1) Although the expression of pSmad 1/5/8 was decreased in cases

1). Although the expression of pSmad 1/5/8 was decreased in cases of non-unions compared to fracture callus, it was still present in osteoblasts and hypertrophic chondrocytes of non-unions (Table 2 and Fig. 1, Fig. 2 and Fig. 3), confirming our previous report showing active BMP signaling in non-unions [8]. The expression of noggin and gremlin was present in all cell types of all specimens. On the other hand, BMP3 (generally referred to as a BMP-inhibitor)

and chordin were not expressed in chondrocytes (hypertrophic and non-hypertrophic) of non-unions. Results of the expression of Smad-6 and Smad-7 were mixed. Although both Smad-6 and Smad-7 are inhibitors, their expression did not follow the same pattern. When comparing sections http://www.selleckchem.com/products/AC-220.html of fracture callus with those of non-unions, our results showed increased expression of Smad-6 in osteoblasts, hypertrophic and non-hypertrophic chondrocytes of non-unions, Smad-7 showed equal expression in osteoblasts of both fracture callus and non-unions, while decreased expression in hypertrophic and non-hypertrophic chondrocytes of non-unions. Representative staining images are shown in Fig. 2 and Fig. 3. In general, results of double and triple immunofluorescence staining showed co-localization of BMP ligands with inhibitors, in all sections of both fracture callus and non-unions. There was also decreased staining of BMP2

in the non-unions (representative images are shown in Fig. 4, Fig. 5, Fig. 6, Fig. 7 and Fig. 8). A summary of the expression data is shown in Table 2. The results of this study PLX4720 support our hypothesis that the balance between expression of endogenous BMP ligands and BMP-inhibitors in non-unions is different than in normal fracture healing. Specifically, our results show that in chondrocytes, expression of BMP2 was markedly decreased in non-unions and that of BMP7 was almost completely absent. On the other hand, expression of BMP-inhibitors (noggin, gremlin, Smad-6 and Smad-7) was almost the same in osteoblasts, chondrocytes and fibroblasts Cepharanthine of both fracture callus

and non-unions. Although these data are consistent with our hypothesis, we had expected that this “imbalance” was due to an increased expression of BMP-inhibitors in non-unions. The current data suggest, however, that it is due to decreased expression of BMPs. In our previous study on delayed and non-unions, we demonstrated that BMP2, BMP4 and BMP7, BMPRs and pSmad 1/5/8 were present in most non-unions in osteoblasts and fibroblasts [8]. However, in that study, we did not specifically analyze the expression of these BMP-related proteins in cartilage cells and we did not compare our findings with those of normal fracture healing. The concept of imbalance between BMP ligands and their antagonists, being a potential cause of the development of non-unions, was first suggested by Niikura et al.

Exatamente uma hora após a administração da substância, cada anim

Exatamente uma hora após a administração da substância, cada animal foi morto por inalação de éter com retirada subsequente do tubo digestivo para análise cintilográfica da distância percorrida pelo traçador no tubo digestivo. Em nenhum dos 34 tubos digestivos dissecados foi evidenciada a presença Y 27632 da substância radioativa no ceco, ou seja, uma hora após a administração do traçador por gavagem, somente o intestino delgado dos animais foi alcançado pelo mesmo, conforme avaliação pela cintilografia. Nos 17 pares de animais avaliados simultaneamente (grupo controle e experimental) notou‐se que o traçador percorreu uma distância maior no tubo

digestivo, durante uma hora, em 12 animais do grupo controle contra 5 animais no grupo experimental. Ao limitar em 75% (3/4 do tubo digestivo) percorrido pelo traçador, nota‐se que apenas 6 animais do grupo controle tiveram mais de 75% de seu trato digestivo percorrido ABT-199 cell line pela substância radioativa (ratos 1E, 9E, 11E, 15E, 17E e 20E), enquanto no grupo controle o número de animais que tiveram mais de 75% do tubo digestivo percorrido pelo traçador foi maior, ou seja, 11 animais (ratos 6C, 7C, 12C, 18C, 11C, 13C, 15C, 16C, 14C, 17C e 20C). A ordem dos animais citados anteriormente obedeceu ao esquema de injeção

da substância, podendo ser acompanhada com mais detalhes nas Tabela 1 and Tabela 2. As medidas do tubo digestivo de cada animal foram calculadas na processadora de imagens, assim como o percentual da distância percorrida pelo traçador. O animal do grupo experimental com maior quantidade de migração pela substância radioativa no tubo digestivo foi o rato 1E, com 85,9% de migração, explicada da seguinte forma: 110,9 cm de tubo digestivo, sendo que 95,3 cm foram marcados pela substância. Por

outro lado, o animal do grupo experimental com menor migração foi o rato 12E, isothipendyl com 52,5% de migração (125,5 cm de tubo digestivo, mas apenas 65,9 cm de marcação pelo traçador). O rato 10E apresentou o tubo digestivo mais longo com 132,2 cm enquanto o rato 3E revelou o tubo digestivo mais curto com 100,8 cm. Todos os dados são mostrados na tabela 1 O animal do grupo controle com maior quantidade de migração pela substância radioativa no tubo digestivo foi o rato 14C, com 86,9% de migração, explicada da seguinte forma: 126 cm de tubo digestivo, sendo que 109,5 cm foram marcados pela substância. Por outro lado, o animal do grupo controle de menor migração foi o rato 5C, com 67% de migração (107,8 cm de tubo digestivo, mas apenas 72,2 cm de marcação pelo traçador). O rato 4C apresentou o tubo digestivo mais longo com 131,5 cm enquanto o rato 5C revelou o tubo digestivo mais curto com 107,8 cm. Todos os dados são mostrados na tabela 2.

, 2002 and Marshall and Schuttenberg, 2006) Reefs with effective

, 2002 and Marshall and Schuttenberg, 2006). Reefs with effective management that minimises anthropogenic stresses are likely to have higher resilience than reefs that are already experiencing multiple stressors (West and Salm, 2003). Cumulative effects from or on related (adjacent) ecosystems such as mangroves and seagrass meadows (including effects from maintenance Nutlin-3a dredging cycles) may also have indirect consequences for the

coral reef ecosystem. This is particularly so for ecological processes, functions and reef species that have important inter-linkages with mangrove and seagrass systems (Hemminga et al., 1994, Adams et al., 2006 and Pollux et al., 2007). The timing of the dredging and

construction activities may also affect the severity of impact, depending on the degree of seasonality and day–night cycles characterising the particular reef. Impacts during, or shortly prior to and after spawning events are of particular concern, since not only Selleckchem STA-9090 adult organisms may be negatively affected, but recruitment for the entire season may be jeopardised. While sedimentation certainly is a major stressor that can lead to significant coral mortality, strong, isolated sediment pulses need not necessarily kill a reef. Many reefs, and certainly corals in most settings, can indeed survive repeated, even severe, sediment input (Browne et al., 2010). One of the most important factors mitigating against permanent damage is strong water motion, either by surge or by currents, that serves to re-suspend and remove the sediment from the corals (Stafford-Smith and Ormond, 1992, Riegl, 1995, Riegl et al., 1996 and Schleyer and Celliers, 2003). As long as the coral’s surface is free from sediment, regeneration is relatively easily achieved,

even if damage occurred. A continuous cover of sediment on corals may lead to beginning tissue necrosis within 24 h in sensitive coral species, while in tolerant species there may still be no signs of necrosis after very 14 days (Table 8). This process is particularly readily observed in soft corals. Once the sediment has been removed, however, even if tissue necroses have occurred, regeneration can take place in the space of only a few weeks (Meesters et al., 1992). Strong currents can aide passive sediment-clearing. Purely oscillating currents or surge, while temporarily cleaning colonies, may not help overall since sediments will build up around the corals and eventually smother them.

Importantly, lentiviral vector-mediated expression of the β2 subu

Importantly, lentiviral vector-mediated expression of the β2 subunit in prelimbic neurons completely restored the attention deficits, revealing a crucial role for β2 subunit-containing heteromeric channels in sustained attention [38]. In contrast to CSF-1R inhibitor β2-KO mice, mice lacking α5 subunits (α5-KO)

had decreased accuracy, but not a decreased omission rate in the 5CSRTT [39]. Nicotinic excitability in layer VI pyramidal neurons is reduced in α5-KO mice and eliminated in β2-KO, and muscarinic responses are enhanced in both β2-KO and α5-KO mice [40]. Thus, the imbalance of muscarinic and nicotinic excitation may in part account for the differential attention deficits in β2-KO and α5-KO mice [40]. α7-KO mice exhibit attention deficits and impulsivity in the 5CSRTT, although the

phenotypes could be paradigm-dependent 41, 38 and 42]. In an attention set-shifting task and a working memory test with CX-4945 in vitro a radial arm maze, α7-KO mice exhibit delayed procedural learning, which may be the central problem of developmental coordination disorders that are comorbid with ADHD [10]. Stergiakouli et al. argued for the role of α7 subunits based on copy number variation and genome-wide association studies using ADHD samples [43]. Fragile X syndrome (FXS), which is caused by the mutation in the X-linked gene FMR1, is the most inherited form of mental retardation and the leading cause of autism [44]. The majority of FXS patients, particularly boys, present with ADHD, and the ADHD symptoms represent a

significant problem for FXS patients [45]. FMR1 encodes fragile X mental retardation protein, an RNA-binding protein that regulates protein synthesis, and its lack in Fmr1-KO mice results in wide range of synaptic abnormalities, possibly via metabotropic glutamate receptor signaling pathways 44 and 46]. In the 5CSRTT, Fmr1-KO mice exhibit an increase in inaccurate responses and omission errors, suggesting attention ID-8 deficits, and an increase in premature responses, indicating impulsivity [47], although conflicting observations have also been reported [48]. It is noteworthy that these studies used mice with different genetic backgrounds. Fmr1-KO mice showed poor performance in an attention set-shifting task [49]. Interestingly, a role for Gmr5 is supported by findings from a human study [16••]. Actin is abundant in presynaptic and postsynaptic structures, and its dynamics have a central role in neuronal circuit development and activity-dependent plasticity 50 and 51]. Actin depolymerizing factor (ADF)/cofilin family members have essential roles in actin dynamics.

, 2008, Deli et al , 2005 and Tóth et al , 2011) The key feature

, 2008, Deli et al., 2005 and Tóth et al., 2011). The key features of the adult BBB result from a sequence of cell:cell learn more interactions during development between the ingrowing vessel sprouts and the associated cells of the NVU (Liebner et al., 2011). When brain microvessels are isolated from adult mammalian brain and brain endothelial cells are cultured from these vessel fragments, they retain many key features of the BBB phe-notype. In 1969, Siakotos and colleagues described for the first

time a method to successfully isolate bovine and human brain endothelial cells (Siakotos et al., 1969). Nearly a decade later, Panula et al. demonstrated the migration of rat brain endothelial cells from isolated capillaries. These cells were able to grow in culture and had strong alkaline phosphatase activity (Panula et al., 1978). Tontsch and Bauer (1989) simplified the culture methods for isolating murine and porcine brain endothelial cells (e.g. avoiding sieving steps, gradient centrifugations) and optimised the culture medium to increase cell yield. They also found that when proliferative factors such as endothelial cell growth supplement (ECGS) and heparin were removed from culture medium, the morphology of cells changed from spindle-shape to cobblestone phenotype. Through a series of experiments, DeBault and Cancilla gave evidence for the influence of

astrocytic factors on BBB phenotype of brain endothelial cells (DeBault and Cancilla, 1980a, DeBault and Cancilla, 1980b and DeBault, 1981). These studies led to the development of co-culture models of the BBB (Joó, Selleck AZD4547 1985). We chose to develop a porcine BBB model for several reasons: (1) A single pig brain gives a high yield of cells compared to that from rat or mouse. (2) Porcine brains are relatively easy to obtain as they are

a by-product of the meat industry; there is no need to have animal breeding facilities PRKACG on site to maintain a continuous supply of brain tissue. (3) Porcine brain endothelial cells (PBECs) generally retain many key features of the BBB following isolation, and the rate of loss of BBB phenotype in culture is less than for rodent or bovine BBB models (Deli et al., 2005), therefore co-culture with astrocytes is not essential to induce functional expression of tight junctions (i.e. high TEER) (Patabendige et al., this issue). (4) The porcine genome, anatomy, physiology and disease progression reflect human biology more closely than many established laboratory animals (Walters et al., 2011). (5) The availability of miniature pigs and novel porcine transgenic disease models make the pig the most suitable animal model to study human disease (Bendixen et al., 2010 and Lunney, 2007). The miniature pig is now a well established ‘large’ mammalian model for pharmacokinetics/toxicology studies (Bode et al., 2010) and is also used for surgical studies to generate organs for xenotransplantation (Vodicka et al., 2005).

Dnmt2 was one of the first cytosine-5 RNA methylases identified i

Dnmt2 was one of the first cytosine-5 RNA methylases identified in a multicellular organism [16••]. Although Dnmt2-mediated methylation of cytosine 38 in the

anticodon loop of tRNAAsp was conserved in plant, flies and mice, none of these organisms lacking the functional Dnmt2 protein displayed any morphological differences to their wild-type counterparts [16••]. In contrast, morpholino-mediated loss of Dnmt2 in zebrafish reduced the size of the morphants by half and specifically affected liver, retina and brain development due to a failure to conduct late differentiation [17]. Over-expression of Dnmt2 on the other hand prolonged the life span of Drosophila by more than 50% and increased the resistance to stress

[ 18]. In line with these studies, Drosophila Dnmt2 loss-of-function Ipilimumab datasheet selleck chemicals mutants showed reduced viability under stress conditions, and Dnmt2-mediated methylation protected tRNAs from stress-induced ribonuclease cleavage ( Figure 1a) [ 9]. Cleavage of tRNAs is a conserved response to several stress stimuli in eukaryotes and the tRNA fragments are produced to repress translation by displacing translation initiation and elongation factors from mRNAs or by interfering with efficient transpeptidation [19, 20 and 21]. However, whether and how increased tRNA cleavage in Drosophila Dnmt2 mutants is directly linked to stress tolerance and protein translation is currently unknown. While tRNA cleavage is mediated by angiogenin in mammals, the only identified tRNA nuclease in Drosophila so far is Dicer [ 22]. Interestingly, also N-acetylglucosamine-1-phosphate transferase expression of Dicer is down-regulated by oxidative stress and Dicer knockout cells can be hypersensitive towards oxidative stress whereas its over-expression confers stress resistance

[ 23]. Other functions that have been linked to Dnmt2 but may be independent of its tRNA methyltransferase activity are silencing of retro-transposons and control of RNA viruses in Drosophila as well as RNA-mediated paramutations in the mouse [ 24]. Together, these data implicate that Dnmt2 is functionally redundant for normal development of most multicellular organisms but implicated in cellular stress responses at least in adult flies [ 24]. At least two more enzymes NSun2 and NSun4 can generate 5-methylcytidine in RNA in mammals (Figure 1a and b) [25 and 26]. Both belong to the S-Adenosylmethionine (AdoMet)-dependent methyltransferase superfamily and at least five more putative m5C RNA methylases in mammals (NOP2, NSun3, and NSun5–7) are predicted to methylate RNA based on sequence conservation of key catalytic residues [12]. Although the substrate specificities are unknown, NSun1 and NSun5, in addition to NSun2 and Nsun4, have been identified as mRNA-binding proteins [27].

, 1996, Majchrowski, 2001 and Woźniak and Dera, 2007) The relati

, 1996, Majchrowski, 2001 and Woźniak and Dera, 2007). The relationship between the number of quanta and the energy of the light absorbed by phytoplankton pigments is given by the so-called quantum equivalent of light energy X, which is equal to the ratio of the number of quanta absorbed to the sum of their energies. By taking this equivalent X into account, we can calculate the energy efficiencies of fluorescence Rfl and ATM/ATR phosphorylation rfl on the basis of the corresponding quantum yields of this process Φfl and qfl, using the equations given in Table 1 (lines 1, 2). For these calculations, we take the value of X that we calculated for the

light absorbed by all phytoplankton pigments 1. using the equations from the earlier comprehensive light-photosynthesis model ( Woźniak et al. 2003). The vertical distributions of X in sea waters of different trophic types and at different depths

in the upper water layers, of thicknesses from 1 to 2 times the depth of the euphotic zone, are given in Figure 2. From the characteristics of the variability of X it becomes clear that the energy efficiencies of chlorophyll Epigenetics inhibitor a fluorescence (Rfl and rfl) are usually somewhat lower than the quantum yields of this process (Φfl and qfl), especially in oligotrophic, mesotrophic and weakly eutrophic basins. Again, the energy efficiencies of photosynthesis (Rph and rph) are usually some four times smaller than the corresponding quantum yields of the process (Φph and qph). This is because a minimum of eight quanta from all the light quanta absorbed by PSP molecules (together with the chlorophyll a molecules at the photosynthetic reaction centres) are required to close off the cycle of endoenergetic chemical

reactions in photosynthesis leading to the assimilation of one atom of carbon, even though not BCKDHA all of the energy of these eight quanta is utilized in these reactions ( Govindjee, 1975 and Najafpour, 2012). The energy equivalent of organic carbon kep contained in various organic substances may fluctuate within quite wide limits, depending on the type of substance involved. For substances photosynthesized by phytoplankton this equivalent kep ≈ 40 kJ g− 1 ( Koblentz Mischke et al. 1985). This calculation shows that for one atom of carbon to be assimilated, that is, for it to be bound in an organic form, the energy contained in two quanta of light from the visible spectrum is more than sufficient. The resulting relationships between the energy efficiencies (Rph and rph) and quantum yields (Φph and qph) of the photosynthesis of phytoplankton in the sea are given in Table 1, lines 2 and 4. Likewise, the efficiencies of the conversion of pigment molecule excitation energy into heat (in the radiationless and nonphotochemical dissipation of this energy) RH and rH differ from the quantum yields of these processes ΦH and qH.

Vitrification has become a method of choice for hESCs and other d

Vitrification has become a method of choice for hESCs and other delicate cell types because of high survival rates and good functionality after thawing [21], [29], [41], [50] and [51]. However, disadvantages of current vitrification-protocols are the small numbers of colonies that can be vitrified at the same time (about 5–10 hESC-clumps) and enzymatic stress due to detachment of cell clumps. Additionally, success is highly dependent on the expertise of the researcher. Handling is difficult and there can be significant cell loss caused by inaccurate incubation times in the highly toxic cryopreservation media [25], [26], [27], [42] and [47]. Vitrification in straws for example

is quite challenging when it comes to transferring the cell ICG-001 clumps into different CPA solutions manually, while maintaining exact incubation times or recovering the few cell clumps from the warming solutions after thawing. Other vitrification principles, e.g. cryoloop vitrification, are only designed to vitrify very few samples at a time, while those developed for more colonies suffer from sterility issues or complicated workflows including manual colony detachment which make them unsuited for automated throughput systems. Although the recently introduced surface-based cryopreservation technique resulted in very high learn more post-thawing survival

rates and low differentiation, it still has Cytidine deaminase limitations that need to be overcome. To achieve the very rapid cooling and warming rates that are needed to successfully

vitrify and devitrify the cells, the samples were immersed directly into liquid nitrogen [5] and [49]. However, the non-sterile properties of liquid nitrogen increase the risk of contamination and infection and can lead to a propagation of contamination from one sample to another [7], [10], [15], [32] and [33]. Even though sterile liquid nitrogen sources are available, maintaining sterile working conditions remains expensive and awkward [35] and [36]. Hence, the development of a successful sterile cryopreservation method for bulk quantities of hESCs is highly appreciated. Also, the technique on modified Thermanox© slides is error prone due to difficult handling issues, overlapping of the discs and the need to explicitly cultivate the cell samples on the modified discs prior to cryopreservation and storage. Therefore this technique needs improvements in sterility, handling, and practicability. The aim of this study was to develop a new cryopreservation technique using a combined cultivation and cryopreservation device. The technique should enable the cultivation of hESCs on a cell culture surface in combination with an efficient vitrification of the adherent stem cell colonies, including the feeder layer, without direct contact with liquid nitrogen.

Purified CD4+ (~ 97%) and CD8+ T (~ 98%) cells were isolated from

Purified CD4+ (~ 97%) and CD8+ T (~ 98%) cells were isolated from the PBMCs using anti-CD4 and anti-CD8 mAbs conjugated MACS beads. PBMCs (5 × 106 cells/ml) or purified CD4+ and CD8+ T cells (1 × 106 cells/ml) in RPMI 1640 supplemented with 10% FCS were stimulated Selleckchem CHIR-99021 with

either 5 μg/ml PHA, co-stimulated with plate bound 5 μg/ml anti-CD3 (OKT3 mAb) and 2.5 μg/ml anti-CD28 in the absence or presence of caspase inhibitors for various time periods in an atmosphere of 5% CO2 in air at 37 °C. Proliferating T cells were derived by activating purified CD4+ and CD8+ T cells with PHA for 24 h and then reseeded in media supplemented with rIL-2 (25 Units/ml). The activated T cells were cultured for 7 days prior to use. The human leukemic

T cell line, Jurkat, clone E6-1 (ATCC) were maintained in logarithmic phase of growth in RPMI 1640 supplemented with 10% FCS and 2 mM L-Glutamine in an atmosphere of 5% CO2 in air at 37 °C. To induce apoptosis, Jurkat T cells (1 × 106 cells/ml) or activated T cells (1 × 106 cells/ml) in complete medium were stimulated with recombinant Flag-tagged FasL (100 ng/ml) followed by cross-linking with anti-Flag (1 μg/ml) for 16 h. Apoptotic cells were determined using RG7422 mouse UV microscopy, annexin V staining and TMRE labelling of mitochondria as previously described (Jayaraman, 2005 and Johnson et al., 2000). Cell viability was determined by suspending treated cells in 500 μl ice-cold PBS with 10 μl of 20 μg/ml propidium iodide (PI) and the uptake of PI was analysis using flow cytometry. T cell proliferation following mitogen clonidine stimulation was determined using [3H]-thymidine incorporation. In brief, PBMCs or purified T cells were seeded at 1 × 106 cells/ml

in 96 well plates and stimulated with either PHA (5 μg/ml) or co-stimulated with anti-CD3 mAb (5 μg/ml) and anti-CD28 mAb (2.5 μg/ml) in the presence or absence of caspase inhibitors. The cells were cultured for 72 h with the last 16 h pulsed with [3H]-labelled methyl-thymidine (0.037 MBq) prior to harvest onto glass fibre filter mats using a Tomtec automated multi-well harvester (Perkin Elmer Life Sciences, Boston USA). Wallac Betaplate scintillation reagent (Perkin Elmer Life Sciences) was added to the glass fibre filter mats and the radioactivity was determined on a 1450 Microbeta liquid scintillation counter (Perkin Elmer Life Sciences, Boston USA). T lymphocyte division following mitogen stimulation was determined using CFSE labelling of the cells (Lyons and Parish, 1994). In brief, PBMCs were suspended in PBS at a density of 5 × 107/ml and incubated with 5 μM CFSE at 37 °C for 10 minutes. Following incubation with CFSE the labelled PBMCs were washed twice in RPMI to remove excess CFSE. The CFSE labelled cells were treated with mitogens as previously described in the presence or absence of caspase inhibitors.


α is the thermal expansion coefficient, taken to be


α is the thermal expansion coefficient, taken to be 3.2 × 10− 4 °C− 1 and cp = 3.98 J g− 1 °C− 1 (salinity ≈ 39.5‰ and temperature 28.5°C); Various studies relating to water column conditions have been carried out in different areas. Holloway (1980) considers thermal stratification in a water body subjected to atmospheric heating and wind-induced vertical mixing. Simpson et al. (1990) discuss how buoyancy input as fresh water exerts a stratifying influence in estuaries and adjacent coastal waters. Liu (2007) found that, in the Bohai Sea, stratification comes into existence in April, peaks in July and decays towards October. Buranapratheprat et al. (2008) discuss the water column conditions

in the upper check details Gulf of Thailand based on surface heat flux, river discharge, tidal and wind mixing. They show that stratification develops in May because of surface heating and is dominant in October due to the large river discharge. Monthly variations VX-809 clinical trial of the surface heat fluxes are taken from Ahmad et al. (1989) and the results are reproduced in Figure 2 along with the net surface heat flux. Wind speed data (1990–2000) for Jeddah airport are provided by PME (Presidency of Meteorology and Environment) of Saudi Arabia. The monthly averages of wind speed are plotted in Figure 3a. The hydrographic data and the tidal current speeds are from Ahmad et al. (1997). The measured tidal current velocities are also plotted in Figure 3b and the temperature and salinity for the months of April and September 1997 for three stations are shown in Figure 4. The tidal current velocity in the main body of the Phosphatidylinositol diacylglycerol-lyase lagoon

varied from about 0.05 m s− 1 to about 0.2 m s− 1 depending on the spring-neap cycle and the seasonal variations of the mean sea level in the Red Sea. The tidal currents at the inlet were faster owing to the narrowness of the entrance. When the net heat at the air-sea interface Q   < 0, from November to March ( Figure 2), then the potential energy due to the surface heat flux will not contribute to stratification and the water column is mixed. When the heat balance Q   > 0, surface heating will contribute to stratification and tidal and wind mixing will be opposed, so stratification will depend on their net contribution. The calculations are therefore made for April to October only. The net surface heat flux at the air-sea interface from April to October, as well as the tidal current velocities and the wind speeds for this period are listed in Table 1. Based on this data dvdt is computed for surface heat flux, tidal and wind mixing terms. The values are given in Table 2 along with the net changes in potential energy. From the hydrographic data at three stations in the Rabigh Lagoon (Ahmad et al.