Search

Waste engine oil one of the most abundant wastes in Malaysia, and through the reutilization of waste automotive engine oil helps to create a sustainable environment. The objective of this research is to develop the best formulation of lithium complex grease derived from waste automotive engine oil as base oil. The main focused parameter in this study is the different formulation ratio of base oil, thickener and co-thickener. Lithium 12-hydroxystearate is mixed with azelaic acid to produce lithium complex 12-hydroxystearate. Two different type of base oils, i.e. fresh automotive engine oil (FAO) and waste automotive engine oil (WEO) are used to formulate Li-complex grease. The grease derived from FAO is used to compare the physical properties derived from WEO. The texture of the formulation of base oil higher than 82 weight percentage was very fluid. The formulation of grease is carried out by differencing the ratio of the waste automotive engine oil, lithium complex 12-hydroxystearate and azelaic acid, which are 82:18, 80:20 and 70:30. The properties of the grease formulated is conducted through several tests, such as ASTM approach, Fourier Transform Infrared Spectroscopy (FTIR) characterization, oil separation and thermogravimetric analysis (TGA). Such interesting properties included consistency, chemical compound of the grease, oil separation and thermal stability. Based on the finding, the best formulated Li-complex grease is WG3, classified NLGI 3. The significant peak derived from FAO and WEO to observe is 1710 cm−1 as this peak indicated the oxidation stability. From the result, the intensity of carboxylic acid is weak that ranged 1709 – 1711 cm−1. Hence, this indicated the grease formulated exhibited better oxidation stability. Furthermore, the formulated grease was thermally stable as the onset temperature was 250.09 °C. In conclusion, the formulation of Li-complex from WEO can be used as an alternative source of base oil in the grease industry, due to the good properties exhibition and preserving the environment as well as the increment of fossil fuel’s demand and cost.

A total of 550 acute burn patients under the age of 15 years were admitted to the Burns Unit of Prince of Wales Hospital, Hong Kong between March 1993 and February 1999. There were 337 males and 213 females with a male to female ratio of 1.58:1. The median age was 2.5 years and the median burn size was 5% total body surface area (TBSA). Toddlers of age < 2 years accounted for 235 (42.7%) of admission. Domestic burns resulted in 481 (87.5%) injuries followed by play-related burns that caused 34 (6.2%) admissions. Scalding was the most common cause of injury, which accounted for 497 (90.4%) admissions, followed by flame burns, which resulted in 45 (8.2%) injuries. Nine patients (1.6%) had inhalation injury requiring intubation and ventilatory support. The median hospital stay was 8 days and there was no seasonal variation in admission. The majority of patients (80.2%) had their wounds healed without any operation. Only 19 out of 550 patients (3.5%) had burns of 30% TBSA or larger, and only nine patients (1.9%) had inhalation injuries. Only one patient died in this series, which yielded a mortality rate of 0.2%.

A total of 6,493 fractures was studied from 6,389 children younger than 16 years admitted as inpatients to one center in a 10-year period. The boy-to-girl ratio increased from 1.4:1 in the infants to 4.9:1 in the adolescents. The most common fractures were the distal radius (20.2%), supracondylar fracture of the humerus (17.9%), forearm shaft (14.9%), and the tibial shaft (11.9%). A distinct age-specific fracture pattern also was found, with supracondylar fracture of the humerus being the most common fracture in the age 0- to 3-year (26.7%) and the 4- to 7-year (31.6%) groups and distal radius in the 8- to 11-year and the 12- to 16-year groups (24.3 and 25.7%, respectively). Although the overall pattern of the major fractures had not changed over the 10-year period, significant changes in the treatment pattern were observed. The closed-reduction and percutaneous pinning rates increased from 9.5 to 38.7% in fracture of the distal radius, 4.3 to 40% in the supracondylar humerus, and 1.8 to 22% in the forearm shaft. The changes in treatment pattern were also accompanied by a corresponding decrease in the open-reduction rate and hospital stay periods from

Since 1992 the solar tower telescope of Nanjing University (118°51′ E, 32°03′ N) as well as its multichannel solar spectrograph, originally established in 1982, have been reconstructed and a two-channel imaging spectrograph has been operated successfully. The apertures of the coelostat and the secondary mirror are both 60 cm. The spherical objective mirror, having an aperture of 43 cm and a focal length of 2170 cm, produces a solar image of 20 cm diameter. Two auxiliary telescopes using a small fraction of the coelostat's aperture were set up for guiding and Hα monochromatic monitoring. A multichannel spectrograph can be operated in six wavebands simultaneously. A CCD imaging spectrograph can be used for data acquisition at Hα and Caii K line wavebands automatically and simultaneously. The instrument consists of two CCD cameras, an image processor (SR-151), a personal computer, and a mechanical scanning device. The principal characteristics of the instruments are described. Some observational results are presented as examples.

To evaluate the outcomes of severely burned patients treated at a regional burns unit and to develop a predictive model for survival and length of hospital stay for major burn patients in Hong Kong.Retrospective study.Burns unit of a regional public hospital, Hong Kong.Two hundred and eighty-six severely burned patients treated from March 1993 to February 2000.Details of demographics, mechanism of burn, extent of burn, incidence of inhalation injury, length of hospital stay, and mortality rate were recorded and entered into a database. Stepwise logistic regression and linear regression were applied to develop a predictive model for mortality and morbidity, respectively.Of 286 major burn patients treated in this 7-year period, 25 patients died from their injuries, yielding a mortality rate of 8.7%. Stepwise logistic regression was applied to develop a predictive model for mortality. We found that inhalation injury, age, and total body surface area involvement were independent significant predictors of death. Accuracy of this predictive model reached 93%. Similarly, stepwise linear regression was used to develop a predictive model for length of hospital stay. Sex, inhalation injury, total body surface area of burn, and total body surface area(2) of burn were significant predictors of length of hospital stay (R(2)=0.2). Only three patients' duration of hospital stay was more than three standard deviations from the predicted length of hospital stay.A predictive model for mortality and length of hospital stay has been developed for major burn patients in Hong Kong. This model may help clinicians to counsel patients and relatives at an early stage of care, to provide a basis from which new treatment plans can be compared, and to facilitate efficient allocation of valuable medical resources.

To evaluate the effectiveness of digital subtraction radiography (DSR) system for diagnosis of small artificial alveolar bone lesions.Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of dry human mandibles. Reference and subsequent radiographs were taken before and after lesions were made. The small lesions were detected by conventional radiography and DSR respectively.For 0.2-0.5 mm3 lesions, detection by both DSR and conventional methods was less than 50%. For 0.7 mm3 lesions, the detection by DSR and conventional methods was 57.5% and 38.7%, respectively (P0.01). For 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P0.01).The detectability of small alveolar bone lesions by DSR was superior to that of the conventional method.

A total of 6,493 fractures was studied from 6,389 children younger than 16 years admitted as inpatients to one center in a 10-year period. The boy-to-girl ratio increased from 1.4:1 in the infants to 4.9:1 in the adolescents. The most common fractures were the distal radius (20.2%), supracondylar fracture of the humerus (17.9%), forearm shaft (14.9%), and the tibial shaft (11.9%). A distinct age-specific fracture pattern also was found, with supracondylar fracture of the humerus being the most common fracture in the age 0- to 3-year (26.7%) and the 4- to 7-year (31.6%) groups and distal radius in the 8- to 11-year and the 12- to 16-year groups (24.3 and 25.7%, respectively). Although the overall pattern of the major fractures had not changed over the 10-year period, significant changes in the treatment pattern were observed. The closed-reduction and percutaneous pinning rates increased from 9.5 to 38.7% in fracture of the distal radius, 4.3 to 40% in the supracondylar humerus, and 1.8 to 22% in the forearm shaft. The changes in treatment pattern were also accompanied by a corresponding decrease in the open-reduction rate and hospital stay periods from10% to 38% of patients being discharged within 1 day of admission in the 10-year period.

Activin regulates the growth and differentiation of a variety of cells and is a member of the transforming growth factor-beta (TGF-beta) family. Previously, we found that the retinoblastoma cell line Y-79 expresses both activins and activin receptors, suggesting that activin may have an autocrine function in these cells. In this study, the effects of exogeneous activin A on cultured Y-79 cells were examined. The results demonstrate that activin A inhibits hexamethylene bisacetamide (HMBA) -induced Y-79 cell differentiation in both serum-containing and serum-free medium. Activin A also inhibits Y-79 cell growth in serum-containing medium but not in serum-free medium.

In this study, human trophoblast cells were isolated from term placentas by trypsin-DNase digestion and Percoll gradient centrifugation. After the cells were cultured in vitro, bioactive inhibin and immunoreactive inhibin were measured in the culture medium and cellular lysate by an ovine pituitary cell culture system and an immunoenzymatic assay. The trophoblast cells were capable of producing inhibin, as indicated by the observation that enhancement of inhibin content and secretion was dependent upon the cell number and time in culture. High levels of inhibin were observed in the culture medium and the cellular lysate with cell numbers of over 1 x 10(6) cells/well, whereas the inhibin levels decreased until they were nearly undetectable when the cell number was less than 0.25 x 10(6) cells/well. In the culture medium, a sharp increase of inhibin levels was observed after 2 days of culture. Bio-inhibin and immuno-inhibin concentrations in the culture medium increased tenfold and fourfold, respectively, from day 2 to day 4. The peak level of bio-inhibin (3.5 U/mL) occurred on day 4 and that of immuno-inhibin (3.55 U/mL) on day 6. In contrast, the maximal level of bio-inhibin (4.45 U/mL) and immuno-inhibin (4.25 U/mL) in the cellular lysate was observed on day 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Summary A 24,000 Dalton protein with follicle stimulating hormone (FSH)-releasing activity, named activin , has been characterized previously from porcine follicular fluid as a heterodimer composed of the β-subunits of inhibins A and B linked by disulfide bond(s) [Ling et al. (1986) Nature, in press]. In this paper we report the isolation of another 24,000 Dalton protein with FSH-releasing activity from porcine follicular fluid, using successive steps of heparin-Sepharose affinity chromatography, gel filtration on Sephacryl S-200, and four steps of reversed-phase HPLC, followed by preparative sodium dodecyl-sulfate-polyacrylamide gel electrophoresis chromatography. Based on the molecular weight of the isolated molecule and its deduced NH2-terminal sequence, we propose that this second FSH-releasing substance present in porcine follicular fluid is a homodimeric protein composed of two β-subunits of inhibin A joined together by disulfide bond(s). The name homo-activin-A is proposed for this substance.

Antiserum to inhibin was produced in rabbits by immunization with a synthetic [Tyr30]alpha-chain(1-30)NH2 fragment of porcine inhibin coupled to bovine serum albumin, and the elicited antiserum was used in conjunction with the avidin-biotin immunoperoxidase procedure to localize inhibin-reactive cells in various rat tissue preparations. In the testes, only the Sertoli cells revealed immunoreactivity with the antiserum. Intense staining was also observed in ovarian follicular granulosa cells but not in the theca layer outside the basement membrane. In addition, the luteal cells in the corpus luteum were also stained by the antiserum. The positive staining in the gonadal tissues could be blocked completely by pre-adsorbing the serum with either the synthetic peptide or native inhibin. Immunostaining was not detected in brain, pituitary, thymus, stomach, pancreas, kidney and adrenal section, thus confirming that inhibin is a polypeptide originating only from specific cells of the gonad.

The concept of a neurohumoral hypothalamic control of the adenohypophysis as originally formulated by G. W. Harris was later expanded to propose that there would be one hypothalamic substance (a releasing factor, as they were called later) involved for controlling the secretion of each pituitary hormone. The concept was ultimately validated with the isolation and characterization in 1969 of TRF, the thyrotropin releasing factor, known now also to release prolactin, and in 1971 of LRF, the luteinizing hormone releasing factor, known now also to release follicle stimulating hormone. Regarding the secretion of growth hormone, it has been known since the early 1960’s that hypothalamic lesions will inhibit body growth along with growth hormone secretion, and in 1964 Durben and Meites reported the presence of a growth hormone releasing factor in extracts of hypothalamic tissues. The search for the isolation and characterization of the growth hormone releasing factor has been on ever since, with no satisfactory results, despite earlier claims to the contrary.

Inhibins are proteins consisting of two subunits, 18 K alpha- and 14 K beta-subunits, linked by disulfide bonds. Two forms of inhibins A and B consisting of a common alpha-subunit and a similar but distinguishable beta-subunit specifically suppress the secretion and cell content of FSH in a delayed action. The production of inhibin is regulated mainly by FSH; therefore, a reciprocal relation between FSH and inhibin is established. Each subunit (alpha-, beta A- or beta B-) is encoded by a different mRNA species. Inhibin secreted in response to FSH from the pituitary originates primarily in the granulosa cells of the ovary and the Sertoli cells or testes. Two beta-subunits, beta A beta A, beta A beta B, or beta B beta B form a new molecule, activin, that has opposite endocrine function to inhibin, but in the presence of inhibin, the activity of inhibin overrode that of activin. Follistatin, a single-chain polypeptide with no structurally similarity to inhibin, also specifically inhibits the release of FSH, approximately one third potency of inhibin. This probably is due to the fact that inhibin suppresses both FSH secretion and cell content of FSH whereas follistatin primarily inhibits the release of FSH. In addition to the endocrine function, these gonadal proteins also exert paracrine function on gonadotropin-mediated steroidogenesis. Outside the reproductive system, inhibin and activin also play a role in hemoglobin production, erythroid cell differentiation; all three proteins, together with TGF beta, are involved in immunosuppresion.

The isolation and characterization of growth hormone-releasing factor (GRF) has initiated a new and exciting era in our understanding of the neuroendocrine regulation of pituitary growth hormone (GH) secretion. This report briefly describes the isolation and characterization of GRF, factors which modulate the GH response to GRF and the effects of chronic administration and deprivation of GRF on somatic growth. The intent of this report is to serve as a general introduction on biochemical and physiological aspects of GRF. The following reports from this symposium will then cover many of these topics in much greater detail.

The insulinotropic and glucagon-releasing activity of acid extracts of rat hypothalami were tested in two bioassay systems using short-time incubation of isolated rat pancreatic islets and a rat insulinoma (RIN) cell line. Release of insulin and glucagon into the incubation medium was measured by radioimmunoassay. The major insulin-releasing and glucagon-releasing activity eluted in a broad zone in Sephacryl S-zoo gel filtration in 30% acetic acid corresponding to the molecular weights between approximately 10 and 40 kD. The highest activity was eluted in a zone corresponding to 14 kD and was purified to homogeneity by means of two steps of reversed—phase HPLC. Amino acid analysis and SDS polyacrylamide gel electrophoresis indicated that the biologically active material was the rat small (myelin) basic protein characterized previously by Dunkley & Carnegie (1974). The purified rat hypothalamic material showed insulinotropic and glucagon-releasing activity indistinguishable from that of purified porcine myelin basic protein, and lost its insulinotropic activity when incubated with anti-myelin basic protein immunosorbent. We conclude that the major insulin-releasing and glucagon-releasing activity in acid extracts of the high-molecular-weight fractions of rat hypothalami is myelin basic protein.

The search for a peptide corresponding to the NH2-terminus of somatostatin-28 (SS-28) in tissues has led to the isolation and characterization of somatostatin-28[1–12] from pancreas and hypothalamus. Somatostatin-28[1–12]-like immunoreactivity [SS-28[1–12]-LI] is widely distributed throughout the central nervous sytem and the digestive system of rodents and primates, reaching levels comparable to those of somatostatin-14 (SS-14). Antibodies directed against the C-terminal end of the dodecapeptide are more specific and constitute excellent markers for the “prosomatostatin” system in mammalian tissues. In rat brain, SS-28[1–12]-LI material is highly concentrated in nerve fibres and terminals, especially in the median eminence, layer I of neocortex, the outer molecular layer of the dentate gyrus and the striatum. Additionally, immunoreactivity is observed in large multipolar or occasionally pyramidal-like neurons of the neocortex. SS-28[1–12] is secreted from hypothalamus and amygdala by a calcium dependent mechanism. No biological role is presently known for the dodecapeptide.