Necrotizing enterocolitis (NEC) is a severe intestinal disease of the newborn infants, associated with high morbidity and mortality. It has been reported that Bifidobacterium could protect the ...intestinal barrier function and reduce the risk of NEC. This study aimed to evaluate the probiotic potential of Bifidobacterium strains isolated from the chicken intestines and its effect on necrotizing enterocolitis in newborn SD rats. Out of 32 isolates, B. breve AHC3 not only exhibited excellent probiotic potential, including tolerance to artificial simulated gastric conditions, adhesion to HT-29 cells, antioxidant capacity and antibacterial activity, but also possessed reliable safety. Additionally, NEC model was established to further investigate the effect of B. breve AHC3 on necrotizing enterocolitis in newborn SD rats. It was illustrated that administration of B. breve AHC3 significantly not only reduced the incidence of NEC (from 81.25% to 34.38%) (P< 0.05), but also alleviated the severity of ileal injury (P< 0.05). Compared with NEC model, B. breve AHC3 could significantly decrease the level of proinflammatory factor TNF-α (P< 0.05) and increase the level of antiinflammatory factor IL-10 (P< 0.05) in the ileum of NEC rats. Through the intervention of B. breve AHC3, the gray value of inducible nitric oxide synthase (iNOS) in intestinal tissue of NEC rats was significantly reduced (P< 0.05). It was indicated that B. breve AHC3 exhibited prominent probiotic potential and reliable safety. In the neonatal SD rat model of NEC, B. breve AHC3 had an available protective effect on the intestinal injury of NEC, which might be related to reducing the inflammatory reaction in the ileum and inhibiting the expression of iNOS in intestinal tissue cells. B. breve AHC3 could be used as a potential treatment for human NEC.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper proposes a new iterative compensation methodology of geometric errors to improve the machining accuracy of a non-orthogonal five-axis machine tool (NOFAMT). Firstly, based on homogeneous ...transform matrix (HTM) and multi-body system (MBS) theory, the relative motion constraint equations (TRMCEs) of the tool tip position and tool orientation vector related to a NOFAMT with a nutating rotary B axis are established. Then, by utilizing TRMCEs, the mapping relationships between tool path and the numerical control (NC) command without and with considering the geometric errors are constructed respectively. In order to truly reproduce tool motion trajectory of the machine tool driven by the given NC command, the mapping relationship between the NC command and tool cutting trajectory is also established. Meanwhile, procedures of iterative compensation are described by using the aforementioned mapping relationships without the traditional inverse calculation, and the actual NC code is generated in self-developed compensation software. It is not difficult to find that the new approach takes the difference between tool path and tool cutting trajectory as the control objective and can directly obtain the actual NC code controlling the machine tool to achieve the desired machining accuracy. Finally, a cutting test is carried out on the DMU60P NOFAMT. Experimental results show the developed iterative compensation methodology is precise and effective for NOFAMTs. Therefore, compared with the existing methods, the new method is more direct and accurate. And its basic idea can be applied to other type of machine tools.
•First, the relative motion constraint equations of a non-orthogonal five-axis machine tool are established.•Second, the mutual mapping relationships between tool path, NC command and tool cutting trajectory are established respectively.•Third, a new iterative compensation methodology is presented.•Fourth, a cutting experiment is proposed to verify the machining accuracy improvement of the researched machine tool.
Thyroid nodules are very common all over the world, and China is no exception. Ultrasound plays an important role in determining the risk stratification of thyroid nodules, which is critical for ...clinical management of thyroid nodules. For the past few years, many versions of TIRADS (Thyroid Imaging Reporting and Data System) have been put forward by several institutions with the aim to identify whether nodules require fine-needle biopsy or ultrasound follow-up. However, no version of TIRADS has been widely adopted worldwide till date. In China, as many as ten versions of TIRADS have been used in different hospitals nationwide, causing a lot of confusion. With the support of the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association, the Chinese-TIRADS that is in line with China’s national conditions and medical status was established based on literature review, expert consensus, and multicenter data provided by the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound.
The phase stability of arc-melted CoCrFeMnxNi2-x (x = 0.25–1.75) high entropy alloys in as-cast and 800 or 1000 °C annealed states were investigated using XRD, SEM, EDS, EBSD and DSC. A uniform FCC ...phase can be obtained in as-cast CoCrFeMnxNi2-x (x = 0.25–1.5) alloys. After being annealed at 1000 °C for 720 h, there was no phase changing in these alloys. However, after being annealed at 800 °C for 720 h, either the Cr-rich BCC phase or the σ phase will precipitate in the alloys with 10–15 at.%Mn or 25–30 at.%Mn, respectively. The precipitation has no orientation relationship with the FCC substrate. DSC test results indicate that the FCC phase is stable before melting and its transition point decreases with Mn content. The σ phase is stable in the as-cast and annealed CoCrFeMn1.75Ni0.25 alloy and will decompose at 1130 °C. Compared with the calculated phase diagram based on the TCFE thermodynamic database, it was confirmed that the calculation can predict the stability of the FCC phase well, but cannot predict the stability of the σ or BCC phases. Moreover, microhardness test results indicate that long time annealing at 800 or 1000 °C has a limited effect on the microhardness of the FCC phase when the Mn content is below 25 at.%. However, precipitation of the σ phase will greatly harden the CoCrFeMnxNi2-x (x = 1.25, 1.5) alloys. These results will help to design the composition and treatment process of the Co–Cr–Fe–Mn–Ni high entropy alloys.
•Uniform FCC phase forms in as-cast CoCrFeMnxNi2-x(x = 0.25–1.5) alloys.•Cr-rich BCC or σ precipitates from FCC matrix after 800 °C annealing.•The CoCrFeMnxNi2-x alloys can be hardened by precipitation of σ or BCC phase.•σ is stable in CoCrFeMn1.75Ni0.25 alloy below 1130 °C.•Thermodynamic calculation fail to predict the stability of the σ or BCC phase.
The aim of this study was to determine the appearance of breast lesions using acoustic radiation force impulse imaging (ARFI) and to correlate the ARFI values with the pathologic results. The area ...ratio (AR) and virtual touch tissue quantification (VTQ) values were analyzed in 86 patients (mean age 45.6 years, range 17-78 years) with 92 breast lesions (65 benign, 27 malignant; mean size 25.7 mm). The diagnostic performance of ultrasound (US) alone and US plus ARFI values were compared with respect to sensitivity, specificity and area under the curve (AUC) using a receiver operating characteristic curve analysis. The mean AR of the benign lesions (1.08 ± 0.21) differed from that of the malignant lesions (1.99 ± 0.63; p < 0.0001), as did the mean VTQ values (3.25 ± 2.03 m/s vs. 8.22 ± 1.27 m/s; p < 0.0001). In conclusion, ARFI provides quantitative elasticity measurements, which may complement B-mode US and potentially improve the characterization of breast lesions.
The corrosion behaviors of pure magnesium (Mg) and three Mg alloys with different Al contents were investigated in a modified simulated body fluid (m-SBF) through immersion tests, Tafel experiments, ...and electrochemical impedance spectroscopic (EIS) experiments. The immersion results show that the corrosion rates (CRs) of the four samples were in an order of AZ91D
<
AZ61
<
AZ31
<
pure Mg after immersion for 1 day. With an increase in immersion time, their corrosion rates decreased and then a stable stage was reached after 16 days. The order of CRs of the four samples changed to AZ91D
<
pure Mg
<
AZ61
<
AZ31 after immersion for 24 days. The results of EIS experiments indicate that the charge transfer resistance (
R
ct) of the three magnesium alloys initially increased and then decreased while the
R
ct of pure Mg was kept lower within 24
h. The results of a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) show that pure Mg and three alloys were heterogeneously corroded in the m-SBF. The corrosion of pure Mg, which showed a more uniform corrosion appearance, resulted from localized corrosion over the entire surface. Alloy AZ91D (of 8.5–9.5
wt.% Al) showed relatively uniform corrosion morphology and the β-Mg
12Al
17 precipitates in alloy AZ91D were more homogeneously and continuously distributed along the grain boundaries. Obvious corrosion pits were found on the surface of alloy AZ61 and AZ31. The corrosion pits of alloy AZ61 were shallower than those of alloy AZ31. Alloy AZ61 (of 5.8–7.2
wt.% Al) possessed more Al
8Mn
5 and a little β-Mg
12Al
17 presented along the grain boundary heterogeneously and discontinuously. Al
8Mn
5 was the main phase of the AZ31 alloy (of 2.5–3.5
wt.% Al) dispersed into the matrix. In conclusion, the microstructure and the Al content in the α-Mg (Al) matrix significantly affected the corrosion properties of the alloys in the m-SBF. With the increase in Al content, the corrosion resistances of the samples were improved.
To investigate the impact of Al and Nb elements on the formation of a protective oxide layer on the surface of Fe-35Ni-20Cr-xAl-yNb (x = 0, 2, 4, 6 wt.%; y = 0, 1, 2 wt.%) alloys, their oxidation ...behavior was examined at 1000 °C, 10
atm. and 10
atm. oxygen pressure, and the oxidation mechanism was analyzed by Factsage and Pandat calculations. Enhancing the Al content at 10
atm. inhibited the generation of FeCr
O
on the alloy surface and increased the Al content in the M
O
layer. When the Al content exceeded 6 wt.%, the oxide film partially peeled off. It was found that the addition of Nb increased the activity of Cr and Al and decreased the activity of Ni and Fe and promoted the formation of Al
O
, and the appearance of Nb
O
in the subsurface layer increased the density of the oxide film. In addition, under an oxygen pressure of 10
atm., the only protective layer on the surface of the alloy comprised of Al
O
. The experimental results demonstrated that the Fe-35Ni-20Cr-4Al-2Nb alloy generated a continuous and dense Al
O
protective film, and the reduction in oxygen pressure and the addition of Nb elements were favorable for selective external oxidation of Al
O
.
Three homologous electrochromic conjugated polymers, each containing an asymmetric building block but decorated with distinct alkyl chains, were designed and synthesized using electrochemical ...polymerization in this study. The corresponding monomers, namely T610FBTT810, DT6FBT, and DT48FBT, comprise the same backbone structure, i.e., an asymmetric 5-fluorobenzoc1,2,5thiadiazole unit substituted by two thiophene terminals, but were decorated with different types of alkyl chain (hexyl, 2-butyloctyl, 2-hexyldecyl, or 2-octyldecyl). The effects of the side-chain structure and asymmetric repeating unit on the optical absorption, electrochemistry, morphology, and electrochromic properties were investigated comparatively. It was found that the electrochromism conjugated polymer, originating from DT6FBT with the shortest and linear alkyl chain, exhibits the best electrochromic performance with a 25% optical contrast ratio and a 0.3 s response time. The flexible electrochromic device of PDT6FBT achieved reversible colors of navy and cyan between the neutral and oxidized states, consistent with the non-device phenomenon. These results demonstrate that subtle modification of the side chain is able to change the electrochromic properties of conjugated polymers.
This paper proposes an integrated geometric error prediction and compensation method to eliminate the positioning inaccuracy of tool ball for a double ball bar (DBB) caused by the translational axes’ ...geometric errors in a multi-axis machine tool (MAMT). Firstly, based on homogeneous transform matrix (HTM) and multi-body system (MBS) theory, the positioning error model only considering the translational axes of a MAMT is established. Then, an integrated error parameter identification method (IEPIM) by using a laser interferometer is proposed. Meanwhile, the identification discrete results of geometric error parameters for the translational axes are obtained by identification experiments. According to the discrete values, the optimal polynomials of 18 position-dependent geometric errors (PDGEs) are founded. As a basis, an iterative compensation method is constructed to modify the NC codes generated with the ordinary compensation method in self-developed compensation software. Finally, simulation verification is conducted with these two compensation methods. Simulation results show the positioning errors for test path of tool ball calculated with the iterative compensation method that are limited within 0.001 mm, and its average accuracy and accuracy stability are improved by 79.5 and 52.2%, respectively. In order to further verify the feasibility of the presented method, a measuring experiment is carried out in
XY
plane of a five-axis machine tool by using DBB. The experiment results show that the maximum circularity error with the iterative compensation method is reduced about 40.4% than that with the ordinary compensation method. It is therefore reasonable to conclude that the proposed method in this paper can avoid the influence of the translational axes’ geometric errors on rotary ones during a DBB test.
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