Applications of cerium-based materials in food monitoring

With the rapid development of society, food safety to public health has been a topic that cannot be ignored. In recent years, lanthanide-based materials are studied to be potential candidates in the detection of food samples. Cerium (Ce)-based materials (such as Ce ions, CeO2, Ce-metal organic framework (Ce-MOF), etc.) have also attracted more attention in food detection by virtue of colorimetric, fluorescence, sensing, and other methods. This is because the mixed valence of Ce (Ce3+ and Ce4+), the formation of oxygen vacancies, and their optical and electrochemical properties. In this review, Ce-based materials will be introduced and discussed in the field of food detection, including biogenesis, construction, catalytic mechanisms, combination, and applications. In addition, the current challenges and future development trend of these Ce-based materials in food safety detection are also proposed and discussed. Therefore, it is meaningful to explore the Ce-based materials for detection of biomarkers in food samples.

[Impact of the examined number of lymph nodes at N1 station on the prognosis of patients with pT1-3N0M0 non-small cell lung cancer]

Objective: To investigate the relationship between the examined number of lymph nodes at the N1 station and the clinicopathological characteristics and prognosis of patients with pT1-3N0M0 non-small cell lung cancer (NSCLC). Methods: A total of 337 patients with pT1-3N0M0 NSCLC who underwent radical lung cancer surgery at the Provincial Hospital Affiliated to Anhui Medical University from January 2013 to March 2015 were selected. The receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off value for predicting 5-year survival in pT1-3N0M0 NSCLC patients by the examined number of lymph nodes at the N1 station. The relationships between the examined number of lymph nodes at the N1 station and the clinicopathological characteristics and prognosis of patients with pT1-3N0M0 NSCLC were analyzed according to the optimal cut-off group. Results: A total of 1 321 lymph nodes at N1 station were examined in 337 patients, with a mean of 3.9 nodes per patient. The median survival time was 42.0 months, with 1-, 3- and 5-year survival rates of 82.2%, 57.1% and 24.9%, respectively. ROC curve analysis showed that the optimal cut-off value of 4.5 lymph nodes examined at the N1 station was used to predict 5-year survival in patients with pT1-3N0M0 NSCLC. After rounding off the number, the number of lymph nodes examined at the N1 station was 5 as the cut-off value, and the patients were divided into the group with <5 lymph nodes examined (212 cases) and the group with ≥5 lymph nodes examined (125 cases). The proportion of patients received adjuvant chemotherapy was 19.2% in the group with ≥5 lymph nodes examined, which was higher than 9.0% in the group with <5 lymph nodes examined (P=0.007), and the differences in other clinicopathological characteristics between the two groups were not statistically significant (P>0.05). The median survival time for patients in the group with <5 lymph nodes examined was 38.0 months, with 1-, 3- and 5-year survival rates of 80.1%, 52.5% and 15.6%, respectively. The median survival time for patients in the group with ≥5 lymph nodes examined was 48.0 months, and the 1-, 3- and 5-year survival rates were 85.6%, 64.0% and 36.0%, respectively. The survival rate of patients in the group with ≥5 lymph nodes examined was better than that in the group with <5 lymph nodes examined (P=0.002). Multifactorial Cox regression analysis showed that T stage (OR=1.408, 95% CI: 1.118-1.670) and the examined number of lymph nodes at N1 station (OR=0.670, 95% CI: 0.526-0.853) were independent influence factors for the prognosis of pT1-3N0M0 NSCLC patients. Conclusion: The examined number of lymph nodes at the N1 station is associated with the prognosis of patients with pT1-3N0M0 NSCLC, and the examination of at least 5 lymph nodes at N1 station at the time of postoperative pathological examination improves the 5-year survival rate of patients.

Response and tolerance mechanism of food crops under high temperature stress: a review

High temperature stress events are critical factors inhibiting crop yield. Meanwhile, world population is growing very rapidly and will be reached up to 9 billion by 2050. To feed increasing world population, it is challenging task to increase about 70% global food productions. Food crops have significant contribution toward global food demand and food security. However, consequences from increasing heat stress events are demolishing their abilities to survive and sustain yield when subjected to extreme high temperature stress. Therefore, there is dire need to better understand response and tolerance mechanism of food crops following exposure to heat stress. Here, we aimed to provide recent update on impact of high temperature stress on crop yield of food crops, pollination, pollinators, and novel strategies for improving tolerance of food crop under high temperature stress. Importantly, development of heat-resistant transgenic food crops can grant food security through transformation of superior genes into current germplasm, which are associated with various signaling pathways as well as epigenetic regulation in response to extreme high temperature stress.

Band-selective Holstein polaron in Luttinger liquid material A0.3MoO3 (A = K, Rb)

(Quasi-)one-dimensional systems exhibit various fascinating properties such as Luttinger liquid behavior, Peierls transition, novel topological phases, and the accommodation of unique quasiparticles (e.g., spinon, holon, and soliton, etc.). Here we study molybdenum blue bronze A_0.3MoO₃ (A = K, Rb), a canonical quasi-one-dimensional charge-density-wave material, using laser-based angle-resolved photoemission spectroscopy. Our experiment suggests that the normal phase of A_0.3MoO₃ is a prototypical Luttinger liquid, from which the charge-density-wave emerges with decreasing temperature. Prominently, we observe strong renormalizations of band dispersions, which are recognized as the spectral function of Holstein polaron derived from band-selective electron-phonon coupling in the system. We argue that the strong electron-phonon coupling plays an important role in electronic properties and the charge-density-wave transition in blue bronzes. Our results not only reconcile the long-standing heavy debates on the electronic properties of blue bronzes but also provide a rare platform to study interesting excitations in Luttinger liquid materials.

Study on a new manner of the magnetization switching actuated by a unidirectional pulse current

A new writing scheme with a unidirectional pulse current is proposed for spin transfer torque (STT) based magnetic random-access memory (MRAM). To investigate the feasibility of the writing scheme, bilayered nano-pillars composed of a soft layer with small in-plane shape anisotropy and a hard layer with either large perpendicular anisotropy (PMA) or in-plane anisotropy (IMA) are designed and their switching behaviors are studied. It is found that in either type of bilayered nano-pillars, with the aid of the attached hard layer, the magnetization of the soft layer can be switched back and forth under a unidirectional pulse current. In an IMA/IMA nano-pillar, the magnetization of the free layer (FL) can achieve excellent alignment, which is in contrast to the IMA/PMA nano-pillar. By optimizing the dimensions and magnetic parameters of the IMA/IMA nano-pillar, a decently low switching current density (4.3 × 10¹¹A m^-2) and ultrashort switching time (<1 ns) can be reached. Based on these results, the unidirectional writing scheme is practical if an IMA/IMA bilayer is used to replace the FL in a magnetic tunnel junction. Considering that a unidirectional writing scheme can enable the application of materials with high spin polarization such as half metals, and avoid the injection of writing current into junction using a special design, it may be very promising for STT-MRAM.

Bypassing the Structural Bottleneck in the Ultrafast Melting of Electronic Order

Impulsive optical excitation generally results in a complex nonequilibrium electron and lattice dynamics that involves multiple processes on distinct timescales, and a common conception is that for times shorter than about 100 fs the gap in the electronic spectrum is not seriously affected by lattice vibrations. Here, however, by directly monitoring the photoinduced collapse of the spectral gap in a canonical charge-density-wave material, the blue bronze Rb_{0.3}MoO_{3}, we find that ultrafast (∼60  fs) vibrational disordering due to efficient hot-electron energy dissipation quenches the gap significantly faster than the typical structural bottleneck time corresponding to one half-cycle oscillation (∼315  fs) of the coherent charge-density-wave amplitude mode. This result not only demonstrates the importance of incoherent lattice motion in the photoinduced quenching of electronic order, but also resolves the perennial debate about the nature of the spectral gap in a coupled electron-lattice system.

[A survey on sexual needs and factors of HIV risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture]

Objective: To understand sexual needs and factors of risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture and provide basis for targeted HIV prevention and intervention. Methods: Two communities in the prefecture were selected as study sites. Questionnaire surveys were carried out among elderly men aged 50 and over who visited or consulted in the communities from June to December 2018, and they were tested for HIV and syphilis antibodies. Results: Among 400 elderly men, 209 (52.2%) were 50-64 years old, and 191(47.8%) were above 65 years old. They were mainly Miao people, accounting for 66.3% (265/400), and 235 (58.8%) had an education no more than 6 years. HIV awareness of the two age groups were only 25.8% (54/199) and 26.2% (50/191), respectively. Among those aged 50-64, 142 (68.0%) felt normal sexual desire, and 153 (73.6%) reported penile erections or erections in most cases whenever sex, and 52.9% (110) ejaculated most of the time. HIV prevalence was 1.0% (4/400). Compared with the over 65-year-old group, the proportion of having sex with spouse/stable partners (89.5%, 179/200), proportion of no condom use with their spouse/stable sexual partners during the most recent sex (93.8%, 168/179), proportion of having casual sex (11.0%, 23/209) and commercial sex (3.8%, 8/209) were all higher among 50-64 age group. In comparison to those aged over 65 years old, average monthly income>3 000, and use of sex helper, aged 50-64 (OR=2.70, 95%CI: 1.22-5.95), average monthly income ≤1 000 yuan (OR=2.79, 95%CI: 1.25-6.21), and no use of sex helper (OR=3.78) (95%CI: 1.65-8.67) were related factors of HIV risky sexual behavior last time. Conclusion: Elderly men in the minority prefecture had low HIV awareness. Compared with those≥65 years old, the 50-64 age group had more active sexual behaviors and higher sexual needs. Those from 50-64 age group, with lower economic level and good sexual ability were more likely to have HIV risky sexual behaviors.

A numerical study of spin torque oscillators based on IMA/PMA bilayer nano-pillars

In this paper, the magnetization dynamics of bilayer structured nano-pillars containing a fixed layer with perpendicular magnetic anisotropy (PMA) and a free layer with in-plane magnetic anisotropy (IMA) are studied using the micro-magnetic simulation method. Unlike typical sandwich-structured spin-torque nano-pillar oscillators (STNOs), the proposed structure does not contain any nonmagnetic spacer layer. It is found that a stable oscillation with a significant amplitude can be established fast after driving out the vortex core by an in-plane magnetic pulse field. The oscillation frequency and amplitude can be easily manipulated by adjusting the side-length of the nanopillar, the thickness and saturation magnetization of the IMA layer, and an applied magnetic field along z axis. In an array with an adequate inter-pillar distance, the mutual interaction between the nano-pillars will lead the oscillations to be phase-locked, resulting in a considerable enhancement of total amplitude. As it is easy to fabricate these kinds of bi-layer nano-pillars and assemble them in arrays, they may have widespread applications in STNOs.

Regulating a novel domain wall oscillator with a steady frequency by changing the current density

The dynamic behaviors of a domain wall (DW) pinned by a notch pair or a single notch with different notch depths are studied. It is found that, in a relatively large current density range, the oscillation frequency of the DW becomes frozen and independent of current density when pinned by a notch pair with a notch depth larger than 12 nm. The current density range for freezing the frequency can be tuned by the notch depth. A chain of notch pairs is designed to introduce more pinned DWs into the nanowire. By increasing the number of DWs and applying a proper magnetic field, the oscillation amplitude can be greatly enhanced. Our finding suggests that nanowires with a series of deep notch pairs may have an important application in the development of DW based spin-transfer nano-oscillators with a high tolerance for current fluctuation.

Laser-induced vapor nanobubbles improve diffusion in biofilms of antimicrobial agents for wound care

Being responsible for delayed wound healing, the presence of biofilms in infected wounds leads to chronic, and difficult to treat infections. One of the reasons why antimicrobial treatment often fails to cure biofilm infections is the reduced penetration rate of antibiotics through dense biofilms. Strategies that have the ability to somehow interfere with the integrity of biofilms and allowing a better penetration of drugs are highly sought after. A promising new approach is the use of laser-induced vapor nanobubbles (VNB), of which it was recently demonstrated that it can substantially enhance the penetration of antibiotics into biofilms, resulting in a marked improvement of the killing efficiency. In this study, we examined if treatment of biofilms with laser-induced vapor nanobubbles (VNB) can enhance the potency of antimicrobials which are commonly used to treat wound infections, including povidone-iodine, chlorhexidine, benzalkonium chloride, cetrimonium bromide and mupirocin. Our investigations were performed on Pseudomonas aeruginosa and Staphylococcus aureus biofilms, which are often implicated in chronic wound infections. Pre-treatment of biofilms with laser-induced VNB did enhance the killing efficiency of those antimicrobials which experience a diffusion barrier in the biofilms, while this was not the case for those compounds for which there is no diffusion barrier. The magnitude of the enhanced potency was in most cases similar to the enhancement that was obtained when the biofilms were completely disrupted by vortexing and sonication. These results show that laser-induced VNB are indeed a very efficient way to enhance drug penetration deep into biofilms, and pave the way towards clinical translation of this novel approach for treatment of wound infections.

Current driven spin oscillation in PMA/IMA composite nanowires-a novel spin torque based nano-oscillators

The spin dynamics in composite nanowires possessing both perpendicular magnetic anisotropy and in-plane magnetic anisotropy (IMA) regions are studied. It is found that, driven by proper currents, spin waves can be excited and propagate along the nanowires, leading to sustained oscillations of the magnetic moments. The frequency and amplitude strongly depend on the length of the longitudinal magnetized part (L _IMA), and can be effectively tuned by applied current. The assistance of an applied field may help to obtain large frequencies and amplitudes simultaneously. Considering their ease of manufacture, these kinds of composite nanowires hold great promise for nano-oscillator applications.

[Learning curve of uniportal video-assisted thoracoscopic surgery lobectomy for the treatment of resectable lung cancer]

Objective: To analyze the learning curve of uniportal video-assisted thoracoscopic surgery (VATS) lobectomy for the treatment of resectable lung cancer. Methods: The clinical data of 160 patients with resectable lung cancer who underwent uniportal VATS lobectomy by a single surgical team between May 2016 and April 2017 at Department of Thoracic Surgery, the First Affiliated Hospital of the University of Science and Technology of China were analyzed retrospectively. The study group consisted of 90 male and 70 female patients with age of 28 to 84 years (median: 62 years). The patients were divided into four groups from group A to D according to chronological order. The operation time, incision length, intraoperative blood loss, number of dissected lymph nodes and nodal stations, the proportion of changes in operation mode, postoperative complications, chest drainage duration and hospitalization time were individually compared among the four groups by variance analysis and χ(2) test. Results: The 4 groups were similar in terms of incision length, chest drainage duration, number of dissected lymph nodes and nodal stations and postoperative hospitalization time (P>0.05). The difference of the operation time ((185.9±17.9) minutes vs. (139.9±10.7) minutes vs.(128.7±7.8) minutes vs.(124.0±9.3) minutes, F=219.605, P=0.000), intraoperative blood loss ((233.9±135.8) ml vs. (126.8±18.1) ml vs. (116.4±22.6) ml vs.(112.8±25.3) ml, F=26.942, P=0.000), the proportion of changes in operation mode (17.5% vs.7.5% vs. 5.0% vs. 5.0%, χ(2)=8.300, P=0.040), and the incidence of postoperative complications (27.5% vs. 10.0% vs. 10.0% vs. 7.5%, χ(2)=8.643, P=0.034) among the 4 groups was statistically significant. Conclusions: Uniportal VATS lobectomy can be safely and feasibly performed for resectable lung cancer, learning curve for uniportal VATS lobectomy is approximately 40 cases. Operation time, intraoperative blood loss, postoperative complications and the proportion of changes in operation mode can be used as the main measures during surgery.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

Abstract P3-04-23: Combination therapy of targeted anticancer pathways and estrogen receptor ligands and their responses in de novo andtamoxifen resistant cell models

Approximately 75% of breast cancers are classified as Estrogen Receptor positive (ER+). Tamoxifen, a selective estrogen receptor modulator (SERM), is the standard of care for many of these ER+ breast cancer patients. Unfortunately, tamoxifen resistance occurs in almost 50% of patients within 5 years of treatment, and endocrine-independence accompanying resistance also negates the effects of aromatase inhibitors. Combination therapy is increasingly used in non-cytotoxic therapeutic approaches in many types of cancer. The potential exists that endocrine resistance can be lessened, eliminated, or overcome through targeted therapy in combination with endocrine therapy. Inhibition of kinase signaling (e.g. via CDK4/6 or PI3K) and other pathways (e.g. HSP90) are expected to be effective in combination with endocrine therapy. We have discovered a variety of ER ligands with potential as endocrine therapeutic agents, based upon a single chemical scaffold with a diverse set of pharmacological responses: including SERMs, selective ER downregulators (SERDs), selective estrogen mimics (SEMs), and selective human ER partial agonists (ShERPAs). To predict which agents in combination with these endocrine-targeted ligands would be of potential therapeutic benefit it was necessary to develop 3D spheroidal cultures of ER+ breast cancer cell lines: including endocrine-dependent lines; and cell lines made endocrine-independent either by extended exposure to tamoxifen or extended deprivation of estradiol. In contrast to 2D cultures, drug response in 3D spheroidal cell cultures was predictive of response to treatment in mouse xenograft studies. Growth of endocrine-dependent cell lines was, as expected, inhibited by SERDs; and endocrine-independent, tamoxifen-resistant cell lines were also sensitive to SERD treatment, although one cell line was largely resistant. Growth of all three tamoxifen-resistant cell lines was inhibited by SEMs/ShERPAs. Importantly, regardless of the type of endocrine therapeutic agent studied, concentrations leading to saturation of the target (ER) did not cause cell death. Equally, all endocrine therapies studied benefited from combination treatment with other agents, leading to enhanced cell death.

Citation Format: Gutgesell LM, Xiong R, Thatcher GRJ, Tonetti DA. Combination therapy of targeted anticancer pathways and estrogen receptor ligands and their responses in de novo andtamoxifen resistant cell models [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-23.

[Analysis on the ' late diagnosis' (LD) phenomena among newly identified HIV/AIDS cases in China, 2010-2014]

OBJECTIVE

To analyze the 'late diagnoses' (LD) phenomena among newly identified HIV/AIDS cases in China from 2010 to 2014.

METHODS

Newly identified HIV/AIDS cases from 2010 to 2014 were selected from the National HIV/AIDS comprehensive information system. Rates related to LD were stratified according to the demographic indicators.

RESULTS

From 2010 to 2014, numbers of newly identified HIV/AIDS cases were reported as 64 338, 74 517, 82 434, 90 119 and 103 501 in China. Among them, proportions of LD were 41.8%, 42.1%, 38.1%, 36.8% and 35.5% respectively. LD proportions appeared high in medical settings, with the minimum proportion as 45% (χ(2)=5 174,P<0.000 1). Proportion of LD among patients who were heterosexually transmitted appeared over 40%, which was significantly higher than that seen among men who have sex with men or injecting drug users (χ(2)=3 066,P<0.000 1). Proportion of LD showed more than 39% in those newly identified cases, and was seen higher in permanent residents than in floating population (less than 30%) (χ(2)=5 265,P<0.000 1).

CONCLUSION

With the expansion testing coverage on HIV, newly identified HIV/AIDS increased year by year. Among the newly identified cases, late diagnosis was high, especially in medical institutions. More effective strategies and measures are needed to promote the early detection of HIV in high risk population.

MicroRNA-922 promotes tau phosphorylation by downregulating ubiquitin carboxy-terminal hydrolase L1 (UCHL1) expression in the pathogenesis of Alzheimer's disease

Decreased levels of soluble ubiquitin carboxy-terminal hydrolase L1 (UCHL1) have been reported in the brains of sporadic Alzheimer's disease (AD) patients, and the introduction of UCHL1 rescued the synaptic and cognitive function of AD model mice. Obviously, a reduction in the levels of UCHL1 may play a role in the pathogenesis of AD. However, the mechanisms underlying the regulation of UCHL1 levels in AD have not been fully elucidated. MicroRNAs (miRs) have been shown to participate in the process of AD. In our study, we discovered that microRNA-922 decreased the levels of UCHL1. Neurofibrillary tangles (NFTs) mainly consisting of the hyperphosphorylated microtubule-associated protein tau are the defining pathological features of AD. In the present study, we found the levels of UCHL1 affected the levels of phosphorylated tau: the phosphorylated tau levels increased after knockdown of UCHL1 expression, and the phosphorylated tau levels decreased when UCHL1 was overexpressed. Furthermore, overexpression of microRNA-922 increased the phosphorylated tau levels. In conclusion, miR-922 increasing the levels of phosphorylated tau by regulating UCHL1 levels contributed to the pathogenesis of AD. Our study partly explained one of the mechanisms underlying the downregulation of UCHL1 levels in AD patients and could enrich the content of tau pathology in the pathogenesis of AD.

Structural modulation and hole distribution in Sr(14-x)Ca(x)Cu(24)O(41)

Structural properties and hole distribution in the spin-ladder compound Sr(14-x)Ca(x)Cu(24)O(41) have been extensively investigated by transmission electron microscopy (TEM). The complex electron diffraction patterns and high-resolution TEM observations reveal a clear incommensurate structural modulation along the c-axis direction attributable to two mismatched sublattices; this modulation strongly depends on hole distribution in the compounds. The fine structures of the O K and Cu L(2,3) ionization edges for the Sr(14-x)Ca(x)Cu(24)O(41) compounds recorded under different conditions indicate that more doped holes reside in the chains than the ladders, and that substituting Ca for Sr atoms results in a charge redistribution between the chains and ladders. Based on the experimental findings, the theoretical results, including the partial density of states and optical conductivity spectra calculated by the density functional theory, are also discussed.

Proteases from Bacillus: a new insight into the mechanism of action for rhizobacterial suppression of nematode populations

AIMS

The aim of this study was to investigate the role of proteases in Bacillus spp. of rhizobacteria in suppressing nematode populations and to understand their mechanism of action.

METHODS AND RESULTS

Rhizobacteria with nematicidal activity were isolated from soil samples of five root knot nematode-infested farms. Among these strains, nematotoxicities of Bacillus strains were intensively analysed. Further assays of nematicidal toxins from Bacillus sp. strain RH219 indicated an extracellular cuticle-degrading protease Apr219 was an important pathogenic factor. The Apr219 shared high similarity with previously reported cuticle-degrading proteases from Brevibacillus laterosporus strain G4 and Bacillus sp. B16 (Bacillus nematocida). The cuticle-degrading protease genes were also amplified from four other nematicidal Bacillus strains isolated from the rhizosphere. In addition to Apr219, a neutral protease Npr219 from Bacillus sp. RH219 was also investigated for activity against nematodes.

CONCLUSIONS

The wide distribution of cuticle-degrading proteases in Bacillus strains with nematicidal activity suggested that these enzymes likely play an important role in bacteria-nematode-plant-environment interactions and that they may serve as important nematicidal factors in balancing nematode populations in the soil.

SIGNIFICANCE AND IMPACT OF THE STUDY

Increased understanding of the mechanism of action of Bacillus spp. against nematodes could potentially enhance the value of these species as effective nematicidal agents and develop new biological control strategies.

Chronic but not acute treatment with caffeine attenuates traumatic brain injury in the mouse cortical impact model

Caffeine, the most consumed psychoactive drug and non-specific adenosine receptor antagonist, has recently been shown to exert a neuroprotective effect against brain injury in animal models of Parkinson's disease (PD) and stroke. However, the effects of caffeine on traumatic brain injury (TBI) are not known. In this study, we investigated the effects of acute and chronic caffeine treatment on brain injury in a cortical-impact model of TBI in mice. Following TBI, neurological deficits, cerebral edema, as well as inflammatory cell infiltration were all significantly attenuated in mice pretreated chronically (for 3 weeks) with caffeine in drinking water compared with the mice pretreated with saline. Furthermore, we found that chronic caffeine treatment attenuated glutamate release and inflammatory cytokine production, effects that were correlated with an upregulation of brain A1 receptor mRNA. By contrast, acute treatment with caffeine (i.p. injection, 30 min before TBI) was not effective in protecting against TBI-induced brain injury. These results suggest that chronic (but not acute) caffeine treatment attenuates brain injury, possibly by A1 receptor-mediated suppression of glutamate release and inhibition of excessive inflammatory cytokine production. These results highlight the potential benefit of chronic caffeine intake for preventing TBI and provide a rationale for the epidemiological investigation of the potential association between TBI and human caffeine intake.

A mathematical model for bacterial inactivation

The first order kinetic model, the Buchanan model and Cerf's model, can model a linear survival curve, a survival curve with a shoulder and a survival curve with a tailing, respectively. However, they are not suitable for fitting a sigmoidal survival curve. The three models were integrated into a new model that was capable of fitting the four most commonly observed survival curves: linear curves, curves with a shoulder, curves with a tailing (biphasic curves) and sigmoidal curves. The new model was compared with the Whiting-Buchanan model using the survival curves of Staphylococcus aureus. The goodness-of-fit of the proposed model is practically as good as that of the Whiting-Buchanan model. Compared with the Whiting-Buchanan model, the proposed model has a more mechanistic background. Since for non-linear survival curves, such as biphasic and sigmoidal curves, the t(m-D) value (the time required for an m-log-cycle reduction of microorganisms under a given condition) cannot be estimated accurately by the existing or traditional method, a new method is also proposed to predict accurately the t(m-D) value for non-linear survival curves.

The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid

The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid solution (citric acid concentration of > or = 4.98% (w/v)) was investigated. It was found that pH of mayonnaise is closely related to the ratio of egg yolk to citric acid, and the inactivation rate of the micro-organisms increases as the ratio decreases and/or incubation temperature increases. To achieve Salm. enteritidis PT4-free home-made mayonnaise prepared with pure lemon juice (citric acid concentration > or = 5% (w/v)), it is recommended that the pH should be 3.30 or below, or, in practice, at least 20 ml pure lemon juice per fresh egg yolk should be used. For the use of 20-35 ml pure lemon juice per egg yolk, the product should be held at 22 degrees C or over for at least 72 h and for the use of over 35 ml pure lemon juice per egg yolk, for at least 48 h before consumption or refrigeration.

[The food habit and its affecting factors of preschool children in Guangzhou]

A survey of nutritional knowledge-attitude-practice was conducted among 1300 preschool children, their parents, 203 teachers and nurses in Kindergarten in 1997. Results showed that the food habit of preschool children was unsuitable. Most preschool children rejected eating animal liver, peanut product and animal blood, but often ate snacks. From statistic analysis among affecting factors, the mother's and teachers' nutritional knowledge and the food habit of parents had significant effect on food habit of preschool children. The family income did not significantly affect food habit of preschool children. Moreover, there was little nutrition education involved in the preschool children courses in 4 kindergartens. The result suggested that the nutrition education plan should be done.