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It is crucial to better understand the magnetization reversal process between soft and hard magnets and to achieve a high maximum energy product in thick composite multilayers. In this study, we find that the exchange interactions dominate in soft–hard-magnetic composite bilayers, while dipole interactions are predominant in soft–hard-magnetic composite trilayers. Based on the first-order reversal curve, magnetization reversal models are developed for both the thick composite bilayer and trilayer. Dipole interactions play an important role in the long range, resulting in higher coercivity and remanence in the thick trilayer. A multilayer in a stacked trilayer structure is achieved, which is composed of thick films with a perpendicular magnetic anisotropy at a thickness of up to 16 μm. The enhanced dipole interactions lead to a remanent polarization of 1 T and a maximum energy product of 22.5 MGOe. This work contributes to the preparation of thick films with a high maximum energy product for applications in magnetic microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Magnetic properties and coercivity mechanism of an anisotropic Ce–Nd–Fe–B film with a high Ce content (70 at. % Nd is replaced by Ce) have been investigated. After grain boundary diffusion with Tb layers, an enhancement of coercivity from 4150 to 9250 Oe is observed. Combining the initial magnetization curves, micromagnetic theory, and in-siut observation of magnetic domains in the demagnetization process, it is confirmed that the coercivity mechanism for the high-Ce-content magnets is the mixed type dominated by the pinning mechanism. Moreover, as the thickness of the Tb diffusion layer increases, the pinning center of domain walls changes from narrow planar inhomogeneities to wide planar inhomogeneities. A growing role of pinning plays in determining the coercivity of samples with increasing the thickness of Tb layer due to the increase in magnetocrystalline anisotropy after Tb substitution in the RE2Fe14B phase. In addition, the CeFe2 intergranular phase leads to the enhancement of coercivity due to decoupling the hard magnetic phase grains. Our results provide an insight into the coercivity mechanism of high-Ce-concentration Ce–Nd–Fe–B magnetic materials and promote the comprehension of the effect of Tb diffusion in the magnetization reversal process. [ABSTRACT FROM AUTHOR]

In composite magnets, an in-depth understanding of magnetization reversal behaviors promotes optimizing the structure design of a magnet and improving its performance. In this work, the perpendicular magnetic anisotropic Ta/La–Pr–Fe–B/Dy/La–Pr–Fe–B/Ta multilayers have been prepared by adjusting the thickness of the Dy layer. The domain reversal evolutionary procedure has been investigated in different aspects including the characterization of domain morphology, micromagnetic analysis, and irreversible reversal distribution. It is confirmed that the nucleation mechanism is dominant in determining the coercivity of the multilayers with Dy diffusion. Dy diffusion helps to enhance the coercivity of the multilayers. The formation of Dy-containing hard magnetic phases and rare-earth-rich grain boundary phases by adding the Dy element leads to a strong nucleation field and isolation of hard magnetic phase grains, respectively. Our results aid in the understanding of magnetization reversal behaviors and enhance the magnetic properties of highly abundant rare-earth permanent magnetic multilayer films with the doping element. [ABSTRACT FROM AUTHOR]

The magnetic properties and the possible interaction mechanisms of anisotropic soft- and hard-magnetic multilayers have been investigated by altering the thickness of different kinds of spacer layers. The metal Ta and the insulating oxides MgO, Cr2O3 have been chosen as spacer layers to investigate the characteristics of the interactions between soft- and hard-magnetic layers in the anisotropic Nd-Dy-Fe-Co-B/α-Fe multilayer system. The dipolar and exchange interaction between hard and soft phases are evaluated with the help of the first order reversal curve method. The onset of the nucleation field and the magnetization reversal by domain wall movement are also evident from the first-order-reversal-curve measurements. Reversible/irreversible distributions reveal the natures of the soft- and hard-magnetic components. Incoherent switching fields are observed and the calculations show the semiquantitative contributions of hard and soft components to the system. An antiferromagnetic spacer layer will weaken the interaction between ferromagnetic layers and the effective interaction length decreases. As a consequence, the dipolar magnetostatic interaction may play an important role in the long-range interaction in anisotropic multilayer magnets. [ABSTRACT FROM AUTHOR]

The effect of sintering process on the electrical properties of CaCu3Ti4O12 (CCTO) ceramic dielectrics were investigated in this paper. It was found that grain size is affected by sintering and the nonlinear current-voltage (I-V) property will decrease with the increased sintering time. Also, the frequency and temperature dependences of dielectric permittivity and loss in the ranges of 10-1-107 Hz and 130-270 K were studied. Two relaxation processes with activation energy of 0.51 eV and 0.10 eV, respectively, were found in the frequency dependence of tan δ and Cole-Cole planes, which can be interpreted in terms of insulating grain boundaries and semiconducting grains. It was suggested that grain boundary Maxwell-Wagner relaxation and ionization of oxygen vacancy VO++, proposed as extrinsic and intrinsic relaxations, are responsible for the dielectric behaviors of CCTO ceramics. [ABSTRACT FROM AUTHOR]

The effect of an ultrathin W interlayer on the perpendicular magnetic anisotropy (PMA), spin orbit torque (SOT), and SOT-induced magnetization switching of Ta/CoFeB/MgO films has been investigated. Both the anisotropy energy density and the spin-torque efficiency are enhanced by inserting the ultrathin W interlayer. The results suggest that the large enhancement of the spin-torque efficiency originates from the increase in the interfacial spin transparency using a simplified drift-diffusion model. The minimum in-plane field required for SOT-induced complete switching is reduced to 12 Oe for the sample with the W interlayer, which is confirmed by polar Kerr microscopy. The reversed domain nucleation and propagation of the reversal processes have been observed by Kerr imaging. It is concluded that the ultrathin W interlayer increases the spin transmission and reduces the strength of the Dzyaloshinskii–Moriya interaction. Our result suggests that the interface modification is an efficient way to modulate the PMA and SOT. [ABSTRACT FROM AUTHOR]

Spin-orbit torques (SOTs) and the perpendicular magnetic anisotropy (PMA) in Ta/W/CoFeB/MgO structures have been investigated by varying the thickness of the W layer. Addition of the W layer gives rise to enhancement of the annealing stability and perpendicular anisotropy field. After annealing at high temperature, a high-resistivity is obtained for samples with W layer (up to 2 nm thickness), which indicates the existence of β-W phase. A giant spin Hall angle of 0.50 is found in Ta/W/CoFeB/MgO structures with a 2 nm W layer by using the harmonic Hall voltage measurement. The lowest switching current density of 6 MA/cm2 is achieved in the sample with 1 nm W layer, indicating that a strong interfacial spin Hall effect may exist in the CoFeB/W interface. The study may provide a way to obtain simultaneously a large PMA as well as a high efficiency of SOTs. [ABSTRACT FROM AUTHOR]

The combustion of anthracite and bituminite blends with different bituminite particle size was investigated with thermogravimetric analysis (TGA). It is indicated in the results that the increase of bituminite particle size may influence the pyrolysis of blends and consequently the decomposition of blends moved to higher temperature zones with the increase of bituminite particle size. However, the negative influence of specific area is not that significant to some bituminite and anthracite mixtures, the comprehensive combustion behavior of blends was stable when particle size of some bituminie PC was increased from 0,074 mm to 0,150 mm. [ABSTRACT FROM AUTHOR]

Magnetic vortices in patterned nanocomposite structures have been studied. A double-vortex structure consisting of two vortex cores with opposite chiralities and two edge half-vortices is realized in a micron-size circular disk, which consists of [Co/Pd]7/Ru/Py. A systemic study of the magnetization reversal of a double-vortex state and a single vortex state in an out-of-plane applied field has been performed by means of magnetic force microscopy. It is found that the interlayer exchange and dipolar interactions are critical for nucleation and annihilation of the double-vortex and the single vortex states. Micromagnetic simulations prove that the double-vortex state can stably exist in a patterned nanocomposite structure. Magnetic configurations ranging from the double-vortex and single vortex states to other multidomain states and the in-plane single-domain state are observed. The dependence of the magnetic configuration on the thickness of the soft-magnetic layer and spacer layer is presented in an experimental phase diagram. The results can significantly widen the practical applications of vortices on the three-dimensional spintronic memory and logic devices. [ABSTRACT FROM AUTHOR]

Although a variety of factors underlying diapause have been identified in arthropods and other organisms, the molecular mechanisms regulating diapause are still largely unknown. Here, to better understand this process, we examined diapause-associated genes in the two-spotted spider mite, Tetranychus urticae, by comparing the transcriptomes and proteomes of early diapausing and reproductive adult females. Amongst genes underlying diapause revealed by the transcriptomic and proteomic data sets, we described the noticeable change in Ca2+-associated genes, including 65 Ca2+-binding protein genes and 23 Ca2+ transporter genes, indicating that Ca2+ signalling has a substantial role in diapause regulation. Other interesting changes in diapause included up-regulation of (1) glutamate receptors that may be involved in synaptic plasticity changes, (2) genes involved in cytoskeletal reorganization including genes encoding each of the components of thick and thin filaments, tubulin and members of integrin signalling and (3) genes involved in anaerobic energy metabolism, which reflects a shift to anaerobic energy metabolism in early diapausing mites. [ABSTRACT FROM AUTHOR]

In this work, Zn particles with magnetic shell were synthesised and investigated. Zn particles with different sizes were synthesised by arc-discharge method, and then the Zn particles were put in a suitable concentration of FeSO4 solution with a surface active agent. After some time, the Zn particles with magnetic shell were produced. The particles contain oxygen shell probably in the form of FeO and ZnO, while the core material is Zn. From the saturation magnetisation at room temperature and transmission electron microscopy (TEM) images, it is noticed that the FeO was first formed on the surface of Zn and then ZnO appeared with increasing reaction time. The microwave absorption is not as good as that reported in other materials, because of the weak magnetisation and the faulty core-shell structure formed by metal core and magnetic shell. [ABSTRACT FROM AUTHOR]

Produced water from polymer flooding was much more difficult to be treated than that from water flooding. The mechanisms of polymer stabilizing the oil-in-water emulsion were the decreases of interfacial tension and electric conductivity, and the increases of zeta potential and bulk phase viscosity. Inorganic flocculant, the combination of inorganic flocculant and polymer degradation agent, and the combination organic flocculant and coagulant were used to break the oil-in-water emulsion stabilized with polymer. It was the most effective way to use the combination of organic flocculant and coagulant for treating polymer stabilizing oil-in-water emulsion. [ABSTRACT FROM PUBLISHER]

A highly selective and sensitive method was developed for the simultaneous determination of four β-agonists (clenbuterol, salbutamol, ractopamine and terbutaline) in beef by immunoaffinity chromatography purification coupled to ultra-high-performance LC-MS/MS. The MS/MS conditions, ultra-high-performance LC mobile phase, injection solution, sample purification process and matrix effect were studied to optimise the operation conditions. The limits of detection (LODs) of the instrument for the studied β-agonists ranged from 0.20 to 0.25 µg l−1, and the LODs of the method for the studied β-agonists ranged from 0.20 to 3.00 µg kg−1 for beef. Calibration curves were constructed using a standard solution diluted with blank beef matrix. The linear ranges of the calibration curves ranged from 5 to 100 µg kg−1 and the coefficients of determination were >0.9942 (n = 10) for all four β-agonists. Samples spiked at 5, 10 and 50 µg kg−1 showed recoveries >72% and RSDs <6.6%. The method is suitable for the simultaneous detection of four β-agonists at trace levels in beef. [ABSTRACT FROM PUBLISHER]

Hepatocellular carcinoma suppressor 1 (HCCS1) was discovered as a novel tumor suppressor gene. We recently observed that adenovirus-mediated gene transfer of HCCS1 leads to cytotoxicity to human hepatocarcinoma cells. Here, we have demonstrated that adenovirus-mediated overexpression of HCCS1 induces apoptosis in hepatocarcinoma cells and have further characterized the apoptotic cascade. The results showed that lysosomal cathepsin D is released into the cytosol in response to HCCS1 overexpression and consequently triggers Bax insertion into the mitochondrial membrane, which leads to the release of cytochrome c. In addition, HCCS1 overexpression can induce an increase in intracellular free Ca2+ concentration, which also results in cytochrome c release. The released cytochrome c activates downstream caspases, leading to the occurrence of the late stages of apoptosis. Moreover, we demonstrated that the disruption of HCCS1 in mice leads to embryonic lethality, accompanied by abnormal labyrinth architecture resulting from the excessive proliferation of trophoblast cells in the placenta. These results suggest that HCCS1 plays a role in apoptosis regulation and development.Cell Death and Differentiation (2008) 15, 1481–1490; doi:10.1038/cdd.2008.73; published online 30 May 2008 [ABSTRACT FROM AUTHOR]

Intestinal transit is accelerated by volume distension and slowed by nutrient load. We hypothesized that the accelerating effect of volume distension might overcome the slowing effect of nutrient. To test this hypothesis, we compared intestinal transit in five dogs equipped with duodenal and mid-intestinal fistulas. The proximal half of the small intestine was perfused with 60 mM oleate, while the distal half of the small intestine was either perfused with buffer (with distension) or left unperfused (without distension). We found that intestinal transit was slowed by oleate (with marker recovery reduced from 85.8 +/- 5.3 to 39.4 +/- 7.5%) (P < 0.01) and that volume distension accelerated intestinal transit so that marker recovery increased from 39.4 +/- 7.5 without distension to 60.8 +/- 6.3% with distension (P < 0.05). We concluded that intestinal transit is accelerated by volume distension during fat-induced jejunal brake. [ABSTRACT FROM AUTHOR]

Patients with fat intolerance complain of early satiety, bloating, nausea, and vomiting. Since these symptoms are similar to those of patients with postgastrectomy dumping syndrome, we hypothesized that fat intolerance may be associated with early, rapid gastric emptying. Using a three-meal gastric emptying study, we compared gastric emptying in nine patients with a history of fat intolerance and nine normal volunteers. On three separate days, 500-ml radiolabeled test meals containing 0, 15, or 60 g of fat were studied. The percentages of the test meal emptied at 15 and 60 min were analyzed by repeated measures two-way ANOVA. At 15 min (p < 0.05) but not 60 min, gastric emptying was faster in patients than normals. Gastric emptying at 15 min (p < 0.001) and 60 min (p < 0.001) depended on the dose of fat. We conclude that fat intolerance is associated with early, rapid gastric emptying. [ABSTRACT FROM AUTHOR]

Fat in the proximal and distal gut inhibits intestinal transit as the jejunal brake and the ileal brake. It is unknown, however, whether the intestinal transit response to fat in the proximal vs distal gut is different. Since surgical removal of the distal small intestine induced faster transit and greater steatorrhea than removal of the proximal small intestine, we hypothesized that the ileal brake inhibited intestinal transit more potently than the jejunal brake. In six dogs equipped with duodenal (10 cm from pylorus) and midintestinal (160 cm from pylorus) fistulas, we compared intestinal transit across an isolated 150-cm test segment (between fistulas), while 0 (buffer), 15, 30, or 60 mM oleate was delivered into either the proximal (between fistulas) or the distal (beyond the midintestinal fistula) half of the gut. The half of the gut not receiving oleate was perfused with buffer. Buffer perfused into both the proximal and the distal half of the gut served as the control. A meal was administered and diverted completely out of the duodenal fistula so that the studies were all done in the fed state. Intestinal transit was measured by counting for the recovery of a radioactive marker from the temporarily diverted output of the midintestinal fistula. We found that (1) intestinal transit was inhibited more potently by oleate in the distal than in the proximal half of the gut (region effect; P < 0.01), (2) oleate inhibited intestinal transit in a load-dependent fashion (dose effect; P < 0.05), and (3) load-dependent inhibition of intestinal transit by oleate depended on the region of exposure (interaction between load and region; P < 0.01). We conclude that intestinal transit is more potently inhibited by fat-induced ileal than jejunal brake. [ABSTRACT FROM AUTHOR]

Soy protein, in both intact and hydrolyzed forms, is widely used as the nitrogen source in infant and adult formulas. This protein is also consumed in vast quantities worldwide as soybean-based food products. Digestion is the rate-limiting step in the assimilation of proteins from the gut. As a result, intestinal transit must be slowed when a higher load of protein is available or when this nutrient is delivered in the intact rather than hydrolyzed form. However, little information is available on the effect of load and degree of hydrolysis of soy protein on intestinal transit and protein absorption. To test the hypothesis that inhibition of intestinal transit and protein absorption depend on the load of soy protein and the state of hydrolysis of this nutrient, we compared intestinal transit and protein absorption in dogs equipped with duodenal and midintestinal fistulas during intestinal perfusion with 0, 50, 100, or 200 g/L solutions of intact soy protein versus 0, 100, 200, 300, or 400 g/L solutions of hydrolyzed soy protein. We found that intestinal transit was slowed in a load-dependent fashion by intact (P < 0.001) and hydrolyzed (P < 0.05) soy protein. Soy protein inhibited intestinal transit more potently in the intact than hydrolyzed form (P < 0.05). A greater amount of protein was absorbed by the proximal half of the small intestine when soy protein was delivered in the hydrolyzed than intact form (P < 0.05), and the efficiency of protein absorption was maintained at a high and nearly constant level of 82.6 to 87.4% for intact soy protein and 89.0 to 92.3% for hydrolyzed soy protein. We conclude that in dogs intestinal transit and absorption of soy protein depend on the load and the degree of protein hydrolysis. [ABSTRACT FROM AUTHOR]

A simple and fast analysis method to sort large data sets into groups with shared distinguishing characteristics is described and applied to single molecular break junction conductance versus electrode displacement data. The method, based on principal component analysis, successfully sorts data sets based on the projection of the data onto the first or second principal component of the correlation matrix without the need to assert any specific hypothesis about the expected features within the data. This is an improvement on the current correlation matrix analysis approach because it sorts data automatically, making it more objective and less time consuming, and our method is applicable to a wide range of multivariate data sets. Here the method is demonstrated on two systems. First, it is demonstrated on mixtures of two molecules with identical anchor groups and similar lengths, but either a π (high conductance) or a σ (low conductance) bridge. The mixed data are automatically sorted into two groups containing one molecule or the other. Second, it is demonstrated on break junction data measured with the p bridged molecule alone. Again, the method distinguishes between two groups. These groups are tentatively assigned to different geometries of the molecule in the junction. [ABSTRACT FROM AUTHOR]

Mic rotopography and combustion characteristics of carbonized corn straw and pine charcoal as well as anthracite were investigated to compare the property of fuel and analyze the application of corn straw in industrial activity. The reduction process of hematite with different reducing agent was studied with thermogravimetric analysis. It is indicated in the results that the initial reduction temperature was lower when carbonized corn straw was blended with hematite and an ideal reduction rate can be achieved with a C/O of 1.1, while the reduction rate of pine charcoal to hematite was lower and higher C/O is needed for anthracite to obtain the same reduction rate. [ABSTRACT FROM AUTHOR]

In fluence of microwave irradiation on gasification behavior and crystallite parameters of coke samples was studied in this research. The results indicated that microwave irradiation have significant influence on the carbon structure and the reactivity of coke in CO2 atmosphere. The thermogravimetric results showed that the temperature of coke at different conversion rates of 10 %, 20 % and 30 % were reduced by 20 °C, 30 °C and 50 °C respectively. Simultaneously, microwave irradiation may lead to variation in lateral size and stacking height of crystallite and subsequently reduce the gasification reaction rate of coke in CO2 atmosphere. [ABSTRACT FROM AUTHOR]

This paper presents a microfluidic system enabling continuous characterization of instantaneous Young's modulus (Einstantaneous) of single cells in suspension. In this study, cells were aspirated continuously through a constriction channel while cellular entry processes were monitored using a high-speed camera. Numerical simulations were conducted to model cellular entry process into the constriction channel where a visco-hyperelastic solid was used to model biological cells and the cellular friction with the constriction channel wall (ƒc) was properly addressed. Both experimental observations and numerical simulations confirmed the two-stage cellular entry process into the constriction channel: an instantaneous jump into the channel quantified by instantaneous aspiration length (Linstantaneous) followed by a creeping increase in aspiration length terminated by transitional aspiration length (Ltransitional). Numerical simulations reveal that Linstantaneous and Ltransitional are reversely proportional to Einstantaneous, which are affected by ƒc regardless of other cellular viscoelastic parameters. By combining measured Linstantaneous and Ltransitional with these obtained from numerical simulations, Einstantaneous and ƒc were quantified as 3.48 ± 0.86 kPa and 0.39 ± 0.11 for A549 cells (ncell = 199) and 2.99 ± 0.38 kPa and 0.37 ± 0.02 for 95C cells (ncell = 164). As a platform technology, this method can be used to characterize Einstantaneous of various cell types in a continuous manner for cellular biophysical property characterization. [ABSTRACT FROM AUTHOR]

Objective: To explore the value of predicting shunt-dependent hydrocephalus (SDHC) in patients with aneurysmal subarachnoid hemorrhage (aSAH) based on whole brain CT perfusion(CTP) and clinical data within 24 hours at admission. Methods: The clinical and imaging data of aSAH patients who received interventional embolization in our hospital were retrospectively collected from March 2018 to August 2022. All patients underwent one-stop whole brain CT examination within 24 hours after symptom onset, and the qualitative and quantitative CTP parameters were obtained after post-processing. Follow-up was conducted once every 2 months by consulting electronic medical records or by telephone for 6 months. According to whether SDHC occurred or not, the patients were divided into SDHC group and non-SDHC group. The differences between the two groups were compared. Logistic regression model was used to analyze and determine the predictive factors of SDHC, and the SDHC predictive model was established. The effectiveness of the predictive model was evaluated by drawing the receiver operating characteristic (ROC) curve of the subjects. Results: A total of 414 patients were included, including 132 males and 282 females, aged (59±11) years. 17.6%(73/414) patients had SDHC. There were significant differences in the occurrence of acute hydrocephalus, the World Neurosurgical League Scale (WFNS), the Hunt-Hess scale, the modified Fisher score (mFS), and the qualitative and quantitative parameters of CTP between the two groups (both P <0.001). Multivariate logistic regression analysis showed that acute hydrocephalus ( OR =8.621, 95% CI : 4.237-17.542),old age ( OR =1.107, 95% CI : 1.068-1.148), high mFS and high Hunt-Hess classification ( OR =3.740, 95% CI : 1.352-10.342) were the risk factors of SDHC in aSAH patients, and high mean cerebral blood flow (mCBF) ( OR =0.931, 95% CI : 0.885-0.980) was a protective factor of SDHC.The area under ROC curve (AUC) of the prediction model constructed by these five variables was 0.923(95% CI : 0.89-0.95), with 84.5% sensitivity and 87.7% specificity. Conclusion: The mCBF and acute hydrocephalus, age, mFS and Hunt-Hess classification within 24 hours at admission can be used to predict SDHC for aSAH patients.

Objective: To explore the safety and myocardial protection efficacy of del Nido cardioplegia in adult cardiac and major vascular surgery with long aortic cross-clamp (ACC) time. Methods: A total of 2 536 patients who underwent adult cardiac and major vascular surgery with ACC time>90 min at Beijing Anzhen Hospital from March 2018 to March 2023 were collected. The patients were divided into two groups according to the type of cardioplegia solution: the del Nido cardioplegia solution group (DC group) and the cold blood cardioplegia solution group (BC group). Preoperative baseline data of the patients (age, gender, comorbidities, ejection fraction, etc) were adjusted using propensity score matching (PSM). Cardiopulmonary bypass (CPB) time, ACC time, total amount of cardioplegia solution, in-hospital mortality rate, length of intensive care unit (ICU) stay, mechanical ventilation time, postoperative complications, left ventricular ejection fraction, and troponin levels were compared between the two groups. Results: After PSM, a total of 306 patients were included, including 223 males and 83 females, with a mean age of (52.0±12.3) years. There were 153 cases in the DC group and 153 cases in the BC group. Compared with the DC group, the cross-clamp time was longer [109(100, 150) min vs 102(91, 133) min, P <0.001], the rate of return to spontaneous rhythm was lower [51.6% (79/153) vs 86.9%(133/153), P <0.001], and intraoperative peak glucose was higher [12.6 (6.5, 15.9) mmol/L vs 10.1 (8.5, 12.4) mmol/L, P= 0.005] in the BC group. In addition, perioperative mortality [4.6% (7/153) vs 3.3% (5/153), P =0.132], stroke[3.9% (6/153) vs 3.3% (5/153), P =0.759], renal insufficiency [3.3% (5/153) vs 6.5% (10/153), P =0.186], atrial fibrillation [4.6% (7/153) vs 2.6% (4/153), P =0.652] and low cardiac output syndrome [3.9% (6/153) vs 4.6% (7/153), P =0.716] did not differ between the two groups. Compared with BC group, DC group had lower level of high sensitivity troponin (hsTnI) [1.2 (0.8, 1.8) μg/L vs 1.3 (0.9, 2.3) μg/L, P =0.030] and creatine kinase isoenzyme (CK-MB) [31.0 (20.0, 48.9) μg/L vs 37.0 (24.0, 58.9) μg/L, P =0.011] at 24 h postoperatively, and shorter length of ICU stay [35.6 (19.8, 60.5) h vs 42.6 (21.9, 83.6) h, P =0.015] and mechanical ventilation time [20.5 (15.5, 41.0) h vs 31.5 (17.1, 56.0) h, P =0.012]. Subgroup analysis showed that in the 120-180 minute subgroup, patients in the DC group had a shorter cross-clamp time [132 (124, 135) min vs 136 (124, 138) min, P <0.001], while levels of hsTnI [1.6 (1.1, 2.0) μg/L vs 1.4 (1.0, 2.6) μg/L, P =0.030] and CK-MB [38.8 (23.5, 55.5) μg/L vs 37.0 (24.5, 62.3) μg/L, P =0.011] were higher than those in the BC group. Conclusions: In adult cardiac and major vascular surgery with ACC times>90 min, comparable myocardial protection is observed with the use of DC compared with BC. Additional advantages in glycemic control, return to spontaneous rhythm, and improved surgical procedures make DN an attractive alternative for myocardial protection in adult cardiac surgery.

The early diagnosis of lung cancer has become the focus of clinical attention, with the incidence and mortality of lung cancer increasing. Aberrant DNA methylation occurs in the primary stage of lung cancer, then the methylation degree can be changed dynamically due to the progress and the treatment of lung cancer. To date, a growing number of studies have reported that special gene methylation exploits in the clinical diagnosis, curative effect monitoring, and prognosis evaluation of lung cancer. Meanwhile, clinical trials about DNA methyltransferase inhibitors for lung cancer therapy are also underway. It is worth looking forward that detecting aberrant DNA methylation helps diagnose and treat lung cancer.

Objective: To investigate the germline mutation status of related genes in breast cancer patients and high-risk individuals by next-generation sequencing. To analyze the correlations between homologous recombination repair (HR) pathway gene mutation status and clinicopathological characteristics of breast cancer patients. To supplement the database of breast cancer related gene mutations in Chinese population. Methods: This study is a cross-sectional study. From October 2020 to September 2021, whole blood samples were collected from 350 breast cancer patients and 49 high-risk individuals, admitted to Peking University People's Hospital and accepted genetic testing voluntarily. Germline mutations in 32 breast cancer related genes were detected by NGS. The clinicopathological characteristics, including age at the onset, family history, unilateral/bilateral tumor, Luminal typing (Luminal A subtype, Luminal B subtype, HER2-enriched subtype and triple negative breast cancer), tumor size and metastasis, were analyzed, and the correlations between HR pathway gene mutation status and clinicopathological characteristics were analyzed by Chi-squared test and Fisher's exact probability test. Results: Among 350 breast cancer patients, 64 (18.3%) cases carried gene pathogenic mutations (including pathogenic and likely pathogenic mutations), including 47 (13.4%) in BRCA1/2, 16 (4.6%) in non-BRCA1/2 genes, 1 (0.3%) in BRCA2 and FANCL. Among 49 high-risk individuals, 7 (14.3%) cases carried gene pathogenic mutations, including 6 (12.3%) in BRCA1/2 and 1 (2%) in ATM genes. BRCA1/2 pathogenic mutations were associated with age at the onset (18%, 8.7%, χ²=6.346, P =0.012), and the BRCA1/2 pathogenic mutation frequency was higher in patients diagnosed at age ≤45 years. HR pathway gene mutations (including pathogenic, likely pathogenic and uncertain significance mutations) were correlated with unilateral/bilateral tumor (49.5%, 68.4%, χ²=4.841, P =0.028) and Luminal typing (45.7%, 62.2%, 32%, 60%, χ²=12.004, P =0.007), and the HR mutation frequencies were higher in patients with bilateral tumor, Luminal B breast cancer and triple negative breast cancer (TNBC). Conclusion: The BRCA1/2 pathogenic mutation frequency in high-risk individuals is similar to that in breast cancer patients, and BRCA1/2 testing is helpful to guide breast cancer screening and prevention in high-risk individuals. Patients with early onset breast cancer, bilateral breast cancer, Luminal B breast cancer and TNBC have higher mutation frequencies of HR pathway genes, and HR pathway genes testing should be conducted as soon as possible to provide laboratory evidence for diagnosis, treatment, prognosis and risk evaluation of breast cancer.

Objective: To explore the value of radiomics model based on dynamic contrast-enhanced magnetic resonance imaging (MRI) in differentiation fat-poor angiomyolipoma (fp-AML) from alpha-fetoprotein-negative hepatocellular carcinoma (n-HCC) in the background of non-cirrhotic liver. Methods: The complete data of 121 patients from Guangdong Provincial People's Hospital, Zhongshan Hospital Affiliated to Fudan University and Sun Yat-sen University Cancer Center with hepatic fp-AML and n-HCC confirmed by pathology from October 2010 to July 2020 were retrospectively analyzed. Among them, 75 were males and 46 were females, aged from 23 to 80 (55±12) years. A total of 93 patients from Zhongshan Hospital Affiliated to Fudan University were divided into the training cohort ( n =75) and internal test cohort ( n =18) according to entry time, and the patients of other 2 hospitals were divided into external test cohort ( n =28). The radiomics features were extracted from the preoperative triple-phase contrast-enhanced images. The feature selection algorithm based on Joint Mutual Information Maximisation (JMIM) was used to extract the optimal feature subset, and support vector machine (SVM) was used to build the radiomics model. The diagnostic performance of radiomics model was evaluated using the receiver operating characteristic (ROC) curve, and was compared with that of two radiologists. Results: In the internal cohort, the area under the curve (AUC) for the differential diagnosis between fp-AML and n-HCC of the radiomics model was 0.819 (with an accuracy of 72.2%), outperforming than radiologist 1 with 10 years of diagnostic experience (AUC=0.542, P =0.029) and radiologist 2 with 2 years of diagnostic experience (AUC=0.375, P =0.004). In the external cohort, the AUC of the radiomics model was 0.772 (with and accuracy of 71.4%), which was comparable to that of radiologist 1 (AUC=0.661, P =0.442) and better than that of radiologist 2 (AUC=0.400, P =0.008). Conclusion: The radiomics model based on dynamic contrast-enhanced MRI is of high accuracy for preoperatively differentiating hepatic fp-AML from n-HCC in the noncirrhotic liver.

Objective: Mitochondrial deoxyribonucleic acid (mtDNA) 8344 A>G (m.8344A>G) mutation is the common mutation associated with mitochondrial myoclonus epilepsy with ragged-red fibers (MERRF) syndrome. Herein we report a rare case with mitochondrial encephalopathy, lactic acidosis and stroke-like episodes/MERRF/Leigh (MELAS/MERRF/Leigh) overlap syndrome caused by m.8344A>G mutation., Methods: The clinical and imaging data of the patient were collected and an open muscle biopsy was carried out. We further employed molecular genetic analyses to detect mtDNA mutation in the proband and his mother. And then a clinical and neuroimaging follow-up was performed., Results: This patient was a 25-year-old male, who developed exercise intolerance since the age of 6. At age 10, he suffered from acute episodes of hemianopia, and cranial magnetic resonance imaging (MRI) showed occipital stroke-like lesions and cranial magnetic resonance spectroscopy (MRS) revealed a lactate peak corresponding to the lesion. After that the patient presented slowly progressive psychomotor decline. He had myoclonic seizures and cerebellar ataxia since the age of 12. At age 21, he was admitted to our hospital because of confusion and cranial MRI revealed symmetrical lesions in bilateral posterior putamen, thalami and midbrain. Then repeated MRI showed progression of original lesions and new frontal multiple stroke-like lesions. Symptomatic and rehabilitation treatment relieved his condition. Follow-up cranial MRI at age 24 showed the lesions in basal ganglia and thalami diminished, and the midbrain lesions even completely vanished. Muscle pathology indicated the presence of numerous scattered ragged-red fibers (RRF), suggestive of a mitochondrial disorder. Polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) detected the m.8344A>G mutation of the MT-TK gene encoding mitochondrial transfer RNA for lysine in the patient's blood. Next generation sequencing (NGS) of the whole mitochondrial genome identified that the proportion of m.8344A>G was 90%, and no other mtDNA mutation was detected. Sanger sequencing further identified this mutation both in the proband and his mother's blood, although the mutation load was much lower in his mother's blood with approximately 10% heteroplasmy., Conclusion: The present study is the first to describe a patient with m.8344A>G mutation in association with the MELAS/MERRF/Leigh overlap syndrome, which expands the phenotypic spectrum of the m.8344A>G mutation.

Objective: To compare eradication rates and compliance of patients with Helicobacter pylori( H. pylori )infection based on clarithromycin sensitivity. Methods: From July 2015 to January 2018,patients with H. pylori infection in Peking university people's hospital were randomly assignedto a 14-day treatment with clarithromycin quadruple therapy versus tailored quadruple therapy for a prospective study. In the group of tailored therapy, medications were adjusted based on clarithromycin sensitivity. In the control group, all patients were given proton pump inhibitors (PPI), amoxicillin, clarithomycin and bismuth. Eradication status was assessed 4 weeks after treatment withurea breath test. Results: The H.pylori eradication rate were higher in the tailor therapy group than that in the control group in intention-to-treat[77.8% vs 65.3%,( P= 0.001)] and per,protocol analyses [86.4% vs 70.2%,( P< 0.001)], the differences between the two groups were statistically significant.The incidence of compliance between the two groups were also comparable. Conclusions: The tailored therapy basedon clarithromycinsensitivity has a better eradication efficacy and a higher eradication ratesin the patients with H. pylori infection.

Background: The extensive involvement of microRNAs (miRNAs) in the pathogenesis of psoriasis is well documented. However, little is known about the contribution of specific miRNAs to the prevalence of this disease., Objectives: To explore the role of miR-145-5p in psoriasis., Methods: miRNA microarray analysis was performed in four patients with psoriasis and four controls. Quantitative reverse-transcriptase polymerase chain reaction and fluorescence in situ hybridization were used to identify the dysregulated miRNAs. Luciferase assays were performed to determine whether miR-145-5p targets mixed-lineage kinase (MLK)3. CCK-8 assay and Magnetic Luminex Assay were performed to measure cell proliferation and chemokine secretion. Western blot analysis was used to investigate the protein levels of MLK3 and its downstream effectors. Mouse models of psoriasis were established for in vivo experiments., Results: miR-145-5p was downregulated in psoriatic lesional skin. Luciferase assays showed that MLK3 is a direct target of miR-145-5p. Overexpression of miR-145-5p in normal human epidermal keratinocytes (NHEKs) suppressed cell proliferation and secretion of chemokines. In contrast, silencing miR-145-5p promoted NHEK proliferation and increased chemokine secretion. Silencing MLK3 abrogated miR-145-5p inhibitor-induced promotion of cell proliferation and chemokine expression. miR-145-5p regulates nuclear factor-κB and signal transducer and activator of transcription 3 by targeting MLK3. Delivery of agomiR-145-5p into the skin decreased epidermal hyperplasia and ameliorated psoriasis-like dermatitis. Delivery of antagomiR-145-5p led to the opposite effects., Conclusions: Our findings indicate that miR-145-5p negatively regulates proliferation and chemokine secretion of NHEKs by targeting MLK3, and downregulation of miR-145-5p contributes to skin inflammation in psoriasis lesions., (© 2018 British Association of Dermatologists.)

Objective: To explore the computed tomography(CT) features of inflammatory myofibroblastic tumor(IMT) in different pathological types, and improve the diagnostic level of this disease. Methods: The CT features of 29 cases pathologically confirmed IMTs were retrospectively reviewed along with a literature review to analyze the CT features and pathological correlations, and three kinds of pathological classification of IMT in patients with gender , shape, boundary and location were respectively analyzed by Chi - Square test. Results: The age ranges from 2 to 78 years.There were 7 cases of mucinous blood vessel type and 13 cases of spindle cell type and 9 cases of fiber type.Immunohistochemically, Vimentin (22/29) and SMA (28/29) were positive in all the cases, ALK (4/29) and CD-67(6/29) were partly positive expression, other markers such as S-100 were negative expression.The Chi - Square test showed that there were statistically differences in the gender of the patients. Conclusion: The CT and clinical features differ according to pathological types of IMT. Its final diagnosis still needs to be combined with pathology and immunohistochemistry result. In all, CT has a role in assessing the extension of IMT and especially about the relationship with adjacent organs which can effectively direct the establishment of clinical treating scheme.

Objective: To retrospectively investigate the clinical characteristics, risk factors of Cytomegalovirus (CMV) infection in patients with underlying rheumatic diseases. Methods: Clinical records of 263 rheumatic patients with or without CMV infection, hospitalized from March 2011 to June 2014 in Peking University People's Hospital, were analyzed.Clinical characteristics were summarized and compared in CMV positive and negative groups, to investigate the risk factors for CMV infection.Statistical analyses were conducted with SPSS 20.0 software. Results: A total of 62 rheumatic patients were found to have CMV infection, with 48 regarded as CMV viremia, 7 diagnosed as CMV pneumonia, while the remaining 7 suffered both CMV viremia and pneumonia.Eleven of 62 patients (17.7%) had a fatal outcome.Systemic lupus erythematosus (SLE) was the most commonly underlying disease (41.9%), followed by Sjögren syndrome (16.1%) and systemic vasculitis (12.9%). Lymphopenia and the reduction of CD4 + T lymphocytes, corticosteroids, cyclophosphamide (CTX) or mycophenolate mofetil (MMF), combined use of more than 2 immunosuppressants and other severe underlying infections as risk factors for CMV infection in rheumatic patients.Meanwhile, the total dose of CTX wasn't different significantly between CMV positive and negative groups.Multivariate analysis revealed that large or pulsed dose of corticosteroids, combined use of immunosuppressants, and severe underlying infections remained independent risk factors for CMV infection. Conclusions: Lymphocytes, particularly the CD4 + T subsets, might play a vital role in the regulation and control of CMV infection.Other underlying infections, undergoing large dose corticosteroids therapy or combined use of immunosuppressants could be the risk factors for CMV infection in rheumatic patients.

We report on the magnetotransport properties of chemical vapor deposition grown films of interconnected Bi2Te3 nanoplates. Similar to many other topological insulator (TI) materials, these granular Bi2Te3 films exhibit a linear magnetoresistance (LMR) effect which has received much recent attention. Studying samples with different degree of granularity, we find a universal correlation between the magnitude of the LMR and the average mobility (⟨μ⟩) of the films over nearly 2 orders of magnitude change of ⟨μ⟩. The granularity controlled LMR effect here is attributed to the mobility fluctuation induced classical LMR according to the Parish-Littlewood theory. These findings have implications to both the fundamental understanding and magnetoresistive device applications of TI and small bandgap semiconductor materials.

Chrysanthemum (Chrysanthemum morifolium Ramat.) is a commercially important ornamental grown worldwide, and is also extensively used as an edible and medicinal plant. In the present work, viruses and viroids infecting chrysanthemum were investigated in China in 2012 and 2013. Typical viral symptoms were observed in field-grown chrysanthemum with leaf yellowing and mottled leaves in Wenjiang District, Sichuan Province, China. The incidence of these symptoms in the field was 12.3%. Chrysanthemum virus B (CVB), Tomato aspermy virus (TAV), Cucumber mosaic virus (CMV), Tobacoo mosaic virus (TMV), Chrysanthemum stunt viroid (CSVd), and Chrysanthemum chlorotic mottle viroid (CChMVd), which had previously been reported to infect chrysanthemum in China (2,3), were not detected by RT-PCR assay. Since these symptomatic chrysanthemum plants grew next to a tobacco field, viruses affecting tobacco were suspected as possible cause. Sixteen symptomatic leaves and 12 non-symptomatic leaves were collected and tested for Potato virus Y (PVY) presence using commercial PVY-specific DAS-ELISA kits (Catalog no. PSA20001, Agdia) Six samples were found positive for PVY. RT-PCR tests using specific primers for CP gene (CP-F 5'-ACTGTGATGAATGGGCTTATG-3'; CP-R 5'-GGCATATATGGTTCCTTTTTG-3') (4) amplified a single, expected 218-bp DNA fragment from chrysanthemum extracts from all six samples positive for PVY in ELISA. These six PCR fragments were sequenced and found 100% identical to each other. The sequence (GenBank Accession No. KJ174515) shared 99% identity with corresponding sequences of several PVY isolates (NC&#95;001616, EF026076, HM590407, and JQ924288). The same six positive samples were subjected to a multiplex RT-PCR assay (1) to identify the PVY strain type, and all six PVY samples from Sichuan were found to belong to the PVY N-Wi strain. To our knowledge, this is the first report of the PVY N-Wi strain infecting chrysanthemum in Sichuan, China. References: (1) M. Chikh Ali et al. Plant Dis. 10:1370, 2013. (2) E. A. Nassar et al. Int. J. Virol. 8:14, 2012. (3) H. Yamamoto et al. J. Gen. Plant Pathol. 71:156, 2005. (4) J. Q. Zhang et al. J. Phytopathol. 161:92, 2013.

This paper reports a microfluidic system that enables the characterization of tumor cell electrical properties where cells were aspirated through a constriction channel (cross-section area smaller than that of biological cells) with cellular impedance profiles measured and translated to specific membrane capacitance (Cspecific membrane) and cytoplasm conductivity (σcytoplasm). Two batches of H1299 cells were quantified by the microfluidic platform with different constriction channel cross-section areas, recording no differences with statistical significance (p<0.001) in both Cspecific membrane (1.63±0.52 vs. 1.65±0.43 μF/cm(2)) and σcytoplasm (0.90±0.19 vs. 0.92±0.15S/m), and thus confirming the reliability of the microfluidic platform. For paired high- and low-metastatic carcinoma strains 95D (ncell=537) and 95C cells (ncell=486), significant differences in both Cspecific membrane (2.00±0.43 vs. 1.62±0.39 μF/cm(2)) and σcytoplasm (0.88±0.46 vs. 1.25±0.35S/m) were observed. Statistically significant difference only in Cspecific membrane (2.00±0.43 vs. 1.58±0.30 μF/cm(2)) was observed for 95D cells (ncell=537) and 95D CCNY-KD cells with single oncogene CCNY down regulation (ncell=479, CCNY is a membrane-associated protein). In addition, statistically significant difference only in σcytoplasm (0.73±0.17 vs. 1.01±0.17S/m) was observed for A549 cells (ncell=487) and A549 CypA-KD cells with single oncogene CypA down regulation (ncell=597, CypA is a cytosolic protein). These results validated the developed microfluidic platform for Cspecific membrane and σcytoplasm quantification and confirmed the feasibility of using Cspecific membrane and σcytoplasm for tumor cell classification., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This study aimed to investigate the effects of single-nucleotide polymorphisms (SNPs) XRCC1 Arg194Trp, XRCC1 Arg280His, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPG His104Asp, and XPG His46His in genes involved in the DNA-repair pathway on the outcomes of platinum-based chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). The study period was from January 2005 to January 2006, and 378 NSCLC patients were enrolled within 1 month after being diagnosed with NSCLC. Genomic DNA was extracted using the Qiagen Blood Kit. Polymerase chain reaction combined with a restriction fragment length polymorphism assay was used for genotyping. Individuals with the XRCC1 399A/A genotype had a higher probability of responding well to platinum-based chemotherapy, indicated by an odds ratio (OR) of 2.27 [95% confidence interval (CI)=1.64-6.97]. Similarly, the XPG T/T genotype was significantly associated with improved responses to chemotherapy, indicated by an OR of 1.90 (95%CI=1.10-3.28). The XRCC1 399A/A genotype was significantly associated with longer disease-free survival and overall survival, indicated by hazard ratios (HRs) of 0.48 (95%CI=0.25-0.88) and 0.51 (95%CI=0.26- 0.98), respectively. Moreover, the XPG 46T/T genotype increased the likelihood of longer disease-free survival and overall survival of NSCLC patients treated with platinum-based chemotherapy (HR=0.47; 95%CI=0.22-0.82 and HR=0.52; 95%CI=0.31- 0.96, respectively). These results indicate that XRCC1 Arg399Gln and XPG His46His might significantly affect the clinical outcomes of platinum-based chemotherapy, highlighting the need for larger studies to confirm the role of these two SNPs in outcomes of NSCLC treatments.

Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In this work, we report on a comprehensive characterization of gene expression profiles of hepatitis B virus-positive HCC through the generation of a large set of 5'-read expressed sequence tag (EST) clusters (11,065 in total) from HCC and noncancerous liver samples, which then were applied to a cDNA microarray system containing 12,393 genes/ESTs and to comparison with a public database. The commercial cDNA microarray, which contains 1,176 known genes related to oncogenesis, was used also for profiling gene expression. Integrated data from the above approaches identified 2,253 genes/ESTs as candidates with differential expression. A number of genes related to oncogenesis and hepatic function/differentiation were selected for further semiquantitative reverse transcriptase-PCR analysis in 29 paired HCC/noncancerous liver samples. Many genes involved in cell cycle regulation such as cyclins, cyclin-dependent kinases, and cell cycle negative regulators were deregulated in most patients with HCC. Aberrant expression of the Wnt-beta-catenin pathway and enzymes for DNA replication also could contribute to the pathogenesis of HCC. The alteration of transcription levels was noted in a large number of genes implicated in metabolism, whereas a profile change of others might represent a status of dedifferentiation of the malignant hepatocytes, both considered as potential markers of diagnostic value. Notably, the altered transcriptome profiles in HCC could be correlated to a number of chromosome regions with amplification or loss of heterozygosity, providing one of the underlying causes of the transcription anomaly of HCC.

Using a combination of hybridization of PAC to a cDNA library and RACE technique, we isolated a novel cDNA, designated as C17orf25 (Chromosome 17 open reading frame 25, previously named it HC71A), from the deletion region on chromosome 17p13.3. The cDNA encodes a protein of 313 amino acids with a calculated molecular mass of 34.8 kDa. C17orf25 is divided into 10 exons and 9 introns, spanning 23 kb of genomic DNA. Northern blot analysis showed that the mRNA expression of C17orf25 was decreased in hepatocellular carcinoma samples as compared to adjacent noncancerous liver tissues from the same patients. The transfection of C17orf25 into the hepatocellular carcinoma cell SMMC7721 and overexpression could inhibit the cell growth. The above results indicate that C17orf25 is a novel human gene, and the cloning and preliminary characterization of C17orf25 is a prerequisite for further functional analysis of this novel gene in human hepatocellular carcinoma.

Slowing of transit through the proximal small intestine by fat in the distal gut is termed the ileal brake. Intravenous naloxone, an opioid receptor antagonist, abolished the fat-induced ileal brake, suggesting that an endogenous opioid pathway may be involved in this response. To test the hypothesis that slowing of intestinal transit by fat in the distal half of the gut depends on an opioid pathway located on the efferent limb of this response, we compared intestinal transit in dogs equipped with duodenal and midgut fistulas while naloxone was either compartmentalized with oleate to the distal half of the gut or with buffer to the proximal half of the gut. We found that intestinal transit depended on the perfusion conditions (P<0.00001). Specifically, compared with ileal brake (marker recovery of 35.7+/-7.4%), intestinal transit was accelerated when naloxone was delivered into the proximal half of the gut (76.2+/-5.2%) (P<0.005) but not the distal half of the gut (29.4+/-5.4%). We conclude that slowing of intestinal transit by fat in the distal half of the gut depends on an opioid pathway located on the efferent limb of the ileal brake.

Fat in small intestine decreases meal-stimulated gastric acid secretion and slows gastric emptying. CCK is a mediator of this inhibitory effect (an enterogastrone). Because intravenously administered peptide YY (PYY) inhibits acid secretion, endogenous PYY released by fat may also be an enterogastrone. Four dogs were equipped with gastric, duodenal, and midgut fistulas. PYY antibody (anti-PYY) at a dose of 0.5 mg/kg or CCK-A receptor antagonist (devazepide) at a dose of 0.1 mg/kg was administered alone or in combination 10 min before the proximal half of the gut was perfused with 60 mM oleate or buffer. Acid secretion and gastric emptying were measured. We found that 1) peptone-induced gastric acid secretion was inhibited by intestinal fat (P < 0.0001), 2) inhibition of acid secretion by intestinal fat was reversed by CCK-A receptor antagonist (P < 0.0001) but not by anti-PYY, and 3) slowing of gastric emptying by fat was reversed by CCK-A antagonist (P < 0. 05) but not by anti-PYY. We concluded that inhibition of peptone meal-induced gastric acid secretion and slowing of gastric emptying by intestinal fat depended on CCK but not on circulating PYY.

Because an increase in flow rate accelerates intestinal transit, a reduction in the flow rate of formula delivery is recommended frequently for treatment of diarrhea that develops during enteral feeding. Because intestinal transit is slowed by nutrient-triggered inhibitory feedback, the rate of intestinal transit during enteral feeding may depend on a balance between the accelerating effect of flow and the inhibiting effect of the nutrient load. The addition of fiber to a formula may alter this balance. By delaying absorption of nutrients, fiber may extend the length of small intestine exposed to nutrients and thereby trigger more intense inhibitory feedback. To determine whether the addition of fiber favors nutrient-triggered inhibition over flow-driven acceleration, we studied intestinal transit after perfusion of a low-residue enteral formula compared with a fiber-supplemented formula at two perfusion rates (50 or 100 mL/h for 2 h) into the duodenum of dogs each with both a duodenal and midgut fistula. With the low-residue formula, intestinal transit accelerated when the flow rate increased from 50 to 100 mL/h (P < 0.05). With the fiber-supplemented formula, however, intestinal transit was inhibited regardless of the flow rate. To determine whether the fiber-supplemented formula inhibited intestinal transit by displacing nutrients distally, we compared intestinal transit when the two formulas, delivered at 100 mL/h, were diverted completely at the midgut fistula. Intestinal transit of the fiber-supplemented formula increased by 400%, eliminating the difference in intestinal transit speed between the two formulas. We concluded that the fiber-supplemented formula slowed intestinal transit by intensifying inhibitory feedback from the distal gut.

Ileal perfusion of protein slows intestinal transit. Because optimal absorption of nutrients requires adequate time in contact with the mucosa, slowed intestinal transit may increase protein absorption by increasing the residence time of nutrients in the small intestine. Although protein supplements are routinely added to enteral feeding to correct protein malnutrition, little information is available on the effect of increasing the load of protein on intestinal transit and the efficiency of protein absorption. In six dogs equipped with duodenal and midintestinal fistulas, intestinal transit and the efficiency of protein absorption (percentage protein absorbed as estimated from the output of midintestinal fistula) were compared during intestinal perfusion with 0-, 50-, 100-, and 200-g/L solutions of a whey-based protein supplement. We found that intestinal transit slowed in a load-dependent fashion (P < 0.05); the amount of protein absorbed within the proximal one-half of the small intestine increased in a load-dependent fashion (P < 0.05) as intestinal transit slowed, and the percentage protein absorbed (reflecting the efficiency of protein absorption) was maintained at a high and nearly constant value of 66.5-72.5% across protein loads of 9-36 g. We conclude that enhanced protein absorption is associated with a load-dependent inhibition of intestinal transit.

Since the intubation study of B. Borgstrom, A. Dahlqvist, and G. Lundh (J. Clin. Invest. 36: 1521-1536, 1957) in humans, the completion of fat absorption within the proximal small intestine has been widely accepted. Based on this report, it has been assumed that the distal small intestine is exposed to fat only in the setting of pathology. This concept may be flawed, since completeness of fat absorption was calculated from the recovery of a water-soluble marker but the aqueous phase is now known to move independently from fat. To reexamine the question of whether fat absorption is complete by midgut, we measured the recovery of a fat-specific marker, 99mTc-thiocyanate, in a canine model equipped with duodenal and midgut fistulas. The fistulous output allowed for the measurement of the amount of fat entering the small intestine and the amount of fat entering the distal one-half of the small intestine. Emulsion meals containing 15 or 60 g of corn oil were tested. The importance of fat exposure of the distal one-half of the small intestine was further confirmed by comparing the fistulous fat recovery under two different patterns of exposure [allowing (ALL) or denying (150 cm) access to the distal small intestine]. We found that fat recovery depended on 1) the dose of fat (15 vs. 60 g; P < 0.0005), 2) the pattern of exposure (150 cm vs. ALL; P < 0.01), and 3) the fistulous position (duodenal vs. midgut; P < 0.005). Specifically, under a 150-cm exposure pattern, whereas 8.8 +/- 1.8 g (means +/- SE) of fat emptied into the duodenum after the 15-g fat meal, 32.6 +/- 3.2 g emptied after the 60-g fat meal. Correspondingly, although 3.5 +/- 1.5 g of fat were recoverable from the midgut fistulous output after the 15-g meal, a much larger amount, 17.1 +/- 5.6 g of fat, was recoverable and therefore not absorbed by the proximal one-half of the small intestine after the 60-g meal. The amount of fat recovery at each fistula was reduced when chyme was allowed access to the whole gut (by triggering fat-induced ileal brake). We conclude that the intestinal length required for fat absorption depends on the load of fat in the meal so that, even after usual meals, absorption of fat is not complete by midgut.