Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 51-52).

Thesis (Ph. D.)--University of Hong Kong, 2007.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 159-167). Also available on the World Wide Web.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: An investigation into the effects of different mulches on the root environment, encompassing physical, chemical and biological factors of the soil, on two different soil types was done in the form of a field trial on ‘Cripps’ Pink’ apples. Three organic mulches were tested: compost, vermi-castings and woodchips, as well as an inorganic mulch, geotextile fabric, and were compared against clean cultivation. The organic treatments resulted in improved physical conditions (lower bulk densities) in the heavier soil, as well as, a reduction in temperature fluctuations and a general increase in soil temperatures during the seasons, in both sites. The geotextile fabric treatment resulted in increased soil moisture levels in the top 40 cm, predominantly in the heavier soil. The compost treatment resulted in high soil moisture levels in the top 40 cm only in the lighter soil. The vermi-castings treatment achieved superior results in terms of changing the nutrient status of the heavier soil. It resulted in significantly higher pH, P (phosphorus), N (nitrogen), K (potassium), Mg (magnesium), Zn (zinc), Mn (Manganese), B (boron), as well as the cation exchange capacity and some exchangeable cations, such as, Na+ (sodium ions), K+ (potassium ions) and Mg+ (magnesium ions). The compost treatment resulted in significantly higher Ca (calcium) and Ca+ (calcium ions) in the heavier soil compared to the other treatments. The organic mulches, including the woodchips treatment, consistently resulted in higher mineral levels and therefore performed the best in this regard and did so in the heavier soil. In contrast to the heavier soil, none of the treatments were successful in ameliorating the nutrient status of the lighter soil, with the exception however of the increased percentage C as a result of the compost and vermi-castings treatments. The compost treatment realised consistently higher mychorrizael colonization in both sites, however, not always significantly higher than the other treatments. The vermi-castings treatment realised consistently lower plant parasitic nematodes numbers. Higher free-living nematodes were also frequently realised during both seasons and in both sites. The organic mulches therefore proved promising with regard to soil biota. The organic treatments, with the exception of the vermi-castings treatment, resulted in improved root number and distribution in the heavier soil. The vermi-castings treatment resulted in a superior root environment and did not need to enhance its root system in order to achieve good fruit yield and quality. In contrast, the geotextile fabric treatment performed better in this regard in the lighter soil. The geotextile fabric treatment also achieved the lowest weed counts, quantified as winter weeds, in both sites. Yield efficiency, in the heavier soil, and the incidence of sunburn in both sites, were influenced by mulching. In the heavier soil, the woodchips treatment resulted in the highest yield efficiency and the compost treatment consistently resulted in the highest incidence of sunburn. In the lighter soil the control treatment resulted in the highest incidence of sunburn. The vermi-castings treatment consistently resulted in lower incidences of sunburn. Due to the limited quantification of irrigation in this trial, the consequence of irrigation on different mulches was not evaluated and should be considered for future research. / AFRIKAANSE OPSOMMING: ‘n Ondersoek na die effek van verskillende deklae op die wortelomgewing, insluitende fisiese, chemiese en biologiese grond faktore, is uitgevoer as ‘n veldproef of twee verskillende grondtipes, op ‘Cripps’ Pink’ appels. Drie organiese deklae is ge-evalueer naamlik: kompos, ‘vermi-castings’ en houtspaanders, asook ‘n anorganiese geotekstiel materiaal deklaag, en vergelyk met ‘n kontrole van skoon bewerking. Die organiese behandelings het verbeterde fisiese kondisies (laer bulkdigtheid) in die swaarder grond, asook ‘n verlaging in temperatuur fluktuasies en algemene verhoging in grondtemperature gedurende die seisoene in beide persele tot gevolg gehad. Die geotekstiel behandeling het verhoogde grondvog-vlakke in die boonste 40 cm in beide persele tot gevolg gehad, alhoewel dit meer prominent in die swaarder grond was. In sanderige grondperseel, het die kompos behandeling hoër grondvog-vlakke in die boonste 40 cm getoon as die ander behandelings. Die ‘vermi-castings’ behandeling het die beste resultate in terme van verbetering van nutrient- vlakke in die swaarder grond behaal. Dit het ‘n betekenisvol hoër pH, P (fosfaat), N (stikstof), K (kalium), Mg (magnesium), Zn (sink), Mn (mangaan), B (boron), katioon uitruilings kapasiteit en sommige uitruilbare katione soos , Na+ (natrium ione), K+ (kalium ione) en Mg+ (magnesium ione) as die ander behandelings in die swaarder gehad. Die kompos behandeling het betekenisvol hoër Ca (kalsium) en Ca+ (kalsium ione) in die swaarder grond getoon. Die organiese behandelings, insluitend die houtspaander behandeling, het dus in die geval, konstant die beste resultate te opsigte van hoër nutriënt vlakke in die swaarder grond getoon. Inteenstelling met die swaarder grond, het geen behandling daarin geslaag om die grondvoedingstatus van die sanderige grond te verbeter nie, met uitsondering die verhoogde persentasie C as ‘n resultaat van die kompos en ‘vermi-castings’ behandelings. Die kompos behandeling het konstant hoër mychorriza-kolonisasie teweeg gebring in beide persele, alhoewel nie altyd betekenisvol hoër as die ander behandelings was nie. Die ‘vermicastings’ behandeling het konstant ‘n laer persentasie plant-parasitiese nematodes getoon. Meer vry-lewende nematodes het ook gereeld oor die totale vier jaar wat die volledige proef gestrek het, op beide persele, voorgekom. Die organiese deklae toon dus belowende resultate in terme van biota. Die organiese behandelings, met uitsondering van die ‘vermi-castings’ behandeling, het verhoogte wortel ontwikkeling en -verspreiding in die swaarder grond tot gevolg gehad, Die ‘vermi-castings’ behandeling het ‘n besondere goeie wortelomgewing geskep en ‘n verbetering in die wortelstelsel om ‘n goeie opbrengs en kwaliteit te behaal, was nie nodig nie. Daarinteen het die geotekstiel behandeling beter resultate in die meer sanderige grond behaal. Die geotekstiel behandeling het ook die laagste onkruidstand in beide persele gehad. Opbrengs, in die swaarder grond, en die voorkoms van sonbrand in beide persele, is beïnvloed deur die dekgewasse. In die swaarder grondperseel het die houtspaanders behandeling die hoogste opbrengs getoon en die kompos behandeling, konstant die hoogste voorkoms van sonbrand. In die ligter, sanderige grondperseel, is die hoogste sonbrand voorkoms gemeet in die kontrole behandeling. Die ‘vermi-castings’ behandeling het die laagste sonbrand voorkoms getoon. Weens die beperkte kwantifisering van die besproeiing in die proef, is die gevolge van besproeiing op verskillende deklae nie ondersoek nie en behoort dit oorweeg te word in toekomstige navorsing.

Background and purpose: Rhizoma Chuanxiong (CX), the dry rhizome of Ligusticum chuanxiong Hort., is a commonly used Chinese herbal medicine to treat gynecological diseases. So far, more than 60 chemical components have been identified from CX such as volatile oils (ligustilide, etc.), phenolic acids (ferulic acid, etc.) and alkaloids (chuanxiongzine, etc.). These components in CX are the basis of its wide pharmacodynamic actions including estrogen-like, progesterone-like and anti-coagulant/anti- platelet effects. In our recent survey based on previous published clinical trials, CX was ranked as one of the top 20 herbs commonly used for anti-miscarriages amongst Chinese pregnant women. However, CX should be used with caution during pregnancy as its property of 2invigorating blood circulation and removing blood stagnation3. Despite its wide applications, the safe dosage of CX in pregnant women remains unclear with no records found in the current Chinese Pharmacopoeia or other guidelines. Thus, verification regarding the impacts of CX preparations and its components in embryonic development is urgently required. In view of the limited experimental evidence that is currently available to assess the safety of CX, this project aims to (1) identify the general impacts of CX aqueous extract in maternal function and fetal development with an in vivo mouse model; and to (2) investigate the adverse impacts and underlying mechanisms of CX aqueous extract in fetal bone development with a biomarker assay and metabolomics analysis.;Concusion: CX aqueous extract at a low dosage of 2 g/kg/day (equals to the daily dosage of human adults) did not cause adverse effect in pregnant mice, and it suggested that this dosage of CX preparations should be safe for pregnant women. Our data demonstrated that high dosage and long-term use of CX aqueous extract might result in embryonic toxicities including fetal bone malformations for the first time. As the CX aqueous extract in this study was not contaminated by pesticide residues and heavy metals, the adverse impacts of CX aqueous extract should be considered as a result of its intrinsic components in the herb. Furthermore, CX aqueous extract might significantly down-regulate biomarkers related to bone formation and metabolism during osteogenesis. It is therefore valuable to establish a practical approach to systematically assess the safety of CX and other herbal medicines.;Method: Referred to the guidelines of WHO, the Chinese Pharmacopoeia and the Hong Kong Chinese Materia Medica Standards, CX aqueous extract was prepared, and its reference marker (ligustilide and ferulic acid) were quantitatively authenticated by HPLC analysis. LC/MS fingerprint analysis was performed for the quality control purposes. In addition, pesticide residues and heavy metals found in CX aqueous extract were examined using GC-MS and ICP-MS analysis. In the Segment II study as per FDA and OECD guidelines, pregnant mice were randomly assigned into 6 groups (n=18 per group): i.e. mice were orally administrated with distilled water as the negative controls (Group 1); or CX aqueous extract of 2, 16, 24 and 32 g/kg/day respectively from the gestation day (GD)6 to 16(Group 2, 3, 4 and 5); or vitamin A (200,000 IU) on GD7, 9 and 11 as the positive controls (Group 6). All mice were sacrificed to assess maternal and fetal parameters on the GD18. In the mechanistic study, the expressions of biomarkers related to fetal bone development including PICP, ICTP, B-ALP, BGP, Gdf-5, BMPs, BMP-6, BMP-8, BMP-11, IL-4, IL-4r, IL-10 and IL-10r in fetal tissue samples of the Group 1 and 5 (32 g/kg/day, n=18) were measured using ELISA analyses on GD16. Meanwhile, the metabolites of two-group samples were also analyzed by the UHD Accurate-Mass Q- TOF LC/MS, and profiling data was further analyzed by specific software. During statistical analysis, measurement data from G1, 2, 3 4 and 5 groups were analyzed using one-way ANOVA(SPSS software, version 16.0). LSD test in Post hoc method was applied to compare differences between every two groups. Pearsons x 2 - test was used to analyze category data from G1, 2, 3, 4 and 5 groups, and Fishers exact test was applied to compare differences between different groups. The student t-test was also used to compare differences between G1 and G6 groups in animal studies as well as G1 and G5 groups using ELISA or metabolomics results. An intragroup difference with a p-value less than 0.05 was considered as statistical significant.;Resutt:(1) There was no statistical significant difference in maternal and fetal parameters found between the Group 1 and 2 (p> 0.05). However, the maternal body weight (BW), gravid uterine weight, corrected BW change, live fetus/litter, mean fetal BW in the Group 4 and 5 were significantly lower than those in the Group 1(p

Orientador: Idomeo Bonetti Filho / Banca: Mario Tanomaru Filho / Banca: Fábio Luiz Camargo Villela Berbert / Banca: Giulio Gavini / Banca: Oscar Faciola Pessoa / Resumo: O objetivo deste estudo foi avaliar o efeito da velocidade de deslocamento na resistência à fratura por fadiga de instrumentos rotatórios de níquel-titânio por meio de ensaio dinâmico de flexão. Foram avaliados instrumentos S1, S2, F1, F2 e F3 pertencentes ao Sistema ProTaper Universal (Dentsply/Maillefer) sendo 20 de cada número num total de 100 instrumentos, que foram divididos em dois grupos. Todos os instrumentos foram submetidos a ensaio de flexão por meio de um dispositivo elaborado especificamente para este estudo. O aparato para teste foi composto por um canal artificial curvo, fabricado em aço inoxidável temperado e que apresentava 5mm de raio e ângulo de curvatura de 45º. Um motor elétrico X-Smart (Dentsply/Maillefer) com um contra-ângulo com redução de 16:1 foi regulado para trabalhar à uma velocidade constante de rotação de 300rpm e com um torque de 2 N.cm. A este contraângulo foram acoplados os instrumentos ProTaper Universal que foram introduzidos no canal artificial e ali giraram livremente até sua fratura. O aparato regulava a velocidade de deslocamento axial do canal artificial para frente e para trás, na direção dos instrumentos, simulando a entrada e saída dos instrumentos no canal radicular. Foram utilizadas duas velocidades de deslocamento do canal simulado, sendo que os instrumentos do Grupo I foram submetidos à uma velocidade mais lenta (146 deslocamentos por minuto) e no Grupo II a velocidade foi mais rápida (189/min). O tempo até a fratura foi registrado por um cronômetro e, a partir daí, encontrou-se o número de rotações para fratura. A comparação do número médio de ciclos até a fratura foi realizada por meio do teste t de Student para amostras independentes. Os resultados mostraram que ocorreu diferença estatisticamente significante do número médio de ciclos até a fratura apenas para o instrumento F3 (p=0,025)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the fracture strength under fatigue load of Nickel-Titanium rotatory endodontic instruments by means of a dynamic flexure strength test. The S1, S2, F1, F2 and F3 instruments from the ProTaper Universal System (Dentisply/Maillerfer) were evaluated. Twenty samples of each instrument, totalizing 100 samples, were divided in two groups. All instruments were submitted to the flexure strength test using a device specially developed for this study. The device was composed by a 45º sloped artificial root canal, made with tempered stainless steel, with radius of 5mm. An X-Smart (Dentisply/Maillefer) electric engine that had a contra-angle with rotatory reduction of 16:1 was stated to work with a constant speed of 300rpm and with a torque of 2N.cm. Each ProTaper Universal Instrument was individually attached to the contra-angle and then introduced into the artificial root canal where they rotate freely until failure. The test apparatus also has a potentiometer that was responsible to regulate the axial dislodgment speed of the artificial root canal forward and backward, against instruments direction, simulating the inward and the outward movement of the instruments into the real root canal. Two displacements speeds of the simulated root canal were used, so that the instruments in Group I were submitted to the slower speed (146 displacements per minute - d/min) and in Group 2 to the faster speed (189d/min). The time elapsed until failure of the instruments was chronometrically measured and registered; then, the number of rotations was calculated from this measurement. The comparison between the mean numbers of cycles until failure was done by the T-Student test. The results of this study showed statistically significant differences in the mean number of cycles until failure only for the F3 instrument (p=0.025). In Group I it was found about 201 fewer cycles... (Complete abstract click electronic access below) / Doutor

Este estudo prospectivo com base universitária buscou avaliar as taxas de sucesso clínico e radiográfico e fatores associados às falhas presentes em pulpectomias realizadas em dentes decíduos, por alunos de graduação de uma instituição de ensino. A amostra de conveniência foi composta por pacientes com idade entre 3 e 10 anos que buscaram atendimento na instituição e necessitavam de tratamento endodôntico. Os dados referentes ao tratamento como, por exemplo, tipo de dente envolvido (anterior ou posterior), condição clinica do dente, diagnóstico pulpar, utilização de EDTA após o preparo químico-mecânico, uso de medicação intra-canal, técnica utilizada para obturação do canal, qualidade da obturação realizada, tipo de material restaurador elegido (RC, CIVRM), número de avaliações e o tempo de consulta clínica foram coletados por um único avaliador em um prontuário específico para o procedimento endodôntico. Ainda, fatores potencialmente associados à falha do tratamento endodôntico também foram investigados incluindo sexo (feminino ou masculino), idade, Índice de Placa Visível (IPV) e Índice de Sangramento Gengival (ISG), número de dentes cariados, perdidos ou obturados (CPOD) e ainda o comportamento da criança durante o atendimento. Curva de sobrevida de Kaplan-Meier com teste de log-rank foi utilizada para analisar a longevidade das pulpectomias (p<0.005). Um total de 81 pulpectomias realizadas em 62 crianças com idade media de 5.6 anos (+-1.5) foram incluídas nas análises. A sobrevida das pulpectomias alcançou 62,9% aos 12 meses de acompanhamento, com taxa de falha anual (TFA) de 28,9% sendo que, a maioria das falhas ocorreu entre o primeiro e o terceiro mês de avaliação (p<0.001). Dentes restaurados com resina composta apresentaram maior longevidade do que aqueles tratados com cimento de ionômero de vidro resinoso (p=0.006). Não foi encontrada diferença estatística em outros parâmetros clínicos e individuais investigados. As pulpectomias realizadas em dentes decíduos por estudantes de graduação apresentaram baixa taxa de sucesso. / This prospective university-based study aimed to evaluate the success rate and factors associated to failure of pulpectomies performed in primary teeth by undergraduate students. The convenience sample comprised patients aged 3 to 10 years who were under care in the institution and underwent primary tooth pulpectomies. Treatment-related data, such as type of tooth involved (anterior or posterior teeth), presence of dental pain, tooth status, pulp diagnosis, EDTA treatment after chemic-mechanical preparation, use of intra-canal medicament, technique used for endodontic filling, quality of endodontic obturation, type of restorative material used (CR; RMGIC), number of appointments and consult time were collected by a single evaluator on a specific chart for endodontic procedure. Also, Factors potentially associated with treatment failure were also investigated, including gender (male; female), patient age, Visible Plaque (VPi) and Gingival Bleeding (GBi) index, decayed, missed and filled teeth (dmft), and child behaviour. Kaplan–Meier survival curve with log-rank test was used to analyze the longevity of pulpectomies (p<0.005). Lastly, 81pulpectomies placed in 62 children (5.6 1.5 years) were included in the analysis. The survival of restorations reached 62.9% up to 12 months of follow-up, with overall annual failure rate (AFR) of 28.9%, and the majority of the failures occurred in the first 3 months (p<0.001). Teeth restored with composite resin presented more longevity than those teeth restored with RMGIC (p=0.006). The use of two or more sessions to perform the endodontic treatment resulted in more failures (p=0.028). Patients presenting gingivitis (GBI>20%) experienced more failures in their pulpectomies (p=0.006). There were no significant differences for the others individual and clinical parameters tested. The pulpectomies of primary teeth performed by undergraduate students presented low success rates.

Os óleos essenciais de três espécies de Schinus foram avaliados quanto à sua atividade fitotóxica na planta alvo Arabidopsis thaliana. Para esse fim, utilizou-se a abordagem convencional, que avalia o efeito dos aleloquímicos sobre a germinação e o crescimento de plântulas, mas também buscaram-se novas técnicas para compreender o modo de ação dos voláteis, a saber o efeito sobre o enraizamento adventício e a análise da expressão de genes por PCR em tempo real. Adicionalmente, foi realizada a caracterização química dos óleos essenciais por cromatografia gasosa bidimensional, demonstrando que o óleo de S. lentiscifolius é principalmente constituído por sesquiterpenos, enquanto que os de S. molle e S. terebinthifolius apresentam maior quantidade de monoterpenos. Os três óleos essenciais afetaram a porcentagem de germinação, o índice de velocidade de germinação, o crescimento da raiz primária e o crescimento da parte aérea de A. thaliana, mas não apresentaram efeito sobre a expressão dos genes ANP1 e CDKB1;1. Os voláteis também afetaram o processo de enraizamento adventício da planta alvo de uma maneira dose-dependente, afetando o tempo médio de enraizamento e o crescimento da maior raiz adventícia, mas não afetou a porcentagem de enraizamento nem o número de raízes por microestaca. A adição de uma auxina não reverteu os efeitos fitotóxicos induzidos pelos voláteis, mas a adição de uma citocina contribuiu na recuperação do atraso do processo de enraizamento quando os óleos essenciais de S. lentiscifolius e S. molle foram utilizados. Além disso, o Trolox®, um potente antioxidante, contribuiu na recuperação parcial dos efeitos inibitórios causados pelos óleos essenciais, indicando que eles induzem estresse oxidativo. Adicionalmente, foi realizada a detecção histoquímica de peróxido de hidrogênio nas microestacas expostas aos óleos essenciais. Os resultados demonstram que os efeitos fitotóxicos dos voláteis ocorrem por diversos mecanismos, incluindo estresse oxidativo e efeito sobre fitormônios. Esse estudo demonstrou que, devido às diversas técnicas que podem ser aplicadas, A. thaliana é uma espécie útil para ser utilizada em experimentos que avaliem o potencial alelopático de produtos naturais. / The essential oils of three Schinus species were evaluated for phytotoxic activity using Arabidopsis thaliana as target species. It was used the conventional approach, evaluating allelochemical effects on seed germination and seedling growth. Additionally, it was also employed new techniques in allelopathic potential area to understand the modes of action of volatiles, as the phytotoxic effects on adventitious rooting and the analysis of expression of genes by RT-qPCR. Furthermore, chemical characterization of essential oils using two-dimensional gas chromatography was carried out. S. lentiscifolius essential oil is mainly composed by sesquiterpenes, whereas S. molle and S. terebinthifolius presented high amounts of monoterpenes. Essential oils affected the germination rate (%), speed of accumulated germination, primary root length and shoot length of A. thaliana. However, the expression of the genes ANP1 and CDKB1; 1 was not affected. Volatiles also interfere on A. thaliana adventitious rooting in a dosedependent manner. Inhibitory effects were observed on mean rooting time and root length. Rooting percentage and number of roots per microcuttings were not affected by volatiles. Addition of an auxin not reversed phytotoxic effects induced by volatiles, but the addition of a cytokinin contributed to A. thaiana recover from the effects on mean rooting time caused by S. lentiscifolius and S. molle essential oils. Furthermore, Trolox®, a potent antioxidant, contributes to the partial recovery of the inhibitory effects caused by essential oils, indicating that volatiles induce oxidative stress. Histochemical detection of hydrogen peroxide after essential oil exposure was also carried out. Results demonstrated that the phytotoxic activity of volatiles may occur by several mechanisms, including oxidative stress and effects on phytohormones. This study also demonstrated A. thaliana is a useful species to be used in allelopathic potential evaluations due to the different techniques that can be applied.

Six topics are presented, relevant to agricultural research on two horticultural varieties of Mirabilis expansa (Ruiz and Pav.) Standl. Chapter 1, “Review of the economic and ethno-botany of the genera of the family Nyctaginaceae," includes a summary of literature on the topics included in the title, and an original taxonomic update of plant names used correctly and incorrectly as synonyms for Mirabilis jalapa, the type name for the plant family Nyctaginaceae. M. jalapa has been substituted for medicinal jalap from Mexico. Names in the Convolvulaceae for medicinal Jalap are also updated here, as they show the origin of many names which have been incorrectly used as synonyms in the Mirabilis literature. Chapter 2, “History of Mirabilis expansa (Ruiz and Pav.) Standl.; Growth and use in the Andes,” is also a literature review, incorporating information from several documents and papers which have only recently become readily available internationally via the Internet. These documents were translated into English for this chapter. Research in Chapter 3, “Field trials of Mirabilis expansa (Ruiz and Pav.) Standl. grown in North America; Growth, yield and quality traits,” showed that M. expansa horticultural varieties 'L' and 'T' are tolerant to the intense weather conditions of southern Illinois, when grown on constructed sand plots. In Chapter 4, “Amino Acid profiles for two horticultural varieties of Mirabilis expansa (Ruiz and Pav.) Standl.: A rare indigenous Andean crop grown in southern Illinois,” M. expansa was examined for its amino acid values and those values considered in terms of differnces between the two varieties and above and below ground structures. In addition, soil amendments peat and steer manure, considered alone and together, as well as structure and variety, were examined for their effect on production of amino acids in ANOVAs and Tukey-adjusted LS-Means run in SAS 9.3. In Chapter 5, “Nutrients, Comparison of Amino Acid Profiles, and Cytotoxicity Testing for Mirabilis expansa (Ruiz and Pav.) Standl.,” the amino acid profiles for M. expansa from the previous chapter are compared to profiles for other crops, eggs and milk. M. expansa is shown relatively to contain extremely high amounts of total protein. In addition published values for other nutrients for M. expansa taken from translated material are combined into two tables. Also, a cytotoxicity assay carried out in collaboration with researchers at Ohio State University was used to see if the southern Illinois M. expansa material was active against highly sensitive HT-29 colon cancer cells. Negative results from that assay serves as preliminary data for a lack of toxicity due to micro-molecules in the crop. Chapter 6, “Inexpensive nitrogen chambers for conservation of herbarium specimens,” was an outgrowth of the need to find a chemically benign manner for storing herbarium specimens of Mirabilis, used in research which led to the work described in the previous chapters. The results show that valved oxygen barrier bags, designed for clothing storage, with a small number of oxygen absorbers, can retain conditions for sufficient periods to treat specimens for pests. This allows the bags to be used as inexpensive nitrogen chambers, to treat herbarium specimens in place of expensive nitrogen systems or freezers, and without the toxic chemicals historically used in herbaria for the same purpose.