Single-order soft x-ray spectra with spectroscopic photon sieve

A single-order diffraction transmission grating named spectroscopic photon sieve(SPS)for soft x-ray region is proposed and demonstrated in this paper.The SPS consists of many circular pinholes located randomly,and can realize both free-standing diffractions and the suppression of higher-order differations.In this paper,the basic concept,numerical simulations,and calibration results of a 1000-lines/mm SPS for soft x-ray synchrotron radiation are presented.As predicted by theoretical calculations,the calibration results of a 1000-lines/mm SPS verify that the higher-order diffractions can be significantly suppressed along the symmetry axis.With the current nanofabrication technique,the SPS can potentially have a higher line density,and can be widely used in synchrotron radiation,laser-induced plasma diagnostics,and astrophysics.

Abdominal metastases of primary extremity soft tissue sarcoma: A systematic review

BACKGROUND Despite the fact that about one third of patients with primary localized extremity soft tissue sarcoma(e STS)will develop metastatic disease,abdominal metastases(AM)and retroperitoneal metastases(RM)constitute rare events.There is no clear consensus on how to achieve follow-up on patients with primary localized e STS following curative resection,especially regarding the surveillance of potential AM/RM.AIM To systematically analyse incidence,diagnosis,treatment and outcome of AM/RM in e STS patients.METHODS In this systematic review,899 studies available in Pub Med and published between 2000 and 2018 were screened,identifying 17 original articles focused on AM or RM in e STS.Article selection was based on the PRISMA guidelines,using the search terms(abdominal metastasis AND soft tissue sarcoma)and(soft tissue sarcoma metastasis abdomen).All studies published between January 1,2000 and December 31,2018 were screened.Further articles were identified by crosssearching article references,with the final search date being February 18,2019.Due to limited data and the different reporting techniques used,the present review focused on descriptive analysis of the included studies.RESULTS Of the 17 studies included,six original articles reported on incidence±diagnosis,therapy and outcome in AM and RM,whilst three original and eight case reports focused on diagnostic pathway,therapeutic procedures or outcomes without allowing conclusions regarding incidence of AM and RM.According to the former six studies,incidence of AM ranged from 0.9%-5.6%in patients with miscellaneous histological subtypes,and up to 12.1%in patients with myxoid liposarcoma.The most common histological subtypes that developed AM or RM were(myxoid)liposarcoma and leiomyosarcoma,but also rare subtypes such asepithelioid sarcoma,myxofibrosarcoma,synovial sarcoma,and malignant peripheral nerve sheath tumour had been reported to develop AM/RM.Surgery for AM/RM was performed in five of eight case-reports(62.5%)and in 20.8%-100.0%of original articles.In particular,patients with hepatic metastases undergoing metastasectomy had a survival benefit compared to patients treated with chemotherapy or best supportive care(>3 years vs<6 mo).CONCLUSION Patients with e STS should undergo surveillance with abdominal ultrasonography/computed tomography,or even whole-body-magnetic resonance imaging to detect AM/RM at an early stage.

Higher order harmonics suppression in extreme ultraviolet and soft x-ray

The extreme ultraviolet and soft x-ray sources are widely used in various domains. Suppressing higher order harmonics and improving spectral purity are significant. This paper describes a novel method of higher order harmonics suppression with single order diffraction gratings in extreme ultraviolet and soft x-ray. The principle of harmonic suppression with single order diffraction grating is described, and an extreme ultraviolet and soft x-ray non-harmonics grating monochromator is designed based on the single order diffraction grating. The performance is simulated by an optical design software. The emergent beams of a monochromator with different gratings are measured by a transmission grating spectrometer. The results show that the single order diffraction grating can suppress higher order harmonics effectively, and it is expected to be widely used in synchrotron radiation, diagnostics of laser induced plasma, and astrophysics.

Yield enhancement of elliptical high harmonics driven by bicircular laser pulses

We theoretically investigate the yield enhancement of elliptical high harmonics in the interaction of molecules with bicircular laser pulses by solving the time-dependent Schrodinger equation.It is shown that by adjusting the relative intensity ratio of the two bicircular field components in specific ranges the yield of the molecular high harmonics for the plateau and cutoff regions can be respectively enhanced.To analyze this enhancement phenomenon,we calculate the weights of the electron classical trajectories.Additionally,we also study the ellipticity distribution of harmonics for different intensity ratios.We find that these enhanced harmonics are elliptically polarized,which we mainly attribute to the recombination dipole moment of the major weighted trajectories.These enhanced elliptical extreme ultraviolet and soft x-ray radiations may serve as essential tools for exploring the ultrafast dynamics in magnetic materials and chiral media.

Clinical and imaging features of desmoid tumors of the extremities

BACKGROUND Desmoid fibroma is a rare soft tissue tumor originating from the aponeurosis,fascia,and muscle,and it is also known as aponeurotic fibroma,invasive fibroma,or ligamentous fibroma.AIM To investigate the clinical and imaging features of desmoid tumors of the extremities.METHODS Thirteen patients with desmoid fibroma of the extremities admitted to our hospital from October 2016 to March 2021 were included.All patients underwent computed tomography(CT),magnetic resonance imaging(MRI),and pathological examination of the lesion.Data on the diameter and distribution of the lesion,the relationship between the lesion morphology and surrounding structures,MRI and CT findings,and pathological features were statistically analyzed.RESULTS The lesion diameter ranged from 1.7 to 8.9 cm,with an average of 5.35±2.39 cm.All lesions were located in the deep muscular space,with the left and right forearm each accounting for 23.08%of cases.Among the 13 patients with desmoid fibroma of the extremities,the lesions were"patchy"in 1 case,irregular in 10,and quasi-round in 2.The boundary between the lesion and surrounding soft tissue was blurred in 10 cases,and the focus infiltrated along the tissue space and invaded the adjacent structures.Furthermore,the edge of the lesion showed"beard-like"infiltration in 2 cases;bone resorption and damage were found in 8,and bending of the bone was present in 2;the boundary of the focus was clear in 1.According to the MRI examination,the lesions were larger than 5 cm(61.54%),round or fusiform in shape(84.62%),had an unclear boundary(76.92%),showed uniform signal(69.23%),inhomogeneous enhancement(84.62%),and"root"or"claw"infiltration(69.23%).Neurovascular tract invasion was present in 30.77%of cases.CT examination showed that the desmoid tumors had slightly a lower density(69.23%),higher enhancement(61.54%),and unclear boundary(84.62%);a CT value<50 Hu was present in 53.85%of lesions,and the enhancement was uneven in 53.85%of cases.Microscopically,fibroblasts and myofibroblasts were arranged in strands and bundles,without obvious atypia but with occasional karyotyping;cells were surrounded by collagen tissue.There were disparities in the proportion of collagen tissue in different regions,with abundant collagen tissue and few tumor cells in some areas,similar to the structure of aponeuroses or ligaments,and tumor cells invading the surrounding tissues.CONCLUSION Desmoid tumors of the extremities have certain imaging features on CT and MRI.The two imaging techniques can be combined to improve the diagnostic accuracy,achieve a comprehensive diagnosis of the disease in the clinical practice,and reduce the risk of missed diagnosis or misdiagnosis.In addition,their use can ensure timely diagnosis and treatment.