Green Glue Research Articles

Bibliometric Analysis of the Green Gluing Technique (2000–2020): Trends and Perspectives

Wood is a sustainable and renewable material with a lower carbon footprint than other materials. However, its transformation into engineered products industrially, such as glulam, requires kiln drying, which implies energy consumption and loss of wood resources. Recent research has carried out green gluing, a variant of glulam characterized by a reduction of the drying process. Interest in it has increased as a new method of improving the use of wood that does not meet industry standards. It has been accomplished by developing adhesives for wood with high moisture content, but the variables involved are not yet completely understood. Therefore, conducting further research and analyzing the relevant publications is necessary. Bibliometric analysis was the method used, which included documents stored (from 2000 to 2020) in Scopus (Elsevier), Web of Science (Clarivate Analytics), and SciELO Citation Index (Web of Science—Clarivate Analytics) databases. The bibliometric analysis identified three main areas to develop: glue wood, glue properties, and analysis methods. The studies were concentrated on a few countries and research groups. The main progress has been made in synthetic and natural (or environmentally friendly) glue topics. The improvement of technique could enlarge the opportunities for collaboration and innovation in wood material science.

On Donald Antrim’s One Friday in April

On Donald Antrim’s One Friday in April Christian Lorentzen (bio) The patient lies on a table in socks and a hospital gown. There are electrodes on his head, chest, arms, and legs. They are glued to his body with a green gel that conducts electricity. There is an oxygen mask over his mouth and a needle in his arm. Blood pressure cuffs around his ankles are inflated to block the flow of the paralytic drug succinylcholine to his feet. During the procedure the patient will be under general anesthesia and paralyzed, and his twitching toes will be the only sign of the convulsions he’s experiencing. The convulsions from electroshock will last thirty seconds and will rearrange his brain with the goal of healing. Afterward he will wake up on a gurney with no memory of the procedure and a nurse will ask him where he is. He will answer that he is at the General Clinical Research Unit on the fifth floor of the New York State Psychiatric Institute at 1051 Riverside Drive in Manhattan. In Allen Ginsberg’s poem “Howl,” this place is called “Rockland.” The patient will walk back to the ward with the nurse [End Page 767] steadying him, eat a breakfast of oatmeal and coffee, and peel the dried green glue off his forehead. “These days, I think of ECT as clean power, good electricity added to a wet, saline medium in which electrical signaling has become chaotic and mistimed,” Donald Antrim writes in One Friday in April: A Story of Suicide and Survival. The book is a memoir of the author’s first brush with suicide. It’s a condition he distinguishes from depression, which Antrim calls “a concavity, a sloping downward and a return”: Suicide, in my experience, is not that. I believe that suicide is a natural history, a disease process, not an act or a choice, a decision or a wish. I do not understand suicide as a response to pain, or as a message to the living. I do not think of suicide as the act, the death, the fall from a height or the trigger pulled. I see it as a long illness, an illness with origins in trauma and isolation, in deprivation of touch, in violence and neglect, in the loss of home and belonging. It is a disease of the body and the brain, if you make that distinction, but its etiology, its beginning, whether early or later in life, in the family or beyond, is social in nature. I see suicide as a social disease. Antrim refers to his book variously as a “report” or a “letter,” and if we think of it as a memoir, it has a peculiar problem: its narrator is recounting a phase of a few months when he existed outside of time. The “one Friday in April” is where the book begins, when Antrim is on the roof of his apartment building in Park Slope, Brooklyn, hanging from a fire escape and almost letting go. We are up there with him for a long time, eighteen pages but a matter of hours, with a helicopter hovering overhead and people on neighboring [End Page 768] roof decks enjoying after-work cocktails. Antrim tells us about his condition and tells us about his past, in stories from memory that spring forth in their own paragraphs without transitions, their naked presentation lending them extra force. Do these stories — of his birth when he was pulled from his mother’s arms; of his mother’s subjection to Munchausen syndrome by proxy, a form of abuse that in her case involved multiple unnecessary childhood heart surgeries; her and his father’s alcoholism — constitute a case study, an explanation of the “social disease” he suffers? Yes and no. This book is not a complete autobiography; it does not tell the whole life or attempt to explain everything. It is a description of psychosis, a break from reality, and the memories it contains represent paths back to that reality, to the “historical time” the patient has departed. The tone of the book is, by necessity, intimate. Antrim clearly has in mind the task of reaching those...

Turning the humble soya bean into a powerful green glue

Turning the humble soya bean into a powerful green glue

Elution Study of Three Light-Cured Orthodontic Adhesives

Objectives: The aim of the study was to evaluate monomer elution from three commercial orthodontic adhesive pastes. Methods: Three monomers BPA, Bis-GMA, and TEGDMA were observed from Green Glue (Hangzhou Westlake Biomaterials Co., Zhejiang, China), GrenGloo (Ormco Co., Glendora, CA, USA), and Transbond XT (3M Unitek, St. Paul, MN, USA). The adhesive was light-cured in a cylindrical mold with 6 mm in diameter and 2 mm thick, before immediately immerse into 10 ml extraction media of 75%ethanol in a tightly sealed container at 37°C. The solution was refreshed at four intervals of time 1, 3, 5, and 7 d. The immersion medium was determined using High-performance liquid chromatography (HPLC). Results and Conclusions: BPA were found from three adhesives. Bis-GMA was found only from Transbond XT. TEGDMA were found from both Green Glue and Grengloo. Green Glue had 10-30 times higher TEGDMA elution than Grengloo. Major elution was found from all orthodontic adhesive paste within 1 d, and decrease with time to 7 d.

Preliminary attempts to isolate ground-radiated noise from exploding balloons

Seismo-acoustic coupling occurs when seismic wave propagation creates air-borne acoustic signals. Research is ongoing to determine methods to distinguish between sound due to seismo-acoustic coupling and purely air-borne transmission. In a field experiment, we detonated 17 in. balloons filled with a stoichiometric oxy-acetylene mix placed both on and in the ground. We attempted to isolate ground-radiated waves by constructing a portable soundproof box to deaden air-borne sound wave. The box was constructed from mass-loaded vinyl, soundproofing composite board, liquid nails, and Green Glue. This design incorporated soundproofing through decoupling, absorption, and insulation techniques. Signals observed from a microphone placed in the box are compared with those obtained on microphones outside the box at various heights. The initial blast wave was not evident inside the box. However, the loudest sound measured in the box matches a subsequent portion of signals on microphones near the ground. Testing in a reverberation chamber is done to measure the frequency response in the transmission loss through the box. These results could suggest a viable technique for isolating ground-borne acoustic waves, which could be useful in experiments where calculating the coupling effect is impractical.

Cytotoxicity of Three Light-Cured Orthodontic Adhesives

Objective: The aim of this study was to evaluate the cytotoxic effects of three commercial light-cured orthodontic adhesives.Materials and methods: The potential cytotoxic effects of three types of orthodontic adhesives, Grengloo, Green Glue, and Transbond XT, were tested on L929 cell culture. The cell line was grown in 96-well tissue culture plates (1x105cells/mm3). Thin resin discs weighing 0.4, 0.6, 0.8, 0.8, and 0.8 gram of each material were prepared and aged for 1, 3, 6, 8, and 10 days, respectively, in Minimum Essential Medium (MEM) at 37°C with 5% CO2at 100% humidity. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay according to ISO 10993-5: 2009 (E). The differences among the groups was statically analyzed by independent paired t-test (α = 0.05).Results: After 1 day of storage, all adhesive systems showed cytotoxic effects. However, ageing tended to considerably reduce the cytotoxicity of Green Glue. Grengloo was essentially non-cytotoxic day 3 onwards, while Green Glue and Transbond XT exhibited potential cytotoxicity at all times of the experiment. Conclusion: All tested light-cured orthodontic adhesives had cytotoxic potential during the first day. Grengloo had the highest cell viability, whereas, Green Glue had the lowest.

Shear Bond Strength of Three Light-Cured Orthodontic Adhesives

Objective: The purpose of this study was to compare shear bond strength (SBS) and adhesive remnant index (ARI) of three light-cured orthodontic adhesives.Methods: Sixty upper human premolars were randomly divided into three groups of 20 teeth each. Stainless steel brackets were bonded to the specimens with two different color-change adhesives (Grengloo and Green Glue) and a control (Transbond XT), according to manufacturer’s instructions. After bonding for 24 hours, a universal testing machine was used to apply an occlusal shear force directly to the enamel/bracket interface at a speed of 0.5 mm/min. The ARI scores were evaluated for each debonded tooth. Mean SBS values were analyzed statistically using the Welch robust analysis of variance and the Games-Howell post hoc statistic. Chi-square test was used to determine significant difference in the ARI scores.Results: There was statistical difference in the mean SBS of the three groups (P<.001). The lowest value was obtained from the Green glue (14.88 MPa), which significantly differed from the Grengloo (29.25 MPa) and the Transbond XT (28.03 MPa) group. Chi-square comparison for the ARI indicated that there was significant difference (P=.018) between the groups. Mixed failure patterns were observed for all materials.Conclusion: Although Green glue yielded lower SBS values than Grengloo and Transbond XT, it was sufficient for orthodontic and biting forces in clinical practice.

Degree of Conversion of Three Light-Cured Orthodontic Adhesives

Introduction: The aim of this in-vitro study was to analyze the polymerization ability of 3 light-cured orthodontic adhesives by determining the degree of conversion (DC). Materials and Methods: Fourier transform infrared spectroscopy (FTIR) was used to evaluate the DC after polymerization immediately, 1 day, 7 days, and 30 days. The adhesives investigated were Transbond XT (3M Unitek, USA), Grengloo (Ormco Corp., USA), and Green Glue (Hangzhou Biomaterials, China). Twelve stainless steel brackets (n=4) were used and the adhesives were cured with Bluephase G2 (Ivoclar Vivadent, Liechtenstein). The data were analyzed by Kruskal-Wallis test for comparing materials and Friedman test for comparing the time periods. Results: The DC values were significantly different among the materials and among the time periods. The highest DC in each period was obtained for Grengloo and the lowest DC was observed for Transbond XT. Thus, there were significant differences between the DC values of Grengloo and Transbond XT in each period. Among the time periods, DC% at T1 (Immediately) and T3 of the material were significantly different. The DC values of all adhesives increased extremely from immediately following curing to 1 day and then slightly increased from 1 day to 7 days. Conclusions: Grengloo showed the highest levels of DC at all tested periods. The percentage values of DC largely increased from immediately following curing to 1 day. This concluded that monomers in orthodontic adhesives kept converting even after completion of photoactivation.

Synthesis and Charaterization of Polymerizable Acryl’s Emulsifier to prepare Green Glue

Synthesis and Charaterization of Polymerizable Acryl’s Emulsifier to prepare Green Glue

Shear fracture characterization of green-glued polyurethane wood adhesive bonds at various moisture and gluing conditions

The shear fracture properties of green-glued one-component polyurethane (PUR) wood adhesive bonds subjected to kiln drying were investigated. The local shear strength and fracture energy of the wood adhesive bonds were determined from experimentally recorded complete shear stress versus deformation curves of the bond line. A stable test set-up and small specimens that were anti-symmetrically loaded were used in order to get a uniform and pure state of shear stress. Different moisture contents (MCs) and pressing times were investigated. The fracture properties of conventionally dry-glued wood adhesive bonds and of solid wood were used as reference. The results show that the fracture energy of green-glued bonds with PUR adhesive is dependent on the MC of wood and on the pressing time. The same fracture energy and strength can be obtained by green gluing as by dry gluing, but there seems to exist a maximum MC of sapwood, in the range between 78% and 160%, and a minimum pressing time, in the range between 3 h and 48 h, for which it can be achieved. Both dry- and green-glued polyurethane adhesive bonds were more ductile than solid wood.

A Teacher's Journal: Celebrate with Mathematics

Creating colorful holiday chains constitutes an excellent activity for a mathematics class. Using red and green construction paper, rulers, scissors, and glue sticks, students enjoy making pattern chains. In my fifth-grade class, two groups came up with simple chains: red, green, red, green, red, green, and so on; one red, two green, three red, four green, and so on. A third group created a chain of triangular numbers: one green, three red, six green, ten red, and so on. The completed chains were displayed around the room at the conclusion of each class, and the patterns became more intricate as the days progressed.