Bio-based Preservative using Methyl-β-cyclodextrin-Essential Oil Complexes for Wood Protection

Developing natural preservatives for wood protection is of great interest in sustainable construction and green building industries. This study was designed to determine the feasibility of using methyl-β-cyclodextrin-essential oils (MβCD-EOs) complexes as potential bio-based preservatives for wood protection. Four essential oils (EOs) with proven antifungal properties, eugenol (EG), trans-cinnamaldehyde (CN), thymol (TM) and carvacrol (CV), were complexed with methyl-β-cyclodextrin (MβCD) by a co-precipitation method. The inclusion of EOs in MβCD and the corresponding inclusion yield of the MβCD-EOs complexes were determined by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and ultraviolet-visible spectroscopy (UV/Vis), respectively. The maximum inclusion yields in MβCD-EG, MβCD-CN, MβCD-CV, and MβCD-TM were estimated to be almost 100%. MβCD-EOs complexes were impregnated into southern pine wood blocks and exposed to two brown rot fungi, Gloeophyllum trabeum and Postia placenta, following procedures described in AWPA Standard E22 and E10. The penetration of MβCD-EOs complexes in wood was confirmed by fluorescence microscopic analysis after the selective dyeing of EOs encapsulated in MβCD. In comparison to the control wood samples, MβCD-EOs complexes treated wood exhibited a significant reduction in the mass loss from 16-36% to 2-18%, accompanied by improvement in radial compression strength loss from 81-92% to 29-67% after four-week fungi exposure.

How nano-wollastonite can change the fundamental properties of a wood fibre and rice straw composites?

The potential of using rice straw (RS) in combination with wood fibre in the production of medium density fibreboard was investigated. Nano-wollastonite (NW) was added to some of the panels to determine if it would enhance the physical and mechanical properties. It was found that satisfactory composite boards could be made with the addition of 10% RS to the wood fibre. Furthermore, the mechanical and physical properties of the composite were enhanced when NW was added.

Fungicidal values of bio-oils and their lignin-rich fractions obtained from wood/bark fast pyrolysis

Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success.

A brief review of the past, present and future of wood preservation

Wood products used in exterior applications must be protected against biodeterioration by decay fungi, insects such as termites, and other organisms. Traditionally, wood products for residential or industrial applications have been protected by treatment with chromated copper arsenate (CCA) or older inexpensive organic biocides, but environmental and disposal concerns and governmental regulations have resulted in a rapid and dramatic worldwide shift to copper-based systems. The current development trend is towards employing totally organic biocides based on relatively benign and expensive agrochemicals, with continuing research directed towards developing non-biocidal methods to protect wood.

Development of environmentally-benign wood preservatives based on the combination of organic biocides with antioxidants and metal chelators

Wood extractives can be envisaged to protect heartwood by at least three different mechanisms, i.e. fungicide, free radical scavengers/antioxidants and as metal chelators. In short-term laboratory decay tests using two different wood species and decay fungi, the combination of different organic fungicides with various antioxidants and/or metal chelators gave enhanced activity as compared to the organic biocide alone, with the best results usually obtained with all three compounds. Outdoor ground-contact stakes treated with a biocide and antioxidant combination and exposed for 30 months also gave enhanced protection against both decay fungi and termites. It was concluded that the combination of an organic biocide with metal chelating and/or antioxidant additives gives enhanced protection to wood against fungi as compared to the biocide alone and, consequently, it may be possible to develop environmentally-benign wood preservative systems based on this idea.

Naturally durable heartwood: evidence for a proposed dual defensive function of the extractives

We previously proposed that extractives in highly durable heartwood may protect wood against fungal colonization and subsequent degradation by dual mechanisms: the extractives have some fungicidal activity and are also free radical scavengers (antioxidants). In short-term laboratory decay tests using two different wood species and decay fungi, the antioxidant 2,6-dimethyl-di-tert-butyl-4-methylphenol (BHT) alone had little or no preservative effect. In contrast, the combination of BHT with different organic commercial biocides always showed an increase in efficacy compared to the organic biocide alone. Consequently, we conclude that the combination of a commercial antioxidant and biocide is synergistic. This implies that extractives may protect wood by more than simply being fungicidal.

Comparative validity of three methods for assessment of the quality of primary health care

OBJECTIVE

This study compared the sensitivity and specificity of three assessment methods to detect the performance of key clinical tasks by health workers in a primary care setting.

DESIGN

Health worker performance during patient encounters for acute respiratory infections, acute diarrhea and family planning counseling was assessed through checklist-based observation of the consultation, interview with the mother following the consultation, and review of the patient's clinical record. The results of each method regarding the performance of key tasks by health workers were compared to a 'gold standard', defined as the application of the observation checklist by observers with extensive quality assessment experience. Patient encounters were studied in three Ministry of Health facilities in the Department of Totonicapán, Guatemala, involving care by physicians, nurses and auxiliary staff

RESULTS

The three methods showed reasonably high levels of sensitivity (generally about 70%) for the detection of failures in the performance of most health worker tasks. The greatest problem experienced by each method related to specificity, i.e. capacity to recognize quality successes and only detect real failures.

CONCLUSION

Direct observation demonstrated the best overall balance of sensitivity and specificity. Exit interview of the mother demonstrated good sensitivity and better specificity than record review.

The Quality Assurance Project: introducing quality improvement to primary health care in less developed countries

Persistently excessive morbidity and mortality rates in less developed countries (LDCs) served by primary health care systems suggest that the quality of services is inadequate. The PRICOR project, sponsored by the United States Agency for International Development, has designed and implemented methods for quality assessment and problem solving in LDC health systems. After developing comprehensive lists of essential activities and tasks, similar to practice parameters, for seven child survival interventions, PRICOR supported comprehensive quality assessment studies in twelve LDC countries. The studies, yielding over 6000 observations of health worker-client encounters, indicated highly prevalent, serious program deficiencies in areas including diagnosis, treatment, patient education and supervision. To facilitate corrective action, PRICOR assisted managers in conducting operations research to resolve priority problems revealed by the assessments. The recently initiated Quality Assurance Project is building on PRICOR techniques in designing and implementing sustainable continuous quality improvement programs for LDC health systems.

Comparison of methods for estimating the frequency of paralytic poliomyelitis in developing countries

Standard reporting systems have proved to be unreliable in estimating the frequency of paralytic poliomyelitis in many developing countries. The effectiveness of three survey methods for estimating the prevalence of lameness attributable to poliomyelitis were compared in the Danfa Health Project district of rural Ghana. Lameness was studied because it is easily identified by inexpensive survey techniques. A postal survey of school headteachers was the least costly and most accurate method, giving a prevalence of lameness attributable to poliomyelitis of 7.2 per 1000 schoolchildren. This method is recommended for countries with an extensive network of primary schools. Medical examinations in a village health survey yielded a prevalence of 4.6 per 1000 children aged 6-15 years. This method was relatively expensive but could be justified if the survey was multipurpose. A question added to the annual district census showed a prevalence of 2.2 per 1000 children, a rate still many times higher than estimates from national statistics. The inclusion of such a question in a census or other national survey entails little additional cost and with more careful questioning results should improve. Repeated surveys can be used to assess the success of poliomyelitis vaccination programmes.

An evaluation of male contraceptive acceptance in rural Ghana

To evaluate the effect of male contraceptive acceptance on fertility, the Danfa Family Planning Project in rural Ghana studied a sample of its male family planning acceptors. The findings show that half of the survey respondents accepted foam for use by their partners and half accepted the condom. The continuation rate (69 percent at 12 months) and use-effectiveness rate (80 percent at 12 months) reported by men were higher than those reported by women program acceptors. It is felt that men can play a significant role in affecting fertility through their influence on a couple's choosing to use contraception and as a result of their motivation to obtain contraception and see that it is used. It is urged that increasing emphasis be placed on providing family planning services for men in African programs.

A mass immunization campaign in rural Ghana. Factors affecting participation

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Attitudes towards family size and family planning in rural Ghana-Danfa project: 1972 survey findings

This report describes a family planning KAP survey conducted in 2000 households in rural Ghana between April and October, 1972, as one of the Danfa Project’s baseline studies. Subsequent re-surveys were done in 1975 and 1977 to assess changes related to project health education and family planning programmes.

Reported knowledge about family planning was three times that reported in previous studies in rural Ghana. About 70% of the respondents approve of family planning, but most want a large family, with over six children. At all ages, males wanted two or three more children than did women.

The current 3% population growth rate in Ghana may increase due to continued early age of marriage, the rising size of the reproductive age group and improved pregnancy outcome.

Although the expected relationships between knowledge and use of family planning and age and education were present, these differentials were typically only 10–15%. In the project area it appears that women will be most important in making the decision to practise family planning, although motivation of males is being stressed.

Most villagers hear about family planning through informal, word-of-mouth channels with relatively little use of news media, family planning workers or clinic health personnel. To improve the practice of family planning, village-based health educators are working with volunteers including traditional birth attendants, community leaders, teachers and church groups.

Haematological values in a rural Ghanaian population

Early in 1973 residents of 20 randomly selected rural villages in southern Ghana were studied to determine the prevalence of anaemia. Laboratory tests were conducted to learn what haemoglobin phenotypes were present and the distribution of white blood cell counts. Moderate anaemia (below 10 g%) was fairly common, particularly in children and 15--29 year old women, but severe anaemia (below 7 g%) was rare. Malaria infection and diets with low iron content were major factors affecting haemoglobin level, while hookworm infestation and high parity had little effect. Neutropenia (about two-thirds of Caucasian values) and the distribution of haemoglobin types (AS 16.3%; AC 11.1%) were similar to findings in earlier studies. To improve haemoglobin levels in children and young women, low-cost intervention programmes based on volunteer village workers are recommended.

The training of traditional birth attendants in Ghana: experience of the Danfa Rural Health Project

Three quarters of deliveries in Ghana are still attended by untrained personnel, including traditional birth attendants (TBA's), and maternal mortality remains high. The Ministry of Health is exploring ways of improving this situation. Recently, training traditional birth attendants to improve maternal and child health practices and promote family planning has been considered. Most TBA's in rural Ghana are elderly illiterate farmers. The Danfa Project has identified and trained 57 of these TBA's with the objective of developing a programme that might be replicated elsewhere in the country. This paper describes the design of the programme and problems encountered and makes recommendations to others who may be considering similar programmes in other countries.

Outside Europe. Is poliomyelitis a serious problem in developing countries?--the Danfa experience

Children were examined for lameness in the Danfa Project district of rural Ghana to assess the impact of endemic poliomyelitis and to test a widely held hypothesis that paralytic poliomyelitis is relatively rare in such districts (less than 1 per 1000 children affected). The observed prevalence of lameness attributable to poliomyelitis was 7 per 1000 school-aged children, and the annual incidence is estimated to be at least 28 per 100 000 population. Although no evidence for an epidemic was found, these rates are comparable with those in the USA and Europe during the years of severe epidemics and indicate that a high price is being paid in the Danfa district for the natural acquisition of immunity. As a result, immunisation against poliomyelitis has been given high priority. A teacher questionnaire was also tested for use in postal surveys as a rapid means of estimating the prevalence of lamenes attributable to poliomyelitis in countries with a reasonable network of primary schools.

Is poliomyelitis a serious problem in developing countries?--lameness in Ghanaian schools

A postal survey of lameness in schools throughout Ghana showed an estimated prevalence of lameness attributable to poliomyetitis of 5-8 per 1000 school-aged children and an estimated mean annual incidence of paralytic poliomyelitis of 23 per 100 000 population. Official reported incidence rates range from 0-1 to 2-1 per 100 000 population, indicating that at least 90% of cases are not reported. No evidence of epidemics was found to account for these high rates. These suggest that mean annual incidence rates in tropical endemic countries have always been as great, if not greater, than those experienced by temperate countries during epidemic periods in the twentieth century and that the total number of cases of paralytic poliomyelitis occurring in the world each year has been reduced by only 25% since the advent of polio vaccine. Immunisation against poliomyelitis must have a high priority in Ghana and other tropical countries where the disease is endemic.

Integration of family planning and maternal and child health in rural West Africa

There is controversy extending beyond that of whether family planning or population control measures should be promoted among various populations. Even when the decision has been made to provide family planning advice, information and service, debate often arises as to the best method of administering a family planning programme—whether to integrate it with maternal and child health (MCH) services, offer it post-partum, or provide it independently of all other health activities.

The Danfa Comprehensive Rural Health and Family Planning Project, Ghana, is investigating the general problem of health service delivery, including family planning, and is doing so with a firm commitment to efficient management, staff training and supervisory maintenance. An established research design and ongoing evaluation efforts, including cost and functional analyses, are an integral part of the project. While it is believed that the integrated MCH/Family Planning approach will yield optimal results in family planning acceptance (as well as reduction in morbidity and mortality), other alternatives of health care and family planning service delivery are being evaluated.