Investigation of the relationship between the condensed structure and the chemically bonded water content in the network of geopolymer cements

The main objective of this work was to investigate the relationship between the condensed structure and the chemically bonded water content in the metakaolin-based geopolymer network. The kaolinite clay used in this work as an aluminosilicate source was transformed to metakaolin by calcination at 700 °C. The powder of the waste glass and the silica fume were used as silica sources for the synthesis of the hardeners. The obtained hardeners were characterized by infrared spectroscopy and MAS-NMR 29Si. The metakaolin and the hardeners were used for producing geopolymers cements. The synthesized products were characterized by X-ray diffractometry, infrared spectroscopy, mercury intrusion porosimetry, scanning electron microscopy, MAS-NMR 29Si and 27Al, thermal analyses (TG and DSC) and compressive strength. The results show that the compressive strength of geopolymer cements using hardener from silica fume and the one from waste glass are 62 and 26 MPa, respectively. The microstructure (SEM observations) geopolymer cements obtained using hardener from silica fume are homogeneous, compact and dense with an average pore diameter around 10 nm. Whereas, the one obtained using hardener from waste glass are heterogeneous and contains larger pores (170 nm). MAS-NMR 29Si and 27Al results show that the specimen obtained using hardener from the silica fume contains more aluminum in four-fold coordination in its network than waste glass geopolymer, GWG. This indicates a higher degree of crosslinking of poly(sialate-siloxo) chains which could lead to a smaller pore sizes and a higher water uptake in the structure of the sample. The amount of chemically bonded water contained in the network of geopolymer cements using hardeners from waste glass and silica fume were 6.82 and 11.23%, respectively, as determined from weigth loss in the range 100-300 °C. All these results indicate that the higher content of chemically bonded water in the network of geopolymer obtained using hardener from silica fume is related to the much smaller average pore size diameter and the hydrophilic character of aluminum, which reveals obviously better mechanical and microstructural properties of the specimen. This could indicate here a higher degree of condensation using silica fume based hardeners for geopolymerisation. Please click Additional Files below to see the full abstract

Current attitudes regarding the use of perioperative analgesics and routine anaesthetic management in dogs and cats by veterinarians in Cameroon

A survey was performed in 2017 to evaluate the use of perioperative analgesia and routine anaesthetic management in dogs and cats by Cameroon veterinarians in 19 veterinary clinics, including 7 and 12 in Douala and Yaounde, respectively. The questionnaire consisted of five sections recording demographic data, attitudes towards pain assessment and use of main analgesics in daily practices. Information about premedication, induction, maintenance and complications associated with anaesthesia in dogs and cats was also obtained. Only 15.79% of surveyed  veterinary surgeons had undergone specialization in surgery and 36% considered their methods of pain quantification and control to be inadequate. The major part of the studied population (52.63%) was above 40 years old. Evaluated by the  behavioural indicators (94.73%), animal pain is usually not quantified. The most used analgesics were glucocorticoids (dexamethasone, prednisone) and non-steroidal anti-inflammatory drugs (phenylbutazone, tolfenamic acid and meloxicam). The percentage of animals receiving analgesics postoperatively was 88.99% in dogs and 79.70% in cats. Few patients (28.72%) were weighed before applying anaesthesia. The most common monitored parameters were heart  (78.95%) and respiratory (73.68%) rates. The use of anaesthesia and the choice of analgesic molecules varied significantly from one town to another (p = 0.00), and from dogs to cats (p = 0.03). Acepromazine was the most common used  premedication in dogs and cats. Ketamine was the induction agent frequently used in dogs and cats. The complications that veterinarians encountered during   anaesthesia were awakening and cardiorespiratory arrest. The anaesthetic death rate was 0.63%. Some improvements, particularly during pre-anaesthetic  examinations and the use of perioperative drugs (analgesia and anaesthesia) can reduce the incidence of complications.Keywords: Pain, anaesthesia, analgesics, survey, cats, dogs, monitoring, Cameroon.  Attitude des vétérinaires vis-à-vis de l’utilisation périopératoire des analgésiques et surveillance anesthésique chez les chiens et chats au CamerounUne étude a été menée en 2017 afin d’évaluer l’utilisation périopératoire des analgésiques et la pratique de l’anesthésique chez les chiens et les chats par des vétérinaires privés du Cameroun. La collecte des données s’est faite dans 19 cliniques vétérinaires, dont 7 à Douala et 12 à Yaoundé. Le questionnaire était composé de cinq sections récoltant les données démographiques, les attitudes vis-à-vis de l’évaluation de la douleur et l’utilisation des principaux  analgésiques dans la pratique quotidienne. Des informations sur la  prémédication, l’induction, l’entretien et les complications associées à l’anesthésie chez les chiens et les chats ont également été obtenues. Seuls 15,79% des vétérinaires interrogés avaient subi une spécialisation en chirurgie et 36% ont considéré leurs méthodes de quantification et de contrôle de la douleur comme étant inadéquates. La majeure partie de la population étudiée (52,63%) était âgée de plus de 40 ans. Évaluée par les indicateurs  comportementaux (94,73%), la douleur animale n’est généralement pas quantifiée. Les analgésiques les plus utilisés étaient les glucocorticoïdes  (dexaméthasone, prednisone) et les anti-inflammatoires non stéroïdiens  (phénylbutazone, acide tolfénamique et méloxicam). Le pourcentage d’animaux recevant des analgésiques après l’opération était de 88,99% chez les chiens et de 79,70% chez les chats. Peu de patients (28,72%) ont été pesés avant  l’anesthésie. Les paramètres les plus fréquemment surveillés sont les fréquences cardiaque (78,95%) et respiratoires (73,68%). L’utilisation de l’anesthésie et le choix des molécules analgésiques varient  significativement d’une ville à l’autre (p = 0,00), et des chiens aux chats (p = 0,03). L’acépromazine était le prémédicant le plus couramment utilisé chez les chiens et les chats. La kétamine était l’agent d’induction anesthésique le plus fréquemment utilisé chez les chiens et les chats. Les complications rencontrées par les vétérinaires lors de l’anesthésie étaient le réveil pendant l’anesthésie et l’arrêt cardiorespiratoire. Le taux de mortalité anesthésique était de 0,63%. Cette étude suggère qu’un soin particulier soit observé, en particulier lors des examens préanesthésiques et l’utilisation périopératoire des médicaments (analgésique et anesthésique) afin réduire l’incidence des complications. Mots-clés : Douleur, anesthésie, analgésie, enquête, chats, chiens, surveillance, Cameroun

Typology of cattle farms in the northern regions of Cameroon

The aim of this study was to establish the typology of cattle farms in the northern regions of Cameroon in order to reveal structural and functional characteristics that could be selected for an artificial insemination program. A survey was carried out among 54 breeders. The results showed that the farmers were predominantly of the Fulani ethnic group (81.5%) with men prevailing (92.6%). Their levels of education were primary (31.5%), secondary (18.5%), and higher (25.9%). They were involved in full-time agricultural production activity (42.6%), cattle breeding and agropastoralism. Civil servants represented more than a third of the sample. The genetic structure of the herds was dominated by local breeds: 53.7% Gudali zebus, 44.4% Djafoun and 5.6% Akou. In addition, 44.4% of them bred crossbreeds and 16.7% Holsteins. A multiple correspondence analysis was performed to determine the typology of the farms studied. Based on the structural (herd size, forage area, dairy productivity per cow per day, and related infrastructure) and functional (feeding, herd management, technological choice) characteristics of the farms, three types were identified. Type I breeders (37%) practiced the extensive system, and type II breeders (18.5%) the semi-intensive system. They were present in the Adamawa region and preferred natural mating (56%) and artificial insemination (100%), respectively, as a reproductive means. Type III breeders (44.5%) practiced the semi-extensive system. They were only present in the North and Far North regions and preferred (98%) natural mating as a reproductive means. Type II farmers were located in Vina Division (Adamawa) and they offered the best potentialities with the practice of artificial insemination. They may be considered as pilot for the revival of the dairy sector in this part of Cameroon

Pathological study of female reproductive organs of local zebus in Adamawa Region

Genital tracts of female zebus (n=501) collected from Ngaoundere Municipal Slaughterhouse (NMSH) were examined with respect to breed, age, body condition score (BCS) and physiological status. Out of these specimens, the pregnancy rate was 20.4%. A total of 292 (58.28%) specimens had abnormalities. Maximum pathological conditions were observed in the ovaries (39.6%), followed by those in the uterus (15.4%), oviduct (2.8%) and vulvo-vagina (0.6%). Pathological conditions observed in the ovaries included anoestrus (25.2%), repeat breeding (8.4%), ovarian cysts (3.8%), double and multiple ovulation (1.2%), oophoritis (0.4%), ovarobursal adhesions (0.4%) and ovarian abscess (0.2%) whereas, those in the uterus included mucometra (7.8%), metritis (5.6%), hydrometra (1.6%) and lymphosarcoma (0.4%). Oviduct abnormalities include parovarian cysts (1.4), hydrosalpinx (0.6), lymphosarcoma (0.4), salpingitis (0.2%) and double oviduct (0.2). A total of 54 female zebus (10.78%) had at least two abnormalities. The ovarian cystanoestrus (3.39%), mucometra - anoestrus (2.20%) and metritis - anoestrus (1.20%) associations were the most observed. The thin cows (body condition score 1-2) aged 4 to 8 years old were more predisposed to genital pathologies. Results of this study indicated that lesions of the female reproductive system represent a significant source of infertility.Keywords: zebu, ovaries, oviducts, uterus, abnormalities, Adamaw

Biometrical study of female reproductive tract (Bos indicus) in Cameroon

The study aims to determine the biometry of 501 genital tracts of local female zebus (Bos indicus) slaughtered at the Ngaoundere municipal slaughterhouse (Cameroon). Average length (cm), width (cm), thickness (cm) and weight (g) were 2.83 ± 0.03, 1.96 ± 0.02, 1.28 ± 0.01 and 5.17 ± 0.11 in right ovary; and 2.64 ± 0.03, 1.78 ± 0.02, 1.15 ± 0.01 and 4.02 ± 0.09 in left ovary, respectively. Using electronic Vernier calipers, 16957 follicles were counted with an average of 16.92 ± 0.32 follicles per ovary. Small (<3 mm), medium (3 to 8 mm) and large (> 8 mm) follicles were 8.53 ± 0.20, 8.06 ± 0.21 and 0.29 ± 0.02, respectively. 20.4% were pregnant. Regarding non pregnant animals, average oviduct, uterine horn, uterine body, cervix, vagina and vulva commissure lengths (cm) were 19.27 ± 0.14, 20.32 ± 0.20, 1.24 ± 0.02, 6.92 ± 0.08, 19.45 ± 0.08 and 4.91 ± 0.03, respectively. The diameters (cm) of cervix and vagina were 3.23 ± 0.04 and 3.49 ± 0.03, respectively. Younger (aged ≤ 4 years old) and thin (body condition score-BCS 1 and 2) animals presented smaller dimensions of genital tract compared to older with a BCS ≥ 3. The right ovaries were heavier in weight as compared to left ones. Pregnant animals presented a higher follicular population and ovaries with a corpus luteum were larger in dimensions. The results indicated that local female zebus in Cameroon had a particular genital biometry.Keys words: biometry, genital tract, local zebus, Ngaoundere, Cameroon

Evaluation of bovine (Bos indicus) ovarian potential for in vitro embryo production in the Adamawa plateau (Cameroon)

An abattoir study was conducted to evaluate the ovarian potential of 201 local zebu cattle from Ngaoundere, Adamawa region (Cameroon) for in vitro embryo production (IVEP). The ovaries were excised, submerged in normal saline solution (0.9%) and transported to the laboratory for a detailed evaluation. Follicles on each ovary were counted, their diameters (Φ) measured and were grouped into 3 categories: small (Φ < 3 mm), medium (3 ≥ Φ ≤ 8 mm) and large (Φ > 8 mm). Each ovary was then sliced into a petri dish; the oocytes were recovered in Dulbecco’s phosphate buffered saline, examined under a stereoscope (x10) and graded into four groups based on the morphology of cumulus oophorus cells and cytoplasmic changes of the oocytes. Grade I (GI): oocytes with more than 4 layers of bunch of compact cumulus cells mass with evenly granulated cytoplasm; grade II (GII): oocyte with at least 2-4 layers of compact cumulus cell mass with evenly granulated cytoplasm; grade III (GIII): oocyte with at least one layer of compact cumulus cell mass with evenly granulated cytoplasm; grade IV (GIV): denuded oocyte with no cumulus cells or incomplete layer of cumulus cell or expanded cells and having dark or unevenly granulated cytoplasm. The effects of both ovarian (ovarian localization, corpus luteum, size and weight of ovary) and non-ovarian factors (breed, age, body condition score (BCS) and pregnancy status of cow) on the follicular population and oocyte recovery rate were determined. There were an average of 16.75±0.83 follicles per ovary. The small, medium and large follicles were 8.39±0.60, 8.14±0.43 and 0.21±0.02 respectively. Oocyte recovery was 10.97±0.43 per ovary (65%). Oocytes graded I, II, III and IV were 3.53±0.19 (32.21%), 2.72±0.15 (24.82%), 2.24±0.15 (20.43%) and 2.47±0.20 (22.54%) respectively. The oocyte quality index was 2.26. Younger non pregnant cows having BCS of 3 and large ovaries presented higher number of follicles and oocyte quality (P < 0.05) compared with other animals. Oocytes with quality (grade I and II) acceptable for IVEP constituted 57.15% of the harvest. This study indicated that factors such as age, pregnancy status, BCS and ovarian size must be taken into account to increase the potential of the ovary for IVEP

Evaluation of the follicular population and oocyte quality of zebu cows (<em>Bos indicus</em>) with anovulatory anestrus

The study aimed to evaluate the ovarian follicular population and oocyte quality of local zebus with anovulatory anestrus. It was conducted at Ngaoundere municipal slaughterhouse, Adamawa region in Cameroon. Of the 496 genital tracts examined, 145 (29.2%) presented an anovulatory anestrus. The mean number of follicles per cow was 37.5 ± 25.2. The number of small, medium and large follicles per cow were 21.7 ± 18.7, 14.9 ± 12.1 and 0.9 ± 1.1, respectively. The mean follicular populations of cyclic or in anovulatory-anestrus cows were 29.1 ± 18.1 and 41.9 ± 27.3 (p  0.05) in cyclic and anestrus cows, respectively. The number of grade I, II, III and IV oocytes were 4.5 ± 4.1 (28.5%), 4.1 ± 3.7 (26.2%), 2.3 ± 2.4 (14.8%) and 4.8 ± 5.6 (30.5%), respectively. This study showed that anovulatory anestrus tended to enhance the follicular population but had no effect on the oocyte yield. The number of grade I and II oocytes acceptable for in vitro maturation were significantly lower in cows with anovulatory anestrus than in cyclic cows (p < 0.05)

Evaluation of bovine (Bos indicus) ovarian potential for in vitro embryo production in the Adamawa plateau (Cameroon)

An abattoir study was conducted to evaluate the ovarian potential of 201 local zebu cattle from Ngaoundere, Adamawa region (Cameroon) for in vitro embryo production (IVEP). The ovaries were excised, submerged in normal saline solution (0.9%) and transported to the laboratory for a detailed evaluation. Follicles on each ovary were counted, their diameters (Φ) measured and were grouped into 3 categories: small (Φ &lt; 3 mm), medium (3 ≥ Φ ≤ 8 mm) and large (Φ &gt; 8 mm). Each ovary was then sliced into a petri dish; the oocytes were recovered in Dulbecco’s phosphate buffered saline, examined under a stereoscope (x10) and graded into four groups based on the morphology of cumulus oophorus cells and cytoplasmic changes of the oocytes. Grade I (GI): oocytes with more than 4 layers of bunch of compact cumulus cells mass with evenly granulated cytoplasm; grade II (GII): oocyte with at least 2-4 layers of compact cumulus cell mass with evenly granulated cytoplasm; grade III (GIII): oocyte with at least one layer of compact cumulus cell mass with evenly granulated cytoplasm; grade IV (GIV): denuded oocyte with no cumulus cells or incomplete layer of cumulus cell or expanded cells and having dark or unevenly granulated cytoplasm. The effects of both ovarian (ovarian localization, corpus luteum, size and weight of ovary) and non-ovarian factors (breed, age, body condition score (BCS) and pregnancy status of cow) on the follicular population and oocyte recovery rate were determined. There were an average of 16.75±0.83 follicles per ovary. The small, medium and large follicles were 8.39±0.60, 8.14±0.43 and 0.21±0.02 respectively. Oocyte recovery was 10.97±0.43 per ovary (65%). Oocytes graded I, II, III and IV were 3.53±0.19 (32.21%), 2.72±0.15 (24.82%), 2.24±0.15 (20.43%) and 2.47±0.20 (22.54%) respectively. The oocyte quality index was 2.26. Younger non pregnant cows having BCS of 3 and large ovaries presented higher number of follicles and oocyte quality (P &lt; 0.05) compared with other animals. Oocytes with quality (grade I and II) acceptable for IVEP constituted 57.15% of the harvest. This study indicated that factors such as age, pregnancy status, BCS and ovarian size must be taken into account to increase the potential of the ovary for IVEP.Keywords: Adamawa breed, Embryo, Follicular population, Oocyte quality, Ovar