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Downward lighting light-emitting diodes require cooling with cylindrical fin heat sinks to be mounted on top and cooled under natural convection air cooling mode. Performance simulation would involve specification of the heat transfer coefficient. Numerous methods are available to simulate the performance of conventional plate fin heat sinks including computational fluid dynamics packages. It would be feasible to perform simulation based on conventional flat plate fin heat sinks. A cylindrical fin heat sinks could be simply treated as a plate fin heat sink, if we imagine it cut open and laid out horizontally. A theoretical model is proposed in this paper. An experimental investigation is conducted here to validate its accuracy. Convective heat transfer coefficients were experimentally determined for a horizontally and vertically inclined bare plate operating under natural and forced air cooling modes. In addition, a vertical plate fin heat sink and a vertical cylindrical fin heat sink under natural convection were investigated. Power inputs were kept from 5 to 40W in order to keep operating temperatures below 100 C. Comparison of the experimental heat transfer coefficients and those obtained from well-known existing Nusselt number correlations show that agreement was poor for the bare plate but satisfactory for the plate and cylindrical fin heat sinks. Although they are within the generally accepted range, it would be advisable for actual measurements to be carried out in order to provide more accurate sizing for thermal measurements. [ABSTRACT FROM AUTHOR]

Solar energy is a renewable energy heat source freely and widely available everywhere throughout the year. Heat pipes are very effective and passive heat transfer devices. A solar heat pipe collector performs well at high temperatures. Thermoelectricity could be utilized for power generation and provide cooling and heating. The combination of a solar heat pipe collector with thermoelectric modules could provide a very useful device for simultaneous power generation and hot water heating. Such hybrid systems could offer small, mobile, transportable and off-grid power and heating systems for small-scale industry or domestic applications. This paper reviews some of the works conducted on the solar/heat pipe/thermoelectric hybrid system. [ABSTRACT FROM AUTHOR]

Heat pipe heat exchangers could be employed as run-around coils in air conditioning systems for enhanced dehumidification and cooling. This article reviews some of the works conducted on the cooling and dehumidification aspects in various air conditioning systems. They have been proved to be effective in enhancing dehumidification and reducing air conditioning costs especially in hot and humid tropical countries. [ABSTRACT FROM AUTHOR]

A conventional natural convection flat plate solar collector needs to be placed at an incline to the horizontal and exposed to the sun in order for the solar hot water heater system to work. This arrangement is satisfactory where there is ample roof top space to locate the collector and storage tank. In a high-rise apartment, space is at a premium and also the hot-water recticulation requires long lengths of piping to distribute the hot water supply to the individual apartment. Most every modern high-rise apartment has a balcony facing outward from the wall structure. Balcony-type solar water heaters (SWHs) are catching up fast in China. Their performance would depend on collector and storage tank designs and sizes, weather conditions (solar radiation intensity and ambient temperature) and direction in which the balconies are facing. This article compares the outdoor performance of two SWH systems incorporating the evacuated glass U-tube solar collectors operating under natural convection. The panels were tested in both the vertical and inclined positions using the same tank but at different times of the year. It was found that the inclined panel system performed better than the system with the vertical panel system. [ABSTRACT FROM AUTHOR]

Flexible poly(p-phenylene vinylene) organic light-emitting diodes (OLEDs) with top-emitting architecture were developed on metal-sandwiched polyethylene terephthalate (PET) substrates. Commercial aluminum-laminated PET (Al-PET) was adopted as initial substrates. Different kinds of metal layers (silver and nickel) were then deposited on Al-PET foil to form metal-sandwiched plastic substrates and also to serve as anodes for the top emitting OLEDs. Interface modification was employed to enhance carrier injection from the metal anodes to the polymeric organic stack. Semitransparent top cathodes were used for the flexible top-emitting diodes. The performance of these OLEDs was characterized and compared among different metal anodes. The flexible top-emitting OLEDs on metal-sandwiched PET foil can be bent to a substantial degree without breaking. Moreover, increased contrast ratio of OLEDs can be achieved with specific anodes due to lower reflectance of nickel material. [ABSTRACT FROM AUTHOR]

Sound measurement, an essential component of any scientific discipline, remains a particular problem in pain research. The measurement of pain intensity, for example, is a difficult and often a subjective undertaking. This is of little surprise to clinicians and researchers, because it is well recognised that pain intensity, like other sensations and perceptions, is a private experience that displays considerable variability both across patients and within a patient across time. Nonetheless, pain measurement and discerning factors that may affect its measurement are important for diagnosis and to determine the effectiveness of treatment interventions. This article reviews the basic concepts, roles, instruments used, and factors affecting pain measurement. A variety of the most commonly used pain measurement instruments are evaluated for their advantages and disadvantages. The article aims to assist clinicians and researchers to select the pain measurement instruments that best serve their purposes. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to investigate the antimicrobial activities of Etlingera pubescens, and to isolate and identify the antimicrobial compound., Methods and Results: The crude extracts of E. pubescens were obtained through methanol extraction, and evaluated for antimicrobial activities. From this extract, 1,7-bis(3,4-dihydroxyphenyl)heptan-3-yl acetate (etlingerin) was isolated. When compared to curcumin (a compound with a similar chemical structure), etlingerin showed twofold lower minimum inhibitory concentration values while also being bactericidal. Through time kill assay, etlingerin showed rapid killing effects (as fast as 60 min) against the Gram-positive bacteria (Staphylococcus aureus ATCC 43300 and Bacillus subtilis ATCC 8188). Further assessment revealed that etlingerin caused leakage of intracellular materials, therefore suggesting alteration in membrane permeability as its antimicrobial mechanism. Cytotoxicity study demonstrated that etlingerin exhibited approximately 5- to 12-fold higher IC 50 values against several cell lines, as compared to curcumin., Conclusions: Etlingerin isolated from E. pubescens showed better antibacterial and cytotoxic activities when compared to curcumin. Etlingerin could be safe for human use, though further cytotoxicity study using animal models is needed., Significance and Impact of the Study: Etlingerin has a potential to be used in treating bacterial infections due to its good antimicrobial activity, while having potentially low cytotoxicity., (© 2019 The Society for Applied Microbiology.)

Aims: The potential of Dicranopteris linearis leaves' extract and its bioactive components were investigated for the first time for its disrupting ability against Staphylococcus aureus biofilms., Methods and Results: The leaves of D. linearis were subjected to sonication-assisted extraction using hexane (HEX), dichloromethane, ethyl acetate and methanol (MeOH). It was found that only the MeOH fraction exhibited antimicrobial activity using broth microdilution assay; while all four fractions do not exhibit biofilm inhibition activity against S. aureusATCC 6538P, S. aureusATCC 43300, S. aureusATCC 33591 and S. aureusATCC 29213 using crystal violet assay. Among the four fractions tested, only the HEX fraction showed biofilm disrupting ability, with 60-90% disruption activity at 5 mg ml -1 against all four S. aureus strains tested. Bioassay-guided purification of the active fraction has led to the isolation of α-tocopherol. α-Tocopherol does not affect the cells within the biofilms but instead affects the biofilm matrix in order to disrupt S. aureus biofilms., Conclusions: α-Tocopherol was identified to be the bioactive component of D. linearis with disruption activity against S. aureus biofilm matrix., Significance and Impact of the Study: The use of α-tocopherol as a biofilm disruptive agent might potentially be useful to treat biofilm-associated infections in the future., (© 2017 The Society for Applied Microbiology.)

Background: Previous data have demonstrated that rofecoxib has good analgesic efficacy for acute postoperative dental pain. However, up to half of these patients require rescue analgesics within the first 24 hours. As the timing of analgesic interventions may be an important factor in pain control, the present study tested the hypothesis that rofecoxib administered preoperatively would improve the analgesic efficacy and reduce rescue analgesic requirements within the first 24 hours compared with postoperative administration., Methods: This was a double-blind, randomized, crossover study where 45 patients had each of their identical impacted mandibular third molars removed under local anesthesia on 2 separate occasions. Patients acted as their own control; one side was pretreated with rofecoxib 50 mg, 2 hours before surgery, followed by placebo 15 minutes after surgery, and the contralateral side was pretreated with placebo 2 hours before surgery and posttreated with rofecoxib 50 mg 15 minutes after surgery. The difference in postoperative pain between 2 sides was assessed by 4 primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 hours, time to rescue analgesic, postoperative analgesic consumption, and patient's global assessment., Results: Patients reported significantly lower pain scores (P = 0.04), longer time to rescue analgesic (P = 0.02), lesser postoperative analgesic consumption (P = 0.008), and better global assessment (P = 0.01) in the pretreated compared with the posttreated sides. There were significantly more patients in the pretreated group who did not required rescue analgesic within the first 24 hours (80% vs. 58%, P = 0.01), and the pain scores were extremely low in both groups during the 12 hours postoperative period (9.8 +/- 5.0 mm vs. 14.3 +/- 7.4 mm)., Conclusion: Rofecoxib is an excellent analgesic for preventing postoperative dental pain and when given 2 hours preoperatively rendered most patients relatively pain free, requiring no rescue analgesics on the first postoperative day.

There is uncertainty regarding the role of preemptive analgesia in preventing postoperative pain. Most previous studies were of parallel design completed under general anesthesia with many confounding inter-patient's variables. The present study evaluated the efficacy of preemptive ketorolac in a crossover design in patients undergoing bilateral mandibular third molar surgery. This was a double blind, randomized, placebo-controlled study where 34 patients had each of their identical impacted mandibular third molars removed under local anesthesia on two occasions. Each patients acted as their own control; one side was pretreated with intravenous ketorolac 30 mg before surgery followed by placebo injection after surgery, and for the other side, the patient was given placebo injection before surgery and post-treated with intravenous ketorolac 30 mg after surgery. The difference in postoperative pain between pretreated and post-treated side in each patient was assessed by four primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 h, time to rescue analgesic, postoperative analgesic consumption, and patient's global assessment. Throughout the 12-h investigation period, patients reported significantly lower pain intensity scores in the ketorolac pretreated sides when compared with the post-treated sides (P = 0.003). Patients also reported a significantly longer time to rescue analgesic (8.9 h versus 6.9 h, P = 0.005), lesser postoperative analgesic consumption (P = 0.007) and better global assessment for the ketorolac pretreated sides (P = 0.01). Pretreatment with intravenous ketorolac has a preemptive effect for postoperative third molar surgery and extended the analgesia by approximately 2 h.

The objective of this study was to compare the analgesic efficacy of a single-dose of preoperative intravenous tramadol versus ketorolac in preventing pain after third molar surgery. Sixty-four patients undergoing elective third molar surgery were randomly assigned into one of the two groups (32 in each group): Group I received tramadol 50 mg, and Group 2 received ketorolac 30 mg intravenously preoperatively before the surgery. After injection of the study drugs, a standard intravenous sedation technique was administered and the impacted third molars were removed under local anaesthetic. The difference in postoperative pain was assessed by four primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 h, median time to rescue analgesic, postoperative acetaminophen consumption, and patient's global assessment. Throughout the 12-h investigation period, patients reported significantly lower pain intensity scores in the ketorolac versus tramadol group (P = 0.05, Mann-Whitney U-test). Patients also reported significantly longer median time to rescue analgesic (9.0 h versus 7.0 h, P = 0.007, log rank test), lesser postoperative acetaminophen consumption (P = 0.02, Mann-Whitney U-test) and better global assessment (P = 0.01, chi2 test) for the ketorolac versus tramadol group. Preoperative intravenous ketorolac 30 mg is more effective than tramadol 50 mg in the prevention of postoperative dental pain.

Chronic pain and depression often occur simultaneously, may have common causal mechanisms, and may also influence each other. An understanding of their precise relationship would be useful for the prediction of response to treatment and for better pain management for chronic pain patients. A biopsychosocial model will be used in this review paper to elucidate the relationship between chronic pain and depression in biological, social, and psychological terms. Due to the enormous amount of information available, only a selective review of the most relevant literature was done. A critical analysis of the selected literature on the relationship between chronic pain and depression was performed to present an insight into this complex relationship.

Trigeminal neuralgia is a type of facial pain that is difficult to treat. The pain can be excruciating and debilitating. The wide range of treatments currently used for trigeminal neuralgia is ample evidence that there is no simple answer to how it should be managed. This review will evaluate the current surgical procedures used for the treatment of trigeminal neuralgia. A critical analysis of the evidence-based studies to date was done to evaluate and compare the efficacy of the different surgical procedures. Arguments for and against the use of surgery for trigeminal neuralgia are presented. In addition, the surgical procedures were compared with other treatments for trigeminal neuralgia.

This article reviews the use of nonsteroidal anti-inflammatory drugs (NSAIDs) for postoperative dental pain. An evidence-based approach is used to evaluate the clinical studies to date on the safe use of these drugs in dental patients. No drugs are without adverse effects or are perfectly safe, but their safe use in clinical practice would entail maximizing the therapeutic efficacy and minimizing the adverse effects. Therapeutic recommendations are made after reviewing the evidence for the safe use of NSAIDs in postoperative dental pain.

Fear and avoidance of dental treatment are major deterrents to oral health. Sedation can be used to control both the patient's fear and anxiety so that proper dental care can be provided for these patients. The purpose of this article is to discuss the use of sedation in dentistry and to provide a recommendation on the requirements and medico-legal aspects of sedation for the practitioner interested in incorporating sedation into their practice.

The advent of osseointegrated dental implants focused initially on functional rehabilitation. Interest today centres on aesthetics and the philosophical ideal of replicating nature. Implants can be placed beyond resorbed anatomic limitations where the final prosthesis should be, rather than within the pre-existing resorbed bone. In order to achieve this, the following must be considered: implant positioning, adequate bone support and the overlying soft tissue envelope. Common techniques to modify the surgical environment include different methods of bone grafting and regeneration, ridge expansion and sinus augmentation. With the advent of growth factors like bone-morphogenetic proteins, restoration of bony contours will become more predictable. Soft tissue management techniques include tissue expansion and contouring, gingiva grafts and advancement or rotational flaps. Though some of these procedures can be done concurrently with implant placement, a secondary surgical procedure is often required. Ideal implant positioning involve establishing correct orientation in all dimensions. Due consideration should also be given to occlusion and harmony of the final restoration with the adjacent dentition.

During lid operations, identifying the lacrimal punctum is sometimes difficult. The difficulty may be increased following local anesthetic infiltration into the medial canthus and manipulation of the lid tissues. Punctal dyeing with a skin marking pen is a simple technique that improves visualization of the lacrimal punctum during surgery in this region. Preceded by punctal dilatation, it lasts for the duration of standard lid or lacrimal procedures.

T cell subpopulations as defined by E rosette formation and Fc receptors for immunoglobulins were determined, using ox red blood cells coated with the IgG or IgM fraction of rabbit anti-ox red blood cells antibody to form rosettes with the peripheral blood lymphocytes of 18 pregnant females and 12 healthy nonpregnant females. It was shown that the TG cell population in the pregnant females is significantly increased as compared to those in the nonpregnant controls (mean +/- SEM % TG cells: 18 +/- 1.2 vs. 9.6 +/- 0.7; p less than 0.001). By using peripheral blood from normal nonpregnant subjects it was also shown that TG cells suppressed one-way mixed lymphocyte reactions (mean +/- SEM suppression: 23 +/- 7.2; p less than 0.01). These findings suggest that the TG cell population may exert a suppressor function on the immune response to alloantigens and act in concert with other humoral factors to protect the fetus from rejection.

The purpose of these studies was to examine the inhibitory effect of human corticosteroid-binding globulin (CBG) on the mitogenic effect of phytohemagglutinin on cultured human lymphocytes. We found that CBG could inhibit the incorporation of [14C] thymidine into lymphocytes, but the observed inhibition could be accounted for by the cortisol which was bound to the purified CBG, CBG stripped of cortisol or bound to 11-deoxycortisol was inactive in this assay.

Triacetyloleandomycin (TAO) and its parent compound oleandomycin have a "steroid-sparing" effect in asthmatic patients. This study was designed to determine whether oleandomycin would enhance the inhibitory action of glucocorticosteroids in suppressing the blast transformation of phytohemagglutinin-stimulated human lymphocytes. Although oleandomycin could not be shown to inhibit the phytohemagglutinin stimulation of lymphocytes, there was a significant potentiation of steroid suppression at each concentration of methylprednisolone examined. This augmentation of glucocorticosteroid suppression of lymphocyte proliferation in vitro appears to support the clinically observed "steroid-sparing" effect of TAO and therefore its usefulness may not be limited to asthma and bronchitis.