[Imaging findings of supratentorial embryonal tumor with multilayered rosettes in children].

We analyzed and summarized the imaging characteristics and clinical data of seven pediatric supratentorial embryonal tumors with multilayered rosettes (ETMR). There were four boys and three girls aged from two to six years old. Pediatric supratentorial ETMR often presented large cystic and solid mass, calcification, significant mass effect and mild peritumoral edema. The solid part often showed heterogeneous mild enhancement. In combination with the location of tumor and age of onset, the typical imaging manifestations of supratentorial ETMR in children are valuable for accurate diagnosis.

[Application of apparent diffusion coefficient histogram in moderate to severe neonatal hypoxic-ischemic encephalopathy].

Objective: To investigate the diagnostic value of apparent diffusion coefficient (ADC) histogram in quantifying moderate to severe neonatal hypoxic-ischemic encephalopathy (HIE). Methods: A total of 49 children with moderate to severe HIE admitted to the Children's Hospital Affiliated to Nanjing Medical University from July 2015 to September 2018 were retrospectively analyzed. Cranial magnetic resonance imaging (MRI) data of 31 full-term neonates without neurological symptoms and signs who visited the hospital during the same period were recruited as the control group. ImgJ software was used to delineate the whole brain area at the thalamus/basal ganglia level as the area of interest, and MRIcron software was used to obtain ADC histogram parameters. The differences of ADC histogram parameters between HIE group and control group were compared. The correlation between ADC histogram parameters and neonatal neurobehavioral neurological assessment (NBNA) in HIE group was analyzed. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency of each parameter. Results: The mean value, minimum value, maximum value, mode-value, variance, heterogeneity and 10%-90% ADC values of HIE group were all greater than those of the control group(634±65,310±36,1 683±18,711±87,66 928±921,5 907±204,477±50,513±53,542±56,568±59,591±61,625±92,661±97,709±105,811±119),the differences were statistically significant(all P<0.05), while mode-count of HIE group was smaller than that of the control group(272±22 to 395±83), and the difference was statistically significant (t=2.996,P<0.05). All the above parameters with statistical differences were correlated with NBNA score, among which mode-count was negatively correlated with NBNA score(r=-0.369,P<0.05), and the rest were positively correlated(all P<0.05). The area under the ROC curve (AUC) of variance had the highest diagnostic efficiency (0.881), followed by 90% ADC value and ADC maximum value. Conclusion: ADC histogram is helpful for the diagnosis of HIE, objectively and quantitatively reflecting the diffusion information of brain, and assessing the severity of HIE.

[Classification of the types of pediatric posterior fossa brain tumors based on routine MRI using wavelet transformation analysis of whole tumor].

Objective: To evaluate the classification of the types of pediatric posterior fossa brain tumors based on routine MRI (T(1)WI, T(2)WI and ADC) using wavelet transformation analysis of whole tumor. Methods: MRI images of medulloblastoma (n=59), ependymoma (n=13) and pilocytic astrocytoma (n=27) confirmed by pathology before treatments in Children's Hospital of Nanjing Medical University from January 2014 to February 2019 were enrolled in this retrospective study as well as the clinical data of age, gender and symptoms. Registration was performed among the three sequences and wavelet features of ROI were acquired. Afterwards, the top ten features were ranked and trained among groups by using random forest classifier. Finally, the results were compared and analyzed according to the classification. Results: The top ten contribution three sequences and wavelet features of ROI were acquired from the ADC sequence. The random forest classifier achieved 100% accuracy on training data and was validated best accuracy (86.8%) when combined of first and third wavelet features. The sensitivity was 100%, 94.8%, 76.9%, and the specificity was 97.6%, 88.0%, 98.8% respectively. Conclusions: Features based on wavelet transformation of ADC sequence of entire tumor can provide more quantitative information, which could provide help in the differential diagnosis of pediatric posterior fossa brain tumors. The optimum combination to distinguish three pediatric posterior fossa brain tumors is sixth and twelfth wavelet features of ADC sequence.

[Brain alteration in neonates with congenital heart disease using apparent diffusion coefficient histograms].

Objective: To evaluate the value of apparent diffusion coefficient (ADC) histogram in neonatal brain alteration with congenital heart disease (CHD). Methods: MRIs of 60 neonates with CHD confirmed by echocardiography were retrospectively analyzed in Children's Hospital of Nanjing Medical University from January 2012 to December 2016.Twenty-two MRIs of neonates with mild pneumonia or scalp hematoma who were suspicious of brain disease but normal MRI findings were enrolled as normal control.MRIcron and ImgJ softwares were used to acquire ADC histogram.The correlation between the gestational age and ADC histogram values were calculated respectively.Then t-test was used to analyze the differences of the histogram values and the diagnostic efficacy of different parameters was analyzed using the receiver operating characteristic curve. Results: The ADC values were significantly correlated with the gestational age (P<0.05). The 70th-90th ADC, skewness, kurtosis and variance were statistically significant (P<0.05). The area under the curve of the 90th ADC value was the largest at 0.698. Conclusions: The ADC histogram can quantify and objectively provide more diffusion information of brain tissue. It is a rapid and feasible quantitative method to identify brain changes in neonates with CHD.

Phonon-Assisted Resonant Tunneling of Electrons in Graphene-Boron Nitride Transistors.

We observe a series of sharp resonant features in the differential conductance of graphene-hexagonal boron nitride-graphene tunnel transistors over a wide range of bias voltages between 10 and 200 mV. We attribute them to electron tunneling assisted by the emission of phonons of well-defined energy. The bias voltages at which they occur are insensitive to the applied gate voltage and hence independent of the carrier densities in the graphene electrodes, so plasmonic effects can be ruled out. The phonon energies corresponding to the resonances are compared with the lattice dispersion curves of graphene-boron nitride heterostructures and are close to peaks in the single phonon density of states.

Development of a quantitative real-time PCR assay for direct detection of growth of cellulose-degrading bacterium Clostridium thermocellum in lignocellulosic degradation.

AIMS: Currently, there is no direct method for detecting Clostridium thermocellum in the insoluble medium. In this study, a quantitative real-time PCR assay was developed for the direct growth detection of C. thermocellum at the single-cell level in lignocellulosic biomasses. METHODS AND RESULTS: The assay targeted the cipA gene and was able to distinguish C. thermocellum from other species with good reproducibility which quantitative detection limit was 10 cell equivalents (CE) per reaction. OD600-based counting and qPCR quantification of C. thermocellum cultured in soluble medium were compared and an excellent consistency was revealed, indicating the appropriateness of the developed qPCR method. Analysis based on yellow affinity substrate and fermentation products may incorrectly estimate its population. CONCLUSIONS: The developed assay can serve as a specific, sensitive and reproducible method for the detection of C. thermocellum in lignocellulosic biomass at the single-cell level. SIGNIFICANCE AND IMPACT OF THE STUDY: With the ability to rapidly detect C. thermocellum, this method will contribute substantially to the understanding of the lignocellulosic biomass degradation mechanism. Moreover, it can also be applied to detect C. thermocellum growth in certain co-culture system for the understanding of the metabolic interactions.

Maternal obesity downregulates microRNA let-7g expression, a possible mechanism for enhanced adipogenesis during ovine fetal skeletal muscle development.

BACKGROUND: Obesity in women of childbearing age is increasing at an alarming rate. Growing evidence shows that maternal obesity induces detrimental effects on offspring health, including pre-disposition to obesity. We have shown that maternal obesity increases fetal intramuscular adipogenesis at mid-gestation. However, the mechanisms are poorly understood. MicroRNAs (miRNAs) regulate mRNA stability. We hypothesized that maternal obesity alters fetal muscle miRNA expression, thereby influencing intramuscular adipogenesis. METHODS: Non-pregnant ewes received a control diet (Con, fed 100% of National Research Council (NRC) recommendations, n=6) or obesogenic diet (OB; 150% NRC recommendations, n=6) from 60 days before to 75 days after conception when the fetal longissimus dorsi (LD) muscle was sampled and miRNA expression analyzed by miRNA microarray. One of miRNAs with differential expression between Con and OB fetal muscle, let-7g, was further tested for its role in adipogenesis and cell proliferation in C3H10T1/2 cells. RESULTS: A total of 155 miRNAs were found with a signal above 500, among which, three miRNAs, hsa-miR-381, hsa-let-7g and bta-miR-376d, were differentially expressed between Con and OB fetuses, and confirmed by quantitative real-time PCR (QRT-PCR) analyses. Reduced expression of miRNA let-7g, an abundantly expressed miRNA, in OB fetal muscle was correlated with higher expression of its target genes. Overexpression of let-7g in C3H10T1/2 cells reduced their proliferation rate. Expression of adipogenic markers decreased in cells overexpressing let-7g, and the formation of adipocytes was also reduced. Overexpression of let-7g decreased expression of inflammatory cytokines. CONCLUSION: Fetal muscle miRNA expression was altered due to maternal obesity, and let-7g downregulation may enhance intramuscular adipogenesis during fetal muscle development in the setting of maternal obesity.

Experimental quantum computing to solve systems of linear equations.

Solving linear systems of equations is ubiquitous in all areas of science and engineering. With rapidly growing data sets, such a task can be intractable for classical computers, as the best known classical algorithms require a time proportional to the number of variables N. A recently proposed quantum algorithm shows that quantum computers could solve linear systems in a time scale of order log(N), giving an exponential speedup over classical computers. Here we realize the simplest instance of this algorithm, solving 2×2 linear equations for various input vectors on a quantum computer. We use four quantum bits and four controlled logic gates to implement every subroutine required, demonstrating the working principle of this algorithm.

The impact of probiotics on gut microbiota in the eradication of Helicobacter pylori infection: a systematic review.

OBJECTIVE: The effect of probiotics supplementation on the gut microbiota in Helicobacter pylori (H. pylori) eradication therapy is controversial. Therefore, this review aimed to illustrate changes in the gut microbiota after standard eradication therapy with probiotics supplements. MATERIALS AND METHODS: A computerized literature search in PubMed, Cochrane Library, Web of Science, and Embase database was performed up to February 1st, 2022, with English language restriction. The extracted outcomes were analyzed, including gut microbiota, adverse effects, and eradication rate. RESULTS: 13 studies reported data on 777 participants who were finally eligible for this systematic review. All of them are randomized controlled trials investigating the effect of H. pylori eradication with probiotics supplementation therapy on gut microbiota. Probiotics supplementation seems to play a positive role in restoring the gut microbiota during H. pylori eradication therapy. However, the changes in the gut microbiota are still controversial. The included studies had significant heterogeneity in the study population, diagnostic methods of H. pylori infection, and detection techniques of the gut microbiota and probiotics species. CONCLUSIONS: The results provided a basis for the rational selection of probiotics in the H. pylori eradication process. Probiotic supplementation might keep the balance of gut microbiota and reduce the gastrointestinal adverse effects of antibiotics, but whether it could improve the eradication rate or not is a debatable point. Therefore, more research is needed to provide evidence.

Application of standard addition for the determination of carboxypeptidase activity in Actinomucor elegans bran koji.

Leucine carboxypeptidase (EC 3.4.16) activity in Actinomucor elegans bran koji was investigated via absorbance at 507 nm after stained by Cd-nihydrin solution, with calibration curve A, which was made by a set of known concentration standard leucine, calibration B, which was made by three sets of known concentration standard leucine solutions with the addition of three concentrations inactive crude enzyme extract, and calibration C, which was made by three sets of known concentration standard leucine solutions with the addition of three concentrations crude enzyme extract. The results indicated that application of pure amino acid standard curve was not a suitable way to determine carboxypeptidase in complicate mixture, and it probably led to overestimated carboxypeptidase activity. It was found that addition of crude exact into pure amino acid standard curve had a significant difference from pure amino acid standard curve method (p < 0.05). There was no significant enzyme activity difference (p > 0.05) between addition of active crude exact and addition of inactive crude kind, when the proper dilute multiple was used. It was concluded that the addition of crude enzyme extract to the calibration was needed to eliminate the interference of free amino acids and related compounds presented in crude enzyme extract.

Wagyu-Angus cross improves meat tenderness compared to Angus cattle but unaffected by mild protein restriction during late gestation.

For the spring-calving beef herds, late gestation coincides with winter and early spring, when cows are dependent on feed supplements with low quality hay, which is hard to meet their nutrient requirements. However, the effects of deficiencies of metabolizable protein intake during late gestation on offspring beef quality are unclear. Wagyu cattle have excellent marbling, and insemination with Wagyu vs Angus semen is a practical option for beef producers to improve beef quality. To test, Angus cows (621 ±â€¯73 kg) were selected and randomly separated into two groups. Each group was inseminated with either Angus or Wagyu semen. During the last 90 days of gestation, cows in each group were further separated and received either a low protein diet (85% of the NRC metabolizable protein requirement), which was a low quality hay-based diet common in northwestern region of the U.S., or an adequate protein diet (108% NRC requirement). All progeny was managed together and harvested at a final BW of 576.5 ±â€¯16.6 kg. Wagyu-sired offspring had higher marbling scores and quality grades than Angus (P < 0.01). Protein supplementation did not affect Slice Shear Force (SSF) in either breeds (P = 0.60). However, Wagyu-sired cattle had lower SSF than Angus-sired (P < 0.01). In addition, Wagyu-sired cattle had higher intramuscular fat (P < 0.05) and total collagen content (P < 0.05), but Angus-sired had greater mature collagen cross-links, as shown by higher contents of Pyridinoline (P < 0.01) and Ehrlich Chromogen (P < 0.01). Consistently, the mRNA expression of enzymes catalyzing collagen cross-linking was higher in Angus-sired offspring, including Plod 1 (P < 0.05), Plod 2 (P = 0.08), and P4Hα 2 (P < 0.01). In conclusion, Wagyu-sired cattle had greater tenderness and marbling score compared to Angus-sired, which was associated with lower collagen cross-links. Feeding mature grass hay-based diet with relatively low protein content during late gestation had no major effect on beef quality of subsequent cattle.

Identification and characterization of microRNAs from porcine skeletal muscle.

MicroRNAs (miRNAs) are a class of non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. There is increasing evidence to suggest that miRNAs participate in muscle development in mice and humans; however, few studies have focused on miRNAs in porcine muscle tissue. Here, we experimentally detected and identified conserved and unique miRNAs from porcine skeletal muscle. Fifty-seven distinct miRNAs were identified, of which 39 have not been reported earlier in the pig. Of these, two miRNAs appear to be novel and pig-specific. Surprisingly, these two differ only by a single nucleotide. A part of their primary transcript was cloned and confirmed by sequencing analysis. Alignment of the two sequences using ClustalW showed that the precursor sequences were almost identical, but the flanking sequences were different, indicating that these two novel miRNAs may represent rapidly evolving miRNAs in the pig genome. The expression patterns of eight miRNAs were characterized by real-time polymerase chain reaction of eight pig tissue samples. The ssc-let-7e and ssc-miR-181b miRNAs were expressed in all tissues analysed. The ssc-let-7c, ssc-miR-125b, ssc-miR-new1 and ssc-miR-new2 miRNAs were expressed in several tissues, while ssc-miR-122 and ssc-miR-206 were specifically expressed in the liver and muscle respectively. Our results add to existing data on porcine miRNAs and are useful for investigating the biological functions of miRNAs in porcine skeletal muscle development.

Increased tau phosphorylation and beta amyloid in the hipocampus of mouse pups by early life lead exposure.

The aim of this study was to investigate the effects of maternal lead exposure on the learning and memory ability and expression of tau protein phosphorylation (P-tau) and beta amyloid protein (Abeta) in hippocampus of mice offspring. Pb exposure initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.5% and 1% groups. On the 21 th of postnatal day, the learning and memory ability of the mouse pups was tested by Water Maze test and the Pb levels in blood and hippocampus of the offspring were also determined. The expression of P-tau and Abeta in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group ( P < 0.05). In Water Maze test, the performances of 0.5% and 1% groups were worse than that of the control group ( P < 0.05). The expression of P-tau and Abeta was increased in Pb exposed groups than that of the control group ( P < 0.05). Tau hyper-phosphorylation and Abeta increase in the hippocampus of pups may contribute to the impairment of learning and memory associated with maternal Pb exposure.

Investigation of Lpin1 as a candidate gene for fat deposition in pigs.

Lpin1 deficiency prevents normal adipose tissue development and remarkably reduces adipose tissue mass, while overexpression of the Lpin1 gene in either skeletal muscle or adipose tissue promotes adiposity in mice. However, little is known about the porcine Lpin1 gene. In the present study, a 5,559-bp cDNA sequence of the porcine Lpin1 gene was obtained by RT-PCR and 3'RACE. The sequence consisted of a 111-bp 5'UTR, a 2,685-bp open reading frame encoding a protein of 894 amino acids and a 2,763-bp 3'UTR. Semi-quantitative RT-PCR analysis revealed that Lpin1 had a high level of expression in the liver, spleen, skeletal muscle and fat, a low level of expression in the heart, lung and kidney. The porcine Lpin1 gene was assigned to 3q21-27 by using the somatic cell hybrid panel (SCHP) and the radiation hybrid (IMpRH) panel. One C93T single nucleotide polymorphism (SNP) was identified and genotyped using the TaqI PCR-RFLP method. Association analysis between the genotypes and fat deposition traits suggested that different genotypes of the Lpin1 gene were associated with percentage of leaf fat and intramuscular fat.

Fate of Listeria monocytogenes in ready-to-eat turkey breast rolls formulated with antimicrobials following electron-beam irradiation.

The objective of this study was to determine the effect of antimicrobials on the survival and proliferation of Listeria monocytogenes in turkey breast rolls following electron-beam irradiation. Six antimicrobial additive treatments that include no preservatives (control), 0.1% potassium benzoate (PB), 2% sodium lactate (SL), 0.1% potassium benzoate plus 2% sodium lactate (PB + SL), 2% sodium lactate plus 0.1% sodium diacetate (SL + SDA), and 0.1% potassium benzoate, 2% sodium lactate, and 0.1% sodium diacetate (PB + SL + SDA) were used. Sliced turkey breast rolls were artificially inoculated with approximately 10(6) cfu/cm(2) of 5-strain L. monocytogenes cocktails, then vacuum-packaged and irradiated at 0, 1.0, 1.5, 2.0, or 2.5 kGy. The radiation dose (kGy) that results in 90% reduction of viable cells for breast rolls, D(10) value, with various additive treatments ranged from 0.56 to 0.58 kGy. Adding PB (0.1%) or SL (2%) in turkey rolls failed to prevent L. monocytogenes from growing during refrigerated storage. In turkey rolls added with 2 (PB + SL or SL + SDA) or 3 (PB + SL + SDA) antimicrobial combinations had 2 or 3 wk of lag phases before L. monocytogenes growth, respectively. Irradiating turkey rolls, which were added with PB + SL or SL + SDA, at 1.0 kGy was effective in suppressing the growth of L. monocytogenes for about 6 wk when stored at 4 degrees C. No growth of L. monocytogenes after irradiation occurred during 42 d of storage for 2.0 kGy irradiated breast rolls formulated with 0.1% PB + 2% SL, 2% SL + 0.1% SDA or 0.1% PB + 2% SL + 0.1% SDA, and 1.0 kGy irradiated turkey breast with 0.1% PB + 2% SL + 0.1% SDA. Sensory panelists found that low-dose irradiation (1.0 kGy) had no effect on the sensory characteristics of ready-to-eat turkey breast rolls. Including SL + SDA had slightly negative effect for nonirradiated turkey breast rolls, but the sensory characteristics of 1.0 kGy irradiated turkey roll containing SL + SDA was not significantly different from the others receiving 1.0 kGy irradiation. For microbial safety, PB + SL and SL + SDA antimicrobial treatments combined with 1.0 kGy or 2.0 kGy irradiation are a promising technology.

KIT oncoprotein interactions in gastrointestinal stromal tumors: therapeutic relevance.

Most gastrointestinal stromal tumors (GISTs) express oncogenic and constitutively active forms of the KIT or platelet-derived growth factor receptor alpha (PDGFRA) receptor tyrosine kinase proteins, and these kinase oncoproteins serve as targets for effective therapies. Given that mutant KIT oncoproteins serve crucial transforming roles in GISTs, we evaluated interactions with the KIT oncoproteins and determined signaling pathways that are dependent on KIT oncogenic activation in GISTs. Tyrosine-phosphorylated KIT oncoproteins interacted with PDGFRA, PDGFRB, phosphatidylinositol 3-kinase (PI3-K) and PKCtheta in GIST cells, and these interactions were abolished by KIT inhibition with imatinib or PKC412 or KIT RNAi. Notably, tyrosine-phosphorylated PDGFRA was prominent in frozen GIST tumors expressing KIT oncoproteins, suggesting that KIT-mediated PDGFRA phosphorylation is an efficient and biologically consequential mechanism in GISTs. Activated signaling intermediates were identified by immunoaffinity purification of tyrosine-phosphorylated proteins in GIST cells before and after treatment with KIT inhibitors, and these analyses show that GRB2, SHC, CBL and MAPK activation are largely KIT dependent in GISTs, whereas PI3-K, STAT1 and STAT3 activation are partially KIT dependent. In addition, we found that phosphorylation of several tyrosine kinase proteins - including JAK1 and EPHA4 - did not depend on KIT activation. Likewise, paxillin activation was independent of the KIT oncogenic signal. These studies identify signaling pathways that can provide both KIT-dependent and KIT-independent therapeutic synergies in GIST, and thereby highlight clinical strategies that might consolidate GIST therapeutic response to KIT/PDGFRA inhibition.

AMP-activated protein kinase is negatively associated with intramuscular fat content in longissimus dorsi muscle of beef cattle.

Marbling, or intramuscular fat, is an important factor in meat quality. As a key regulator of lipid metabolism, AMP activated protein kinase (AMPK) may be associated with intramuscular fat accumulation. Our objective was to evaluate the relationship among AMPK and its associated signaling mediators, with marbling and lean growth in beef cattle. Steers with high intramuscular fat content (High IMF, 5.71±0.36%, n=5) and low intramuscular fat content (Low IMF, 2.09±0.19%, n=5) were selected. High IMF was associated with increased tenderness (P<0.05) and backfat thickness (P<0.01). Muscle weights were higher in Low compared to High IMF (P<0.05). High IMF steers had a reduced AMPK activity (P<0.01), reduced acetyl-CoA carboxylase phosphorylation (P<0.05), and reduced total mTOR (P=0.02) content. Data provide evidence that AMPK is involved in IMF deposition in beef cattle.

Effects of irradiation on survival and growth of Listeria monocytogenes and natural microflora in vacuum-packaged turkey hams and breast rolls.

The effect of electron beam irradiation on the survival and growth of Listeria monocytogenes and natural microflora in oven-roasted turkey breast rolls and turkey hams was evaluated. Slices of turkey breast rolls and hams were inoculated with a 5-strain mixture of L. monocytogenes to achieve 10(6) to 10(7) cfu/cm2; vacuum-packaged; irradiated at 0 (control), 1.0, 1.5, 2.0, or 2.5 kGy; and stored at 4 degrees C for up to 28 d. Numbers of naturally occurring bacteria on sliced turkey hams and breast rolls were 2.72 and 6.22 log10 cfu/cm2, respectively. The values of the radiation dose that results in 90% reduction of viable L. monocytogenes in breast rolls and hams were 0.52 and 0.47 kGy, respectively. For breast rolls, the log10 reductions of L. monocytogenes after irradiation at 1.0 and 2.5 kGy were 1.5 and 4.7, respectively, whereas they were 2.0 and 5.5 for hams. The log10 reductions of aerobic plate count (APC) in breast rolls after 1.0 and 2.0 kGy of irradiation were 2.9 and 5.2, whereas that of hams was < 10 cfu/cm2 after 1.0 and 2.0 kGy of irradiation. In 2.0-kGy irradiated hams, L. monocytogenes grew to 4.82 log10 cfu/cm2 after 28 d of storage at 4 degrees C, whereas APC increased to 2.98 log10 cfu/cm2, respectively. In breast rolls after 14 d of storage, APC in 1.0-kGy irradiated samples increased to 7.53 log10 cfu/cm2, and APC increased to 2.63 and 4.68 log10 cfu/cm2 for 2.0-kGy irradiated breast rolls after 14 and 28 d of storage. However, during the storage of breast rolls, L. monocytogenes grew slowly or even stopped to grow in both nonirradiated and irradiated breast rolls due to the competitive inhibition of natural flora in breast rolls. This study showed that irradiation (1.0 to 2.5 kGy) effectively reduced the number of L. monocytogenes and natural flora. However, L. monocytogenes and natural flora that survived irradiation could multiply during the 28-d storage period at 4 degrees C. Thus, additional hurdles are needed to ensure the microbial safety after low-dose irradiation.