Mechanical properties related to the microstructure of seven different fiber reinforced composite posts

de la Pena, V?ctor Alonso,Darriba, Iria L,Valea, Martin Caserio,Rivera, Francisco Guitian The Korean Academy of Prosthodonitics 2016 The Journal of Advanced Prosthodontics Vol.8 No.6

PURPOSE. The aim of this in vitro study was to evaluate the mechanical properties (bending strength and hardness) of seven different fiber reinforced composite posts, in relation to their microstructural characteristics. MATERIALS AND METHODS. Two hundred eighty posts were divided into seven groups of 40, one group for each type of post analyzed. Within each group, 15 posts were subjected to three-point bending strength test, 15 to a microhardess meter for the Knoop hardness, and 10 to Scanning Electron Microscope in order to determine the diameter of the fibers and the percentage of fibers embedded in the matrix. To compare the flexural strength in relation to the type of fiber, matrix, and the hardness of the posts, a Kruskal-Wallis H test was used. The Jonckheere-Terpstra test was used to determine if the volume percent of fibers in the post influenced the bending strength. RESULTS. The flexural strength and the hardness depended on the type of fibers that formed the post. The lower flexural strength of a post could be due to deficient bonding between the fiber and the resin matrix. CONCLUSION. According to the results, other factors, besides the microstructural characteristics, may also influence the mechanical properties of the post. The feature that has more influence on the mechanical properties of the posts is the type of fiber.

The psychopharmacological activities of Vietnamese ginseng in mice: characterization of its psychomotor, sedative-hypnotic, antistress, anxiolytic, and cognitive effects

dela Pena, Irene Joy I.,Kim, Hee Jin,Botanas, Chrislean Jun,de la Pena, June Bryan,Van Le, Thi Hong,Nguyen, Minh Duc,Park, Jeong Hill,Cheong, Jae Hoon The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.2

Background: Panax vietnamensis Ha et Grushv. or Vietnamese ginseng (VG) is a recently discovered ginseng species. Studies on its chemical constituents have shown that VG is remarkably rich in ginseng saponins, particularly ocotillol saponins. However, the psychopharmacological effects of VG have not been characterized. Thus, in the present study we screened the psychopharmacological activities of VG in mice. Methods: VG extract (VGE) was orally administered to mice at various dosages to evaluate its psychomotor (open-field and rota-rod tests), sedative-hypnotic (pentobarbital-induced sleeping test), anti-stress (cold swimming test), anxiolytic (elevated plus-maze test), and cognitive (Y-maze and passive-avoidance tests) effects. Results: VGE treatment increased the spontaneous locomotor activity, enhanced the endurance to stress, reduced the anxiety-like behavior, and ameliorated the scopolamine-induced memory impairments in mice. In addition, VGE treatment did not alter the motor balance and coordination of mice and did not potentiate pentobarbital-induced sleep, indicating that VGE has no sedative-hypnotic effects. The effects of VGE were comparable to those of the Korean Red Ginseng extract. Conclusion: VG, like other ginseng products, has significant and potentially useful psychopharmacological effects. This includes, but is not limited to, psychomotor stimulation, anxiolytic, antistress, and memory enhancing effects.

Neurobiological Functions of the Period Circadian Clock 2 Gene, Per2

Kim, Mikyung,Pena, June Bryan de la,Cheong, Jae Hoon,Kim, Hee Jin The Korean Society of Applied Pharmacology 2018 Biomolecules & Therapeutics(구 응용약물학회지) Vol.26 No.4

Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.

Rapid physicochemical characterization of innovative fucoidan/fructan powders by ATR-FTIR

Espinosa-Velazquez, Gerardo,Ramos-de-la-Pena, Ana Mayela,Montanez, Julio,Contreras-Esquivel, Juan Carlos 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.2

Functional food has been highly demanded lately because of its benefits in counteracting diseases. Fucoidan and agave fructan are ingredients that enhance the growth of beneficial bacteria in the gut (prebiotics). This mixture has great potential to develop innovative products but it has never been explored before. Because of fucoidan is more expensive than agave fructan, the innovative proposed mixture is vulnerable to adulteration. This research was aimed to assess the accuracy of Fourier transform infrared spectroscopy with attenuated total reflectance (ATR-FTIR) coupled with chemometrics to identify and predict concentration of both polysaccharides in powder mixtures (0-100%). Absorption bands at 1240-1255 and $836-840cm^{-1}$ were attributed to fucoidan and a strong peak at ${\sim}936cm^{-1}$ confirmed the fructan presence. Peak areas were best fitted into linear models ($R^2_{adj}{\geq}0.92$, $RMSE{\leq}3.54%$). This achievement may be useful to certificate ingredients contained in fucoidan-fructan mixtures, preventing adulteration.

흰쥐에서 월계수, 자리, 백년초 혼합물에 의한 숙취완화 효과

김희진,irene Joy dela Pena,윤서영,Jun Bryan de la Pena 대한약학회 2014 약학회지 Vol.58 No.6

The aim of this study was to find optimal ratio of herbal extracts to ameliorate ethanol-induced psychomotor alterations. Four mixtures of Laurus nobilis (L. nobilis), Rosa roxburghii (R.R.) and Opuntia ficus indica (OFI) were pre-treated 30 minutes before ethanol administration in rats. Behavioral activities were evaluated. Blood ethanol and acet-aldehyde levels were also measured. These effects of mixture of R.R (50 mg/kg)+OFI (100 mg/kg)+L.nobilis (100 mg/kg) were better than those of other mixtures. This mixture could be used as an effective substance to develop a functional food.

Evaluation of the abuse potential of AM281, a new synthetic cannabinoid CB₁ receptor antagonist

Botanas, C.J.,de la Pena, J.B.,dela Pena, I.J.,Tampus, R.,Kim, H.J.,Yoon, S.S.,Seo, J.W.,Jeong, E.J.,Cheong, J.H. North-Holland ; Elsevier Science Ltd 2015 european journal of pharmacology Vol.766 No.-

AM281 (1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide) is a new synthetic cannabinoid CB<SUB>1</SUB> receptor antagonist. Similar to other cannabinoid antagonists, AM281 has been suggested to have therapeutic indications. However, recent reports have suggested that cannabinoid CB<SUB>1</SUB> receptor antagonists may share similar behavioral effects with other drugs of abuse such as cocaine and amphetamine. These reports cast doubts on the safety profile of AM281. Thus, in the present study we evaluated the abuse potential (rewarding and reinforcing effects) of AM281 through two of the most widely used animal models for assessing the abuse potential of drugs: the conditioned place preference (CPP) and self-administration (SA) tests. Experiments were performed in Sprague-Dawley rats in various dosages [CPP (0.1, 0.5 or 2.5mg/kg), SA (0.005, 0.025 or 0.1mg/kg/infusion)]. We also delved into the consequences of repeated drug exposure on the subsequent response to the drug. Thus, parallel experiments were carried out in rats pretreated with AM281 for 7 or 14 days. Our findings indicated that AM281, at any dose, did not induce CPP and SA in drug-naive rats. Interestingly, significant CPP (0.5mg/kg of AM281), but not SA, was observed in 14 days pretreated rats. These observations suggest that AM281 per se has no or minimal rewarding and reinforcing properties, but alterations in neuronal functions and behavior due to repeated AM281 exposure may contribute in part to the abuse potential of this drug. In view of this finding, we advocate the careful use, monitoring, and dispensation of AM281.

The Abuse Potential of α-Piperidinopropiophenone (PIPP) and α-Piperidinopentiothiophenone (PIVT), Two New Synthetic Cathinones with Piperidine Ring Substituent

Botanas, Chrislean Jun,Yoon, Seong Shoon,de la Pena, June Bryan,dela Pena, Irene Joy,Kim, Mikyung,Woo, Taeseon,Seo, Joung-Wook,Jang, Choon-Gon,Park, Kyung-Tae,Lee, Young Hun,Lee, Yong Sup,Kim, Hee Jin The Korean Society of Applied Pharmacology 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.2

A diversity of synthetic cathinones has flooded the recreational drug marketplace worldwide. This variety is often a response to legal control actions for one specific compound (e.g. methcathinone) which has resulted in the emergence of closely related replacement. Based on recent trends, the nitrogen atom is one of the sites in the cathinone molecule being explored by designer type modifications. In this study, we designed and synthesized two new synthetic cathinones, (1) ${\alpha}-piperidinopropiophenone$ (PIPP) and (2) ${\alpha}-piperidinopentiothiophenone$ (PIVT), which have piperidine ring substituent on their nitrogen atom. Thereafter, we evaluated whether these two compounds have an abuse potential through the conditioned place preference (CPP) in mice and self-administration (SA) in rats. We also investigated whether the substances can induce locomotor sensitization in mice following 7 days daily injection and challenge. qRT-PCR analyses were conducted to determine their effects on dopamine-related genes in the striatum. PIPP (10 and 30 mg/kg) induced CPP in mice, but not PIVT. However, both synthetic cathinones were not self-administered by the rats and did not induce locomotor sensitization in mice. qRT-PCR analyses showed that PIPP, but not PIVT, reduced dopamine transporter gene expression in the striatum. These data indicate that PIPP, but not PIVT, has rewarding effects, which may be attributed to its ability to affect dopamine transporter gene expression. Altogether, this study suggests that PIPP may have abuse potential. Careful monitoring of this type of cathinone and related drugs are advocated.

Conditioned Place Preference and Self-Administration Induced by Nicotine in Adolescent and Adult Rats

( Hafiz Muhammad Ahsan ),( June Bryan ),( De La Pena ),( Chrislean Jun Botanas ),( Hee Jin Kim ),( Gu Yong Yu ),( Jae Hoon Cheong ) 한국응용약물학회 2014 Biomolecules & Therapeutics(구 응용약물학회지) Vol.22 No.5

Nicotine addiction is a worldwide problem. However, previous studies characterizing the rewarding and reinforcing effects of nicotine in animal models have reported inconsistent findings. It was observed that the addictive effects are variable on different factors (e.g. route, dose, and age). Here, we evaluated the rewarding and reinforcing effects of nicotine in different routes of administration, across a wide dose range, and in different age groups. Two of the most widely used animal models of drug addiction were employed: the conditioned place preference (CPP) and self-administration (SA) tests. Nicotine CPP was evaluated in different routes [intraperitoneal (i.p.) and subcutaneous (s.c.)], doses (0.05 to 1.0 mg/kg) and age [adolescent and adult rats]. Similarly, intravenous nicotine SA was assessed in different doses (0.01 to 0.06 mg/kg/infusion) and age (adolescent and adult rats). In the CPP test, s.c. nicotine produced greater response than i.p. The 0.2 mg/kg dose produced highest CPP response in adolescent, while 0.6 mg/kg in adult rats; which were also confirmed in 7 days pretreated rats. In the SA test, adolescent rats readily self-administer 0.03 mg/kg/infusion of nicotine. Doses that produced nicotine CPP and SA induced blood nicotine levels that corresponded well with human smokers. In conclusion, we have demonstrated that nicotine produces reliable CPP [0.2 mg/kg dose (s.c.)] in adolescents and [0.6 mg/kg dose (s.c.)] in adults, and SA [0.03 mg/kg/infusion] in adolescent rats. Both tests indicate that adolescent rats are more sensitive to the rewarding and reinforcing effects of nicotine.

Assessment of the Abuse Liability of Synthetic Cannabinoid Agonists JWH-030, JWH-175, and JWH-176

( Reinholdgher Tampus ),( Seong Shoon Yoon ),( June Bryan De La Pena ),( Chrislean Jun Botanas ),( Hee Jin Kim ),( Joung-wook Seo ),( Eun Ju Jeong ),( Choon Gon Jang ),( Jae Hoon Cheong ) 한국응용약물학회 2015 Biomolecules & Therapeutics(구 응용약물학회지) Vol.23 No.6

The emergence and use of synthetic cannabinoids have greatly increased in recent years. These substances are easily dispensed over the internet and on the streets. Some synthetic cannabinoids were shown to have abuse liability and were subsequently regulated by authorities. However, there are compounds that are still not regulated probably due to the lack of abuse liability studies. In the present study, we assessed the abuse liability of three synthetic cannabinoids, namely JWH-030, JWH-175, and JWH-176. The abuse liability of these drugs was evaluated in two of the most widely used animal models for assessing the abuse potential of drugs, the conditioned place preference (CPP) and self-administration (SA) test. In addition, the open-field test was utilized to assess the effects of repeated (7 days) treatment and abrupt cessation of these drugs on the psychomotor activity of animals. Results showed that JWH-175 (0.5 mg/kg), but not JWH-030 or JWH-176 at any dose, significantly decreased the locomotor activity of mice. This alteration in locomotor activity was only evident during acute exposure to the drug and was not observed during repeated treatment and abstinence. Similarly, only JWH-175 (0.1 mg/kg) produced significant CPP in rats. On the other hand, none of the drugs tested was self-administered by rats. Taken together, the present results indicate that JWH-175, but not JWH-030 and JWH-176, may have abuse potential. More importantly, our findings indicate the complex psychopharmacological effects of synthetic cannabinoids and the need to closely monitor the production, dispensation, and use of these substances.

Experimental validation of the seismic analysis methodology for free-standing spent fuel racks

Alberto Gonzalez Merino,Luis Costas de la Pena,Arturo Gonzalez 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.3

Spent fuel racks are steel structures used in the storage of the spent fuel removed from the nuclear powerreactor. Rack units are submerged in the depths of the spent fuel pool to keep the fuel cool. Their freestandingdesign isolates their bases from the pool floor reducing structural stresses in case of seismicevent. However, these singular features complicate their seismic analysis which involves a transientdynamic response with geometrical nonlinearities and fluid-structure interactions. An accurate estimationof the response is essential to achieve a safe pool layout and a reliable structural design. Ananalysis methodology based on the hydrodynamic mass concept and implicit integration algorithms wasdeveloped ad-hoc, but some dispersion of results still remains. In order to validate the analysis methodology,vibration tests are carried out on a reduced scale mock-up of a 2-rack system. The two rackmockups are submerged in free-standing conditions inside a rigid pool tank loaded with fake fuel assembliesand subjected to accelerations on a unidirectional shaking table. This article compares theexperimental data with the numerical outputs of a finite element model built in ANSYS Mechanical. Thein-phase motion of both units is highlighted and the water coupling effect is detailed. Results show agood agreement validating the methodology.