PENGARUH ANIMASI BERGERAK TERHADAP PEMAHAMAN KONSEP MATEMATIKA SISWA KELAS XII DI SMAN 1 LANGSA

Pemahaman konsep merupakan suatu kemampuan yang sangat penting dalam pembelajaran matematika. Dengan kemampuan pemahaman konsep siswa akan mampu memanfaatkan atau mengaplikasikan apa yang telah dipahaminya serta mengungkapkannya kembali dengan makna yang sama dalam kegiatan belajar. Tujuan dalam penelitian ini adalah untuk mengetahui apakah animasi bergerak dengan berbantuan software Cabri 3D berpengaruh terhadap pemahaman konsep matematika siswa pada materi dimensi tiga. Penelitian ini dilaksanakan di SMAN 1 Langsa tahun ajaran 2019/2020. Penelitian ini termasuk dalam jenis penelitian kuantitatif dengan desain One Group Pretest-Posttest Design. Populasi dalam penelitian ini adalah seluruh siswa  kelas XII SMA Negeri 1 Langsa sebanyak 317 orang yang terdiri dari 10 kelas, sedangkan sampelnya adalah siswa kelas XII MIA-8 dengan jumlah siswa 32 orang. Hasil penelitian menunjukkan bahwa thitung = 22,88 dan ttabel = 1,696 maka thitung  >  ttabel yaitu 22,88 > 1,696 sehingga diperoleh H0 ditolak dan Ha diterima. Dengan demikian dapat disimpulkan bahwa terdapat pengaruh animasi bergerak terhadap pemahaman konsep matematika siswa kelas XII di SMA Negeri 1 Langsa

Anatomi Jaringan, Identifikasi Mikroskopis, serta Kadar Polifenol Ekstrak Etanol Daun dari Tiga Jenis Jambu Genus Syzygium

Tiga spesies dari genus Syzygium, seperti jambu air (Syzygium aqueum (Burm.f.) Alston), jambu bol (Syzygium malaccense (L.) Merr. & L.M. Perry), dan jambu semarang (Syzygium samarangense (Blume) Merr. & L. M. Perry), telah dimanfaatkan daunnya dalam pengobatan tradisional karena kandungan polifenolnya. Penelitian ini bertujuan untuk mempelajari anatomi jaringan, mikroskopis, kadar senyawa fenol, flavonoid, dan tanin ekstrak etanol daun dari tiga jenis jambu tersebut. Daun jambu biji (Psidium guajava) digunakan sebagai pembanding. Anatomi jaringan daun dan identifikasi mikroskopis dilakukan menggunakan mikroskop. Penentuan kadar senyawa pada ekstrak etanol 70% ditentukan dengan metode kolorimetri yang absorbansinya diukur pada spektrofotometer UV- Vis. Anatomi jaringan daun dan fragmen pengenal secara mikroskopis ada kemiripan pada ketiga jenis daun jambu genus Syzygium. Secara statistik, ada perbedaan signifikan antara kadar fenol, flavonoid, dan tanin pada ekstrak etanol 70% daun jambu air, daun jambu bol, dan daun jambu semarang dibandingkan dengan ekstrak etanol 70% daun jambu biji. Daun jambu air merupakan spesiesterpilih dari genus Syzygium yang diuji pada penelitian ini dengan kandungan polifenol yang tinggi.   Leaves of three guava species of the genus Syzygium, such as water apple/jambu air (Syzygium aqueum (Burm.f.) Alston), malay apple/jambu bol (Syzygium malaccense (L.) Merr. & L.M. Perry), and wax apple/jambu Semarang (Syzygium samarangense (Blume) Merr. & L. M. Perry), have been used in traditional medicine because of its polyphenol content. This study aims to investigate the anatomy of leaf tissues, powder microscopical characteristic, and total phenolic, flavonoids, and tannins content in the ethanol extract of the leaves of the three types of selected guava species of the genus Syzygium. Guava leaves (Psidium guajava) were used as a comparison. Leaf tissue anatomy and microscopic identification were carried out using a microscope. Determination of the polyphenol content in 70% ethanol extract was determined by the colorimetric method in which the absorbance was measured on a UV-Vis spectrophotometer. Leaf tissue anatomy and microscopic recognition fragments are similar in the three types of Syzygium guava leaves. Statistically, there were significant differences between the total phenols, flavonoids, and tannins content in the 70% ethanol extract of water apple, Malay apple, and wax apple compared to the 70% ethanol extract of guava leaves. Water apple leaves are selectedspecies from the genus Syzygium tested in this study with high polyphenol content

PENETAPAN KADAR FENOL EKSTRAK ETANOL 70% EMPAT SPESIES DAUN JAMBU FAMILI Myrtaceae

Senyawa fenolik adalah kelompok senyawa terbesar dalam tanaman. Senyawa ini memiliki aktivitas antioksidan, antikarsinogenik, dan antimikroba yang sangat bermanfaat untuk kesehatan. Penelitian ini bertujuan untuk membandingkan kadar fenol total daun jambu bol (Syzygium malaccense (L.) Merr. & Perry), jambu Semarang (Syzygium samarangense (Blume) Merr. & L. M.) dan jambu air (Syzygium aqueum (Burm.f.) Alston) terhadap kadar fenol tanaman jambu biji (Psidium guajava Linn). Ekstraksi dilakukan dengan metode maserasi menggunakan pelarut etanol 70%. Kandungan fenolik total ditentukan dengan reagen Folin-Ciocalteu menggunakan alat spektrofotometri UV-Vis. Pembanding yang digunakan pada penelitian ini adalah asam galat. Absorbansi diukur pada panjang gelombang 765,10 nm. Kadar fenol total daun jambu bol, jambu semarang, jambu air dan jambu biji berturut-turut adalah (33,2379 mg GAE/g simplisia ± 0,2898; 44,9818 mg GAE/g simplisia ± 0,3666; 69,5898 mg GAE/g simplisia ± 0,8525; 91,3210 mg GAE/g simplisia ± 0,8010). Data yang diperoleh dianalisa secara statistik dengan bantuan program SPSS Statistics 25 dilakukan uji normalitas, homogenitas, Analysis of Variance (ANOVA) dan dilanjutkan dengan uji pos hoc tukey. Hasil uji ANOVA satu arah diperoleh nilai sig. 0,000 < 0,05 maka adanya perbedaan bermakna pada rata-rata kadar fenol total ke-empat jenis jambu tersebut. Hasil post hoc tukey pada tiap perbandingan ekstrak daun jambu bol, jambu semarang dan jambu air terhadap daun jambu biji diperoleh nilai sig. 0,000 < 0,05 maka dapat disimpulkan ada perbedaan rata-rata kadar fenol antara ke-tiga jenis daun jambu tersebut terhadap daun jambu biji. Kata kunci: famili Myrtaceae, Syzygium malaccense (L.) Merr. & Perry, Syzygium samarangense (Blume) Merr. & L. M, Syzygium aqueum (Burm.f.) Alston, Psidium guajava Linn, kadar fenol total

Antibiotic susceptibility study of metal-gentamycin complexes against pseudomonas aeruginosa biofilms

Inherent resistance of biofilm bacteria to conventional antibiotics is alarming because biofilms induce antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Pseudomonas aeruginosa is an infectious organism that causes the hallmark of chronic infections including hospital acquired infections that leads to high morbidity and mortality. One of the reasons for the occurrence of resistance is its ability to form biofilms. In this study, the resistance of P. aeruginosa biofilms against a series of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against the biofilms was conducted using broth microdilution assay. Results: The results showed that P. aeruginosa is susceptible against all the metal-gentamicin complexes, which include, Ni(II), Fe(II), Cu(II), Zn(II) and Co(II) complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusions: The results show that all metal-gentamicin complexes have higher antimicrobial activity than gentamicin (0.25 to 1 mmol) on its own. Finally, mechanisms of P. aeruginosa biofilms resistance to these metal-antibiotics are also proposed

Enhanced electrical properties and large electrocaloric effect in lead-free Ba0.8Ca0.2ZrxTi1−xO3 (x = 0 and 0.02) ceramics

The effects of 2% Zr introduction in Ba0.8Ca0.2TiO3 (BCT) system on its electrical and electrocaloric properties was investigated. BCT and Ba0.8Ca0.2Zr0.02Ti0.98O3 (BCZT) ceramics synthesized by solid-state processing were crystallized in a pure perovskite phase with a group space P4mm. After Zr insertion, the enhanced dielectric constant was obtained around the Curie temperature (Tc) in BCZT ceramic (εr = 6330 at Tc = 388 K) compared to BCT ceramic (εr = 5080 at Tc = 388.6 K). Moreover, the large-signal piezoelectric coefficient (d∗33) was improved from 270 to 310 pm/V in BCT and BCZT ceramics, respectively, under a moderate electric field of 25 kV/cm. The electrocaloric effect was determined via indirect and direct methods. In the indirect approach, the electrocaloric temperature change (ΔT) was calculated via Maxwell relation, and the measured ferroelectric polarization P (E, T) extracted from the P–E curves recorded at 24 kV/cm. The maximum values of ΔT = 0.68 K and the electrocaloric responsivity ζ = 0.283 K mm/kV obtained at 385 K in BCZT ceramic were found to be higher than those observed in BCT ceramic (ΔT = 0.37 K and ζ = 0.154 K mm/kV at 387 K). In the direct approach, ΔT was measured utilizing a modified high-resolution calorimeter at 14 kV/cm. As the direct method is more sensitive to the latent heat, it provided larger values for smaller applied field, i.e., ΔT = 0.474 and 0.668 K for BCT and BCZT ceramics, respectively. A significant ζ of 0.477 K mm/kV was obtained in BCZT at 385 K and 14 kV/cm that matches the values found in lead-based materials. These results suggest that BCZT lead-free ceramics could have an excellent potential to be used in solid-state refrigeration applications