Structural, optical and conductivity properties in tetragonal BaTi1-x Co x O3 (0≤ x ≤0.1).

This work investigates the structure, optical and electrical conductivity properties of BaTi1-x Co x O3 (0≤ x ≤0.1) ceramics prepared by the hydrothermal method. The X-ray diffraction and Raman scattering analysis demonstrates that the prepared samples have a single-phase tetragonal structure with P4mm symmetry. The UV-vis diffuse reflectance spectrum confirms the influence of Co concentration on the direct optical band gap of BaTi1-x Co x O3 ceramics. The optical band gap shifts from 3.14 eV to 3.44 eV as the Co concentration increases from 0 to 0.1. The dielectric constant increases with the depletion of frequency according to the Maxwell-Wagner and Koops model. The AC conductivity versus frequency curve indicates that the conduction mechanism is determined by using the correlated barrier hopping (CBH) model. The Cole-Cole plot of the complex impedance was investigated for the prepared samples. The compounds showed dielectric relaxation of the non-Debye type.

Investigation of alkali and alkaline earth solvation structures in tetraglyme solvent.

This study compares molecular calculations performed with molecular and periodic codes through an investigation of the solvation structures of alkali and alkaline earth metal ions in tetraglyme solution. The two codes are able to produce equivalent structural and energetic information at the same level of theory, and in the presence of the implicit solvation model or not. This comparison reveals that molecular optimisations can be performed with periodic codes and used directly as input models for interface or electrochemistry calculations in order to preserve the solvent-solute interaction and the cavitation energy. By a rigorous comparison, we have demonstrated that equivalent energetic values can be obtained with the conventional PBE-D3 and the newly developed SCAN-rVV10 functionals. Nevertheless, as far as the vibrational features are concerned and when the molecule possesses a highly conjugated system, the SCAN-rVV10 functional is required to describe the vibrational modes properly. The computed IR/Raman spectra can thus be used as essential information to determine the first solvation shell of metal ions in glyme-based solutions. In tetraglyme solution, the alkali and alkaline earth metal ions exhibit a diverse solvation structure. Small ions like Li+ and Mg2+ tend to adopt a coordination number of five or six, while larger ions, Na+, K+, and Ca2+, prefer an eight-coordinated environment, and the metal-ligand interaction increases in the order K+-O < Na+-O < Li+-O < Ca2+-O < Mg2+-O. The solvation spheres play a significant role in the stability and the reactivity of the solvated ions, and can thus be used as input models to construct the solvation structure in more sophisticated electrolytes, such as polyethylene oxide, or perform electrochemical calculations.

Optimal symptom combinations to aid COVID-19 case identification: Analysis from a community-based, prospective, observational cohort.

OBJECTIVES: Diagnostic work-up following any COVID-19 associated symptom will lead to extensive testing, potentially overwhelming laboratory capacity whilst primarily yielding negative results. We aimed to identify optimal symptom combinations to capture most cases using fewer tests with implications for COVID-19 vaccine developers across different resource settings and public health. METHODS: UK and US users of the COVID-19 Symptom Study app who reported new-onset symptoms and an RT-PCR test within seven days of symptom onset were included. Sensitivity, specificity, and number of RT-PCR tests needed to identify one case (test per case [TPC]) were calculated for different symptom combinations. A multi-objective evolutionary algorithm was applied to generate combinations with optimal trade-offs between sensitivity and specificity. FINDINGS: UK and US cohorts included 122,305 (1,202 positives) and 3,162 (79 positive) individuals. Within three days of symptom onset, the COVID-19 specific symptom combination (cough, dyspnoea, fever, anosmia/ageusia) identified 69% of cases requiring 47 TPC. The combination with highest sensitivity (fatigue, anosmia/ageusia, cough, diarrhoea, headache, sore throat) identified 96% cases requiring 96 TPC. INTERPRETATION: We confirmed the significance of COVID-19 specific symptoms for triggering RT-PCR and identified additional symptom combinations with optimal trade-offs between sensitivity and specificity that maximize case capture given different resource settings.

Correction: Sensitive MnFe2O4-Ag hybrid nanoparticles with photothermal and magnetothermal properties for hyperthermia applications.

[This corrects the article DOI: 10.1039/D1RA03216J.].

Sensitive MnFe2O4-Ag hybrid nanoparticles with photothermal and magnetothermal properties for hyperthermia applications.

In this study, we present an experiment showing that designing multifunctional MnFe2O4-Ag nanoparticles to act as a dual hyperthermia agent is an efficient route for enhancing their heating ability. Interestingly, the specific absorption rate of the heteromeric MnFe2O4-Ag nanoparticles increased 2.7 times under simultaneous irradiation of a 100 Oe magnetic field and 0.14 W cm-2 laser compared to the action by the magnetic field alone, and more interestingly, is 30% higher than the sum of the two individual actions. The synergistic benefit of the magneto- and photo-thermal properties of the heteromeric structure can reduce the strengths of the magnetic field and laser intensities as well as their irradiation time to levels lower than those required in their hyperthermia applications individually. In vitro cytotoxicity analysis performed on HepG2 liver cancer and Hela cervical cancer cell lines showed that IC50 values were 83 ± 5.6 µg mL-1 (for HepG2) and 122.6 ± 19.8 µg mL-1 (for Hela cells) after 48 h of incubation, therefore, the nanoparticles are moderately cytotoxic and nontoxic to HepG2 and Hela cells, respectively; which offers the potential of safe therapy.

Optimal symptom combinations to aid COVID-19 case identification: analysis from a community-based, prospective, observational cohort.

OBJECTIVES: Diagnostic work-up following any COVID-19 associated symptom will lead to extensive testing, potentially overwhelming laboratory capacity whilst primarily yielding negative results. We aimed to identify optimal symptom combinations to capture most cases using fewer tests with implications for COVID-19 vaccine developers across different resource settings and public health. METHODS: UK and US users of the COVID-19 Symptom Study app who reported new-onset symptoms and an RT-PCR test within seven days of symptom onset were included. Sensitivity, specificity, and number of RT-PCR tests needed to identify one case (test per case [TPC]) were calculated for different symptom combinations. A multi-objective evolutionary algorithm was applied to generate combinations with optimal trade-offs between sensitivity and specificity. FINDINGS: UK and US cohorts included 122,305 (1,202 positives) and 3,162 (79 positive) individuals. Within three days of symptom onset, the COVID-19 specific symptom combination (cough, dyspnoea, fever, anosmia/ageusia) identified 69% of cases requiring 47 TPC. The combination with highest sensitivity (fatigue, anosmia/ageusia, cough, diarrhoea, headache, sore throat) identified 96% cases requiring 96 TPC. INTERPRETATION: We confirmed the significance of COVID-19 specific symptoms for triggering RT-PCR and identified additional symptom combinations with optimal trade-offs between sensitivity and specificity that maximize case capture given different resource settings.

Hearing loss in pediatric temporal bone fractures: Evaluating two radiographic classification systems as prognosticators.

INTRODUCTION: Temporal bone fractures (TBF) are traditionally classified by their angle of fracture relative to the petrous ridge, and more recently by whether or not they violate the otic-capsule. This study compared rates of hearing loss (HL) and signs of otologic dysfunction among fracture types of both classification systems, within the pediatric population. METHODS: Pediatric patients were retrospectively characterized from a previously identified cohort of TBF patients, diagnosed from 2000 to 2014. CT scans were reviewed and TBFs were classified first as longitudinal (L), transverse (T) or mixed (M), and then as otic-capsule sparing (OCS) or otic-capsule violating (OCV). Medical records were reviewed, and rates of HL and presenting signs were compared among L, T and M fractures, and OCS and OCV fractures. RESULTS: Forty-three patients with 47 TBFs met the inclusion criteria. Eighteen, 4 and 25 TBFs were classified as L, T and M fractures, respectively. Thirty-three and 9 were classified as OCS, and OCV, respectively. Among 24 cases of HL: 20, 3, and 1 were conductive HL (CHL), sensorineural HL (SNHL) and mixed HL, respectively. Two cases of SNHL were found among OCV fractures, with none in OCS fractures (estimated difference 0.22; 95% confidence interval 0.01-0.60). Similar rates of CHL were found across L, T and M fractures (range 36-50%), and across OCV and OCS fractures (range 42-44%). Hemotympanum was the most common presenting sign, found in 68% of TBFs and 80% of CHL cases. There were no significant differences in the incidence of signs or symptoms between fracture types. CONCLUSIONS: In our cohort, both the traditional and otic-capsule radiographic classification systems failed to predict the incidence of CHL and other otologic signs in the pediatric population. Though OCV fractures conferred an increased risk for developing SNHL, we found a lower incidence than anticipated given violation to the bony labyrinth.

Allergen sensitisation among chronic respiratory diseases in urban and rural areas of the south of Viet Nam.

OBJECTIVE: To evaluate the prevalence of and risk factors for allergen sensitisation among patients with chronic respiratory disease (CRD) in southern Viet Nam. DESIGN: An environmental questionnaire and skin prick tests for airborne and food allergens were administered to patients with CRD, defined as individuals with respiratory symptoms and lung function defects. RESULTS: Of 610 CRD patients, 56% had chronic obstructive pulmonary disease and 31% were asthma patients; 80% were males. The most frequent sensitisers were dust mites (Dermatophagoides farinae 22%, Blomia tropicalis 19%, D. pteronyssinus 18%) and cockroach droppings (13%). Among study participants, 37% were from rural settings and 36% from urban areas, whereas 27% had migrated from rural to urban areas. Compared with people from rural areas, being born in an urban area was a risk factor for sensitisation to mites (OR 1.56, 95%CI 1.11-2.20, P < 0.02). In multivariate analysis, place of birth remained a risk factor for mite sensitisation. Compared with the native urban population, the risk of mite sensitisation was not significantly different among patients born in rural areas and those migrating to urban areas. CONCLUSION: Dust mites and cockroach droppings were the most frequent allergens among people with CRD in the south of Viet Nam. Compared with the urban population, being native to a rural area was protective against mite sensitisation, but this effect ceased to be significant after migration from rural to urban areas.

Systematic review with meta-analysis: rifaximin for the prophylaxis of spontaneous bacterial peritonitis.

BACKGROUND: The primary and secondary prevention of spontaneous bacterial peritonitis (SBP) is recommended in high-risk patients with cirrhosis. Several studies evaluating the efficacy of rifaximin for SBP prophylaxis have yielded conflicting results. Rifaximin has the potential advantage of preventing bacterial overgrowth and translocation without the systemic side effects of broad-spectrum antibiotics. AIM: To evaluate the efficacy of rifaximin in the primary and secondary prevention of SBP. METHODS: A literature search using five databases was performed to identify studies on the association between rifaximin and SBP. We performed two meta-analyses: (1) rifaximin compared to systemic antibiotics and (2) rifaximin compared to no antibiotics. Random-effect modelling was conducted to determine overall pooled estimates and 95% confidence intervals (CIs). RESULTS: Five studies with 555 patients (295 rifaximin, 260 systemic antibiotics) compared rifaximin with systemic antibiotics. The pooled odds ratio (OR) for SBP was 0.45 (95% CI 0.16-1.27; P = .13) in patients receiving rifaximin and strengthened on sensitivity analysis (OR 0.38, 95% CI 0.19-0.76, P = .01). In the analysis comparing rifaximin with no antibiotics, there were five studies with 784 patients (186 rifaximin, 598 no antibiotics). The OR for SBP was 0.34 (95% CI 0.11-0.99; P < .05) in patients receiving rifaximin. In subgroup analysis, rifaximin reduced the risk of SBP by 47% compared to no antibiotics for primary prophylaxis and by 74% compared to systemic antibiotics for secondary prophylaxis. CONCLUSION: Rifaximin may be effective in preventing SBP in patients with cirrhosis and ascites compared to systemically absorbed antibiotics and compared to placebo.

Securing an OTL-HNS residency: how competitive is it? Comparing medical student perceptions to actual Canadian statistics.

BACKGROUND: The residency match is an important event in an aspiring physician's career. Otolaryngology - Head and Neck Surgery (OTL-HNS) is a surgical specialty that has enjoyed high numbers of applicants to its residency programs. However, recent trends in Canada show a decline in first-choice applicants to several surgical fields. Factors thought to influence a medical student's choice include role models, career opportunities and work-life balance. The notion of perceived competitiveness is a factor that has not yet been explored. This study sought to compare competitiveness of OTL-HNS, as perceived by Canadian medical students to residency match statistics published yearly by CaRMS (Canadian Residency Matching Service), with the hope of informing future decisions of surgical residency programs. METHODS: An electronic survey was created and distributed to all medical students enrolled in the 17 Canadian medical schools. After gathering demographic information, students were asked to rank what they perceived to be the five most competitive disciplines offered by CaRMS. They were also asked to rank surgical specialties from most to least competitive. Publically available data from CaRMS was then collected and analyzed to determine actual competitiveness of admissions to Canadian OTL-HNS residency programs. RESULTS: 1194 students, from first to fourth year of medical school, completed the survey. CaRMS statistics over the period from 2008 to 2014 demonstrated that the five most competitive specialties were Plastic Surgery, Dermatology, Ophthalmology, Emergency Medicine and OTL-HNS. Among surgical disciplines, OTL-HNS was third most competitive, where on average 72% of students match to their first-choice discipline. When students were questioned, 35% ranked OTL-HNS amongst the top five most competitive. On the other hand 72%, 74% and 80% recognized Opthalmology, Dermatology and Plastic Surgery as being among the five most competitive, respectively. We found that fourth-year medical students were significantly more knowledgeable about the competitiveness of both OTL-HNS and Plastic Surgery compared to first-year students (p < 0.01). CONCLUSION: Overall, Canadian medical students may underestimate the competitiveness of OTL-HNS. Furthermore, competitiveness would appear to be a concept that resonates with medical students during the match process.

Ethnic differences in incidence of hepatitis B surface antigen seroclearance in a real-life multicenter clinical cohort of 4737 patients with chronic hepatitis B infection.

BACKGROUND: Hepatitis B surface antigen (HBsAg) positivity is associated with increased risk for cirrhosis and hepatocellular carcinoma (HCC). HBsAg seroclearance is thought to be rare in general, but cohort data from US patients are limited. AIM: To determine the incidence of HBsAg seroclearance in a real-life US cohort. METHODS: In total, 4737 patients with chronic hepatitis B from five primary care, gastroenterology and multispecialty centres, and a university medical centre were retrospectively enrolled between 2001 and 2014 with data obtained by manual review of individual patient medical records. Seroclearance was determined by loss of HBsAg seropositivity. Persistent HBsAg was confirmed by direct serology or by proxy with positive hepatitis B e-antigen (HBeAg) or HBV DNA levels. RESULTS: HBsAg seroclearance occurred in 52 patients over 16 844 person-years (0.31% annually, 1.2% overall). Median follow-up was 32 months, and mean age 45 ± 14 years. Incidence of HBsAg seroclearance was higher in non-Asians, age >45, males, and those with baseline HBV DNA ≤10 000 IU/mL. On multivariate Cox proportional modelling, non-Asian ethnicity (HR 2.8), male sex (HR 2.1), baseline HBVDNA ≤10 000 (HR 2.0) and age >45 (HR 1.8) were significant independent predictors of seroclearance. CONCLUSION: HBsAg seroclearance rates were lower than previously described in this real-life cohort of patients with chronic hepatitis B, especially among Asian, female and younger patients.

Pediatric temporal bone fractures: A case series.

OBJECTIVES: Temporal bone fractures are relatively common findings in patients with head trauma. The aim of this study was to evaluate the characteristics of temporal bone fractures in the pediatric population. STUDY DESIGN: Retrospective case series. Tertiary care pediatric academic medical center. METHODS: The medical records of patients aged 18 years or less diagnosed with a temporal bone fracture at the Montreal Children's Hospital from January 2000 to August 2014 were reviewed. Patient demographics, clinical presentation, mechanism of injury and complications were analyzed. Imaging studies and audiograms were also evaluated. RESULTS: Out of 323 patients presenting to the emergency department with a skull fracture, 61 presented with a temporal bone fracture. Of these, 5 presented with bilateral fractures. 47 patients had associated fractures, and 3 patients deceased. We observed a male to female ratio of 2.8:1, and the average age was 9.5 years. Motor vehicle accidents were the primary mechanism of injury (53%), followed by falls (21%) and bicycle or skateboard accidents (10%). The most common presenting signs included hemotympanum, decreased or loss of consciousness, facial swelling and nausea and vomiting. 8 patients had otic involvement on computed tomography scans, and 30 patients had documented hearing loss near the time of accident with a majority being conductive hearing loss. 17 patients underwent surgical management of intracranial pressure. CONCLUSION: In children, fractures of the temporal bone were most often caused by motor vehicle accidents and falls. It is common for these patients to have associated fractures.

Systematic review with meta-analysis: the proportion of chronic hepatitis B patients with normal alanine transaminase ≤ 40 IU/L and significant hepatic fibrosis.

BACKGROUND: Chronic hepatitis B (CHB) may lead to cirrhosis, hepatocellular carcinoma and premature death. Elevated alanine transaminase (ALT) levels ≥ the upper limit of normal (ULN) are a major determinant for initiating anti-viral therapy; however, ALT levels alone may not be predictive of hepatic fibrosis. AIM: To determine the proportion of CHB patients with ALT ≤ 40 IU/L and liver fibrosis stage ≥ 2. Secondary goals include subgroup analysis by hepatitis B e antigen (HBeAg) status, high hepatitis B virus (HBV) DNA levels, Asian ethnicity, lower ULN of ≤ 30 IU/L (males) and 19 IU/L (females), and advanced age. METHODS: Studies identified in EMBASE and MEDLINE (1/1990-6/2012) using the search criteria: "Hepatitis B"[Mesh] OR "Hepatitis B virus"[Mesh] OR "Hepatitis B, Chronic"[Mesh])) AND "Alanine Transaminase"[Mesh]) and abstracts containing the term 'hepatitis' from recent major U.S. gastroenterology and liver society meetings were considered. RESULTS: Among nine studies (N = 830 patients), a significant proportion (20.7%; 95% CI: 16.2-26.0%) of CHB patients with ALT levels ≤ 40 IU/L had significant fibrosis irrespective of HBeAg status, high HBV DNA levels, ethnicity or age, although this proportion may be higher in patients older than 30-40 years old. The corresponding proportion was 27.8% even when the newer ULN of 30 IU/L (males) and 19 IU/L (females) was applied. CONCLUSIONS: Approximately one fifth of CHB patients with ALT ≤ 40 IU/L may have significant hepatic fibrosis. The approach to such patients should be individualised, as further evaluation and treatment may be appropriate.

Systematic review: Asian patients with chronic hepatitis C infection.

BACKGROUND: Chronic hepatitis C (CHC) infection is a risk factor for both the development of end-stage liver disease and hepatocellular carcinoma (HCC). Globally, approximately 170 million people are chronically infected with the hepatitis C virus (HCV), and the majority of these individuals come from the western Pacific and Southeast Asia regions (94.6 million persons combined). CHC is an understudied and underappreciated health problem in many Asian countries and in the US, where Asians represent one of the fastest growing groups of new Americans. AIM: To perform a systematic review of the current literature on the epidemiology, diagnosis and screening, clinical characteristics and response to anti-viral therapy of Asians with CHC. METHODS: Using a PubMed search of 'hepatitis C' and 'Asia,' 341 original manuscripts published in peer-reviewed journals were identified, and 99 were selected based on their relevance. RESULTS: Many Asian CHC patients do not have easily identifiable risk factors and may be underdiagnosed. Rates of HCV infection in Asians on community screening in the US are unexpectedly high, and there is a high prevalence of HCV genotype 6 in Southeast Asia and Southern China. HCV-infected Asians tend to present at older age and may have higher risk of HCC; however, they respond better to anti-viral therapy than non-Asians across all HCV genotypes. CONCLUSIONS: Given the high HCV endemicity in Asia, lack of identifiable risk factors and favourable treatment response rates in Asians, we advocate the screening for HCV infection of all Asians who come from areas where HCV prevalence is ≥2%.

Prevalence of hepatitis B virus DNA polymerase mutations in treatment-naïve patients with chronic hepatitis B.

BACKGROUND: One of the most important factors in treatment failure using nucleos(t)ide analogues in chronic hepatitis B is anti-viral resistance. Primary drug resistance refers to amino acid changes in the hepatitis B virus polymerase/reverse transcriptase (rt) that result in reduced susceptibility to anti-viral agents. Pre-existing drug resistance mutations may occur in untreated patients and may affect their treatment outcomes. AIM: To determine the prevalence of hepatitis B DNA polymerase mutations in treatment-naïve patients. METHODS: We used a direct PCR sequencing test to detect DNA polymerase mutations in 472 consecutive treatment-naïve patients at two community gastroenterology clinics in Northern California. RESULTS: A majority of patients were Asians (>95%), had either genotype B or C (95%) and had no evidence of cirrhosis or liver cancer (94%). Mean age was 45 +/- 13 and mean hepatitis B virus DNA was 5.3 +/- 1.8 log(10) IU/mL. Most patients did not have any detectable mutations (82.4%). Some (16.7%) had mutations of unknown clinical significance (rtV207M/L/I) and only 4 patients had rtA181A/S, rtA194S or M250I. CONCLUSIONS: No rtM204V/I or rtN236T mutations were observed in our study. Less than 1% of our patients had mutations that can be associated with primary resistance to existing anti-viral therapies for hepatitis B virus.

Promoter recognition and discrimination by EsigmaS RNA polymerase.

Although more than 30 Escherichia coli promoters utilize the RNA polymerase holoenzyme containing sigmaS (EsigmaS), and it is known that there is some overlap between the promoters recognized by EsigmaS and by the major E. coli holoenzyme (Esigma70), the sequence elements responsible for promoter recognition by EsigmaS are not well understood. To define the DNA sequences recognized best by EsigmaS in vitro, we started with random DNA and enriched for EsigmaS promoter sequences by multiple cycles of binding and selection. Surprisingly, the sequences selected by EsigmaS contained the known consensus elements (-10 and -35 hexamers) for recognition by Esigma70. Using genetic and biochemical approaches, we show that EsigmaS and Esigma70 do not achieve specificity through 'best fit' to different consensus promoter hexamers, the way that other forms of holoenzyme limit transcription to discrete sets of promoters. Rather, we suggest that EsigmaS-specific promoters have sequences that differ significantly from the consensus in at least one of the recognition hexamers, and that promoter discrimination against Esigma70 is achieved, at least in part, by the two enzymes tolerating different deviations from consensus. DNA recognition by EsigmaS versus Esigma70 thus presents an alternative solution to the problem of promoter selectivity.

The human interferon- and estrogen-regulated ISG20/HEM45 gene product degrades single-stranded RNA and DNA in vitro.

The human ISG20/HEM45 gene was identified independently on the basis of its increased level of expression in response to either interferon or estrogen hormone. Notably, the encoded protein is homologous with members of the 3' to 5' exonuclease superfamily that includes RNases T and D, and the proofreading domain of Escherichia coli DNA polymerase I. We provide here direct biochemical evidence that Isg20 acts as a 3' to 5' exonuclease in vitro. This protein displays a pH optimum of approximately 7.0, prefers Mn2+ as a metal cofactor, and degrades RNA at a rate that is approximately 35-fold higher than its rate for single-stranded DNA. Along with RNase L, Isg20 is the second known RNase regulated by interferon. Previous data showed that Isg20 is located in promyelocytic leukemia (PML) nuclear bodies, known sites of hormone-dependent RNA polymerase II transcription and oncogenic DNA viral transcription and replication. The combined data suggest a potential role for Isg20 in degrading viral RNAs as part of the interferon-regulated antiviral response and/or cellular mRNAs as a regulatory component of interferon and estrogen signaling.

Micrometastasis to in-transit lymph nodes from extremity and truncal malignant melanoma.

BACKGROUND: The sentinel lymph node (SLN) is the first lymph node in the regional nodal basin to receive metastatic cells. In-transit nodes are found between the primary melanoma site and regional nodal basins. To date, this is one of the first reports on micrometastasis to in-transit nodes. METHODS: Retrospective database and medical records were reviewed from October 21, 1993, to November 19. 1999. At the UCSF Melanoma Center, patients with tumor thickness > 1 mm or < 1 mm with high-risk features are managed with preoperative lymphoscintigraphy, selective SLN dissection, and wide local excision. RESULTS: Thirty (5%) out of 557 extremity and truncal melanoma patients had in-transit SLNs. Three patients had positive in-transit SLNs and negative SLNs in the regional nodal basin. Two patients had positive in-transit and regional SLNs. Three patients had negative in-transit SLNs but positive regional SLNs. The remaining 22 patients were negative for in-transit and regional SLNs. CONCLUSIONS: In-transit SLNs may harbor micrometastasis. About 10% of the time, micrometastasis may involve the in-transit and not the regional SLN. Therefore, both in-transit and regional SLNs should be harvested.