Global increase in the occurrence and impact of multiyear droughts.

Persistent multiyear drought (MYD) events pose a growing threat to nature and humans in a changing climate. We identified and inventoried global MYDs by detecting spatiotemporally contiguous climatic anomalies, showing that MYDs have become drier, hotter, and led to increasingly diminished vegetation greenness. The global terrestrial land affected by MYDs has increased at a rate of 49,279 ± 14,771 square kilometers per year from 1980 to 2018.

Interannual Dynamics of Ice Cliff Populations on Debris-Covered Glaciers From Remote Sensing Observations and Stochastic Modeling.

Ice cliffs are common on debris-covered glaciers and have relatively high melt rates due to their direct exposure to incoming radiation. Previous studies have shown that their number and relative area can change considerably from year to year, but this variability has not been explored, in part because available cliff observations are irregular. Here, we systematically mapped and tracked ice cliffs across four debris-covered glaciers in High Mountain Asia for every late ablation season from 2009 to 2019 using high-resolution multi-spectral satellite imagery.

Surface Pond Energy Absorption Across Four Himalayan Glaciers Accounts for 1/8 of Total Catchment Ice Loss.

Glaciers in High Mountain Asia, many of which exhibit surface debris, contain the largest volume of ice outside of the polar regions. Many contain supraglacial pond networks that enhance melt rates locally, but no large-scale assessment of their impact on melt rates exists. Here we use surface energy balance modeling forced using locally measured meteorological data and monthly satellite-derived pond distributions to estimate the total melt enhancement for the four main glaciers within the 400-km Langtang catchment, Nepal, for a 6-month period in 2014.

Aspect controls the survival of ice cliffs on debris-covered glaciers.

Supraglacial ice cliffs exist on debris-covered glaciers worldwide, but despite their importance as melt hot spots, their life cycle is little understood. Early field observations had advanced a hypothesis of survival of north-facing and disappearance of south-facing cliffs, which is central for predicting the contribution of cliffs to total glacier mass losses. Their role as windows of energy transfer suggests they may explain the anomalously high mass losses of debris-covered glaciers in High Mountain Asia (HMA) despite the insulating debris, currently at the center of a debated controversy.

Promoting pollinating insects in intensive agricultural matrices: field-scale experimental manipulation of hay-meadow mowing regimes and its effects on bees.

Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES).

The expression and impact of antifungal grooming in ants.

Parasites can cause extensive damage to animal societies in which many related individuals frequently interact. In response, social animals have evolved diverse individual and collective defences. Here, we measured the expression and efficiency of self-grooming and allo-grooming when workers of the ant Formica selysi were contaminated with spores of the fungal entomopathogen Metarhizium anisopliae.

Delivery of antibiotics to the eye using a positively charged polysaccharide as vehicle.

The positively charged polysaccharide chitosan is able to increase precorneal residence time of ophthalmic formulations containing active compounds when compared with simple aqueous solutions. The purpose of the study was to evaluate tear concentration of tobramycin and ofloxacin after topical application of chitosan-based formulations containing 0.3% wt/vol of antibiotic and to compare them with 2 commercial solutions: Tobrex and Floxal, respectively.

Failure of Helicobacter pylori eradication: is poor compliance the main cause?

Objective: The aim of the study was to evaluate whether poor compliance can be considered as the main cause of the low Helicobacter pylori (H. pylori) eradication rate observed in an ambulatory population.

Methods: Seventy-eight patients with non-ulcer dyspepsia or gastroduodenal ulcer in whom H.

Permeation of a myristoylated dipeptide across the buccal mucosa: topological distribution and evaluation of tissue integrity.

The ex vivo permeation of an acylated model dipeptide, Myristoyl-Tryptophan-Leucine (Myr-Trp-Leu) was studied using pig buccal mucosa. Myr-Trp-Leu, being lipophilic, did not readily penetrate across the membrane. Rather, it accumulated in the epithelial and connective tissue of the mucosal barrier.

Factors and strategies for improving buccal absorption of peptides.

Peptides and polypeptides have important pharmacological properties but only a limited number (e.g. insulin, oxytocin, vasopressin) have been exploited as therapeutics because of problems related to their delivery.

Chitosan as tear substitute: a wetting agent endowed with antimicrobial efficacy.

A cationic biopolymer, chitosan, is proposed for use in artificial tear formulations. It is endowed with good wetting properties as well as an antibacterial effect that are desirable in cases of dry eye, which is often complicated by secondary infections. Solutions containing 0.

Synthesis and characterization of an acylated di-peptide (Myr-Trp-Leu) with modified transmucosal transport properties.

In order to improve the buccal absorption of a dipeptide model compound, Tryptophan-Leucine (Trp-Leu), we have synthesised a lipophilic derivative by myristoylation of the N- terminal amino group of Trp-Leu. The acylated peptide (Myr-Trp-Leu) was characterized by HPTLC, purified and isolated by chromatography on a silica gel column. Its structure was confirmed by (13)C and (1)H NMR and mass spectroscopy.

Topical use of chitosan in ophthalmology: tolerance assessment and evaluation of precorneal retention.

The mucoadhesive polysaccharide chitosan was evaluated as a potential component in ophthalmic gels for enabling increased precorneal drug residence times. This cationic vehicle was expected to slow down drug elimination by the lacrymal flow both by increasing solution viscosity and by interacting with the negative charges of the mucus. The molecular weight (Mw) and concentration of polysaccharide were studied in four types of chitosan as parameters that might influence ocular tolerability and precorneal residence time of formulations containing tobramycin as therapeutic agent.

Failure of a 1-day high-dose quadruple therapy for cure of Helicobacter pylori infection.

Background: The optimal duration of treatment for eradication of Helicobacter pylori has still to be defined. A 1-day high-dose quadruple therapy with a combination of amoxycillin (or tetracycline), metronidazole, a bismuth salt and a proton pump inhibitor has led to eradication rates of 57-77%. In view of the high frequency of metronidazole-resistant strains of H.

Chitosan: a unique polysaccharide for drug delivery.

The aim of this review is to give an insight into the many potential applications of chitosan as a pharmaceutical drug carrier. The first part of this review concerns the principal uses of chitosan as an excipient in oral formulations (particularly as a direct tableting agent) and as a vehicle for parenteral drug delivery devices. The use of chitosan to manufacture sustained-release systems deliverable by other routes (nasal, ophthalmic, transdermal, and implantable devices) is discussed in the second part.

The effect of keratolytic agents on the permeability of three imidazole antimycotic drugs through the human nail.

The permeability of three imidazole antimycotics (miconazole nitrate, ketoconazole, and itraconazole) through the free edge of healthy human nail was evaluated in vitro using side-by-side diffusion cells. The influence of keratolytic substances (papain, urea, and salicylic acid) on the permeability of the antimycotics was also studied. The results suggested that the nail constituted an impermeable barrier for these antimycotics; it could be considered that the nail behaved as a hydrophilic gel membrane, through which drugs of low solubility could not permeate.

Comparative pharmacokinetic study of a floating multiple-unit capsule, a high-density multiple-unit capsule and an immediate-release tablet containing 25 mg atenolol.

The purpose of this study was to evaluate the possible advantages of floating and high-density dosage forms and their influence on pharmacokinetic parameters. Atenolol was chosen as a model drug because of its poor absorption in the lower gastrointestinal tract. Three formulations containing 25 mg atenolol, a floating multiple-unit capsule, a high-density multiple-unit capsule, and an immediate-release tablet were compared with respect to estimated pharmacokinetic parameters.

Buoyancy and drug release patterns of floating minitablets containing piretanide and atenolol as model drugs.

The purpose of this study was to evaluate factors for improving the in vitro buoyancy and the drug release characteristics of floating minitablets containing either piretanide or atenolol as model drugs. The buoyancy of the minitablets was achieved either by the swelling of the excipient or by incorporation of the gas-generating agent sodium bicarbonate. Resultant-weight kinetics were performed in order to evaluate the buoyancy.

An investigation of the physical behaviour of moisture-activated mucoadhesive hydrogels upon contact with biological and non-biological substrates.

The physical behaviour of moisture-activated mucoadhesive hydrogels in contact with a Plexiglas plate or artificial mucin gels was investigated using an adapted tensile tester fitted with force and displacement transducers. Our study of the 'Plexiglas-hydrogel' interface showed that the intrinsic mechanical response of most poly(acrylic acid) polymers is quite different from that exhibited by cellulose derivatives. The former exert an attractive interaction towards the substrate in contrast to the latter where the interaction is essentially repulsive.

Gamma scintigraphic comparison of eyedrops containing pilocarpine in healthy volunteers.

The aim of the present study was to compare, in healthy human volunteers (male and female), the corneal contact time of various formulations, each containing one viscosity enhancer from the following list: a phase-transition system (gellan gum, Gelrite), a heteropolysaccharide (xanthan gum) and currently used polymers hydroxyethylcellulose, hydroxypropylmethylcellulose, or poly(vinyl alcohol). These different solutions were compared to a reference solution containing no viscosity enhancers. The corneal contact time of the formulations was evaluated over more than 20 minutes by gamma scintigraphy using Technetium-99m (Tc-99m DTPA) as a radioactive label.

In vivo evaluation of an indomethacin monolithic, extended zero-order release hard-gelatin capsule formulation based on saturated polyglycolysed glycerides.

The sustained release properties of an indomethacin hard-gelatin capsule formulated with saturated polyglycolysed glycerides (Gelucire) were demonstrated in vivo. Indomethacin was selected as a model drug with very poor solubility in water and acidic media. It is known to exhibit high intersubject variability because of enterohepatic circulation.

Effect of formulation additives upon the intranasal bioavailability of a peptide drug: tetracosactide (ACTH1-24).

Nasal absorption of tetracosactide (ACTH1-24; Synacthen) was evaluated in anesthetized rats and compared to intravenous and intramuscular (i.m.) administration.

In vivo evaluation of dosage forms: application of gamma scintigraphy to non-enteral routes of administration.

The trend to deliver drugs to defined areas of the body involves sophisticated carriers systems. In addition to the in vitro drug release profile one must be aware of the in vivo behaviour of the dosage form and the drug. Gamma scintigraphy is an elegant way to gain insights of the actual in vivo distribution pattern of dosage forms.