Judul: Efforts to Control and Prevent Pathogenic Infection of Multi-Drug Resistant Organism (MDRO) of Methicillin-Resistant Staphylococcus aureus (MRSA) Clone Using Alcohol-Base Hand Rub.
Abstrak: The pandemic that is occurring caused both by COVID-19 (currently occurring) as well as the clone of the methicillin-resistant staphylococcus aureus (MRSA) in the previous period has really threatened human life. This condition requires materials that can break the chain of transmission from human to human and from the environment to human. An alcohol-based antiseptic (hand rub/hand sanitizer) often contains ethanol, isopropanol or n-propanol, or a combination of two of these types. Alcohol has an excellent germicidal activity in vitro against gram-positive and gram-negative vegetative bacteria (including multidrug-resistant pathogens such as MRSA and VRE) as well as viruses. Hand rub/hand sanitizer products are declared good if they have formulation stability, no irritation effect when they are used and are able to kill pathogens more than 90%. This study aimed to evaluate the quality of alcohol-based hand rub with WHO-based-standard formulation based on the stability of the formulation, the risk of irritation and the ability to kill bacteria. Hand rub/hand sanitizer was made by modifying the levels of the WHO formula with a hygiene procedure for 500 ml/bottle with the composition: Ethanol 96%; H2O2 3%; Glycerol 98%; and Aqua Sterile ad 500ml. Assessment on the presence of rancidity, clarity, discoloration, final alcohol content and skin irritation risk was done to know the quality of product formulation. A bacterial Methicillin-resistant staphylococcus aureus (MRSA) was used to assess the percentage of bacterial killing power. The selected bacteria were bacteria commonly found in the hospital environment. The results of formulation stability from four variants of level modification showed that MD.4 has good stability compared to other formulation modifications. The results of the percentage kill test against MRSA showed that the percentage kill is 99.90% at 1st, 2nd, and 5th minute. The selected manufacturer's product also showed the same percentage kill value at 1st, 2nd, and 5th minute. The results of percentage kill test showed that the effective value for each contact time is ≥ 90%. The SEM observations showed that MD.4 hand rub effect in the form of MRSA cell lysis. The LC50 test, it is known that MD.4 hand rub value is 620 ppm while softaman (control) is 114 ppm. In terms of irritation risk, twenty-three selected subjects were generally well tolerated in use.
Keyword: hand rub, hand sanitizer, ahmad Subhan, percentage kill bacteria, MRSA, WHO

Judul: Study of Antimicrobial Effectiveness from Sweet Orange, Lavender, And Citronella Essential Oil Against Staphylococcus aureus And Escherichia coli Bacteria
Abstrak: Kebutuhan perilaku hidup sehat pada era new normal meningkatkan kesadaran masyarakat akan higienitas. Berbagai macam penyakit disebabkan oleh beberapa jenis mikroba seperti bakteri dan jamur yang menempel pada tangan melalui kontak fisik. Upaya menjaga kebersihan dilakukan dengan membersihkan tangan menggunakan hand sanitizer. Minyak atsiri sebagai alternatif antiseptik berbahan alami mengandung senyawa metabolit sekunder yang memiliki aktivitas antimikroba. Kajian ini bertujuan memberikan informasi ilmiah mengenai efektivitas minyak atsiri jeruk (Citrus sinensis L.), lavender (Lavandula angustifolia Mill.), dan serai wangi (Cymbopogon nardus L.) sebagai antimikroba terhadap bakteri Staphylococcus aureus dan Escherichia coli. Kajian sifat antibakteri minyak atsiri dilakukan berdasarkan data sekunder diameter zona hambat untuk uji difusi, konsentrasi hambat minimum atau minimum inhibition concentration (MIC) untuk uji dilusi dan tingkat pertumbuhan untuk fase uap. Hasil kajian menunjukkan bahwa berdasarkan data zona hambat antibakteri, minyak atsiri jeruk yang mengandung limonen, lavender mengandung linalool dan dan serai wangi mengandung sitronelal, sitronelol, dan geraniol bersifat antibakteri. Semakin besar nilai diameter zona hambat pada setiap uji, maka minyak atsiri tersebut semakin efektif menghambat pertumbuhan bakteri uji. Berdasarkan data diameter zona hambat, adanya zona bening pada uji difusi dari pengaplikasian minyak atsiri lavender, jeruk, dan serai wangi efektif sebagai antibakteri pada gel hand sanitizer terhadap bakteri Staphylococcus aureus dan Escherichia coli.
Keyword: antimikroba, gel hand sanitizer, minyak atsiri, Staphylococcus aureus, Escherichia coli

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf