultraintense circularly polarized laser pulses in near-critical density plasmas. When the self-generated quasistatic axial magnetic field is strong enough to pinch and trap thermal relativistic electrons, an overdense electron bunch is formed in the center of the laser channel. In the trapping process, the electron betatron frequencies and phases can be adjusted automatically to match the resonance condition. The matched electrons are accelerated continuously and a collimated electron beam with overcritical density, helical structure, and plateau profile energy spectrum is hence generated.