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Objectives. Acupoint catgut embedding therapy has shown effectiveness in treating functional constipation; however, relevant, high-quality clinical evidence is scarce. This study aimed to systematically assess the effectiveness and safety of acupoint catgut embedding in treating poststroke constipation. Methods. Correlative randomized controlled trials were identified through a comprehensive literature search of PubMed, Cochrane Library/Cochrane Central Register of Controlled Trials, Web of Science, Embase, China National Knowledge Internet, Chinese Biomedical Literature Database, Wanfang, and VIP databases from inception until February 2022. Meta-analysis was performed using RevMan 5.3 software. Results. Fifteen trials involving 1084 patients were identified. The meta-analysis revealed that the acupoint catgut embedding group was significantly superior to the non-catgut embedding group with regard to the efficacy rate (RR = 1.27, 95% CI (1.19, 1.37), P < 0.05 ), the first defecation time (MD = −3.08, 95% CI (−4.53, −1.63), P < 0.05 ), the defecation sensation score (MD = −0.44, 95% CI (−0.61, −0.26), P < 0.05 ), the degree of difficulty in defecation (MD = −0.73, 95% CI (−1.10, −0.37), P < 0.05 ), the PAC-QOL scale score (MD = −10.06, 95% CI (−13.47, −6.64), P < 0.05 ), and the symptom integral (MD = −3.15, 95% CI (−3.60, −2.71), P < 0.05 ). However, there was no significant difference in the stool property score (MD = 0.06, 95% CI (−0.39, 0.50), P > 0.05 ) as well as the incidence of adverse reactions (RD = 0.01, 95% CI (−0.01, 0.03), P > 0.05 ) between the two groups. Conclusions. The results showed that acupoint catgut embedding is probably an effective and safe acupuncture treatment strategy for poststroke constipation. Nevertheless, more rigorously designed, standardized, large-sample, and multicenter randomized controlled designs are warranted to further verify the findings of this study.

Rutherford backscattering (RBS)/channelling and high resolution x-ray diffraction (HRXRD) have been used to characterize the tetragonal distortion of a GaN epilayer with four AlxGa1−xN and single AlN buffer layers grown on a Si (111) substrate by metal-organic vapour phase epitaxy (MOVPE). The results show that a 1000 nm GaN epilayer with a perfect crystal quality (χ min = 1.54%) can be grown on the Si (111) substrate in virtue of multiple buffer layers. Using the RBS/channelling angular scan around an off-normal 113 axis in the (100) plane and the conventional HRXRD θ−2θ scans normal to GaN (002) and (112) planes at the 0° and 180° azimuth angles, the tetragonal distortion eT, which is caused by the elastic strain in the epilayer and different buffer layers, can be obtained respectively. The two experiments are testified at one result, the tetragonal distortion of GaN epilayer is nearly to a fully relaxed (eT = 0).

The composition, elastic strain and structural defects of InGaN/GaN multiple quantum wells (MQWs) are comparatively investigated by using x-ray diffraction (XRD), transmission electron microscopy and Rutherford backscattering/channelling. The InGaN well layers are fully strained on GaN, i.e. the degree of relaxation is zero. The multilayered structure has a clear defined periodic thickness and abrupt interfaces. The In composition is deduced by XRD simulation. We show how the periodic structure, the In composition, the strain status and the crystalline quality of the InGaN/GaN MQWs can be determined and cross-checked by various techniques.

The structure and crystal quality of GaN using Rutherford Backscattering Spectrometry and Channeling were studied. The samples were grown on sapphire by metal-organic vapor-phase epitaxy. The H + , He + , N + with different ion energies and doses were implanted into GaN. Post-implantation annealing were investigated. We observed 7–8 orders increasing of resistivity by Hall measurements after specific temperature annealing, and the optimized annealing temperature is approximately 200–400 °C for H + , He + and N + respectively. Even after 600–700 °C annealing, the resistivity is still very high. We think vacancies and radioactive damage by implantation are responsible for resistivity changes in GaN samples.

Epitaxial ZnO films are grown on Al2O3 (0001) by the MOCVD method. These films are high quality wurtzite crystals with (0001) orientation. Big hexagonal crystallites (diameter from several decades to 100 μm) are found on the surface. Inside these crystallites, a stronger luminescence is observed compared with the plain area. Transmission electronic microscopy reveals that the film is thicker inside the hexagonal crystallites than the plain area, and some crystallites are not connected with each other and are slightly rotated with respect to their neighbours.

AlxGa1−xN/GaN heterostructures are grown on c-sapphire with the Al composition x from 0.2 to 0.4 and thicknesses from 20 nm to 30 nm. The lattice parameters a and c are determined from 2θ/ω scan. The AlGaN layers are found to be under tensile strain by using x-ray diffraction. Vegard's law induces a large deviation in Al composition determination by only considering the linear relationship between one lattice parameter (a or c) and Al composition. The accurate determination of Al composition is only possible with consideration of both the lattice parameters a and c, by assuming the tetragonal distortion in the AlGaN layer. Additionally, the results obtained from x-ray diffraction are verified by Rutherford backscattering.

Ga(In, Al)N alloys are used as an active layer or cladding layer in light emitting diodes and laser diodes. x-ray diffraction is extensively used to evaluate the crystalline quality, the chemical composition and the residual strain in Ga(Al,In)N thin films, which directly determine the emission wavelength and the device performance. Due to the minor mismatch in lattice parameters between Ga(Al, In)N alloy and a GaN virtual substrate, x-ray diffraction comes to a problem to separate the signal from Ga(Al,In)N alloy and GaN. We give a detailed comparison on different diffraction planes. In order to balance the intensity and peak separation between Ga(Al,In)N alloy and GaN, (0004) and (1015) planes make the best choice for symmetric scan and asymmetric scan, respectively., 9 pages, 5 figures

Mg+ and Mg++P+ were introduced into GaN by ion implantation. The structure and crystalline quality of the GaN samples were analysed by Rutherford backscattering and channelling spectrometry before (χmin = 1.6%) and after implantation (χmin = 4.1%). X-ray diffraction reveals the existence of implantation-induced damage in the case of post-implantation followed by rapid thermal annealing. The resistivity, average factor, carrier concentration and carrier mobility were measured by the Hall effect. The transformation from n-type to p-type for GaN was observed.

Charge transport properties of polyimide films implanted with 80 keV Co ions at two different fluences (series I: 1.25 x 10(17) ions/cm(2), series II: 1.75 x 10(17) ions/cm(2)) are studied in detail. For series I, the temperature dependence of surface resistivity fits Mott's equation very well. It is on the insulating side of the insulator-metal transition (IMT). However, for series II, the temperature dependence of surface resistivity is not in agreement with Mott's equation. It is on the metallic side of IMT. The magnetotransport properties of these two series are also studied. No significant magnetoresistive effect is observed for series I at both 5K and 300 K. For series II, an obvious magnetoresistive effect is observed at 5K, while there is no magnetoresistive effect at 300 K. Rutherford backscattering spectrometry (RBS) is applied to confirm the actual fluence for these two series.

5-at% Mn-doped and undoped BaTiO3 thin films have been grown under different oxygen partial pressures by Pulsed Laser Deposition (PLD) on platinum-coated sapphire substrates. X-ray diffraction (XRD) measurements for all the thin films reveal a similar polycrystalline single-phase perovskite structure. Ferroelectricity is observed in the Mn-doped and undoped BaTiO3 thin films grown under relatively high oxygen partial pressure. Ferromagnetic coupling of the Mn dopant ions, on the other hand, is only seen in Mn-doped BaTiO3 thin films prepared under low oxygen partial pressure in a wide temperature range from 5 K to 300 K, and is attributed to the enhanced exchange coupling between Mn dopants and electrons at oxygen vacancies. Our results show that the leakage current is decreased with the doped Mn, but increases the dielectric loss and decreases the dielectric constant, and the ferroelectricity is impaired. To produce ferromagnetism, oxygen vacancies are necessary, which unfortunately increase the leakage current. This confirms that the mutual interplay between the ferroelectricity and ferromagnetism can be tuned by exchange coupling of the doped-Mn and oxygen vacancies in the BaTiO3 thin films.

Due to its potential application to diluted magnetic oxides, transition metal doped ZnO has been under intensive investigation. We present a correlation between the structural and the magnetic properties of Fe implanted ZnO bulk crystals. Crystalline damage recovery, structural and magnetic properties are studied by Rutherford backscattering spectrometry and channelling (RBS/C), synchrotron radiation X-ray diffraction (SR-XRD), and superconducting quantum interference device magnetometer (SQUID), respectively. The 623 K Fe ion implantation and the high vacuum annealing at 823 K lead to the formation of secondary phase -Fe and -Fe nanoparticles. The discrepancy between the zero-field cooling and the field cooling curves further indicates that Fe-implanted ZnO is superparamagnetic and the observed ferromagnetism originates from the Fe nanoparticles.

The Raman back scattering/channeling technique was used to analyze the damage recovery at different annealing temperatures and to determine the lattice locatio n of the Er-implanted GaN samples. A better damage recovery was observed with in creasing annealing temperature below 1000℃, but a complete recovery of the impl antation damage cannot be achieved. For a sample annealed for at 900℃ 30 min th e Er and Ga angular scans across the axis was measured, indicating that a bout 76% of Er ions occupies substitutional sites. Moreover, the photoluminscenc e (PL) properties of Er-implanted GaN thin films have been also studied. The exp erimental results indicate that those samples annealed at a higher temperature b elow 1000℃ had a stronger 1539nm PL intensity. The thermal quenching of PL inte nsity for samples annealed at 900℃ measured at temperatures from 15K to 300K is 30%.