SINTESIS ELASTOMER POLIURETAN DENGAN BAHAN DASAR MINYAK GORENG REGENERASI DAN METILEN-4,4-DIFENILDIISOSIANAT SEBAGAI BAHAN PELAPIS PERMUKAAN ROL

Minyak goreng regenerasi merupakan minyak sisa peng¬goreng¬an. Minyak goreng yang banyak diperjualbelikan umumnya merupa¬kan minyak sawit yang mengandung trigliserida. Pemanas¬an minyak goreng secara berulang kali dapat merusak minyak ter¬sebut, yang sangat berbahaya apabila masih digunakan untuk meng¬goreng karena bersifat karsinogenik. Dengan demikian harus diupayakan suatu cara untuk memanfaatkan minyak goreng regenerasi yang tidak memiliki nilai jual menjadi suatu produk yang bermanfaat dan memiliki nilai jual relatif tinggi. Pada penelitian ini dicoba memanfaatkan minyak goreng regenerasi sebagai monomer pada sintesis poliuretan. Minyak goreng re¬generasi memungkinkan untuk digunakan sebagai monomer pada sintesis poliuretan karena masih memiliki gugus aktif seperti gugus –OH, -COO- dan ikatan rangkap yang dapat dimodifikasi secara hidrasi untuk digunakan sebagai sumber poliol. Gugus –OH dapat berikatan dengan gugus isosianat (-NCO) dari metilen-4,4-difenidiisosianat (MDI) membentuk poliuretan. Sintesis poliuretan dari minyak goreng regenerasi yang telah maupun tidak mengalami proses adsorbsi dengan karbon aktif, minyak goreng regenerasi terhidroksilasi, asam lemak hasil isolasi minyak goreng regenerasi, dan asam lemak teroksidasi direaksikan dengan MDI sehingga dihasilkan berbagai produk poliuretan. Reaksi polimerisasi dilakukan pada temperatur kamar, dengan memvariasikan perbandingan mol MDI terhadap mol poliol dan temperatur curing. Karakterisasi poliuretan hasil sintesis, meliputi penentuan gugus fungsi dengan IR, uji penggembungan dalam larutan kanji, uji kekerasan dengan menggunakan alat share A durometer dan uji termal dengan menggunakan DTA. Hasil penelitian menunjukkan bahwa minyak goreng regenerasi sebagai limbah rumah tangga dan industri dapat dimanfaatkan sebagai bahan dasar pembuatan poliuretan, ditunjukkan dengan terbentuknya gugus fungsi uretan pada spektrum inframerah produk poliuretan. Komposisi minyak goreng regenerasi makin besar menunjukkan kualitas produk poliuretan yang makin menurun, sebaliknya komposisi MDI makin besar menunjukkan kualitas poliuretan yang makin bagus. Proses adsorbsi minyak goreng regenerasi dengan menggunakan karbon aktif cukup efektif untuk mengadsorbsi pengotor dalam minyak goreng regenerasi sehingga kualitas produk poliuretan menjadi lebih baik. Proses hidroksilasi dengan cara hidrasi maupun oksidasi mampu menurunkan bilangan iodin dan meningkatkan gugus hidroksil minyak goreng regenerasi sehingga kualitas produk poliuretan menjadi lebih baik. Proses adsorbsi dan hidroksilasi pada minyak goreng regenerasi menyebabkan proses curing dapat berlangsung pada temperatur lebih rendah, yakni 70 0C. Penggunaan asam lemak hasil isolasi minyak goreng regenerasi pada sintesis poliuretan mampu menurunkan derajat peng-gembungan dan meningkatkan tingkat kekerasan produk poliuretan bila dibandingkan produk poliuretan berbasis minyak goreng regenerasi tanpa adsorbsi dan tanpa hidroksilasi. Proses hidroksilasi asam lemak hasil isolasi minyak goreng regenerasi mampu meningkatkan kualitas produk poliuretan. Proses hidroksilasi dengan cara oksidasi menggunakan larutan KMnO4 dengan kadar 35% menunjukkan produk poliuretan yang relatif lebih bagus. Kata kunci: minyak goreng regenerasi, produk poliuretan, sumber poliol FMIPA, 2008 (PEND. KIMIA

Receptor oligomerization: from early evidence to current understanding in class B GPCRs

Dimerization or oligomerization of G protein-coupled receptors (GPCRs) are known to modulate receptor functions in terms of ontogeny, ligand-oriented regulation, pharmacological diversity, signal transduction, and internalization. Class B GPCRs are receptors to a family of hormones including secretin, growth hormone-releasing hormone, vasoactive intestinal polypeptide and parathyroid hormone, among others. The functional implications of receptor dimerization have extensively been studied in class A GPCRs, while less is known regarding its function in class B GPCRs. This article reviews receptor oligomerization in terms of the early evidence and current understanding particularly of class B GPCRs.published_or_final_versio

Can\u27t You See? : You Were Made For Me

https://digitalcommons.library.umaine.edu/mmb-vp/3854/thumbnail.jp

An Update on Breast Cancer Screening and Prevention.

The goal of this article is to provide clinical guidance on breast cancer screening and prevention in primary care. The discussion highlights the importance of risk assessment, including screening options and risk-reduction strategies, for women at average and high risk. We review recommendations for breast cancer screening, evaluate current evidence on primary prevention, examine current practice patterns, and consider the impact of recent changes within health care

以前瞻性雙盲隨機對照方式, 試驗香港華籍人士在進行經直腸超聲波導引的前列腺活組織切除術時, 使用含利多卡因的凝膠與純粹潤滑劑在止痛效用上的分別

OBJECTIVE. To compare the level of pain experienced by patients during transrectal ultrasound-guided prostatic biopsy using intrarectal 2% lidocaine gel versus plain lubricant gel. DESIGN. Prospective double-blind randomised controlled trial. SETTING. Regional hospital, Hong Kong. PATIENTS. From March 2002 to December 2003, patients who underwent ultrasound-guided prostate biopsy at a Geriatric Urology Centre. MAIN OUTCOME MEASURES. Pain and discomfort scores measured by horizontal visual analogue scales. RESULTS. A total of 338 consecutive patients were randomised to lidocaine gel or plain lubricant gel groups. The two groups were statistically similar in demographic and disease characteristics. There were no significant statistical differences in pain or discomfort score in the lidocaine gel and plain lubricant groups—pain score: 1.75 versus 1.79 (P=0.66) on day 0 and 0.21 versus 0.15 (P=0.97) on day 1; discomfort score: 0.79 versus 0.77 (P=0.86) on day 0 and 0.12 versus 0.12 (P=0.76) on day 1. No major complications were recorded in this cohort. CONCLUSIONS. Transrectal ultrasound-guided trucut biopsy of the prostate can be safely performed with no anaesthesia in Chinese patients. Pain and discomfort are minimal. It was found that 2% lidocaine gel has no statistical therapeutic or analgesic benefit over plain lubricant gel.published_or_final_versio

Luminescence enhancement in dinuclear alkynylplatinum(II) complexes driven by Hierarchical Assembly through Pt···Pt and π-π stacking interactions

Poster: no. 1A luminescent dinuclear alkynylplatinum(II) complex containing an amphiphilic binaphthol bridge was designed and synthesized, and was shown to display cylindrical columnar assemblies in aqueous acetonitrile solutions, presumably mediated by the Pt•••Pt and π-π stacking interactions. The length of the binaphthol bridge was found to have a profound effect on the degree of helicity for hierarchical helices of helices and serves as a critical determinant in the formation of tertiary structures for foldamers. Interestingly, the reciprocal association of multiple helices has led to luminescence enhancement behavior, which provides a luminescence turn-on switch for the reporting of the hierarchical assembly of foldamers into higher-order structures, distinct from that of the pure organic systems. Such a transverse aggregation of multiple helices driven by metallophilic interactions has been studied by electronic absorption, circular dichroism, emission spectroscopy and electron microscopy.published_or_final_versio

瑪麗醫院進行腹腔鏡腎臟切除術的早期經驗

OBJECTIVE: To report our early experience of laparoscopic nephrectomy. DESIGN: Prospective data collection. SETTING: Queen Mary Hospital, Hong Kong. PATIENTS: Transperitoneal laparoscopic nephrectomies were performed on 40 patients between July 1997 and December 2002. MAIN OUTCOME MEASURES: Demographic and perioperative data including operating time, blood loss, postoperative pain score, analgesic requirement, complications, time to resume oral intake, ambulatory state, and length of hospital stay. RESULTS: Laparoscopic nephrectomy was performed for 21 solid renal masses, five transitional cell carcinomas, and 14 non-functioning kidneys. Seven (17.5%) patients had previous abdominal surgery. The mean body mass index of the patients was 23.9 kg/m(2) and the mean operating time was 229 minutes. The mean estimated blood loss was 370 mL, and two patients required conversion to open surgery because of intra-operative bleeding. Other complications include diaphragmatic injury, port-site bleeding, chyle leakage, bleeding peptic ulcer, and myocardial ischaemia. The postoperative mean analgesic requirement was 26 mg of morphine sulphate equivalent. The mean time for patients to resume oral diet and full ambulation was 1.3 and 2.8 days, respectively, and the mean length of hospital stay was 6.7 days. The mean diameter of the solid renal tumour was 4.1 cm and the surgical margins of all resected specimen for malignant tumours were negative. CONCLUSION: Laparoscopic nephrectomy is a safe and efficacious approach for resection of benign non-functioning kidneys and malignant renal tumours.published_or_final_versio

Limited use of virtual reality in primary care physiotherapy for patients with chronic pain

Background: Chronic pain is a disabling condition which is prevalent in about 20% of the adult population. Physiotherapy is the most common non-pharmacological treatment option for chronic pain, but often demonstrates unsatisfactory outcomes. Virtual Reality (VR) may offer the opportunity to complement physiotherapy treatment. As VR has only recently been introduced in physiotherapy care, it is unknown to what extent VR is used and how it is valued by physiotherapists. The aim of this study was to analyse physiotherapists’ current usage of, experiences with and physiotherapist characteristics associated with applying therapeutic VR for chronic pain rehabilitation in Dutch primary care physiotherapy. Methods: This online survey applied two rounds of recruitment: a random sampling round (873 physiotherapists invited, of which 245 (28%) were included) and a purposive sampling round (20 physiotherapists using VR included). Survey results were reported descriptively and physiotherapist characteristics associated with VR use were examined using multivariable logistic regression analysis. Results: In total, 265 physiotherapists participated in this survey study. Approximately 7% of physiotherapists reported using therapeutic VR for patients with chronic pain. On average, physiotherapists rated their overall experience with therapeutic VR at 7.0 and “whether they would recommend it” at 7.2, both on a 0–10 scale. Most physiotherapists (71%) who use therapeutic VR started using it less than two years ago and use it for a small proportion of their patients with chronic pain. Physiotherapists use therapeutic VR for a variety of conditions, including generalized (55%), neck (45%) and lumbar (37%) chronic pain. Physiotherapists use therapeutic VR mostly to reduce pain (68%), improve coordination (50%) and increase physical mobility (45%). Use of therapeutic VR was associated with a larger physiotherapy practice (OR = 2.38, 95% CI [1.14–4.98]). Unfamiliarity with VR seemed to be the primary reason for not using VR. Discussion: Therapeutic VR for patients with chronic pain is in its infancy in Dutch primary care physiotherapy practice as only a small minority uses VR. Physiotherapists that use therapeutic VR are modestly positive about the technology, with large heterogeneity between treatment goals, methods of administering VR, proposed working mechanisms and chronic pain conditions to treat.</p