Canopy gaps characteristics and structural dynamics in a natural unmanaged oriental beech (Fagus orientalis Lipsky) stand in the north of Iran

Canopy gaps are one of the most important structural features of forest ecosystems, and studying them can have useful results and implications for forest management. The aim of this study was to investigate the characteristics and regeneration within canopy gaps in an intact beech stand in Shastkalateh experimental forest of Hyrcanian region, north of Iran. All canopy gaps and related forest parameters were measured within a permanent plot of 16 ha. Then, for each canopy gap, two parameters were measured—the length (L) as the longest distance within the gap, and the width (W) as the largest distance perpendicular to the length. Considering the composition of the forest, the dominant tree species was oriental beech with 36.3% of the stem number and 56.6% of the stand volume. Totally, 54 canopy gaps were identified which covered about 5% of the forest area. An average of 4.32 gaps.ha-1 existed in the permanent plot and gap sizes varied from 48.3 to 622.7 m^2. Over three-quarters (77.7%) of canopy gaps were smaller than ≤200 m^2 and also over half of the gaps (53%) were formed by a single tree-fall event. The beech made up 52% of gap makers and 23.4% of gap fillers and also had the second largest proportion on standing deadwood of gap maker in the study area, while velvet maple was the most frequent gap filler in approximately 30% of the gaps. Despite the high frequency of small gaps 100 m^2, their proportion of the overall gap area reached only 25%, suggesting the important role of intermediate and large gaps in the gap dynamics. Considering the recent occurring disturbances in the Hyrcanian forests, the study analyzed the main characteristics of disturbance regime with the emphasis on the role of wind and longevity of trees. In general, findings of this study showed that creating small and average gaps in intact beech forests could be based on natural disturbance regimes, and suitable conditions provides for successful regeneration of beech forests in close to nature silviculture

Protection Group Effects During α,γ-Diol Lignin Stabilization Promote High-Selectivity Monomer Production

Protection groups were introduced during biomass pretreatment to stabilize lignin's α,γ-diol group during its extraction and prevent its condensation. Acetaldehyde and propionaldehyde stabilized the α,γ-diol without any aromatic ring alkylation, which significantly increased final product selectivity. The subsequent hydrogenolysis catalyzed by Pd/C generated lignin monomers at near-theoretical yields based on Klason lignin (48 % from birch, 20 % from spruce, 70 % from high-syringyl transgenic poplar), and with high selectivity to a single 4-n-propanolsyringol product (80 %) in the case of the poplar. Unlike direct hydrogenation of native wood, hydrogenolysis of protected lignin with Ni/C also led to high selectivity to this single product (78 %), paving the way to high-selectivity lignin upgrading with base metal catalysts. The use of extracted lignin facilitated valorization of polysaccharides, leading to high yields of all three major biomass polymers to a single major product

Carbohydrate stabilization extends the kinetic limits of chemical polysaccharide depolymerization

Polysaccharide depolymerization is an essential step for valorizing lignocellulosic biomass. In inexpensive systems such as pure water or dilute acid mixtures, carbohydrate monomer degradation rates exceed hemicellulose—and especially cellulose—depolymerization rates at most easily accessible temperatures, limiting sugar yields. Here, we use a reversible stabilization of xylose and glucose by acetal formation with formaldehyde to alter this kinetic paradigm, preventing sugar dehydration to furans and their subsequent degradation. During a harsh organosolv pretreatment in the presence of formaldehyde, over 90% of xylan in beech wood was recovered as diformylxylose (compared to 16% xylose recovery without formaldehyde). The subsequent depolymerization of cellulose led to carbohydrate yields over 70% and a final concentration of ~5 wt%, whereas the same conditions without formaldehyde gave a yield of 28%. This stabilization strategy pushes back the longstanding kinetic limits of polysaccharide depolymerization and enables the recovery of biomass-derived carbohydrates in high yields and concentrations

Comparing the Effectiveness of the Attachment-based Therapy, Dietary Therapy, and Combined Treatment Method on Weight Loss in Obese Adolescents of Yasuj High Schools

Background & aim: At the present time, obesity as one of the most important public health problems which has widely prevailed throughout the world. The aim of this study was to compare the effectiveness of the attachment-based therapy, dietary-therapy, and the combined treatment method on weight (body mass index) loss in obese high school adolescents of Yasuj city. Methods: This clinical trial study was conducted on sixty female high school students of Yasuj, Iran, diagnosed with overweight and obesity. Subjects were randomly selected and divided into four equal groups, and their body mass indexes were assessed. Three intervention groups were exposed to the attachment-based therapy, dietary-therapy, and combined treatment method. The fourth group (control) did not receive any intervention. Following the treatment period, body mass indexes of the four groups were assessed. The data were analyzed by implementing Univariate analysis of covariance and LSD post hoc tests. Results: All three intervention methods of weight loss significantly increased compared with the control group (p < 0.001). However, the combination therapy was more effective. Conclusions: According to the findings of this study, it was concluded that although interventional techniques such as attachment-based therapy and dietary therapy are effective for weight loss, the combination of these two methods were more effective for weight loss

The effect of a multifaceted ergonomic intervention program on reducing musculoskeletal disorders in dentists

Background: Work-related musculoskeletal disorders (WMSDs) are the most common occupational injuries in dentists. These disorders occur due to the specific characteristics of dentistry occupation such as the use of tools and instruments and awkward posture. The present study aimed at evaluating the effect of multifaceted ergonomic program on reducing musculoskeletal disorders in dentists. Methods: One hundred-two male dentists who worked in dentistry clinics of Tehran's hospitals participated in this interventional study. Participants were randomly divided into control (n=50) and intervention (n=52) groups. Dentists in the intervention group (n=52) underwent multifaceted ergonomic intervention program for 8 weeks and dentists in the control group (n=50) only received the measurements. The prevalence of musculoskeletal disorders was evaluated in each of the 2 groups at 3 time points before the intervention, 3, and 6 months after the intervention using the Nordic Musculoskeletal Questionnaire (NMQ). Paired t-test was used to compare the prevalence of musculoskeletal disorders before and after the ergonomic intervention program at the end of 3 and 6 months. Results: The results revealed that the prevalence of musculoskeletal disorders was reduced after the intervention in the neck, shoulder, arm, wrist, back, thigh, knees, and feet (p < 0.05). On the other hand, the prevalence of musculoskeletal disorders increased in the control group in the neck, shoulder, arm, wrist, thigh, and knee, respectively. The survey results revealed that 98 of the participants agreed with this intervention program. Conclusion: The results of this study revealed that the multifaceted ergonomic intervention program, which included improving working conditions, identifying ergonomic risk factors, regular exercise, and discussion group meetings, could decrease the prevalence of musculoskeletal disorders in dentists

Fractionation of lignocellulosic biomass to produce uncondensed aldehyde-stabilized lignin

Lignin is one of the most promising sources of renewable aromatic hydrocarbons. Current methods for its extraction from lignocellulosic biomass—which include the kraft, sulfite, and organosolv processes—result in the rapid formation of carbon–carbon bonds, leading to a condensed lignin that cannot be effectively depolymerized into its constituent monomers. Treatment of lignocellulosic biomass with aldehydes during lignin extraction generates an aldehyde-stabilized lignin that is uncondensed and can be converted into its monomers at near-theoretical yields. Here, we outline an efficient, reproducible, and scalable process for extracting and purifying this aldehyde-stabilized lignin as a solid, which can easily be re-dissolved in an organic solvent. Upon exposure to hydrogenolysis conditions, this material provides near-theoretical yields of aromatic monomers (~40–50% of the Klason lignin for a typical hardwood). Cellulose and hemicellulose are also efficiently fractionated. This protocol requires 6–7 h for the extraction of the stabilized lignin and a basic proficiency in synthetic chemistry

Regulation of luteinizing hormone receptor in hippocampal neurons following different long-lasting treatments of castrated adult rats

218-227The aim of this study was to investigate the effects of different Luteinizing hormone (LH) and steroid hormones levels on LH receptor (LHR) expression in the hippocampal cells. Rats (24 males and 24 females) were assigned to four groups: one control and three experimental [gonadectomy (GDX), gonadectomy + gonadotropin releasing hormone analogue (GDX+GnRHa) and GDX+GnRHa+estradiol (E2) or testosterone (T)] independently for each gender. All experimental rats were gonadectomized; then GnRHa was administrated to GDX+GnRHa group, and GnRHa plus steroid hormone to GDX+GnRHa+E2 or T group in both genders for four-month. LHR mRNA expression and its protein level in hippocampal cells were measured using QRT-PCR and Western blotting. Quantification of mRNA revealed a decrease in LHR transcripts level in GDX+GnRHa group of females. A significant change was observed between GDX groups and GDX+GnRHa+E2 or T versus GDX+GnRHa group in females. High levels of LH decreased significantly the immature isoform of LHR in GDX group compared to control group in both genders, but low LH concentrations in GDX+GnRHa group induced immature LHR isoform production only in females. Therefore increased LH concentration induces production of incomplete LHR transcripts in hippocampal cells and decreases immature LHR at the protein level. This implies that LH decreases the efficiency of translation through either producing non-functional LHR molecules or preventing their translation

Catalytic valorization of the acetate fraction of biomass to aromatics and its integration into the carboxylate platform

In many plant species, the acetate fraction is the fourth most prominent fraction by weight after cellulose, hemicellulose and lignin, and can be easily extracted as a single stable molecule, acetic acid, at high yields. Despite this, upgrading the acetate fraction of biomass has received very limited attention. Here, we demonstrate a valorization route for the acetate fraction as well as mixtures of acetic acid and other volatile fatty acids produced from the polysaccharide fraction. Aqueous solutions of acetic acid, including solutions produced during steam explosion pretreatment and subsequently purified can be upgraded at high selectivity to a valuable mixture of aromatics, substituted cycloalkenes and gas olefins in a single step using Cu/ZrO2. The catalyst displays remarkable stability despite the presence of acids, water and other biomass-derived impurities. We also show that acetic acid can be further valorized over the same catalyst by converting it in the presence of butanoic acid that was produced in a consolidated bioprocess from the same pretreated wood that was the source of the acetic acid. In this case, the acetic acid rapidly ketonizes with the butanoic acid and the resulting beta-ketones further condense to form aromatics and cycloalkenes with a higher average carbon number than those produced solely from acetic acid. Overall, our process yields a biomass-derived organic oil consisting of aromatics and cycloalkenes that spontaneously separates from water, can be tuned by varying the incoming mixture of carboxylic acids and has suitable properties for being used as a direct blend with aviation fuel