Parental use and acceptance of an accessible, commercially available intraoral camera for teledentistry in their children.

PURPOSE: The potential of combining teledentistry and engaging parents as underutilised resources to monitor paediatric dental health was emphasised during the COVID-19 pandemic and remains underexplored. This study aims to assess parental acceptance and use of a commercially available intraoral camera (IOC) for effective remote monitoring. METHODS: 47 child-parent dyads, where the parent was the main caregiver and the child was treated under general anaesthesia for early childhood caries, were recruited. Caregivers were trained to image their child's teeth on a commercially available IOC. Subsequently, submitted images were reviewed asynchronously by dentists for image quality, presence of dislodged fillings, abscesses, cavitation, and oral hygiene. Post-surgery monitoring was performed using teledentistry at 1 and 2 months and in-person at 4 months. A modified Telehealth Usability Questionnaire (TUQ) was used to record caregiver acceptance for study procedures. RESULTS: A mean TUQ of 6.09 out of 7 was scored by caregivers. Caregiver-reported issues were limited to problems with technique and child uncooperativeness. The number of clear images during the second teledentistry review was improved compared to the first (p = 0.007). 68% of children liked having images of their teeth taken. CONCLUSION: This study supports the feasibility of using an IOC as a clinically appropriate avenue for teledentistry with a high level of caregiver-child acceptance.

A controlled evaluation of the effect of social prescribing programs on loneliness for adults in Queensland, Australia (protocol).

BACKGROUND: In social prescribing, link workers support individuals whose persistent health problems are exacerbated by loneliness by connecting them to community-based social activities. This approach is well established in the UK and is gaining attention in Australia. However, a major limitation of research to date has been a lack of theoretically informed and rigorous evaluations of social prescribing. We will address these points in this study, applying a social identity framework to examine the effects of group-based social prescribing (SP) activity compared to primary care treatment as usual (TAU). METHODS: Ninety participants experiencing loneliness recruited from primary care services and community centres across five sites in Southeast Queensland will be assigned to one of two conditions (SP, TAU) and assessed at two timepoints (baseline, + 8 weeks). Individuals will be aged 18 years and over, have sufficient English language skills to provide consent, and at the time of recruitment they will not be experiencing acute symptoms or social issues that require urgent intervention. Primary outcomes are loneliness, mental well-being, and health service use (total number of GP, hospital, and allied health visits in the past 3 months). Secondary outcomes will assess social group processes, including number of important social groups, new group identification, multiple identity compatibility, and group-based support and emotion regulation. DISCUSSION: This study will provide comprehensive data about the extent to which, and how, social prescribing to community-based group activities may help people to feel less lonely, more socially integrated, and healthy over the first 8 weeks. If effective, this social identity-informed model of social prescribing can be disseminated in communities across Australia. TRIAL REGISTRATION: ANZCTR, Registered 8 June 2022 - Retrospectively registered, https://www.anzctr.org.au/ACTRN12622000801718.aspx.

Quantum device designing (QDD) for future semiconductor engineering.

In semiconductor device history, a trend is observed where narrowing and increasing the number of material layers improve device functionality, with diodes, transistors, thyristors, and superlattices following this trend. While superlattices promise unique functionality, they are not widely adopted due to a technology barrier, requiring advanced fabrication, such as molecular beam epitaxy and lattice-matched materials. Here, a method to design quantum devices using amorphous materials and physical vapor deposition is presented. It is shown that the multiplication gain M depends on the number of layers of the superlattice, N, as M = kN, with k as a factor indicating the efficiency of multiplication. This M is, however, a trade-off with transit time, which also depends on N. To demonstrate, photodetector devices are fabricated on Si, with the superlattice of Se and As2Se3, and characterized using current-voltage (I-V) and current-time (I-T) measurements. For superlattices with the total layer thicknesses of 200 nm and 2 µm, the results show that k200nm = 0.916 and k2µm = 0.384, respectively. The results confirm that the multiplication factor is related to the number of superlattice layers, showing the effectiveness of the design approach.

Nutritional Status and Risks of Cognitive Decline and Incident Neurocognitive Disorders: Singapore Longitudinal Ageing Studies.

BACKGROUND: Studies suggest that nutritional interventions using the whole diet approach such as the Mediterranean diet may delay cognitive decline and dementia onset. However, substantial numbers of older adults are non-adherent to any ideally healthy dietary pattern and are at risk of malnutrition. OBJECTIVE: The present study investigated the relationship between global malnutrition risk and onsets of cognitive decline and neurocognitive disorders (NCD), including mild cognitive impairment (MCI) or dementia in community-dwelling older adults. METHODS: Participants aged ≥ 55 years in the Singapore Longitudinal Ageing Studies (SLAS) were assessed at baseline using the Elderly Nutritional Indicators for Geriatric Malnutrition Assessment (ENIGMA) and followed up 3-5 years subsequently on cognitive decline (MMSE drop ≥ 2) among 3128 dementia-free individuals, and incident neurocognitive disorders (NCD) among 2640 cognitive normal individuals. RESULTS: Individuals at high nutritional risk score (≥ 3) were more likely to develop cognitive decline (OR=1.42, 95%CI=1.01-1.99) and incident MCI-or-dementia (OR=1.64, 95%CI=1.03-2.59), controlling for age, sex, ethnicity, low education, APOE-e4, hearing loss, physical, social, and mental activities, depressive symptoms, smoking, alcohol, central obesity, hypertension, diabetes, low HDL, high triglyceride, cardiac disease, and stroke. Among ENIGMA component indicators, low albumin at baseline was associated with cognitive decline and incident NCD, and 5 or more drugs used, few fruits/vegetables/milk products daily, and low total cholesterol were associated with incident NCD. CONCLUSION: The ENIGMA measure of global malnutrition risk predicts cognitive decline and incident neurocognitive disorders, suggesting the feasibility of identifying vulnerable subpopulations of older adults for correction of malnutrition risk to prevent neurocognitive disorders.

Tea Consumption and Depression from Follow Up in the Singapore Longitudinal Ageing Study.

OBJECTIVES: Experimental evidence suggest that tea polyphenols have anti-depressant effect and tea consumption may reduce the risk and severity of depression. We investigated whether tea consumption was associated with changes in depressive symptoms over time among Asian older adults. DESIGN: Population-based prospective cohort study with mean 4 years of follow up. SETTING: Singapore Longitudinal Ageing Study (SLAS) of community-living older persons. PARTICIPANTS: 3177 participants overall (mean age 67 years) and 3004 participants who were depression-free at baseline. MEASUREMENTS: Baseline tea consumption which include Chinese (black, oolong or green) tea or Western (mixed with milk) tea and change in Geriatric Depression Scale (GDS) measure of depression. Incident depression was defined by GDS≥5, and GDS depression improvement or deterioration by GDS change of ≥4 points. Estimated odds ratio and 95% confidence intervals (OR, 95%CI) were adjusted for baseline age, sex, ethnicity, education, housing type, single/divorced/widowed, living alone, physical and social activity, smoking, alcohol, number of comorbidities, MMSE, and baseline GDS level. RESULTS: Compared to non-tea drinkers, participants who consumed ≥3 cups of tea of all kinds were significantly less likely to have worsened GDS symptoms: OR=0.32, 95% CI=0.12, 0.84. Among baseline depression-free participants, the risk of incident GDS (≥5) depression was significantly lower (OR=0.34, 95%CI=0.13, 0.90) for daily consumption of all types of tea, and Chinese (black, oolong or green) tea (OR=0.46, 95%CI=0.21,0.99). CONCLUSION: This study suggests that tea may prevent the worsening of existing depressive symptoms and the reduce the likelihood of developing threshold depression.

International consensus (ICON) on functional and aesthetic rhinoplasty.

During the 2017 IFOS international congress in Paris, a roundtable discussion on the topic of functional and aesthetic rhinoplasty was organised. Five experts, from the five continents and renown in the field of rhinoplasty, were brought together to discuss the issue from an international perspective and to put forward a consensus or on the contrary practical differences. Five questions were put to the experts beforehand to guarantee independent answers, which were then discussed during the roundtable. The questions were the following: - What are the age limits for achieving a rhinoplasty? - Do you use objective measurements before, during and after surgery? (facial landmarks, airflow, peroperative measurements) - How do you manage the preoperative general information and computer imaging of the patient? - What are the indications in your practice to perform a CT-scan or endoscopic examination before doing a rhinoplasty? - What kind of graft or prosthesis do you use for an augmentation rhinoplasty? This paper offers a synthesis of the roundtable based on the experts' answers to the different questions.

The modified 'Jo'burg' technique for securing intercostal chest drains.

Insertion of an intercostal chest drain (ICD) is a common intervention in the management of either blunt or penetrating thoracic trauma. It is frequently performed by junior medical personnel as an emergency procedure during the initial resuscitation period and often within a stressful environment. Approximately one-fifth of all ICD insertions are associated with complications. In a retrospective review of over 1000 ICD insertions, 7% of the complications observed were due to inadequate fixation, resulting in dislodgement. The risk of dislodgement is greatest during transit or transfer of a casualty. In a military setting, this may involve movement of a casualty in a non-permissive environment and includes transfer on and off rotary wing, fixed wing, road vehicle and maritime transport platforms as well as between stretchers and hospital beds. While ICD insertion follows a standard technique in accordance with the Advanced Trauma Life Support guidelines, the method of securing ICDs has not been standardised across the Defence Medical Services (DMS). The aim of this paper is to first propose a modified version of a tried and tested technique of securing ICDs with alternative steps described for medical staff unfamiliar with surgical knot tying by hand. Second, we present the results from a pilot validation study of this technique when introduced to candidates on a trauma surgical skills course. We describe and demonstrate a robust, easily teachable and reproducible technique for securing ICDs. We would advocate the use of this technique among both surgically and non-surgically trained medical personnel and suggest that this should become the standardised technique for securing ICDs across the DMS. This could be easily implemented by introducing this technique into the various military trauma courses, for example the Military Operational Surgical Training, Medical Emergency Response Team and Critical Care Air Support Team courses.

Marginal ulcer perforation: a single center experience.

PURPOSE: Marginal ulcer (MU) is defined as ulcer on the jejunal side of the gastrojejunostomy (GJ) anastomosis. Most MUs are managed medically but those with complications like bleeding or perforation require intervention. It is recommended that GJ anastomosis be revised in patients with MU perforation (MUP). The aim of this case series is to study the clinical presentation and management of MUP. METHODS: Three hundred and thirty-two patients who underwent emergency surgery for perforated peptic ulcer at a single center were studied over a period of 5 years. RESULTS: Nine patients (2.7 %) presented with MUP. GJ was previously done for either complicated peptic ulcer (n = 4) or for suspected gastric malignancy (n = 5). Two patients had previously completed H. pylori therapy. None of the patients presented with septic shock. MU was on the jejunal side of GJ in all patients. The median MUP size was 10 mm. Four patients (44.4 %) had omental patch repair, three (33.3 %) had primary closure, and one each had revision of GJ and jejunal serosal patch repair. There were no leaks, intra-abdominal abscess or reoperation and no malignancies. CONCLUSION: MUP patients do not present with septic shock. Omental patch repair or primary closure is sufficient enough. Revision of Billroth-II-GJ into Roux-en-Y-GJ is not mandatory.

Five year experience in management of perforated peptic ulcer and validation of common mortality risk prediction models - are existing models sufficient? A retrospective cohort study.

BACKGROUND: Emergency surgery for perforated peptic ulcer (PPU) is associated with significant morbidity and mortality. Accurate and early risk stratification is important. The primary aim of this study is to validate the various existing MRPMs and secondary aim is to audit our experience of managing PPU. METHODS: 332 patients who underwent emergency surgery for PPU at a single intuition from January 2008 to December 2012 were studied. Clinical and operative details were collected. Four MRPMs: American Society of Anesthesiology (ASA) score, Boey's score, Mannheim peritonitis index (MPI) and Peptic ulcer perforation (PULP) score were validated. RESULTS: Median age was 54.7 years (range 17-109 years) with male predominance (82.5%). 61.7% presented within 24 h of onset of abdominal pain. Median length of stay was 7 days (range 2-137 days). Intra-abdominal collection, leakage, re-operation and 30-day mortality rates were 8.1%, 2.1%, 1.2% and 7.2% respectively. All the four MRPMs predicted intra-abdominal collection and mortality; however, only MPI predicted leak (p = 0.01) and re-operation (p = 0.02) rates. The area under curve for predicting mortality was 75%, 72%, 77.2% and 75% for ASA score, Boey's score, MPI and PULP score respectively. DISCUSSION AND CONCLUSION: Emergency surgery for PPU has low morbidity and mortality in our experience. MPI is the only scoring system which predicts all - intra-abdominal collection, leak, reoperation and mortality. All four MRPMs had a similar and fair accuracy to predict mortality, however due to geographic and demographic diversity and inherent weaknesses of exiting MRPMs, quest for development of an ideal model should continue.

SAA1 polymorphisms are associated with variation in antiangiogenic and tumor-suppressive activities in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a cancer that occurs in high frequency in Southern China. A previous functional complementation approach and the subsequent cDNA microarray analysis have identified that serum amyloid A1 (SAA1) is an NPC candidate tumor suppressor gene. SAA1 belongs to a family of acute-phase proteins that are encoded by five polymorphic coding alleles. The SAA1 genotyping results showed that only three SAA1 isoforms (SAA1.1, 1.3 and 1.5) were observed in both Hong Kong NPC patients and healthy individuals. This study aims to determine the functional role of SAA1 polymorphisms in tumor progression and to investigate the relationship between SAA1 polymorphisms and NPC risk. Indeed, we have shown that restoration of SAA1.1 and 1.3 in the SAA1-deficient NPC cell lines could suppress tumor formation and angiogenesis in vitro and in vivo. The secreted SAA1.1 and SAA1.3 proteins can block cell adhesion and induce apoptosis in the vascular endothelial cells. In contrast, the SAA1.5 cannot induce apoptosis or inhibit angiogenesis because of its weaker binding affinity to αVß3 integrin. This can explain why SAA1.5 has no tumor-suppressive effects. Furthermore, the NPC tumors with this particular SAA1.5/1.5 genotype showed higher levels of SAA1 gene expression, and SAA1.1 and 1.3 alleles were preferentially inactivated in tumor tissues that were examined. These findings further strengthen the conclusion for the defective function of SAA1.5 in suppression of tumor formation and angiogenesis. Interestingly, the frequency of the SAA1.5/1.5 genotype in NPC patients was ~2-fold higher than in the healthy individuals (P=0.00128, odds ratio=2.28), which indicates that this SAA1 genotype is significantly associated with a higher NPC risk. Collectively, this homozygous SAA1.5/1.5 genotype appears to be a recessive susceptibility gene, which has lost the antiangiogenic function, whereas SAA1.1 and SAA1.3 are the dominant alleles of the tumor suppressor phenotype.

Porous nitrogen-doped carbon microspheres as anode materials for lithium ion batteries.

Nitrogen-doped carbon microspheres (NCSs) were fabricated via a simple, fast and energy-saving microwave-assisted method followed by thermal treatment under an ammonia atmosphere. NCSs thermally treated at different temperatures were investigated as anode materials for lithium ion batteries (LIBs). The results show that NCSs treated at 900 °C exhibit a maximum reversible capacity of 816 mA h g(-1) at a current density of 50 mA g(-1) and preserve a capacity of 660 mA h g(-1) after 50 cycles, and even at a high current density of 1000 mA g(-1), a capacity of 255 mA h g(-1) is maintained. The excellent electrochemical performance of NCSs is due to their porous structure and nitrogen-doping. The present NCSs should be promising low-cost anode materials with a high capacity and good cycle stability for LIBs.

Post-operative outcomes of atypical femoral subtrochanteric fracture in patients on bisphosphonate therapy.

Management of bisphosphonate-associated subtrochanteric fractures remains opinion- or consensus-based. There are limited data regarding the outcomes of this fracture. We retrospectively reviewed 33 consecutive female patients with a mean age of 67.5 years (47 to 91) who were treated surgically between May 2004 and October 2009. The mean follow-up was 21.7 months (0 to 53). Medical records and radiographs were reviewed to determine the post-operative ambulatory status, time to clinical and radiological union and post-fixation complications such as implant failure and need for second surgery. The predominant fixation method was with an extramedullary device in 23 patients. 25 (75%) patients were placed on wheelchair mobilisation or no weight-bearing initially. The mean time to full weight-bearing was 7.1 months (2.2 to 29.7). The mean time for fracture site pain to cease was 6.2 months (1.2 to 17.1). The mean time to radiological union was 10.0 months (2.2 to 27.5). Implant failure was seen in seven patients (23%, 95 confidence interval (CI) 11.8 to 40.9). Revision surgery was required in ten patients (33%, 95 CI 19.2 to 51.2). A large proportion of the patients required revision surgery and suffered implant failure. This fracture is associated with slow healing and prolonged post-operative immobility.

Can population differences in chemotherapy outcomes be inferred from differences in pharmacogenetic frequencies?

Inter-ethnic differences in drug handling and frequencies of pharmacogenetic variants are increasingly being characterized. In this study, we systematically assessed the feasibility of inferring ethnic trends in chemotherapy outcomes from inter-ethnic differences in pharmacogenetic variant frequencies. Frequencies of 51 variants and chemotherapy outcomes of East Asian and Caucasian colorectal cancer patients on standard chemotherapy regimens were summarized by meta-analyses, and variant frequencies were validated by MassARRAY analysis. Inferences of relative chemotherapy outcomes were made by considering minor allele function and population differences in their frequency. Significant population differences in genotype distributions were observed for 13/23 (60%) and 27/35 (77%) variants in the meta-analyses and validation series, respectively. Across chemotherapy regimens, East Asians had lower rates of grade 3/4 toxicity for diarrhea and stomatitis/mucositis than Caucasians, which was correctly inferred from 13/18 (72%, P=0.018) informative genetic variants. With appropriate variant selection, inferring relative population toxicity rates from population genotype differences may be relevant.

Obstructive sleep apnoea in a case of thyroglossal duct cyst carcinoma.

OBJECTIVES: To report a rare case of thyroglossal duct cyst carcinoma which presented with obstructive sleep apnoea, and to highlight the difficulties in making this clinical diagnosis. METHOD: Case report and review of the English language literature concerning thyroglossal duct cyst carcinoma. RESULTS: Thyroglossal duct cyst carcinoma is a rare clinical entity found in only approximately 1 per cent of all patients operated upon for thyroglossal duct cyst. This condition usually presents in an identical manner to its benign counterpart; atypical presentations have not previously been reported. Our patient is the first reported case of a thyroglossal duct cyst carcinoma first presenting with symptoms of obstructive sleep apnoea, without a neck mass. Complete surgical excision with total thyroidectomy and lymph node clearance was performed, in view of the positive lymph node metastases (seen on imaging) and the need for post-operative radioiodine therapy. CONCLUSION: Thyroglossal duct cyst carcinomas may present atypically, posing a diagnostic dilemma for the clinician. For patients diagnosed with obstructive sleep apnoea, it is imperative that a thorough otolaryngological examination be performed to exclude any underlying pathology.

Anti-angiogenic and tumor-suppressive roles of candidate tumor-suppressor gene, Fibulin-2, in nasopharyngeal carcinoma.

Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carcinoma (NPC). Originally identified through a chromosome 3 NotI genomic microarray screen, it shows frequent deletion or methylation in NPC. FBLN2 is located on chromosome 3p25.1 and is associated with tumor development through its important interactions with the extracellular matrix (ECM) proteins. FBLN2 encodes two isoforms. The short isoform (FBLN2S) is expressed abundantly in normal tissues, but is dramatically downregulated in NPC, while the long isoform (FBLN2L) is either not detectable or is expressed only at low levels in both normal and tumor tissues. Reintroduction of this FBLN2S inhibited cell proliferation, migration, invasion and angiogenesis in vitro. Furthermore, in vivo studies in nude mice show its expression is associated with tumor and angiogenesis suppression. FBLN2-associated angiogenesis occurs via concomitant downregulation of vascular endothelial growth factor and matrix metalloproteinase 2. This study provides compelling evidence that FBLN2S has an important tumor-suppressive and anti-angiogenic role in NPC.

Characterization of tumor suppressive function of P300/CBP-associated factor at frequently deleted region 3p24 in esophageal squamous cell carcinoma.

Deletion of 3p is one of the most frequent genetic alterations in many tumors, including esophageal squamous cell carcinoma (ESCC). In our recent study, deletion of 3p24 was frequently detected in ESCC and one candidate tumor suppressor gene (TSG), p300/CBP-associated factor (PCAF), was identified within the region. In this study, downregulation of PCAF was detected in 23/40 (57.5%) of primary ESCCs and 4/9 (44.4%) of the ESCC cell lines. A further study found that downregulation of PCAF was also associated with hypermethylation of the promoter region of PCAF gene. Methylation-specific PCR found that promoter methylation was detected in 28/40 (70%) of primary ESCCs and 5/9 (55.6%) of ESCC cell lines. In addition, the expression of PCAF could be reactivated in ESCC cell line KYSE510 after demethylation treatment with 5-aza-dC. Functional studies showed that PCAF was able to suppress tumorigenicity of ESCC cells both in vitro and in vivo, including foci formation, colony formation in soft agar and tumor formation in nude mice. Molecular study found that the tumor suppressive mechanism of PCAF was associated with its role in cell cycle arrest at the G1/S checkpoint by the downregulation of CDK2 and upregulation of p21(waf1/Cip1), Smad4, Rb and p27(Kip1). In conclusion, PCAF might be the target TSG responsible for the 3p24 deletion event, which has an important role in the development and progression of ESCC.

Functional polymorphisms in the BRCA1 promoter influence transcription and are associated with decreased risk for breast cancer in Chinese women.

BACKGROUND: The BRCA1 gene is an important breast-cancer susceptibility gene. Promoter polymorphisms can alter the binding affinity of transcription factors, changing transcriptional activity and may affect susceptibility to disease. METHODS AND RESULTS: Using direct sequencing of the BRCA1 promoter region, we identified four polymorphisms c.-2804T-->C (rs799908:T-->C), c.-2265C-->T (rs11655505:C-->T), c.-2004A-->G (rs799906:A-->G) and c.-1896(ACA)(1)-->(ACA)(2) (rs8176071:(ACA)(1)-->(ACA)(2)) present in Hong Kong Chinese. Each polymorphism was studied independently and in combination by functional assays. Although all four variants significantly altered promoter activity, the c.-2265T allele had stronger binding than the C allele, and the most common mutant haplotype, which contains the c.-2265T allele, increased promoter activity by 70%. Risk association first tested in Hong Kong Chinese women with breast cancer and age-matched controls and replicated in a large population-based study of Shanghai Chinese, together totalling >3000 participants, showed that carriers of the c.-2265T allele had a reduced risk for breast cancer (combined odd ratio (OR) = 0.80, 95% CI 0.69 to 0.93; p = 0.003) which was more evident among women aged >or=45 years at first diagnosis of breast cancer and without a family history of breast cancer (combined OR = 0.75, 95% CI 0.61 to 0.91; p = 0.004). The most common haplotype containing the c.-2265T allele also showed significant risk association for women aged >or=45 years without a family history of breast cancer (OR = 0.64, 95% CI 0.46 to 0.89; p = 0.008). CONCLUSION: This comprehensive study of BRCA1 promoter polymorphisms found four variants that altered promoter activity and with the most significant contribution from c.-2265C-->T, which could affect susceptibility to breast cancer in the Chinese population. Its significance in other populations remains to be investigated.

An insight into cathode options for microbial fuel cells.

Microbial fuel cell (MFC) is an emerging and promising technology, particularly in the field of wastewater treatment. The MFC capability of achieving organic removal and generating in situ electricity could make it an attractive alternative wastewater treatment technology over conventional treatment technologies. However, MFC is still far from being economically viable, especially because of the cost of the platinum (Pt) catalyst that makes possible the reaction at the cathode. In this study, we tested alternative cathode catalysts, namely sputter-deposited Cobalt (Co) and denitrifying bacteria (biocathode). The performance of these innovative cathodes was compared with that of classic Pt-cathodes. Co competed well with Pt, but further research is still required for biocathodes. However, biocathodes MFC have showed promise.

Fresh-cut lettuce in modified atmosphere packages stored at improper temperatures supports enterohemorrhagic E. coli isolates to survive gastric acid challenge.

Incidences of foodborne outbreaks involving enterohemorrhagic Escherichia coli strains with mutations in a key regulatory gene, rpoS, have been reported. Incentives, if any, for losing this regulatory function are not clear since the RpoS regulator is required for the expression of several environmental stress tolerance genes. RpoS also positively regulates 2 of the 3 acid-resistance systems of E. coli under aerobic growth conditions and enables the pathogen to survive gastric acid challenge. We selected 7 enterohemorrhagic E. coli isolates, 6 of which are known to carry defective rpoS gene, and then analyzed resistance to synthetic gastric juice after the strains were inoculated on fresh-cut lettuce and stored under modified atmosphere packaging (MAP) conditions. Subatmospheric oxygen partial pressures in MAP enabled all 6 rpoS-defective isolates to induce acid resistance over the 8-d storage period if the temperature was >or= 15 degrees C. No acid resistance was induced for MAP-stored lettuce left at temperatures