Abstract

The exposure of the developing foetal heart to hyperglycaemia in mothers with diabetes mellitus is a major risk factor for foetal cardiac complications that lead to heart failure. We studied the effects of hyperglycaemia on the layout of cardiac myofilament proteins in stem cell-derived cardiomyocytes and their possible underlying mechanisms. Mouse embryonic stem cells (mESCs) were differentiated into cardiac-like cells and cultured in media containing baseline- or high glucose concentrations. Cellular biomarkers were detected using Western blot analysis, immunocytochemistry, 5–ethynyl–2-deoxyuridine (EdU) cell proliferation assay, and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay. High glucose decreased the proportion of cardiac troponin T and α-actinin 2 positive mESCs as well as disrupted the α-actinin 2 striated pattern and the distribution of the cardiac myosin heavy chain α- and β isoforms. However, there was no alteration of the cellular EdU uptake nor the expression of the receptor of advanced glycation end-product (RAGE). High glucose also increased the presence of the oxidative stress marker nitrotyrosine as well as the number of TUNEL-stained nuclei in cardiaclike cells. Treatment with the antioxidant N-acetyl cysteine decreased the number of TUNEL-stained cells in high glucose and improved the α-actinin 2 striated pattern. Hyperglycaemia negatively impacted the expression and cellular organisation of cardiac myofilament proteins in mESC-derived cardiomyocytes through oxidative stress. The results add further insights into the pathophysiological mechanisms of cardiac contractile dysfunction in diabetic cardiac developmental disease.

Medicinal herbs are used for growth promotion, disease control and other health benefits in aquaculture industry.

Here, we examined the effect of dietary laurel-leaf cistus (Cistus laurifolius) ethanolic extract on growth

performance, digestive enzyme activity, haematological profile and nonspecific immune responses in common

carp (Cyprinus carpio). In addition, resistance against Aeromonas hydrophila infection was examined. Common

carp was fed diets containing 0 (Control), 0.1 (CL0.1), 0.5 (CL0.5) and 1 (CL1) g kg􀀀 1 laurel-leaf cistus extract for

45 days. After 30 days, superoxide anion production (SAP) increased in CL0.1 and CL0.5 fish groups and at the

end of the study all experimental fish groups had higher SAP compared to that of the control (P ˂ 0.05).

Lysozyme activity (LA) was elevated in CL0.5 and CL1 treated groups on 30th day (P < 0.05), and this increase

was only observed in C0.1 fish group at the end of study compared to control (P ˂ 0.05). Myeloperoxidase activity

was significantly increased in CL0.5 and CL1 fish groups at the end of study. IL-1βgene expression was

significantly increased in treated fish in a dose-depended manner. Similar results were observed for transcription

of IL-6 and IL-8 (P < 0.05). Anti-inflammatory cytokines, IL-10 and TGF-β were highly up-regulated in the intestine

and head kidney of CL treated fish groups compared to control (P < 0.05). At the end of experiment,

significantly higher final body weight, weight gain, and specific growth rate were obtained in CL0.1 treated fish

group compared to control. However, growth was negatively affected in CL1 fish group (P < 0.05). CL1 fish

group had also a significantly higher FCR. Amylase activity was significantly increased in all experimental fish

groups compared to control (P ˂ 0.05). Trypsin activity was decreased in CL0.1 and CL1 fish groups (P ˂ 0.05).

WBC and RBC were significantly increased (P ˂ 0.05) in CL0.5 and CL1 fish groups, whereas haemoglobin,

haematocrit, mean cell, mean cell haemoglobin contents were no significantly changed among control and

treatment groups. Result of challenge test with A. hydrophila exhibited that survival rate in all treatment groups

was significantly higher than that of control. These findings demonstrated that laurel-leaf cistus at 0.1 g kg􀀀 1 can

be a suitable candidate for growth promotion, immune system induction and infection control in fish.

Previous studies have established that male and female speakers differ in their production of foreign language (FL) vowels due to biological differences in the vocal tract. These differences present a challenge when subjects recruited for an instrumental analysis of speech sounds include speakers of both genders. Most previous studies, therefore, focus on only one gender to avoid the problem of biological differences between males and females. However, different gender groups may perform differently in speaking tasks as their language experience may be influenced by other social factors. Therefore, the aim of this study is to assess the differences between Libyan male and female speakers in the production of English vowels, by examining the data with and without the use of normalization to determine the most difficult English vowels for Libyan male and female speakers. To achieve this goal, seventy Libyan participants (35 male and 35 female) were recruited to perform a speech production task of eleven English vowels embedded in carrier sentences. The data were collected and analyzed using PRAAT to extract the F1 and F2 formant frequencies for each vowel and to calculate the Euclidean distance (ED) of the English vowels produced by using the centroid as the reference point. With the unnormalized data, more overlaps were found for the male speakers when compared to the female speakers as the vowel space were more centred for the males compared to the females. With the unnormalized data, different pairs of vowel contrasts were identified as potentially problematic. However, with the normalized data, better categorical distinction is found in general. Only three vowels emerged as potentially problematic as the other pairs could potentially be disambiguated using vowel duration as a cue. The study demonstrated the utility of the Lobanov method for normalizing speech data to reduce variability associated to gender differences. The efficacy of the Lobanov method of normalization remains to be tested further to verify if the predictions made about difficult vowel pairs for Libyan EFL learners are indeed attested in their discrimination of these vowel pairs in future research. 

This article indicates that Arab Libyan EFL learners are incompetent in oral communication. Despite spending years in learning English, they fail to employ that knowledge in real communicative situations. This might be the outcome of inadequate teaching approaches that are employed by Arab EFL teachers. Diaaba (2016) pointed out that, their overreliance on traditional approaches which emphasize extensive linguistic input rather than communicative output result in what Wolff (2010 cited in ibed, 2016 p. 338) calls 'mute English learners', who can read and write but cannot speak. The purpose of this study was to uncover challenges facing Arabic-speaking ESL students as well as teachers .13 participations are included in this article. Research questions focused on the needs of the Arab Libyan-speaking ESL students, the factors that influence their learning, and the problems the teachers face in supporting these students. Data sources included teacher and student interviews, classroom observations the results revealed that Arab Libyan learners face challenges in speaking skills due to linguistic and psychological barriers. The study concluded that several important challenges for teachers and students exist, including time, language support, and knowledge insufficient exposure to the target language and frequent use of Arabic were the main factors contributing to the Libyan EFL learners' speaking difficulties. Lack of speaking activities and overemphasis on accuracy at the expense of fluency by the teachers were other contributing factors.

Keywords: Speaking skills; speaking difficulties; instructional approaches; linguistic and psychological barriers