Easy method to measure the packaging-induced stress of a semiconductor laser diode by lasing wavelength shifting.

In this paper, the packaging-induced stresses are theoretically calculated by modeling multilayered structures for different packaging structures. We report a method to measure the packaging-induced stress of a laser diode array (LDA) by comparing the emission wavelength of the single emitter located in the middle of a laser bar before and after packaging. The wavelength is tested under a low duty cycle (50 µs/10 Hz, DC 0.05%) to eliminate the thermal effect to wavelength shifting. Experimental calculation results for the packaging-induced stress of LDAs are in good agreement with the theoretical calculations and simulation results. For a GaAs laser bar, we find the packaging stresses are compression stresses, which make the emission wavelength blue-shift in terms of 1.09×10-2 nm/MPa. We propose a mapping of packaging-induced stress distribution in laser bars on a microscopic scale by considering the emission spectra of each emitter in a laser bar. Compared to single-emitter resolved photo-current or micro-photoluminescence measurements, as proposed by other authors, we offer a much easier tool to test and map the distribution of packaging-induced stress in laser bars.

NEFA-Sensitive Orai1 Expression in Regulation of De Novo Lipogenesis.

BACKGROUND/AIMS: Non-esterified fatty acids (NEFAs) are important inducers of inflammatory responses and hepatic lipid accumulation, which lead to non-alcoholic fatty liver disease (NAFLD). High plasma NEFA is found in NAFLD patients, and associated with metabolic syndrome and type-2 diabetes. NFκB is known to upregulate Orai1, the Ca2+ channel responsible for store-operated Ca2+ entry. The present study explored the role of NEFA-sensitive NFκB-dependent Orai1 expression in the regulation of lipid synthesis. METHODS: BRL-3A rat liver hepatocyte lines were studied in the absence and presence of NEFA. Transcript and protein expression levels of factors involved in lipid synthesis were quantified by quantitative polymerase chain reaction (qPCR) and western blot analyses. Fatty acids were measured by immunofluorescence. RESULTS: NEFA significantly increased, as indicated by the expression of sterol regulatory element-binding protein 1 (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase α (ACC1), Orai1, and NFκB p65 by qPCR and western blot analyses. These effects were reversed by the Orai1 inhibitor, 2-aminoethoxydiphenyl borate, and the NFκB inhibitor, wogonin. Furthermore, SREBP-1c, FAS, ACC1, and Orai1 were significantly decreased by Orai1 silencing. CONCLUSIONS: Taken together, these results demonstrated that NEFA-sensitive NFκB-dependent Orai1 expression regulates de novo lipogenesis.

Thermally induced chirp studies on spectral broadening of semiconductor laser diode arrays.

Spectral-width broadening has many factors. Diode lasers are not always monochromatic due to several broadening mechanisms, widening the energy distribution of emitted photons. In this paper, we report the two main factors affecting time average spectral-width broadening of a laser diode array (LDA)-a transient rise of the active region temperature of an LDA due to injection current, and the temperature and stress nonuniform distribution of different emitters within an LDA. We find that temperature and stress nonuniformity broadens the spectral width by almost 0.1-1.0 nm as a function of different operating conditions, while the thermally induced chirp that is attributed to injection current plays a more signification role in spectral-width broadening.

Effect of submount thickness on near-field bowing of laser diode arrays.

Near-field bowing a laser diode bar (i.e., the "SMILE" effect) degrades the laser beam brightness, adversely affecting optical coupling and beam shaping. Due to thermally induced stress during the bonding process, the emitters in a laser diode array (LDA) are vertically displaced, which causes the SMILE effect. The mismatch between the coefficients of thermal expansion of an LDA (GaAs with 6.4 ppm/K) and a heat sink (Cu with 16.4 ppm/K) is a large obstacle in the LDA bonding process, because it provokes thermal stress and a large SMILE value, resulting in a larger divergence angle and a wider line after focusing and collimation. In this paper, the changes in stress and strain (SMILE value) and their effects on the laser bar as a function of the copper-tungsten (CuW) submount thickness were theoretically and experimentally studied. The finite element modeling simulations and experimental results show that the compression stress on the laser bar decreases with increasing CuW submount thickness because the CuW submount works as a buffer layer and can absorb stress. However, the laser bar out-of-plane strain (SMILE value) is approximately zero when the LDA is directly bonded onto the heat sink without a submount; the SMILE value is maximized when the CuW submount thickness is increased to approximately one half or 44% of the heat sink. Beyond that, the SMILE value decreases with increasing CuW submount thickness.

Significant changes in ITIH4, AHSG, ORM1, and CD46 content in milk fat globule membrane proteins of ketotic dairy cows.

High concentrations of non-esterified fatty acid (NEFA) and ß-hydroxybutyrate (BHBA) in cows' blood caused by ketosis are associated with inflammatory states. We hypothesised that ketosis in postparturient dairy cows would result in altered levels on inflammation-related proteins not only in plasma but also in the milk fat globule membranes (MFGM). Thirty cows were selected from a dairy farm in Heilongjiang, China. Inflammatory milk fat globule membrane proteins were detected using ELISA kits, and a fully automatic biochemical analyser was used to measure the concentrations of BHBA, NEFA, glucose (GLU) and triglyceride (TG) in plasma. MFGM protein from milk of ketotic cows contained significantly different concentrations of acute-phase response proteins (complement C3 (C3), prothrombin (F2), alpha-1-acid glycoprotein (ORM1), inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), alpha-2-HS-glycoprotein (AHSG), complement C9 (C9), complement regulatory protein variant 4 (CD46)) in comparison with milk from non-ketotic cows. Blood concentrations of C3, complement C9 (C9), tumour necrosis factor α (TNFα), MFGM C3, monocyte differentiation antigen CD14 (CD14) and ORM1 levels were correlated with energy balance. ITIH4 and CD46 increased, and AHSG and ORM1 decreased before the onset of ketosis. These biomarkers offer potential as predictors and monitors of ketosis in at-risk cows.

Differentially expressed serum proteins associated with calcium regulation and hypocalcemia in dairy cows.

OBJECTIVE: Hypocalcemia is an important metabolic disease of dairy cows during the transition period, although the effect of hypocalcemia on biological function in dairy cows remains unknown. METHODS: In this study, proteomic, mass spectrum, bioinformatics and western blotting were employed to identify differentially expressed proteins related to serum Ca concentration. Serum samples from dairy cows were collected at three time points: 3rd days before calving (day -3), the day of calving (day 0), and 3rd days after calving (day +3). According to the Ca concentration on day 0, a total of 27 dairy cows were assigned to one of three groups (clinical, subclinical, and healthy). Samples collected on day -3 were used for discovery of differentially expressed proteins, which were separated and identified via proteomic analysis and mass spectrometry. Bioinformatics analysis was performed to determine the function of the identified proteins (gene ontology and pathway analysis). The differentially expressed proteins were verified by western blot analysis. RESULTS: There were 57 differential spots separated and eight different proteins were identified. Vitamin D-binding protein precursor (group-specific component, GC), alpha-2-macroglobulin (A2M) protein, and apolipoprotein A-IV were related to hypocalcemia by bioinformatics analysis. Due to its specific expression (up-regulated in clinical hypocalcemia and down-regulated in subclinical hypocalcemia), A2M was selected for validation. The results were consistent with those of proteomic analysis. CONCLUSION: A2M was as an early detection index for distinguishing clinical and subclinical hypocalcemia. The possible pathogenesis of clinical hypocalcemia caused by GC and apolipoprotein A-IV was speculated. The down-regulated expression of GC was a probable cause of the decrease in calcium concentration.

Protein profiling of plasma proteins in dairy cows with subclinical hypocalcaemia.

Subclinical hypocalcaemia (SH) is an important metabolic disease in dairy cows that has a serious impact on production performance. The objective of this study was to investigate novel aspects of pathogenesis using proteomics technology to identify proteins that are differentially expressed in diseased and healthy animals. Dairy cows were divided into an SH group (T, n = 10) and a control group (C, n = 10) based on plasma calcium concentration. A total of 398 differentially expressed proteins were identified, of which 265 proteins were overlapped in the two parallel experiments. Of these, 24 differentially expressed proteins were statistically significant. Gene Ontology analysis yielded 74 annotations, including 7 cellular component, 55 biological process and 12 molecular function categories. Bioinformatics analysis indicated that calcium regulation, immune and inflammatory response, blood coagulation and complement pathway were all related to SH. Our iTRAQ/LC-MS/MS (isobaric tags for relative and absolute quantification/liquid chromatography-mass spectrometry/mass spectrometry) approach proved highly effective for plasma protein profiling of dairy cows with SH, and the results pave the way for further studies in this area.

(1)H-Nuclear Magnetic Resonance-Based Plasma Metabolic Profiling of Dairy Cows with Fatty Liver.

Fatty liver is a common metabolic disorder of dairy cows during the transition period. Historically, the diagnosis of fatty liver has involved liver biopsy, biochemical or histological examination of liver specimens, and ultrasonographic imaging of the liver. However, more convenient and noninvasive methods would be beneficial for the diagnosis of fatty liver in dairy cows. The plasma metabolic profiles of dairy cows with fatty liver and normal (control) cows were investigated to identify new biomarkers using (1)H nuclear magnetic resonance. Compared with the control group, the primary differences in the fatty liver group included increases in ß-hydroxybutyric acid, acetone, glycine, valine, trimethylamine-N-oxide, citrulline, and isobutyrate, and decreases in alanine, asparagine, glucose, γ-aminobutyric acid glycerol, and creatinine. This analysis revealed a global profile of endogenous metabolites, which may present potential biomarkers for the diagnosis of fatty liver in dairy cows.

Male-specific phosphorylated SR proteins in adult flies of the Mediterranean fruitfly Ceratitis capitata.

Alternative splicing is a widely used mechanism of gene regulation in sex determination pathways of Insects. In species from orders as distant as Diptera, Hymenoptera and Coleoptera, female differentiation relies on the activities of conserved splicing regulators, TRA and TRA-2, promoting female-specific expression of the global effector doublesex (dsx). Less understood is to what extent post-translational modifications of splicing regulators plays a role in this pathway. In Drosophila melanogaster phosphorylation of TRA, TRA-2 and the general RBP1 factor by the LAMMER kinase doa (darkener of apricot) is required for proper female sex determination. To explore whether this is a general feature of the pathway we examined sex-specific differences in phosphorylation levels of SR splicing factors in the dipteran species D. melanogaster, Ceratitis capitata (Medfly) and Musca domestica (Housefly). We found a distinct and reproducible pattern of male-specific phosphorylation on protein extracts enriched for SR proteins in C. capitata suggesting that differential phosphorylation may also contribute to the regulation of sex-specific splicing in the Medfly.

Plasma metabolomic profiling of dairy cows affected with ketosis using gas chromatography/mass spectrometry.

BACKGROUND: Ketosis is an important problem for dairy cows` production performance. However, it is still little known about plasma metabolomics details of dairy ketosis. RESULTS: A gas chromatography/mass spectrometry (GC/MS) technique was used to investigate plasma metabolic differences in cows that had clinical ketosis (CK, n=22), subclinical ketosis (SK, n=32), or were clinically normal controls (NC, n=22). The endogenous plasma metabolome was measured by chemical derivatization followed by GC/MS, which led to the detection of 267 variables. A two-sample t-test of 30, 32, and 13 metabolites showed statistically significant differences between SK and NC, CK and NC, and CK and SK, respectively. Orthogonal signal correction-partial least-square discriminant analysis (OPLS-DA) revealed that the metabolic patterns of both CK and SK were mostly similar, with the exception of a few differences. The development of CK and SK involved disturbances in many metabolic pathways, mainly including fatty acid metabolism, amino acid metabolism, glycolysis, gluconeogenesis, and the pentose phosphate pathway. A diagnostic model arbitrary two groups was constructed using OPLS-DA and receiver-operator characteristic curves (ROC). Multivariate statistical diagnostics yielded the 19 potential biomarkers for SK and NC, 31 for CK and NC, and 8 for CK and SK with area under the curve (AUC) values. Our results showed the potential biomarkers from CK, SK, and NC, including carbohydrates, fatty acids, amino acids, even sitosterol and vitamin E isomers, etc. 2-piperidinecarboxylic acid and cis-9-hexadecenoic acid were closely associated with metabolic perturbations in ketosis as Glc, BHBA and NEFA for dealing with metabolic disturbances of ketosis in clinical practice. However, further research is needed to explain changes of 2,3,4-trihydroxybutyric acid, 3,4-dihydroxybutyric acid, α-aminobutyric acid, methylmalonic acid, sitosterol and α-tocopherol in CK and SK, and to reveal differences between CK and SK. CONCLUSION: Our study shows that some new biomarkers of ketosis from plasma may find new metabolic changes to have clinically new utility and significance in diagnosis, prognosis, and prevention of ketosis in the future.

Effect of NEFA and glucose levels on CPT-I mRNA expression and translation in cultured bovine hepatocytes.

The objective of this study was to determine the effects of NEFA and glucose on carnitine palmitoyltransferase-I (CPT-I) mRNA expression in cultured bovine hepatocytes using real-time reverse transcription polymerase chain reaction and ELISA methods. The results indicated that CPT-I transcription increased gradually, but that CPT-I translation was not significantly changed, with glucose concentrations ranging from 0 to 3.0 mmol/L (P<0.01). Furthermore CPT-I transcription and translation were enhanced significantly when the NEFA concentrations increased from 0 to 1.2 mmol/L and decreased significantly when the NEFA concentrations increased from 1.2 to 4.8 mmol/L (P<0.01). A high concentration NEFA was found to reduce fatty acid oxidation, potentially explaining the development from NEB to ketosis in dairy cows.

Plasma Proteomics Characteristics of Subclinical Vitamin E Deficiency of Dairy Cows During Early Lactation.

Vitamin E (VE) is an essential fat-soluble nutrient for dairy cows. Vitamin E deficiency leads to immune suppression and oxidative stress and increases the susceptibility of cows to reproductive disorders in the early post-partum period. However, studies on plasma proteomics of VE deficiency have not been reported so far. Therefore, the purpose of this study was to understand the changes of blood protein profile in cows with subclinical VE deficiency in the early post-partum period. In this study, plasma protein levels of 14 healthy cows (>4 µg/ml α-tocopherol) and 13 subclinical VE-deficient cows (2-3 µg/ml α-tocopherol) were analyzed by tandem mass tag (TMT). The results showed that there were 26 differentially expressed proteins (DEPs) in the plasma of cows with subclinical VE deficiency compared with healthy controls. Twenty-one kinds of proteins were downregulated, and five kinds were upregulated, among which eight proteins in protein-protein interactions (PPI) network had direct interaction. These proteins are mainly involved in the MAPK signaling pathway, pantothenic acid and coenzyme A (CoA) biosynthesis, PPAR signaling pathway, and glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The top four DEPs in PPI (APOC3, APOC4, SAA4, PHLD) and one important protein (VNN1) by literature review were further verified by ELISA and Western blot. The expression levels of APOC3, VNN1, and SAA4 were significantly lower than those of healthy controls by ELISA. VNN1 was significantly lower than those of healthy controls by Western blot. VNN1 is closely related to dairy cow subclinical VE deficiency and can be a potential biomarker. It lays a foundation for further research on the lack of pathological mechanism and antioxidative stress of VE.

Follicular Fluid Metabolite Changes in Dairy Cows with Inactive Ovary Identified Using Untargeted Metabolomics.

The metabolism of dairy cows with inactive ovaries differs from that of healthy dairy cows. However, the molecular mechanisms underpinning these physiological and metabolic changes remain unclear. The purpose of this study was to investigate follicular fluid metabolite changes in dairy cows with inactive ovaries. Untargeted metabolomics technology and multivariate statistical analysis were used to screen differential metabolites in follicular fluid samples between inactive ovaries and estrus cows at 45-60 d postpartum. Fourteen differential metabolites were identified, consisting of amino acids, lipids, sugars, and nucleotides. When compared with healthy animal samples, eight follicular fluid metabolites were significantly increased, and six metabolites were significantly decreased in dairy cows with inactive ovaries. Metabolic pathway analyses indicated that differential metabolites were primarily involved in glycerol phospholipid metabolism, arachidonic acid metabolism, valine, leucine and isoleucine biosynthesis, and phenylalanine metabolism. These metabolites and their enrichment pathways indicate that the enhancement of lipid metabolism and the weakening of carbohydrate production of amino acids in dairy cows with impaired follicular development. Overall, these data provide a better understanding of the changes that could affect follicular development during the postpartum period and lay the ground for further investigations.

[Isolation, identification and rumen fermentation characteristics of Propionibacterium acnes].

OBJECTIVES: Characteristic of energy metabolism in ruminant is a negative energy balance in perinatal period. Propionic acid from ruminal microbe fermentation is a vital glyconeogenesis substrate for preventing negative energy balance. We isolated and screened a Propionibacterium acnes strain from health cow rumen fluid, and studied its rumen fermentation characteristics. METHODS: A Propionibacterium acnes strain from rumen fluid of health cow with permanent rumen fistula under sterile condition was isolated by segregation procedure of anaerobic bacterium and Sodium Lactate Broth (SLB), and identified by extraction of the genome DNA, cloning of the 16S rRNA gene, and sequencing. We studied the effect of the strain on pH, volatile fatty acid and lactic acid in rumen fluid in vitro and in vivo. RESULTS: A bacterium isolated from health cow rumen fluid was identified as Propionibacterium acnes by morphology, biochemical characteristics and sequence homology. In vitro, pH in rumen fluid decreased to the lowest after rumen fermentation of the strain for 12 h, then increased gradually. However, concentration of volatile fatty acid, such as acetic acid, propionic acid and butyric acid, increased to the highest after rumen fermentation of the strain for 12 h, then decreased gradually in vitro. The concentration of lactic acid and ratio of acetate to propionate decreased overall in vitro. In vivo, pH in rumen fluid decreased overall, concentration, of the volatile fatty acid increased overall. CONCLUSIONS: A strain of Propionibacterium acnes was isolated successfully from health cow rumen fluid. It is an important basis to develop microecological preparation for preventing cows' negative energy balance in perinatal period in future.

Agricultural waste-derived activated carbon/graphene composites for high performance lithium-ion capacitors.

Agricultural waste, corncob-derived activated carbon (AC) is prepared by pre-carbonization of the precursors and activation of KOH of the pyrolysis products. The AC oxidized by HNO3 is called OAC. The OAC/reduced graphene oxide (rGO) composites are prepared by urea reduction (aqueous mixture of OAC and graphene oxide). The influence of the mass ratio of graphene oxide (GO) on the electrochemical properties of OAC/rGO composites as electrode materials for electrochemical capacitors is studied. It is found that the rGO sheets were used as a wrinkled carrier to support the OAC particles. The pore size distribution and surface area are dependent on the GO mass ratio. In addition, the rate capability of OAC is improved by introducing GO. For the OAC/rGO composites prepared from precursors with a GO mass ratio of 5%, the best rate performance was achieved. The lithium ion capacitor, based on OAC/rGO as cathode and Si/C as anode, exhibits a high energy density of 141 W h kg-1 at 1391 W kg-1. 78.98% capacity retention is achieved after 1000 cycles at 0.4 A g-1.

Effects of Ketosis in Dairy Cows on Blood Biochemical Parameters, Milk Yield and Composition, and Digestive Capacity.

INTRODUCTION: This study aimed to characterise the effects of ketosis on milk yield and composition and digestive capacity in transition dairy cows. MATERIAL AND METHODS: Seven ketotic and seven healthy cows were housed in individual stalls for six days. Samples of plasma, milk, refused total mixed ration, and faeces were collected, and the blood biochemical parameters, milk yield and composition, dry matter intake, and faecal dry matter (FDM) production were determined. RESULTS: Compared with healthy cows, the ketotic cows had significantly higher concentrations of milk fat and citrate, but lower levels of milk protein and lactose. The cows exhibited a need for acid detergent fibre in forage and better digestion of neutral detergent fibre, starch, crude protein, and phosphorus than healthy cows, but more fat and gross energy were excreted in their faeces. Ketotic cows had higher energy-corrected milk yields and lower FDM than healthy cows. CONCLUSION: Lower feed intake coinciding with the requirement to maintain high milk production is considered to be the cause of ketosis in dairy cows. Ketotic cows exhibited lower dry matter fat digestion.

Corrigendum: NFκB/Orai1 Facilitates Endoplasmic Reticulum Stress by Oxidative Stress in the Pathogenesis of Non-alcoholic Fatty Liver Disease.

[This corrects the article DOI: 10.3389/fcell.2019.00202.].

NFκB/Orai1 Facilitates Endoplasmic Reticulum Stress by Oxidative Stress in the Pathogenesis of Non-alcoholic Fatty Liver Disease.

Non-esterified fatty acids (NEFAs) promote de novo lipogenesis, which caused abnormal hepatic lipid accumulation, by the NFκB-Orai1 pathway. Oxidative stress and endoplasmic reticulum (ER) stress have been recognized as key mechanisms in non-alcoholic fatty liver disease (NAFLD) pathogenesis. Whether Orai1 facilitates ER stress by oxidative stress remains unknown. The rat model of NAFLD was constructed by feeding high-fat diet (HFD). BRL-3A cells were treated with NEFAs, Orai1inhibtor BTP2, NFκB inhibitor wogonin, or small interfering Orai (siOrai) 1, respectively. The content of intracellular reduced glutathione (GSH) and malondialdehyde (MDA), indicating oxidative stress, was measured by a spectrophotometer. ER stress major proteins PERK, IRE1, ATF6, CHOP, and GRP78 were quantified using Western blot and qRT-PCR analyses. For the intracellular location of reactive oxygen species (ROS) and Orai1 were measured by Western blot and immunofluorescence, and cytosolic Ca2+ was measured by flow cytometry. As we expected, the liver of rats with NAFLD showed lipid droplets in HE and Oil Red O. The decreased GSH and increased MDA were found in rats fed with HFD. ER stress major proteins PERK, IRE1, ATF6, GRP78, and CHOP were significantly increased in the HFD group. In BRL-3A cells, GSH content dramatically decreased from 1 h, MDA content dramatically increased from 3 h, and expression levels of ER stress significantly increased from 3 h by NEFA treatment. Furthermore, cytosolic Ca2+ increased from 0.5 h by NEFAs treated in BRL-3A cells. It indicated that NEFAs increased cytosolic Ca2+ to induce oxidative stress, thus ER stress. The content of oxidative stress and ER stress proteins showed the same trends by NEFAs treated in BRL-3A cells. These effects were reversed by the Orai1 inhibitor BTP2 and the NFκB inhibitor wogonin. Moreover, siOrai1 abrogated NEFAs' influence in BRL-3A cells. Last, ROS was found by NEFAs treated in BRL-3A cells, and NEFA treatment enhanced the nuclear localization of NF-κB p65 and ORAI1. It was considered that high NEFAs increased cytosolic Ca2+ and enhanced NFκB-dependent SOCE and its moiety protein Orai1 to decrease GSH and thus induced oxidative stress at earlier stages and furthermore tempted ER stress in the pathologic progress of NAFLD.

Electrode Materials, Electrolytes, and Challenges in Nonaqueous Lithium-Ion Capacitors.

Among the various energy-storage systems, lithium-ion capacitors (LICs) are receiving intensive attention due to their high energy density, high power density, long lifetime, and good stability. As a hybrid of lithium-ion batteries and supercapacitors, LICs are composed of a battery-type electrode and a capacitor-type electrode and can potentially combine the advantages of the high energy density of batteries and the large power density of capacitors. Here, the working principle of LICs is discussed, and the recent advances in LIC electrode materials, particularly activated carbon and lithium titanate, as well as in electrolyte development are reviewed. The charge-storage mechanisms for intercalative pseudocapacitive behavior, battery behavior, and conventional pseudocapacitive behavior are classified and compared. Finally, the prospects and challenges associated with LICs are discussed. The overall aim is to provide deep insights into the LIC field for continuing research and development of second-generation energy-storage technologies.

Predictive Value of Plasma Parameters in the Risk of Postpartum Ketosis in Dairy Cows.

INTRODUCTION: The predictive value of selected parameters in the risk of ketosis and fatty liver in dairy cows was determined. MATERIAL AND METHODS: In total, 21 control and 17 ketotic Holstein Friesian cows with a ß-hydroxybutyrate (BHBA) concentration of 1.20 mmol/L as a cut-off point were selected. The risk prediction thresholds for ketosis were determined by receiver operating characteristic (ROC) curve analysis. RESULTS: In the ketosis group, paraoxonase-1 (PON-1) activity and concentration of PON-1 and glucose (GLU) were decreased, and aminotransferase (AST) activity as well as BHBA and non-esterified fatty acid (NEFA) contents were increased. The plasma activity and concentration of PON-1 were significantly positively correlated with the level of plasma GLU. The plasma activity and concentration of PON-1 were significantly negatively correlated with the levels of AST and BHBA. According to ROC curve analysis, warning indexes of ketosis were: plasma PON-1 concentration of 46.79 nmol/L, GLU concentration of 3.04 mmol/L, AST concentration of 100 U/L, and NEFA concentration of 0.82 mmol/L. CONCLUSION: This study showed that the levels of PON-1, GLU, AST, and NEFA could be used as indicators to predict the risk of ketosis in dairy cows.