Fabrication of Laser-reduced Graphene Oxide in Liquid Nitrogen Environment.

Porous structure of reduced graphene oxide (rGO) plays an important role in developing flexible graphene-based devices. In this work, we report a novel methodology for reduction of freestanding graphite oxide (GO) sheet by picosecond pulse laser direct writing in liquid nitrogen. Non-agglomerate and porous structure of rGO is fabricated successfully due to frozen effect during laser processing. Compared with laser-irradiated rGO developed in N2 gas at ambient environment, the frozen rGO developed in liquid N2 shows better ordered structure with less defects, crack-free morphology as well as better electron supercapacitor performance including 50-60 Ω/sq in sheet electrical resistance. Mechanism of cryotemperature photoreduction GO is also discussed.

Influence of the material removal mechanisms on hole integrity in ultrasonic machining of structural ceramics.

Micro-chipping via micro-cracks, due to rapid mechanical indentations by abrasive grits, is the fundamental mechanism of material removal during ultrasonic machining (USM) of hard-brittle materials like ceramics and glass. This study aims mainly to investigate the adverse effects of this inherent removal phenomena on the hole integrity such as entrance chipping, wall roughness and subsurface damage. It also presents the material removal mechanism happens in the gap between the tool periphery and the hole wall (called 'lateral gap'). To do so, experiments were conducted for drilling holes on three advanced structural ceramics, namely, silicon carbide, zirconia, and alumina. Earlier published basic studies on the initiation of different crack modes and their growth characteristics are employed to explain the experimental findings in this USM study. It is realized that the radial and the lateral cracks formed due to adjacent abrasives, which are under the tool face, extends towards radial direction of the hole resulting in entrance chipping. Additionally, the angle penetration and the rolling actions of the abrasives, which are at the periphery of the tool, contribute to the entrance chipping. Later on, in the 'lateral gap', the sliding (or abrasion) and the rolling mechanisms by the larger abrasives take part to material removal. However, they unfavorably produce micro-cracks in the radial direction resulting in surface and subsurface damages, which are ultimately responsible for higher wall-surface roughness. Since the size of micro-cracks in brittle materials is grit size dependent according to the earlier studied physics, it is realized that such nature of the hole integrity during USM can only be minimized by employing smaller grit size, but cannot fully be eliminated.

Variations in the course of the cervical vagus nerve on thyroid ultrasonography.

BACKGROUND AND PURPOSE: Only 1 ultrasonography study that described the variation of the VN had been published at the time our research was begun. The purpose of this study was to evaluate the incidence and type of variation in the course of the cervical VN on thyroid ultrasonography. MATERIALS AND METHODS: From August 2009 to September 2010, 163 consecutive patients were evaluated by sonography for the screening and characterization of thyroid nodules (mean age, 49.0 ± 14.4 years, male:female, 20:143). Two types of variation were defined as follows: 1) anterior variation, when the course of the VNs changed from the typical location to an anterior location in front of the CCA; and 2) medial variation, when the course of the VNs changed from the typical location to a location medial to the CCA (between CCA and thyroid gland). The incidence of the each variation was studied. RESULTS: Variation in the course of the VN occurred in 5.5% (18/326) of cases. The anterior variation was observed in 4.3% (14/326, right:left = 4:10), and the medial variation was observed in 1.2% (4/326, right:left = 3:1). For both variations, the VN was close to or nearly abutted the thyroid gland after it changed course. CONCLUSIONS: Variation in the course of the cervical VN could be assessed by ultrasonography. Two variations were observed in 5.5% of cases. The anterior variation was more common than the medial variation.

National Cancer Patient Registry--a patient registry/clinical database to evaluate the health outcomes of patients undergoing treatment for cancers in Malaysia.

Cancer burden in Malaysia is increasing. Although there have been improvements in cancer treatment, these new therapies may potentially cause an exponential increase in the cost of cancer treatment. Therefore, justification for the use of these treatments is mandated. Availability of local data will enable us to evaluate and compare the outcome of our patients. This will help to support our clinical decision making and local policy, improve access to treatment and improve the provision and delivery of oncology services in Malaysia. The National Cancer Patient Registry was proposed as a database for cancer patients who seek treatment in Malaysia. It will be a valuable tool to provide timely and robust data on the actual setting in oncology practice, safety and cost effectiveness of treatment and most importantly the outcome of these patients.

Enhanced human osteoblast cell adhesion and proliferation on 316 LS stainless steel by means of CO2 laser surface treatment.

An effective and novel technique for improving the biocompatibility of a biograde 316 LS stainless steel through the application of CO(2) laser treatment to modify the surface properties of the material is described herein. Different surface properties, such as surface roughness, surface oxygen content, and surface energy for CO(2) laser-treated 316 LS stainless steel, untreated, and mechanically roughened samples were analyzed, and their effects on the wettability characteristics of the material were studied. It was found that modification of the wettability characteristics of the 316 LS stainless steel following CO(2) laser treatment was achieved. This improvement was identified as being mainly due to the change in the polar component of the surface energy. One-day cell adhesion tests showed that cells not only adhered and spread better, but also grew faster on the CO(2) laser-treated sample than on either the untreated or mechanically roughened sample. Further, compared with the untreated sample, MTT cell proliferation analysis revealed that the mechanically roughed surface resulted in a slight enhancement, and CO(2) laser treatment brought about a significant increase in cell proliferation. An increase in the wettability of the 316 LS stainless steel was observed to positively correlate with the cell proliferation.

The formation of a hydroxyl bond and the effects thereof on bone-like apatite formation on a magnesia partially stabilized zirconia (MgO-PSZ) bioceramic following CO2 laser irradiation.

For the purpose of improving the bioactivity of a magnesia partially stabilized zirconia (MgO-PSZ) and to explore a new technique for inducing OH group and apatite formation, a CO(2) laser has been used to modified the surface properties. The bioactivity of the CO(2) laser modified MgO-PSZ has been investigated in stimulated human fluids (SBF) with ion concentrations almost equal to those in human blood plasma. Some hydroxyl groups were found on the MgO-PSZ following CO(2) laser treatment with selected power densities. The surface melting on the MgO-PSZ induced by CO(2) laser processing provides the Zr(4+) ion and OH(-) ion, in turn, the incorporation of the Zr(4+) ion and the OH(-) ion creates the Zr-OH group on the surface. After 14 days of SBF soaking, the apatites formed on the MgO-PSZ with relatively high amount of hydroxyl groups generated by the CO(2) laser treatment, while no apatite was observed on the untreated with few hydroxyl groups. It exhibits that the Zr-OH groups on the MgO-PSZ surface is the functional groups to facilitate the apatite formation. The increased surface roughness provides more active sites, meantime, increased surface energy benefits to the adsorption and reaction on the surface.

Work stress and psychological well-being among the nursing profession in Singapore.

OBJECTIVE: To investigate the work stress of nursing and its relationship with the psychological well-being of the nurses. DESIGN: A survey research method was adopted in which a questionnaire was designed for data collection. SETTING: The study was conducted in the hospital setting. SUBJECTS: Nurses (N = 1,043) of different grades participated in this study on an anonymous and voluntary basis. MEASURES: A work stress measure (ie, the Nursing Stress Inventory) and GHQ-12 were incorporated in a questionnaire which also contained items on subject's background information. RESULTS: The eight areas of work stress identified were found to be negatively related to psychological well-being of the nurses, with stronger effects on anxiety and depression than sense of adequacy. CONCLUSION: Certain work stressors were more detrimental than those others. They may also exert differential effects on the affective and cognitive stress reactions.

Adjuvant chemotherapy for colorectal cancer: a Malaysian experience.

This study aims to evaluate the practice of adjuvant chemotherapy in colorectal cancer at the Institute of Radiotherapy and Oncology, Hospital Kuala Lumpur. A retrospective analysis of 320 patients' records from 1986 to 1994 was carried out. Adjuvant chemotherapy was given to 98 patients. Cancers of the rectum and sigmoid colon constituted over 60% of the patients. All the regimes used were 5-fluorouracil-based. The oral route was the most commonly used (55.1%). Toxicity was seldom the reason for stopping treatment (2%). The adjuvant treatment employed has been tolerable while the survival was comparable with other centres.

Experience of radioactive needle implants in the Institute of Radiotherapy Hospital Kuala Lumpur.

This retrospective study of radioactive needle implants at the Institute of Radiotherapy and Oncology, Kuala Lumpur Hospital serves as an audit of our practice as well as a demonstration of the usefulness of this technique of brachytherapy. A variety of tumour sites were implanted, of which over two-thirds involved the tongue and buccal mucosa. Although most of the implants were carried out with radical intent, one-tenth of these implants were performed for palliation. Radiotherapy techniques employed are described. The crude survival ranged from 1 month to 109 months while the disease free interval ranged from 0 months to 102 months.

Efficacy of phototherapy for hyperbilirubinaemia in infants with the respiratory distress syndrome.

OBJECTIVE: To evaluate the efficacy of phototherapy for hyperbilirubinaemia in preterm infants with and without the respiratory distress syndrome (RDS). METHODOLOGY: Prospective cohort study of preterm infants cared for at Kandang Kerbau Hospital, Singapore: 170 with RDS and 477 without RDS, sepsis or other complications (control group) presenting with non-haemolytic hyperbilirubinaemia at about the same time were exposed to daylight phototherapy when bilirubin concentrations exceeded 255 mumol/L or 222 mumol/L if < 48 h of age. Bilirubin values were monitored 6-hourly during exposure, and daily for at least 2 days post-phototherapy. RESULTS: The infants were comparable in birthweight, gestational age, postnatal age, haemoglobin, haematocrit and bilirubin values, at start. The response to phototherapy of the infants with RDS was comparable to that of the well preterm infants; the duration of exposure was 50.1 +/- 1.6 (mean +/- s.e.m.) versus 50.1 +/- 1.4 h, 24-hour decline rate 25.71 +/- 1.29% versus 26.32 +/- 0.65, and overall decline rate 0.96 +/- 0.03%/h versus 0.95 +/- 0.02%/h. CONCLUSION: The presence of RDS did not affect the efficacy of phototherapy for neonatal hyperbilirubinaemia in preterm infants.

Phototherapy for neonatal jaundice in infants with cephalhematomas.

The efficacy of phototherapy in a group of infants with nonhemolytic hyperbilirubinemia and no cephalhematomas was compared with a second group of infants with large cephalhematomas (> 7 cm across), but similar in all other aspects. The cephalhematoma group demonstrated significantly lower hemoglobin (Hb) and hematocrit (hct) values (P < .0001, P < .002 respectively) than the standard group, even after the latter group had been adjusted by stratification (P < .0001, P < .005) such that the starting bilirubin concentration, birth weight, and gestational age were highly comparable to the cephalhematoma group. The bilirubin concentrations of the cephalhematoma, original, and adjusted groups were 277.8 +/- 5.8 mumol/L (16.24 +/- 0.03 mg/dL), [mean +/- sem], 265.2 +/- 0.5 mumol/L (15.50 +/- 0.03 mg/dL), and 275.2 +/- 0.9 mumol/L (16.09 +/- 0.05 mg/dL), respectively. The postnatal age at the start of phototherapy in the cephalhematoma group was comparable with that of the standard group before and after adjustment. Phototherapy was equally effective in the cephalhematoma and standard (original and adjusted) groups of infants, in terms of duration, 24-hr decline, and overall decline/hr for the duration of exposure. The proportionate 24-hr decline was 24.02 +/- 1.90% vs 20.99 +/- 0.23% and 22.61 +/- 0.48% and overall decline/hr was 0.83 +/- 0.06% vs 0.74 +/- 0.01% and 0.78 +/- 0.01%. We conclude that the sequestrated blood in the cephalhematomas did not significantly interfere with the efficacy of phototherapy.

Interleukin 1-beta in symptomatic and asymptomatic human periradicular lesions.

Interleukin 1 beta (IL-1 beta) has been shown to be a potent mediator of bone resorption and has been implicated in resorption in periradicular lesions. In this study we compared the local concentrations of IL-1 beta in symptomatic and asymptomatic human periradicular lesions. Periradicular tissues from patients with symptomatic and asymptomatic lesions were obtained and stored at -70 degrees C. Pulpal tissues from unerupted third molars and chronically inflamed gingival tissues were also obtained and used as negative and positive controls, respectively. Tissue samples were homogenized, and supernatants were assayed for IL-1 beta by the enzyme-linked immunosorbant assay. Significantly higher levels of IL-1 beta were found in symptomatic and asymptomatic lesions and inflamed gingival tissues compared with uninflamed pulp tissues. There was a trend toward higher levels of IL-1 beta in symptomatic lesions compared with asymptomatic lesions, but the difference was not significant. The results suggest that IL-1 beta may play a significant role in the pathogenesis of human periradicular lesions.

Efficacy of "high-intensity" blue-light and "standard" daylight phototherapy for non-haemolytic hyperbilirubinaemia.

We report our clinical experience with phototherapy in 3802 infants; 3629 were exposed to "standard" daylight phototherapy and 173 to "high-intensity" blue-light phototherapy. High-intensity blue-light phototherapy was twice as effective as standard daylight phototherapy in decreasing bilirubin concentrations. No failures occurred with high-intensity phototherapy compared with an overall failure rate of 1.84/1000 with daylight lamps; these cases were transferred to high-intensity phototherapy with prompt response. Rebound after cessation of phototherapy was greater in those exposed to high-intensity blue light with a significantly greater number requiring a second exposure. However, the incidence was still low. No third exposure was required in any infant. Nursing of infants under high-intensity blue light was more difficult and inconvenient as was clinical monitoring. The light also caused more stress on the nursing and medical personnel. However, the infants tolerated both types of phototherapy equally well. High-intensity blue-light phototherapy would seem to be the treatment of choice for infants with rapidly increasing or very high bilirubin levels, as well as in those not responding adequately to daylight phototherapy.

Phototherapy for ABO haemolytic hyperbilirubinaemia.

The efficacy of 'standard' daylight phototherapy and 'high intensity' blue light phototherapy for neonatal jaundice from ABO-HD, or of a non-haemolytic nature was evaluated. Altogether 77 full-term infants with ABO-HD and 3,020 with non-haemolytic jaundice were studied. Both groups of infants responded well to standard daylight phototherapy; the response in non-haemolytic hyperbilirubinaemia was significantly greater. High intensity blue light phototherapy was significantly more effective in reducing bilirubin levels than standard daylight phototherapy in both group of infants with no failure being encountered. Four infants with non-haemolytic jaundice did not respond adequately to white light (1.4/1,000); they needed high intensity blue light for adequate response. Bilirubin rebound was mild. Four infants in the blue light group needed a second exposure (28.3/1,000) compared with 20 in the white light group (6.9/1,000), a difference that was significant. Standard white light phototherapy is usually adequate for ABO-HD as well as non-haemolytic hyperbilirubinaemia. High intensity blue light would be preferable where a more rapid and greater response is desirable.