Recent Study Advances in Flexible Sensors Based on Polyimides.

With the demand for healthy life and the great advancement of flexible electronics, flexible sensors are playing an irreplaceably important role in healthcare monitoring, wearable devices, clinic treatment, and so on. In particular, the design and application of polyimide (PI)-based sensors are emerging swiftly. However, the tremendous potential of PI in sensors is not deeply understood. This review focuses on recent studies in advanced applications of PI in flexible sensors, including PI nanofibers prepared by electrospinning as flexible substrates, PI aerogels as friction layers in triboelectric nanogenerator (TENG), PI films as sensitive layers based on fiber Bragg grating (FBG) in relative humidity (RH) sensors, photosensitive PI (PSPI) as sacrificial layers, and more. The simple laser-induced graphene (LIG) technique is also introduced in the application of PI graphitization to graphene. Finally, the prospect of PIs in the field of electronics is proposed in the review.

Synthesis of copper naphthalocyanine/graphene oxide composites as anode materials for lithium-ion batteries.

Naphthalocyanine and its derivatives are new types of functional materials with wide application prospects. This paper discusses the synthesis of copper tetra tert-butyl-naphthalocyanine (CuNc) and analyses its molecular and electronic structure. Next, CuNc is combined with graphene oxide (GO) through π-π interaction and then pyrolyzed to form a CuNc/GO composite. A systematic investigation of the morphology, structure, composition and properties of CuNc/GO revealed that N-doped graphene is decorated with CuO particles. The electrochemical properties of CuNc/GO are compared with those of directly pyrolysed CuNc. The prepared CuNc/GO (1 : 1) electrode shows a large specific capacity (655.1 mA h g-1) after 100 cycles at 100 mA g-1. Its high capacity, enhanced cycling stability and strong rate performance are attributed to the synergetic effect of N-doped graphene and CuO particles. Besides expanding the use of naphthalocyanine compounds, this work presents a promising candidate material for lithium-ion battery anodes.

Improved Interlaminar Properties of Glass Fiber/Epoxy Laminates by the Synergic Modification of Soft and Rigid Particles.

Poor interlaminar fracture toughness has been a major issue in glass fiber-reinforced epoxy resin (GF/EP) laminate composites. In this paper, soft carboxy-terminated nitrile (CTBN) rubber particles and rigid nano-SiO2 are used to toughen the epoxy resin (EP) matrix to improve the interlayer properties of GF/EP laminate composites. The effects of adding two toughening agents on the mechanical and interlayer properties of GF/EP laminates were studied. The results showed that adding the two kinds of particles improved the mechanical properties of the epoxy matrix. When the additional amount of flexible CTBN rubber particles was 8 wt%, and the rigid nano-SiO2 was 0.5 wt%, the fracture toughness of the matrix resin was increased by 215.8%, and the tensile strength was only decreased by 2.3% compared with the pure epoxy resin. On this basis, the effects of two kinds of particles on the interlayer properties of GF/EP composites were studied. Compared with the unmodified GF/EP laminates, the interlayer shear strength and mode I interlayer fracture toughness is significantly improved by a toughening agent, and the energy release rate GIC of interlayer shear strength and interlayer fracture toughness is increased by 109.2%, and 86.8%, respectively. The flexible CTBN rubber particles and rigid nano-SiO2 improve the interfacial adhesion between GF and EP. The cavitation of the two particles and the plastic deformation of the matrix is the toughening mechanism of the interlayer properties of the composite. Such excellent interlaminar mechanical properties make it possible for GF/EP laminates to be widely used as engineering materials in various industries (e.g., aerospace, hydrogen energy, marine).

Ligand-Assisted Self-Assembly of 3D Perovskite Nanocrystals into Chiral Inorganic Quasi-2D Perovskites (n = 3) with Ligand-Ratio-Dependent Chirality Inversion.

Chiral inorganic quasi-2D perovskites are prepared by self-assembling 3D perovskites in solution for the first time. The quasi-2D perovskite synthesized is a pure-phase perovskite with = 3 and is periodically arranged, which is a big breakthrough in quasi-2D inorganic perovskites.  With the individual chiral CsPbBr3 nanocrystals (NCs) assemble into quasi-2D perovskite, the g-factor significantly improved (≈5 × 10-3 ). In addition, the chiroptical activity of quasi-2D perovskites is explored to be improved with the lateral size increasing. In the first stage of assembly, chiral optical activity is increased due to the lateral size-dependent optical activity, while the changes in the later stages are attributable to the chiral morphology. Interestingly, chirality inversion is found to be correlated to the number of ligands. It is believed that different conformers of chiral ligands caused by steric hindrance of the original ligand oleylamine result in opposite circular dichroism (CD) polarities. The chirality inversion phenomenon is universal, regardless of the choice of ligands. This work opens up a new path for the synthesis of quasi-2D perovskites and provides more opportunities for the modulation of chiral optical activity.

Single-Shot Multi-Frame Imaging of Femtosecond Laser-Induced Plasma Propagation.

Single-shot ultrafast multi-frame imaging technology plays a crucial role in the observation of laser-induced plasma. However, there are many challenges in the application of laser processing, such as technology fusion and imaging stability. To provide a stable and reliable observation method, we propose an ultrafast single-shot multi-frame imaging technology based on wavelength polarization multiplexing. Through the frequency doubling and birefringence effects of the BBO and the quartz crystal, the 800 nm femtosecond laser pulse was frequency doubled to 400 nm, and a sequence of probe sub-pulses with dual-wavelength and different polarization was generated. The coaxial propagation and framing imaging of multi-frequency pulses provided stable imaging quality and clarity, as well as high temporal/spatial resolution (200 fs and 228 lp/mm). In the experiments involving femtosecond laser-induced plasma propagation, the probe sub-pulses measured their time intervals by capturing the same results. Specifically, the measured time intervals were 200 fs between the same color pulses and 1 ps between the adjacent different. Finally, based on the obtained system time resolution, we observed and revealed the evolution mechanism of femtosecond laser-induced air plasma filaments, the multifilament propagation of femtosecond laser in fused silica, and the influence mechanism of air ionization on laser-induced shock waves.

Second-order nonlinear optical properties of copper-based hybrid organic-inorganic perovskites induced by chiral amines.

Recently, chiral hybrid organic-inorganic perovskites (HOIPs) are drawing wide attention due to their intrinsic noncentrosymmetric structures which result in fascinating properties such as ferroelectronics and second-order nonlinear optics (NLO). However, previous research mainly focused on chiral lead-based halide perovskites ignoring that the toxic Pb element is harmful to humans and the environment. Herein, we successfully synthesized block-like (R-/S-NEA)2CuCl4 (NEA = 1-naphthylethylamine) and needle-like (R-/S-CYHEA)6Cu3Cl12 (CYHEA = 1-cyclohexylethylamine) single crystals, which crystallize in the Sohncke P21 and I2 space group, respectively. Each pair of chiral perovskite enantiomers shows mirror circular dichroism (CD) signals. The thin films show an efficient second harmonic generation (SHG) response and the NLO coefficients of (R-NEA)2CuCl4 and (R-CYHEA)6Cu3Cl12 are 11.74 and 3.04 pm V-1, respectively, under 920 nm excitation with Y-cut quartz as a reference, which shows that the chiral amine has a significant effect on the SHG behavior. The high SHG response of (R-NEA)2CuCl4 is perhaps due to the rigidity of the aromatic amine, which leads to highly asymmetrical space groups. Our results provide guidelines for designing and tuning the SHG response in chiral HOIPs.

Ligand Exchange Strategy to Achieve Chiral Perovskite Nanocrystals with a High Photoluminescence Quantum Yield and Regulation of the Chiroptical Property.

Chiral nanomaterials have drawn extensive attention on account of numerous application prospects in optoelectronics, asymmetric catalysis, chiral recognition, and three-dimensional (3D) display. Thereinto, chiral perovskite has been a hotspot due to brilliant optoelectronic properties, but some problems limit the development, including low quantum yield, low chiral intensity, and the lack of facile regulation. To overcome these issues, an effective ligand exchange strategy, i.e. the interface modification has been proposed for chiral perovskite nanocrystals (PNCs). With the surface modification of CsPbBr3 PNCs with chiral organic ammonium in methyl acetate in the typical purification process, excellent circular dichroism (CD) signals were obtained and defects were eliminated, leading to an increase in the photoluminescence quantum yield (PLQY) from 50% to nearly 100%. The CD signal can be regulated through a ligand exchange strategy in the longitudinal dimension, the chiral intensity, and the transverse dimension, the wavelength range. Here, the proper addition of R-α-PEAI into the R-α-PEABr-capped CsPbBr3 PNCs can produce a superstrong CD signal with the highest anisotropy factor (g-factor) of 0.0026 in the visible region among reported chiral colloidal PNCs. Simultaneously, the luminescence emission can be tuned from the green to red region with boosted PLQY through the approach. The density functional theory (DFT) calculation result supports that chirality comes from the hybridization between the energy level of a perovskite structure and that of chiral organic molecules. These properties can be used in the structural engineering of high-performance chiral optical materials, spin-polarized light-emitting devices, and polarized optoelectronic devices.

Effect ofα-substitute group on the chirality of monocarboxylic acid stabilized CdSe nanocrystals.

The effect ofα-substitute groups at the asymmetric carbon of chiral monocarboxylic acid ligand, on the chirality of CdSe nanocrystals (NCs) was studied. When the substitution groups have strong electron-withdrawing capability, the CdSe NCs displayed an enhanced chirality where theg-factors were comparable to those with dicarboxylic chiral ligands. In addition, adding ethanol was demonstrated as an effective way to stabilize NCs, however, completely oppositeg-factor evolution behavior was found for NCs with differentα-substituted ligands. Specifically, theg-factor has increased/decreased with strong/weak electron-withdrawingα-substitute groups probably due to the different intermolecular hydrogen bonding between carboxylic acids and ethanol.

Controllable chiral behavior of type-II core/shell quantum dots adjusted by shell thickness and coordinated ligands.

Chiral semiconductor nanomaterials induced by capped chiral ligands are of great interest for both theoretical studies and advanced applications. In this study, CdTe/CdSe quantum dots (QDs), defined as type-II core/shell nanostructure, with the advantage of a good separation of holes and electrons are imparted chirality with L/D-cysteine and L/D-penicillamine molecules. Circular dichroism (CD) at exciton transitions from cysteine- and penicillamine-capped QDs is different in shape and intensity. CD intensities decrease with increasing shell thickness from three monolayers to six monolayers, indicating a decreased hybridization degree between the holes in CdTe core and the electrons in chiral ligands. Elevated cysteine concentration leads to decreased g-factor, probably due to an altered binding mode from tridentate to bidentate. Our observations provide further insights into the understanding of chiral phenomenon as well as optimized design and applications of chiral nanostructures.

Chiral 3D CdSe Nanotetrapods.

Three-dimensional (3D) nanomaterials have been intensively investigated because of their unique properties and wide range of potential applications; however, the ligand-induced chirality in 3D semiconductor nanocrystals has been scarcely studied. In this paper, we report the synthesis of hydrophobic 3D CdSe nanotetrapods (Tps) with a high degree of uniformity in their morphology by using the hot-injection method. The core and arms of Tps are distinct in their crystal structure, thus creating an intracrystal heterojunction. The size of Tps, primarily the length of four arms, is controlled by changing the amount of didecyldimethylammonium bromide and reaction time. Next, enantiopure cysteine ligands were introduced to replace the hydrophobic native stabilizers to prepare chiral l- and d-cysteine-capped CdSe Tps. Importantly, the circular dichroism (CD) line shapes of l/d-cysteine-capped CdSe Tps are assigned to the different excitonic transitions of the core and arms, respectively. In addition, the observed CD activities are found to be sensitive to the size of the CdSe Tps, where the anisotropic g factors have increased and reached the maximum value at a moderate aspect ratio (AR) and a further increase of the AR leads to a decrease of the g factor. Because of charge transfer between the core and arms, we propose a plausible mechanism potentially responsible for the induced CD line shapes in terms of the excitonic states of Tps with two different crystal structures. We believe that chiral 3D nanomaterials with anisotropic morphologies could offer new opportunities for relevant applications.

The time of Calcium Feeding Affects the Productive Performance of Sows.

This study aims to investigate the effect of Calcium (Ca) feeding time on a sow's productive performance and the profiles of serum mineral elements during late pregnancy and lactation. A total of 75 pregnant sows were assigned to three groups: The control (C), earlier-later (E-L), and later-earlier (L-E) groups. During late pregnancy, the C group was fed an extra 4.5 g Ca (in the form of CaCO3) at both 06:00 and 15:00, the E-L group was fed an extra 9 g Ca at 06:00, and the L-E group was fed an extra 9 g Ca at 15:00. Similar treatments with double the amount of Ca were applied during lactation. The results show that, compared with the C group, L-E feeding decreased the number of stillbirths and the duration of farrowing and placenta expulsion (FARPLA) and increased the average daily weight gain (ADG) of piglets. Similarly, E-L feeding increased the ADG of piglets (p < 0.05). Furthermore, both E-L and L-E feeding increased the Ca levels in sow serum and umbilical serum, and the Fe levels in umbilical serum, but decreased the Ca levels in the placenta and colostrum (p < 0.05). Experiments on the genes involved in mineral element transport showed that E-L feeding activated the mRNA expression of TRPV5, S100G, SLC30A7, SLC39A4, and Ferroportin1, while it inhibited the mRNA expression of ATP7A in the placenta (p < 0.05). Moreover, L-E feeding up-regulated the mRNA expression of ATP2B and IREB2, while it down-regulated the mRNA expression of ATP7B in the placenta (p < 0.05). In conclusion, the present study demonstrated that maternal Ca feeding at 15:00 h during late pregnancy and lactation decreased FARPLA and stillbirths and improved the growth performance of suckling piglets by altering the mineral element of the metabolism in the umbilical serum and milk, compared to conventional feeding regimes.

Chiroptical Activity of Type II Core/Shell Cu2S/CdSe Nanocrystals.

Ligand-induced chirality in core/shell nanocrystals (NCs) has attracted extensive attention because of many valuable potential applications. However, the cause of chirality especially in semiconductor nanomaterials is still under debate despite the creation of chiral type I core/shell structures. Herein, we synthesized a kind of new Cu2S/CdSe core/shell nanostructure to study the underlying reason. Four samples of Cu2S/CdSe were synthesized utilizing successive ion layer adsorption and reaction to vary the thickness of the CdSe shell upon a Cu2S core with 5 nm diameter. The chirality of type II Cu2S/CdSe NCs is imparted by l-/d-cysteine and penicillamine, which could be modulated with an increasing thickness of the CdSe shell. To the best of our knowledge, this is the first report of chiral type II core/shell semiconductor NCs. The hybridization theory can explain the variation trend of g factors with every increase in shell thickness from four monolayers (4 ML) to 7 ML. The results indicate that the chiroptical activity of semiconductor NCs is mainly due to hybridization between the holes in the valence band of NCs and the highest occupied molecular orbitals of the chiral ligands. In addition, Cu2S/CdSe NCs show a better chiroptical intensity in comparison with the type I structure according to previous work. The first design of chiral type II Cu2S/CdSe core/shell NCs and a detailed investigation of chiral variation trend help to give a better understanding of the chiral interaction between ligands and core/shell semiconductor nanostructures.

Enhanced photothermal behavior derived from controllable self-assembly of Cu1.94S microstructures.

New ordered architectures or morphologies could be obtained through the self-assembly process and usually generate new physical and chemical properties. Here we report an adjustable self-assembly research study on copper sulphide nanocrystals (Cu1.94S NCs) forming five kinds of plant-like morphologies. Hydrophobic Cu1.94S quantum dots were prepared in the CHCl3 phase and transferred to the aqueous phase and capped with cysteine or penicillamine through a ligand exchange technique. Afterwards, a facile and eco-friendly self-assembly process (without using any template or surfactant) was employed. Through regulating the conditions including the solvent composition, surface ligand and starting concentration of Cu1.94S NCs, five delicate architectures were obtained. In addition, the possible formation process and growth mechanism of the obtained three-dimensional (3D) Cu1.94S architectures was also proposed and discussed. The assembled Cu1.94S architectures show improved molar extinction coefficients compared with individual Cu1.94S NCs, and in this way, better photothermal performance is achieved.

Effects of dynamic feeding low- and high-methionine diets on the variation of glucose and lipid metabolism-related genes in the liver of laying hens.

We examined the effects of dynamic feeding low- and high-methionine diets on the transcriptional level of glucose and lipid metabolism-related genes in the liver of laying hens. A total of 180 laying hens (Brown Hy-line, 41 wk old) were exposed to 16 h of light and 8 h of darkness with lights on at 06:00 h local time (Zeitgeber time [ZT] 0) and allocated into 3 equal groups with 6 replicates. The control group was fed a 0.30% methionine diet. The low-high (LH) group was fed 0.27% methionine diet at ZT1.5 and 0.33% methionine diet at ZT8.5. The feeding regime in high-low (HL) group was opposite to that of the LH group. After 10 wk, a total of 108 hens (6 hens/group/time point) were randomly and equally selected for further analysis. Blood and liver tissues were collected at ZT21.5, ZT1.5, ZT5.5, ZT9.5, ZT13.5, and ZT17.5. The results showed that the serum ALP activity in the HL group was the highest at ZT9.5 and ZT13.5, and that the serum glucose content in the HL group was lowest at ZT21.5 compared to the other 2 groups (P < 0.05). The mesors, amplitudes, and acrophases of the cosine curves for the CLOCK, BMAL1, CRY1, PER2, and PER3 genes were altered in the LH and HL groups. G6PC3, PCK2, GPAT, INSIG2, FASN, ACACA, ACOX1, HMGCR, LDLR, and PPARA expression in the liver were affected by the feeding regime at some time point (P < 0.05). Two-way analysis of variance comparisons showed some significant effects of time on the mRNA expression of G6PC3, G6PC2, PCK2, FBP1, FBP2, GCK, GYS2, FASN, GPAT, HMGCR, LDLR, ACC, SREBP2, and INSIG1 (P < 0.05). Moreover, different feeding regimes significantly affected the expression of FASN, GPAT, HMGCR, LDLR, ACACA, SREBP1, and INSIG1 (P < 0.05). In conclusion, dynamical feeding low- and high-methionine diets affected the variation of serum ALP and glucose levels, as well as the mRNA expression of circadian clock- and glucose and lipid metabolism-related genes in the liver of laying hens.

Maternal supplementation with calcium varying with feeding time daily during late pregnancy affects lipid metabolism and transport of placenta in pigs.

To investigate effects of Ca level varying with feeding time daily in sows during late pregnancy on placental lipid metabolism and transport in pigs, sixty pregnant sows were assigned to 3 groups: the CON group was fed low-Ca diet with 11.25 g CaCO3 at 0600 h and 1500 h, H-L group was fed low-Ca diet with 22.5 g CaCO3 at 0600 h and low-Ca diet at 1500 h, and L-H group was fed low-Ca diet at 0600 h and low-Ca diet with 22.5 g CaCO3 at 1500 h, respectively. Serum from sows and umbilical cord and placenta were collected during delivery. Results showed that, compared with the CON group, H-L feeding significantly increased maternal serum total triglyceride (TG) and umbilical serum high-density lipoprotein (HDL) (P < 0.05). The results showed that long chain fatty acid (FA) contents in placenta were significantly increased in H-L and L-H groups (P < 0.05). Experiments on genes involved in glycolipid metabolism showed that H-L or L-H feeding inhibited mRNA expression of GLUT3, GLUT4, FAS, FABP1, FABPpm, FAT/CD36, while activated the mRNA expression of FASD1, FASD2 and SCD in placenta (P < 0.05). In addition, experiments on genes involved in biological clock showed that L-H feeding sequence activated the mRNA expression of per1 and clock, while H-L and L-H feeding sequence inhibited mRNA expression of per2 in placenta (P < 0.05). It is concluded that maternal supplementation with Ca varying with feeding time daily during late pregnancy affects placental lipid metabolism and transport in pigs by regulating the mRNA expression related to lipid metabolism and the circadian clock.

The influence of phosphine ligand substituted [2Fe2S] model complexes as electro-catalyst on proton reduction.

To probe the influence of phosphine ligand substitution on the well-known [2Fe2S] model, two new [FeFe]-hydrogenase model complexes with the phosphine ligands, PMe3 or P(CH3O)3, were synthesized, such as µ-(SCH(CH2CH3)CH2S)-Fe2(CO)5PMe31, and µ-(SCH(CH2CH3)CH2S)-Fe2(CO)5P(CH3O)32 Confirmation of structures was provided by FTIR, 1H NMR, 13C NMR, 31P NMR, elemental analyses and single-crystal X-ray analysis. The crystal structure of complex 2 shows that the P(CH3O)3 ligand has less steric effect on the coordination geometry of the Fe atom than the PMe3 ligand. In the presence of HOAc in CH3CN solution, the hydrogen evolution overpotentials of complexes 1 and 2 were 0.91 V and 0.81 V, respectively. Comparatively, complex 2 produces hydrogen at an overpotential of 0.1 V, lower than that for complex 1. A further electrocatalytic study showed the maximum charges for 1 and 2 were 31.3 mC and 56.3 mC at -2.30 V for 10 min, respectively. These studies showed that the complexes 1 and 2 have the ability, as novel electrocatalysts, for catalysis of hydrogen production, and complex 2 has better electrocatalytic ability than complex 1.

A Maternal Two-meal Feeding Sequence with Varying Crude Protein Affects Milk Lipid Profile in A Sow-Piglet Model.

The effects of a two-meal feeding sequence on production performance and milk lipid profile were investigated. Sixty pregnant sows (d 85 of gestation) were assigned to 3 groups: 2 C group (fed a control crude protein [CP] diet at 0600 and 1500 daily), LH group (fed a low CP diet and a high CP diet at 0600 and 1500), or HL group (fed a high CP diet and a low CP diet at 0600 and 1500). Reproductive performance of sows, and lipid profiles of plasma and milk were measured. Results showed that the HL feeding sequence dramatically increased average piglet weight/litter, average daily gain of piglet/litter, and milk production of sows. LH feeding sequence increased milk fat proportion, and HL feeding sequence significantly increased the proportion of milk MUFA on d 14 and 21 of lactation. Interestingly, the HL feeding sequence also reduced the ratio of C18:1 cis /C18:1 trans in milk, which may account for the greater milk production of sows and growth performance of piglets during lactation. These findings indicated that both the maternal two-meal feeding sequences with varying crude protein improved milk production and milk lipid profiles of sows, which might contribute to improving growth performance of piglets.

Chiral Ceramic Nanoparticles and Peptide Catalysis.

The chirality of nanoparticles (NPs) and their assemblies has been investigated predominantly for noble metals and II-VI semiconductors. However, ceramic NPs represent the majority of nanoscale materials in nature. The robustness and other innate properties of ceramics offer technological opportunities in catalysis, biomedical sciences, and optics. Here we report the preparation of chiral ceramic NPs, as represented by tungsten oxide hydrate, WO3-x·H2O, dispersed in ethanol. The chirality of the metal oxide core, with an average size of ca. 1.6 nm, is imparted by proline (Pro) and aspartic acid (Asp) ligands via bio-to-nano chirality transfer. The amino acids are attached to the NP surface through C-O-W linkages formed from dissociated carboxyl groups and through amino groups weakly coordinated to the NP surface. Surprisingly, the dominant circular dichroism bands for NPs coated by Pro and Asp are different despite the similarity in the geometry of the NPs; they are positioned at 400-700 nm and 500-1100 nm for Pro- and Asp-modified NPs, respectively. The differences in the spectral positions of the main chiroptical band for the two types of NPs are associated with the molecular binding of the two amino acids to the NP surface; Asp has one additional C-O-W linkage compared to Pro, resulting in stronger distortion of the inorganic crystal lattice and greater intensity of CD bands associated with the chirality of the inorganic core. The chirality of WO3-x·H2O atomic structure is confirmed by atomistic molecular dynamics simulations. The proximity of the amino acids to the mineral surface is associated with the catalytic abilities of WO3-x·H2O NPs. We found that NPs facilitate formation of peptide bonds, leading to Asp-Asp and Asp-Pro dipeptides. The chiroptical activity, chemical reactivity, and biocompatibility of tungsten oxide create a unique combination of properties relevant to chiral optics, chemical technologies, and biomedicine.

Effects of a two-meal daily feeding pattern with varied crude protein levels on growth performance and antioxidant indexes in pigs.

The present study aimed to evaluate the effects of daily feeding pattern on growth performance, blood biochemistry, and antioxidant indexes in pigs. One hundred and eighty female Duroc × Landrace × Yorkshire (DLY) pigs with similar body weight (11.00 ± 0.12 kg) were randomly assigned to 3 groups: the control group (fed 17.01% CP diet, twice daily); high-low group (H-L group, fed 18.33% CP diet in the morning, followed by 15.70% CP diet in the afternoon); and low-high group (L-H group, fed 15.70% CP diet in the morning, followed by 18.33% CP diet in the afternoon) (n = 6). Comparable amounts of their respective diets were given at 05:30 and 15:00 throughout the experimental periods to make all the treatments consumed the same type of food and the same amount of calories on a daily basis. On day 30, one pig was randomly selected per litter for blood samples. Compared with the control group, ADG in the H-L and L-H groups increased by 8.11% and 16.23%, but not significant (P > 0.05); and blood urea nitrogen (BUN) in the H-L and L-H groups decreased by 26.76% and 41.04% (P < 0.05), respectively. The H-L group feeding pattern could significantly improve levels of serum superoxide dismutase (SOD), when compared with the control group. These findings suggest that the two-meal daily feeding pattern with varied levels of CP affects serum levels of BUN and SOD. These changes could effectively silightly improve growth performance and antioxidant capacity in pigs without incurring increased feeding costs.

Experimental investigation of all-optical nonreturn-to-zero differential phase-shift keying to return-to-zero DPSK format conversion based on nonlinear polarization rotation of semiconductor optical amplifier.

A novel all-optical nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) to return-to-zero DPSK (RZ-DPSK) format conversion scheme is proposed and experimentally demonstrated. This conversion is based on nonlinear polarization rotation of a semiconductor optical amplifier. Experimental results show that a 10 Gb/s RZ-DPSK signal with an extinction ratio over 10 dB can be converted with a tunable duty cycle from 33% to 66%, and the ER of the converted signal decreases with the increase in the duty cycle. For all cases of different duty cycles, the converted signals experience a -0.4 to -1.2 dB power penalty at a bit error rate of 10(-9) compared with the original signal. In addition, the spectra show that this format conversion is a wavelength-preserved operation.