Influential Metrics Estimation and Dynamic Frequency Selection Based on Two-Dimensional Mapping for JPEG-Reversible Data Hiding

JPEG Reversible Data Hiding (RDH) is a method designed to extract hidden data from a marked image and perfectly restore the image to its original JPEG form. However, while existing RDH methods adaptively manage the visual distortion caused by embedded data, they often neglect the concurrent increase in file size. In rectifying this oversight, we have designed a new JPEG RDH scheme that addresses all influential metrics during the embedding phase and a dynamic frequency selection strategy with recoverable frequency order after data embedding. The process initiates with a pre-processing phase of blocks and the subsequent selection of frequencies. Utilizing a two-dimensional (2D) mapping strategy, we then compute the visual distortion and file size increment (FSI) for each image block by examining non-zero alternating current (AC) coefficient pairs (NZACPs) and their corresponding run lengths. Finally, we select appropriate block groups based on the influential metrics of each block group and proceed with data embedding by 2D histogram shifting (HS). Extensive experimentation demonstrates how our method's efficiently and consistently outperformed existing techniques with a superior peak signal-to-noise Ratio (PSNR) and optimized FSI.

Retinol dehydrogenases: membrane-bound enzymes for the visual function

Retinoid metabolism is important for many physiological functions, such as differenciation, growth, and vision. In the visual context, after the absorption of light in rod photoreceptors by the visual pigment rhodopsin, 11-cis retinal is isomerized to all-trans retinal. This retinoid subsequently undergoes a series of modifications during the visual cycle through a cascade of reactions occurring in photoreceptors and in the retinal pigment epithelium. Retinol dehydrogenases (RDHs) are enzymes responsible for crucial steps of this visual cycle. They belong to a large family of proteins designated as short-chain dehydrogenases/reductases. The structure of these RDHs has been predicted using modern bioinformatics tools, which allowed to propose models with similar structures including a common Rossman fold. These enzymes undergo oxidoreduction reactions, whose direction is dictated by the preference and concentration of their individual cofactor (NAD(H)/NADP(H)). This review presents the current state of knowledge on functional and structural features of RDHs involved in the visual cycle as well as knockout models. RDHs are described as integral or peripheral enzymes. A topology model of the membrane binding of these RDHs via their N- and (or) C-terminal domain has been proposed on the basis of their individual properties. Membrane binding is a crucial issue for these enzymes because of the high hydrophobicity of their retinoid substrates.

Stereoselective synthesis of (R)-phenylephrine using recombinant Escherichia coli cells expressing a novel short-chain dehydrogenase/reductase gene from Serratia marcescens BCRC 10948

(R)-Phenylephrine [(R)-PE] is an α1-adrenergic receptor agonist and is widely used as a nasal decongestant to treat the common cold without the side effects of other ephedrine adrenergic drugs. We identified a short-chain dehydrogenase/reductase (SM_SDR) from Serratia marcescens BCRC 10948 that was able to convert 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) into (R)-PE. The SM_SDR used NADPH and NADH as cofactors with specific activities of 17.35±0.71 and 5.57±0.07mU/mg protein, respectively, at 30°C and pH 7.0, thereby indicating that this enzyme could be categorized as an NADPH-preferring short-chain dehydrogenase/reductase. Escherichia coli strain BL21 (DE3) expressing SM_SDR could convert HPMAE into (R)-PE with more than 99% enantiomeric excess. The productivity and conversion yield were 0.57mmolPE/lh and 51.06%, respectively, using 10mM HPMAE. Fructose was the most effective carbon source for the conversion of HPMAE to (R)-PE.

AUStralian Indigenous Chronic Disease Optimisation Study (AUSI-CDS) prospective observational cohort study to determine if an established chronic disease health care model can be used to deliver better heart failure care among remote Indigenous Australians: Proof of concept-study rationale and protocol

BACKGROUND

The congestive heart failure syndrome has increased to epidemic proportions and is cause for significant morbidity and mortality. Indigenous patients suffer a greater prevalence with greater severity. Upon diagnosis patients require regular follow-up with medical and allied health services. Patients are prescribed life saving, disease modifying and symptom relieving therapies. This can be an overwhelming experience for patients. To compound this, remoteness, differentials in conventional health care and services pose special problems for Indigenous clients in accessing care. Additional barriers of language, culture, socio-economic disadvantage, negative attitudes towards establishment, social stereotyping, stigma and discrimination act as barriers to improved care. Recent focus supported by clinical evidence support the role of chronic disease self-management programs. A patient focused, problem identification, goal setting and psychosocial modification based program should in principal highlight these issues and help tailor a patient focused comprehensive care plan to complement guideline based care. At present there are no Indigenous focused chronic disease self-management programs. There is a need for research on ways to provide chronic disease management to this group. We therefore designed a study to assess a model of patient focussed comprehensive care for Indigenous Australians with heart failure.

STUDY DESIGN

AUSI-CDS is a prospective, cohort, observational study to evaluate the efficacy of the standard "Flinders Program of Chronic Condition Management" for Indigenous patients with chronic heart failure. Eligible patients will be Indigenous, suffering from chronic heart failure, in the Northern Territory. The primary end-point is the satisfaction score based on the PACIC. The study will recruit 20 patients and is expected to last 12 months.

SUMMARY

The rationale and design of the AUSI-CDS using the Flinders Model is described.