Discovery of a novel class of rosmarinic acid derivatives as antibacterial agents: Synthesis, structure-activity relationship and mechanism of action.

Twenty-seven rosmarinic acid derivatives were synthesized, among which compound RA-N8 exhibited the most potent antibacterial ability. The minimum inhibition concentration of RA-N8 against both S. aureus (ATCC 29213) and MRSA (ATCC BAA41 and ATCC 43300) was found to be 6 µg/mL, and RA-N8 killed E. coli (ATCC 25922) at 3 µg/mL in the presence of polymyxin B nonapeptide (PMBN) which increased the permeability of E. coli. RA-N8 exhibited a weak hemolytic effect at the minimum inhibitory concentration. SYTOX Green assay, SEM, and LIVE/DEAD fluorescence staining assay proved that the mode of action of RA-N8 is targeting bacterial cell membranes. Furthermore, no resistance in wildtype S. aureus developed after incubation with RA-N8 for 20 passages. Cytotoxicity studies further demonstrated that RA-N8 is non-toxic to the human normal cell line (HFF1). RA-N8 also exerted potent inhibitory ability against biofilm formation of S. aureus and even collapsed the shaped biofilm.

Measuring productive syntactic abilities in Mandarin-speaking children in Taiwan.

PURPOSE: This study aimed to develop a fine-grained measure for evaluating syntactic abilities in Mandarin-speaking children for educational and clinical purposes as a supplement to MLU. METHOD: In total, 99 typically developing children, aged 2;0 to 5;11, living in Taipei, Taiwan, participated in this study. Spontaneous language samples were elicited in free-play situations. The first 100 intelligible utterances were coded with a newly developed scheme: the Mandarin Assessment of Productive Syntax-Revised (MAPS-R). For the examination of concurrent validity, MLU was also computed. RESULTS: Significant age-related differences were observed in both MLU and MAPS-R scores. Strong correlations were found between MLU and MAPS-R scores, confirming the validity of MAPS-R as a measure of syntactic development. MAPS-R further revealed that Mandarin-speaking children expanded noun phrases with the general classifier 'GE' very early on, followed by a locative expression. Verb expansions began with resultative complements and aspect markers. Sentences with complex predication structures, such as serial verbs/pivotal sentences, were still not widely used when the MLU value is below 4.5. CONCLUSIONS: The study showed that MAPS-R is a reliable and valid measure that can provide a rich profile of the syntactic development of Mandarin-speaking children. It can be a useful reference for speech therapists to set a baseline for developing language intervention plans and to monitor their outcome.

Within-eye and between-subject variability for reflectance of the retinal nerve fibre layer.

PURPOSE: Reflectance of retinal nerve fibre layer (RNFL) can contribute to detecting the presence of glaucomatous damage and defining its extent. As a step towards developing a normative database for RNFL reflectance, we assessed within-eye and between-subject variability for RNFL reflectance in healthy eyes. METHODS: Vertical 30° × 15° volume scans at the optic disc were gathered using SD-OCT (Spectralis OCT) from people free of eye disease. Scans were gathered for both eyes of 30 younger adults (mean ± SD = 27 ± 3 years) and for one eye of 30 older adults (68 ± 8 years). Reflectance was quantified for each voxel as the depth-resolved attenuation coefficient (AC). Values for AC were extracted for four slabs (0-52, 24-52, 24-36 and 36-60 µm) and at depths from 24 to 60 µm below the inner limiting membrane (ILM) in 4 µm steps. RESULTS: Between-subject and within-eye standard deviations (SDs) for the logarithm of AC were similar; median differences were 0.02-0.03 log unit across all four slabs and depths from 24 to 48 µm. Means for the logarithm of AC were higher for younger than older eyes by ~0.1 log unit; this age effect was not due to differences in the raw reflectance of the RNFL, but rather to age-related changes in reflectance of deeper retina affecting the calculation of AC. CONCLUSIONS: In both groups, within-eye variability in RNFL reflectance near the optic disc was similar to between-subject variability. A better understanding of within-eye variability would be useful for developing normative databases.

Presumed activated retinal astrocytes and Müller cells in healthy and glaucomatous eyes detected by spectral domain optical coherence tomography.

PURPOSE: To investigate presumed activated retinal astrocytes and Müller cells (ARAM) detected by scanning laser ophthalmoscopy (SLO) and spectral domain optical coherence tomography, and to investigate its presence in healthy controls as well as its relationship to posterior vitreal detachment (PVD) and glaucoma. METHODS: This retrospective study involved 1337 eyes of 805 controls between ages 8 and 90, and 250 eyes of 146 patients with glaucoma between the ages of 28 and 95. Subjects were counted as possessing ARAM only if they met the following criteria: (1) a patchy, discrete, glittering appearance on SLO, (2) a distinct, flat, hyper-reflective layer at the internal limiting membrane on at least one B-scan crossing the glittering area and (3) absence of any surface wrinkling retinopathy. The diagnosis of PVD was based on both the patient's clinical examination and imaging data. Frequency tables were used to describe categorical variables and differences were compared by means of χ2 . Analyses were separated based on right and left eye, first on controls and then between glaucomatous eyes and age-similar sex-matched controls. RESULTS: ARAM was found in both healthy controls and patients with glaucoma at similar frequencies. There was no association between having glaucoma and the presence of ARAM. ARAM was not different between the sexes but was associated with age and having a PVD. CONCLUSIONS: This large retrospective study found that ARAM can be seen in healthy controls, is associated with PVD and possibly independently with age, and occurred at similar frequency in glaucomatous eyes.

The role of vocabulary and grammar in the listening text comprehension of school-age Cantonese-speaking children with developmental language disorder.

The current study examined the role of vocabulary and grammar in the listening comprehension of school-age Cantonese-speaking children with developmental language disorder in Hong Kong. Participants were 692 typically developing children (TD) and 53 children with developmental language disorder (DLD) and they were tested with a standardized test of oral Cantonese, which includes measures on listening comprehension, receptive and expressive grammar, expressive vocabulary, word definition and lexical relations. The results from multiple regression analysis revealed that listening comprehension of the TD group was explained by receptive grammar, expressive vocabulary, and lexical relationships. However, children of the DLD group mainly relied on a subset of their vocabulary knowledge, as measured in a lexical relation task on antonym, in understanding the text under the constraint of a limited grammatical knowledge.

Predictors of work-related musculoskeletal symptoms in shoulders among nursing assistants working in nursing homes.

Nursing assistants (NAs) working in nursing homes (NHs) are at higher risk for work-related musculoskeletal symptoms (WRMSs) than their counterparts working in other health care settings. Worldwide, NAs have ranked shoulders in the top three body parts at risk of WRMSs. However, factors associated with their shoulder WRMSs are currently unknown. The aim of this study was to identify these associated risk factors among NAs working in NHs. 440 NAs from 47 nursing homes (with 60-90% response rate from each nursing home), recruited by convenience sampling, participated in this cross-sectional study in 2014-2015. A validated and reliable questionnaire was used for data collection. Information on demographic, job content questionnaire (JCQ), perceived physical exertion (PE), workstyle, ergonomic and manual handling knowledge and other work-related factors was collected using a self-administered questionnaire. 53% of the participants reported experiencing with WRMSs in their shoulders. Nine associated factors of shoulder WRMSs were identified using bivariate analysis. With the adjustment of age and gender using multivariable logistic regression, body mass index (OR = .931, 95% CI [.874-.991]), job title of health workers (OR = 2.72, 95% CI [1.18-6.25]) and workstyle-working through pain (OR = 1.06, 95% CI [1.01-1.11]) remained as predictors. Effort should be directed at integrating "workstyle intervention" into lifestyle physical activity training for NAs.

A novel triphenylamine-based bis-Schiff bases fluorophores with AIE-Activity as the hydrazine fluorescence turn-off probes and cell imaging in live cells.

Developing a specific and sensitive method for endogenous hydrazine detection in living systems is valuable to understand its various pathological events. In this work, two novel fluorescent chemosensors (C1, C3) based on triphenylamine Schiff-base derivative and reference dyes (C2, C4) were prepared in relatively high yield (more than 72% yield). The aggregation induced emission (AIE) properties of sensors were investigated through UV-Visible, dynamic light scattering, X-ray diffraction, fluorescence spectrophotometric analyses as well as scanning electron microscope images (SEM). The results indicated that probes C1 and C3 exhibited strong AIE property in DMF/H2O (1:1, v/v) mixture system with brilliant yellow fluorescence emission (560 nm) observed under 365 nm UV lamp. The experiments of sensing indicated that probes C1 and C3 possessed the sequentially detecting abilities for hydrazine with high sensitivity, specificity as well as an extremely low detection limit (55.1 nM), which was due to blocking of AIE process of probes C1 and C3 by special chemical reaction (-CHN- moiety transformed into -CH2-NH- group) after hydrazine addition, resulting in the increase in water solubility and a weak emission in aqueous media. Furthermore, 1H NMR, SEM and fluorescence titration experiment was also conducted to confirm the sensing mechanism. For biological application, probes C1 and C3 presented a good bio-imaging performance and showed the similar fluorescence quenching after adding hydrazine. Therefore, the probes are suitable for the fluorescence imaging of exogenous hydrazine in HeLa cells.

Narrative assessment for Cantonese-speaking children.

BACKGROUND: This study examined the narrative skills of Cantonese-speaking school-age children to fill a need for a normative language test for school-age children. PURPOSE: To provide a benchmark of the narrative skills of Cantonese-speaking children; to identify which of the microstructure components was the best predictor of age; and to determine the diagnostic accuracy of the test components. METHOD AND PROCEDURE: Data were collected from 1,120 Cantonese-speaking children between the ages of 4;10 (years;months) and 12;01, using a story-retell of a 24-frame picture series. Four narrative components (syntactic complexity, semantic score, referencing, and connective use) were measured. OUTCOMES AND RESULTS: Each measure reflected significant age-related differences in narrative ability. Regression analyses revealed that vocabulary and syntactic complexity were the best predictors of grade. All measures showed high sensitivity (86%-94%) but relatively low specificity (60%-90%) and modest likelihood ratio (LR) values: LR+ (2.15-9.42) and LR- (0.07-0.34). CONCLUSION AND IMPLICATIONS: Narrative assessment can be standardized to be a reliable and valid instrument to assist in the identification of children with language impairment. Syntactic complexity is not only a strong predictor of grade but was also particularly vulnerable in Cantonese-speaking children with specific language impairment. Further diagnostic research using narrative analysis is warranted.