Comparison of teak wood properties according to forest management: short versus long rotation

Key message: Teak (Tectona grandis L.f.) is one of the most important tropical hardwood tree species, which is widely planted in Indonesia. Wood properties are strongly influenced by forest management conditioning further utilization of wood. Context: In Indonesia, teak wood has been supplied from the state forests (Perhutani) for long rotation teak and from community teak plantations for short rotation teak. Short rotation teak has been harvested at 7–10 years and long rotation teak at 40–60 years. Aims: This paper discusses the characterization of technical properties of short and long rotation teak wood based on the chemical, anatomical, physical, and mechanical properties. Methods: The properties of short rotation and long rotation teak woods were characterized by measuring their density, extractive contents, chemical composition, swelling, wettability, water sorption isotherm, decay resistance, anatomical properties, bending strength (modulus of rupture (MOR), modulus of elasticity (MOE)), and hardness. Results: The results indicate that short rotation teak was not particularly different in swelling, MOE and MOR, and Brinell hardness compared to long rotation teak, although it was less dense and less durable due to lower heartwood and extractive contents. Therefore, careful attention should be given to the use of short rotation teak in some wood-processing technologies. Conclusion: Lower wood density and durability of the short rotation compared to the long rotation teak will restrict its utilization to some extent for both indoor and outdoor applications. Fast-growing teak from community cannot be used as usual heartwood teak from Perhutani because of the very low proportion of useful heartwood in the stem

Investigations of the reasons for fungal durability of heat-treated beech wood

International audienc

Investigation of wood wettability changes during heat treatment on the basis of chemical analysis

International audienc

Evaluation of essential oil composition and antioxidant capacity of hydromethanolic extracts of Tetraclinis articulata, depending on location and seasonal variations

International audienceThis work describes the seasonal and geographical variation in essential oils composition, the in vitro lipid peroxidation inhibitions, the anti-radical activities and total phenolic contents of two aqueous methanol (methanol: water, 80:20 and 50:50 v/v) and essential oils fractions of aromatic wild plant, Tetraclinis articulata (Vahl) Masters, grown in two arboreta in the North East Tunisia. Chemical composition of the essential oils was evaluated by GC/MS and GC/FID. The inhibition of lipid peroxidation and DPPH radical scavenging ability were studied to evaluate the antioxidant activity for six extracts of Tetraclinis articulata. The results show that essential oil content was not affected by geographical origin and was significantly affected by season (p≤ 0.05). The essential oil yields ranged from 0.10% to 0.26%, the maximum amount was observed during winter (January) and the minimum was obtained in spring (May). GC/MS analysis revealed 29 constituents in this plant. For both geographical origins (Korbous and Jbel abderrahmen) and four season periods (January; April; May and November 2010), highly significant differences were observed for oil compositions (p≤ 0.05). The main compounds identified in the leaves of this plant were α-Pinene (26.3-36.6%), bornyl acetate (19.0-25.4%), camphor (5.5-15.3%), and limonene (5.3-8.9%). Others representative components were detected such as β-myrcene (3.9-6.6%), borneol(3.0-6.8%) and caryophyllene (0.2-5.1%). For the antioxidant data, the methanol: water (50:50 v/v) fraction of the January harvest exhibited the highest DPPH radical scavenging activity, and exerted the highest percentage inhibition of the induced autoxidation of methyl linoleate. The total phenolic content of various extracts was in the range of 17.7±0.7 to 30.1±1.0 eq. gallic acid/g. This study demonstrated that inhibition of lipid peroxidation and the DPPH radical scavenging ability of Tetraclinis articulata leaf are correlated with the amount of phenolic constituents

Hippocampal subfields alterations in adolescents with post‐traumatic stress disorder

International audienceReexperiencing symptoms in adolescent Post-Traumatic Stress Disorder (PTSD) are characterized by the apparition of vivid intrusive images of the traumatic event. The emergence of these intrusions is thought to be related to a deficiency in context processing and could then be related to hippocampal alterations. The hippocampus is a complex structure which can be divided into several subfields, namely, the Cornu Ammonis (CA1, CA2, and CA3), the subiculum, and the dentate gyrus (DG). As each subfield presents different histological characteristics and functions, it appears more relevant to consider hippocampal subfields, instead of only assessing the whole hippocampus, to understand the neurobiology of PTSD. Hence, this study presents the first investigation of structural alterations within hippocampal subfields and their links to reexperiencing symptoms in adolescent PTSD. Hippocampal subfields were manually delineated on high-resolution MRI images in 15 adolescents (13-18 years old) with PTSD and 24 age-matched healthy controls. The volume of the region CA2-3/DG region was significantly smaller in the PTSD group compared to controls in both hemispheres. No other significant difference was found for other subfields. Moreover, the volume of the left CA2-3/DG was negatively correlated with the intrusion score (as measured by the Impact of Events Scale-Revised) in the PTSD group. To conclude, an alteration in the hippocampal subregion CA2-3/DG, known to resolve interferences between new and similar stored memories, could participate in the apparition of intrusive trauma memories in adolescents with PTSD

Repetitive transcranial magnetic stimulation for patients with functional paralysis: a randomized controlled study

International audienceBackground and purpose: Repetitive transcranial magnetic stimulation (rTMS) has been proposed to treat functional neurological disorders. Here, the aim was to assess the efficacy of rTMS to treat functional paralysis in a controlled randomized trial.Methods: Patients received two sessions of active or sham 0.25 Hz rTMS (60 stimuli each), with a 1-day interval, applied over the motor cortex contralateral to the paralysis. The primary outcome was the number of patients with an increase in motor score between baseline and after the second rTMS session, rated by two investigators blinded to the treatment allocation. Secondary outcomes were changes in global and fine motor scores between groups after rTMS, and the occurrence of adverse events.Results: Sixty-two patients (46 female; mean [SD] age, 35.2 [13.9] years) were enrolled and randomized. Thirteen out of 32 (41%) and 11/30 (37%) patients had increased motor strength after active or sham rTMS, respectively (p = 0.80). Changes in both global and fine motor scores after rTMS relative to baseline were also not significantly different between treatment groups (median difference in the global motor score 0.62 [0.83] and 0.37 [0.61], and in the fine motor scores 0.12 [0.18] and 0.08 [0.11], in active and sham rTMS groups, respectively; p = 0.14). Six serious adverse events, consisting of three cephalalgia in the active group and two cephalalgia and one asthenia in the sham group, were observed.Conclusions: Two sessions of sham or active low frequency rTMS were effective to improve functional paralysis, suggesting a placebo effect of this non-invasive brain stimulation technique